Heli ditch North Sea G-REDL: NOT condolences [Archive] - Page 2

WAH

11th Apr 2009, 14:56

Quote:
Originally Posted by WAH http://static.pprune.org/images/buttons/viewpost.gif (http://www.pprune.org/rotorheads/368283-heli-ditch-north-sea-again-not-condolences-post4853515.html#post4853515)
Quote:
Originally Posted by AAIB
The investigation has so far revealed that the MGB had suffered from a major failure within the epicyclic module. This is supported by HUMS data; however, this is not yet fully understood.

So HUMS done exactly what it was supposed to be doing in respects to alerting the engineer that there was something abnormal.

I read that part of the AAIB report to mean that the HUMS data from the time of the accident supports their determination that the failure was within the epicyclic module.

The daily inspections were initiated not due to HUMS indications but:

Quote:
Originally Posted by AAIB
As the result of the discovery of a particle on the main rotor gearbox epicyclic module magnetic chip detector

Furthermore, while the HUMS data were under close monitoring:

Quote:
Originally Posted by AAIB
No further abnormalities were identified during this period.

I'd say your eagerness to hang the operator and manufacturer HUMS guys out to dry is not warranted by the evidence.

That does not make sense as you are assuming that 1 second the gearbox was fine, and then a second later it comes to a catastrophic collapse without anything causing it. How do you suspect this would have happened? A crack in a gear or a missing tooth will have developed over x amount of time, it does not just appear instantaneous and then cause catastrophic failure. This crack or whatever it was (i do not know) will have been under close monitoring HUMS wise. (Hums on epicyclic was put under close monitoring, that is factual)

You have got it the wrong way round, what would have happened is the aircraft would have landed on the 25th March and the engineer would have downloaded the days flight. An exceedance would have been generated and then reported to BOND HUMS dept. Bond hums dept would then have given advice on what to do or referred it back to EC for their input. The advice given would then have been to carry out frequent mag probe checks along with putting the AC under close monitoring. (This is standard procedure)

Are you suggesting they found chips on the detector out of the blue, i.e during a scheduled maintenance check? They then checked the HUMS to find that it was over threshold and then put it on close monitor? That is back to front, any engineer who is familiar with HUMS will tell you that. Basically HUMS would not go under close monitoring unless there was a reason to do so, i.e it had breached a threshold. You could not possibly close monitor every single component and relevant indicator in the MGB just because there was debris found on the mag pickup probe. It's far too big a job, there are hundreds of different indicators that you could potentially be looking at.

Im not out to hang anyone out to dry, that is unfair as i do not have all the facts, nor have i seen the trend graphs from BOND so it is impossible to make that judgement. I did state however that there are 16 families in grieving and if it does prove that the prior HUMS warnings was pointing to the impending failure then questions are going to need to be asked.

On the other hand, if there were no prior warnings on HUMS in the week or so before the accident then you would have to ask questions as to why and then hope the manufacturer would develop the HUMS system to make sure something like this never happened again.

mckeg4

11th Apr 2009, 15:02

Wiz,

Thanks for the swift reply and I hope I have not offended any pilots or engineers as that was never the intent, just really jumpy guys out here as I am sure you will be aware of, I am trying to go on the principle that if you guys are happy to drive then we should be as passangers, Further questions have been asked which we wondered may have prevented the failure and that is if the aircraft had the detectors checked when it returned to aberdeen after the first flight in the morning may there have been further build up of debris which would have resulted in the helicopter being taken out of service for a more in depth investigation??? sorry to flood you with what ifs but we wondered if this should be the case in the future for added prevention, again your thoughts would be appreciated

Thanks

WAH

11th Apr 2009, 15:07

I think I'm understanding the chip scenarios.

Given the catastrophic failure and earlier comments that cracks may not produce chips why on earth can the recommendation be to continue in a situation where this can happen again?

A chip was produced in REDL's gear box?

No more appeared for 25 hours so extra minitoring stopped, then the gearbox failed.

What is to stop a gearbox failing again? I've not read anything that suggests a nice shower of metal chips will appear in a timely fashion to alert the maintenance guys.

Any load or fatigue data to explain the REDL failure?

What suggests that we have a 'warning system' even live or manual that will predict the failure of another one.

Am I missing something?

What are the pilots of L2's feeling on the 'checks' ?
I generally get in the back if there's someone in the front willing to drive, I'm currrently working on that principle in my head.

Appreciate some more discussion about the failure mode and the likelihood of warning of deterioration.

Regards, Clive

If it turns out to be a gear crack (Im not saying that it is) then inspection of the mag probes alone will be in my opinion inadequate.

However this coupled with a check of the gearbox HUMS data to see what the epicyclic is doing should put operators minds at ease for releasing these aircraft back to service.

I would not worry about it, this aircraft has an exceptional safety record and the operators would not release an aircraft that was not safe to fly.

As to the bit i highlighted in italic underline in your quote, no this was not the case. the aircraft was still under close monitoring at the time of the accident. The close monitoring refers to the HUMS data, although a daily inspection of the plug would also have been carried out.

I wont repost on this thread again as it may appear like i am trying to incriminate, that really is not what i am getting it. I suppose i'm just thinking out loud so if you choose to agree or disagree with my points then so be it. We will all find out in the end. I've made my point and i'll move on.

Thanks for your time,

WAH

mckeg4

11th Apr 2009, 15:08

Thanks for that much appreciated

ramen noodles

11th Apr 2009, 15:22

Ppruners agonize as to how their beloved savior, HUMS, could have failed them. It should go without saying that HUMS is a fine producer of information, tons of it. That information tells many things, and must be related to the health of the system only when all the fault modes are understood. Knowing the modes is the great unknown, and all the HUMS in the world will not foretell failure if all the mode of failure are not yet understood.

Thus, the HUMS, as brilliant as it is, is along for the ride in this latest tragedy, but provides valuable clues to prevent the next one.

HUMS is sort of like a very fine security camera looking out into the dark. It shows everything - it is up to us to figure out what it is telling us.

JimL

11th Apr 2009, 15:35

mckeg4,

It is unlikely that any of us here have enough information to provide you with the assurances that you appear to require. However, we have all seen the AAIB interim report which provides us with some indications about the current thinking. We also have the AD from EASA which, fortunately, has been succinctly summarised in plain words in the Flightglobal report:
Preliminary findings of the inquiry, says EASA, suggest the accident is "connected with a degradation" of the epicyclic module of the main gearbox.

"In the light of this information the detection of any contamination of the main gearbox is of utmost importance as a precautionary measure," it adds.

Operators of AS332L2s need to check the magnetic plug of the main gearbox's epicyclic reduction gear module daily, and ensure that correct maintenance has been applied in case of the discovery of any particle on the plug.

If particles were detected during the previous 200 flight hours without a complete maintenance check, it says, the epicyclic module must be disassembled and inspected.

Companies operating the EC225LP must disassemble and inspect this module each time particles are detected on the magnetic plug, and comply with a similar 200-hour historical check.
It is extremely improbable that the epicyclic module of the MGB can fail without warning - i.e. some debris. Although it appears like a 'one-pony-trick' at this stage, any appearance of particles, in the past (i.e. in the last 200 flight hours), or from now on, will result in a removal and inspection of the epicyclic module (if it wasn't done at the time).

My reading would be that there is an assumption that if that removal and inspection had occurred on the 25th March, the location of the source of the debris might have been established and any crack propagation identified. This is a heavyweight procedure because it would be unlikely, under normal procedures, that such intervention would occur without further confirmation/corroboration.

This is obviously a 'conservative' holding procedure whilst further investigation proceeds. In the interim report, it states:

Investigations are continuing in order to understand completely the accident sequence.

It then goes on to say:

The investigation has so far revealed that the MGB had suffered from a major failure within the epicyclic module. This is supported by HUMS data; however, this is not yet fully understood. The examination of the MGB is continuing in conjunction with detailed analysis of the HUMS and other recorded information.

Earlier in the interim report, the AAIB told us:

The HUMS data for the day’s operation, including the accident flight, has also been recovered.

The HUMS data leading up to this flight, and that which was recorded during the flight, can now be examined (in the light of the accident) to see if there is any evidence of the proximity of the failure. This is quite unlike the way that HUMS data is usually analysed because it is being done in hindsight (we all appear to be quite good at that).

Notwithstanding the comments by Sultan a few posts back, about past analyses of seeded faults of the epicyclic module, my guess would be that some signature will be found - along with a timeline. There are also other tools that could be used in this analysis; in an earlier post, HC informed you of a trial that had been taking place on historic data using software that was not looking for events (which are difficult to find using just threshold data). This software, which has been developed by GE and tested on Bristow data from the warehouse, finds 'clusters' in 'n-dimensional space' - i.e. clusters of data points that would not have raised an alert but which form unusual patterns. It would be amazing if the 'normal tools' and the 'neural net tools' between them cannot spot some precursor pattern.

There are no guarantees here but the best brains in the industry will be working day and night to establish a methodology to prevent this happening again.

Finally, the AD is very conservative - EASA, EC would have risk assessed this to ensure that it contains the situation. The last thing they need is to have another occurrence.

Jim

SASless

11th Apr 2009, 15:42

Helicopter flying by its very nature entails risk as does any kind of flying.

Technology and engineering knowledge has progressed over the years and made great improvements in the safety of helicopter flying.

Passengers should remember pilots are not suicidal by nature and engineers are not serial killers.

If we are willing to fly the machine and share the risk with you then you should be comforted by that fact. You may rest assured most pilots will the first to refuse to fly a suspect machine either a particular machine or a type of machine as one has to be alive to spend the big bucks.

There will be an improvement in the system as a direct result of this tragedy and thus we should be more confidant than before.

If you are a member of the "White Knuckle Club".....lean back, relax, and get a good grip on the armrest....and try to enjoy the flight!

LastMinute

11th Apr 2009, 15:59

what an epicyclic gearing system looks like...
I'm no mechanical engineer so I'm a bit confused by that diagram. How do you get the sun and planet gears rotating in the same direction? And how do you get shafts 28 and 30 rotating in opposite directions?

[Edit: OK - I've looked at the patent explaining the diagram, and I think I just about understand it now...]

I do know that the L2 drive train isn't quite like that. The two engine drive shafts don't drive the epicyclic ring directly; rather, they combine (through their freewheel units) to drive the tail rotor drive shaft, and that connects through bevel gears to the central shaft of a two-stage epicyclic train (whose output is the main rotor shaft).

A picture would say a thousand words, of course, and I've got the diagram from the RFM, but I'm not sure whether it's permissible/appropriate to post that, and besides I've got nowhere handy to host it.

Are you suggesting they found chips on the detector out of the blue, i.e during a scheduled maintenance check? They then checked the HUMS to find that it was over threshold and then put it on close monitor?
What I am suggesting is that the AAIB report makes no mention of the HUMS exceedances you assert were already known about, and that it does suggest that the discovery of the particle on the magnetic plug was the first event that led to the increased checks.

I am not saying you're wrong, I'm just questioning the inferences that you have made from the information that is available.

mckeg4

11th Apr 2009, 16:05

Guys,

I want to thank you all for taking the time out to explain in great detail what this means to us, we all know that you are very professional in your job and thank you for the countless trips that you have achieved to take us to and from work safely, its just when something so terrible happens like this we can all put ourselves in the same helpless situation and it dosent bear thinking about, we all know that helicopter travel entails risk but knowing what you guys think means alot to us. Thanks again and I hope you have a pleasent weekend

Greig

T4 Risen

11th Apr 2009, 16:08

Another thing to bear in mind guys, if you work offshore, you only have to do the trip every couple of weeks, us Pilots do it more or less evey day we go to work. We would not do it if every time we flew we were wondering if something like what has happened was going to happen.......

T4

HeliComparator

11th Apr 2009, 16:23

mckeg4

If you are asking "could it happen again" then in all honesty I think the answer has to be yes, since cracks in gearbox components are very difficult to find until you strip down the gearbox - they don't release significant chips and HUMS is not very good at detecting them.

However you also have to ask yourself the probability of that happening. Bearing in mind its the first such event on an AS332L/L2/225 that I am aware of, and the fleet hours runs to tens of millions of hours, you will almost certainly die another way, such as from a road accident, from cancer, from an injury offshore, from a stabbing on Union St on Saturday night etc.

16 people died in a tragic accident, but how many more people that have worked offshore are now dead - surely it must be thousands, many having died of that fatal disease called old age, and a good number from work injuries offshore (more than in all helicopter accidents)

Perhaps I am not being comforting, but life is dangerous and fragile and all we can do is to try to maximise safety and avoid taking unnecessary risks. You can be sure that those of us driving up front try to do just that. Despite the risk of an undetected gearbox crack, offshore helicopters including the L2 are very safe. Its just that there is no such thing as absolute safety.

HC

jimjim1

11th Apr 2009, 16:27

Wiz mentioned -
The most dangerous part of your trip will continue to be the drive to the airport.

Hmmm - seems unlikely for this type of flying.

Searching the internet for random sources brings up:-

http://www.pprune.org/archive/index.php/t-331176.html
Presenting a paper at the Royal Aeronautical Society’s Maritime Operations of Rotorcraft conference on Wednesday, Stevens referred to air safety performance figures that put offshore transport in third place with 4.5 fatal per one million flying hours compared to 2.0 for commuter airlines and 0.6 for average commercial airlines.

Death rate: the number of road deaths per billion vehicle kilometres (http://www.swov.nl/uk/research/kennisbank/inhoud/00_trend/25_internationaal/death_rate_the_number_of_road_deaths_per_billion_vehicle_kil ometres.htm)
1 fatality per 7 or 8 per billion vehicle kilometers for the UK.

So rounding the numbers slightly for arithmetic convenience, it seems that we would need about 2000km driving per hour flying.

8,000 / 4 (all millions).

7000 / 4.5 gives about 1,000 miles.

Of course quite a few offshore workers will indeed travel that far
but I think the average will be significantly less.

Luckily, driving a shorter distance to the airport does not
make the flight more (or less) hazardous:)

This is clearly not a rigorous analysis and the road numbers will be affected by multiple vehicle occupancy for one thing.

dieseldo

11th Apr 2009, 16:36

I agree with you there LASTMINUTE, unless WAH has access to information not provided by the AAIB then the chip and not HUMS seems to be the starting point. They make no mention of a HUMS exceedence prior to the last flight. It also seems likely that the close monitoring 25 hours had also been concluded prior to the last flight. Normally a specified period is put in place for close monitoring and 25 hours would not be unusual.AAIB "HUMS data was downloaded and analysed each time the helicopter returned to it's base at Aberdeen for the next 25 flying hours. No further abnormalities were identified DURING this period."Just my interpretation of the AAIB statement

you want what??

11th Apr 2009, 16:43

well, if it makes anyone feel better, our epicyclic chip detectors were checked every 25hrs previous to this happening, so if it means doing it every 10 now, then its no great hassle to do this. it takes literally 10 seconds to check, so could be done on every turnround if that is what was mandated, without any impact on sheduling/operations.

i for one as an L2 engineer, amoungst other aircraft, would happily carry this task out after every flight if it helped to allay the fears of those flying on the A/C.

one other thing about the HUMS though, that i dont think anyone mentioned. when you fit a new component that has a threshhold, they often have to be re learned due to differences between the items fitted. no two are exactly the same.

pulling greaboxes in the circumstances laid out in the SB, thats going to put a lot of pressure on the Engineers, but alas is something we'll just have to get on with. sourcing gearboxes will be a nightmare. spares for overhaul arent easy to come by. It takes two years for an epicyclic ring gear to age harden so there is a massive lead time needed for spares support on them! same for a main rotor mast.

sox6

11th Apr 2009, 16:49

I don't think 25 flying hours would have been made 25 March - 1 April.

PoloJamie

11th Apr 2009, 16:52

I remember reading in an earlier posting on this thread, a day or so after the accident that the helicopter was supposed to be having it's MGB changed the next day. Could anyone shed any more light on this?

The Sultan

11th Apr 2009, 17:03

You want what??

Modern helicopters (i.e. those designed since 1972 or so) have at a minimum multiple main transmission chip detectors which have indications on which one is tripping. Some of these are ganged into a single alert to the crew.

There is also this great new technology (again 30+ plus years ago) which has the ability to burn off nuisance fusz and leaves only substantial debris as an idication of the seriousness. They are called fuzz burnering chip detectors. The crew are aware when a chip is burned and this generally is treated just a little lower than a chip (i.e. Multiple burns is bad).

Later technology (20+ years ago) have quanity debris monitors which can tell the volume of material acruing on the detector.

History has shown crew annuciated chip detectors are "god's gift" to flight safety. HUMS vibration monitoring only adds to this, but never can replace it or provide even an equal level of eqivalent safety.

Striation counts and what debris is in the filter may be able to tell how much time elapsed between initiation and total failure on the Bond aircraft.

As to checking mag plugs, before every flight would be prudent.

The Sultan

ericferret

11th Apr 2009, 17:30

THE SULTAN

Not necessarily so. The Eurocopter SA365N series as standard have no indicating mag plugs or fuzz burners for the transmissions. They have a mag plug quick disconnect for the MRGB and the TRGB. A mag plug which requires tools to remove it for the mast.

I believe the BO105 had an indicating system for the MRGB but it was removed on UK aircraft because of the high number of spurious warnings!!!!

MITCHAA

I pull mag plugs on a daily basis and as part of a sceduled maintenance program. I've yet to pull one specifically as the result of a HUMS report.

In truth in this case it could be either. However there is no mention of a HUMS issue before the accident in the AAIB report. I would have thought it would get a mention.

you want what??

11th Apr 2009, 17:32

Sultan,
not really sure why the tech lesson was directed at me, i was only stating a fact as to what happens on the a/c i work on. i am type rated on L2 and other types, so am well aware of the chip detectors in the system.

L2 has Sump detector with "XMSN" caption on 10ww panel and Warnings
flared housing, manual detection on hourly based removal (19mm spanner)
epicyclic with HUMS detection,
IGB with HUMS detection,
TGB with HUMS detection,
Particle detector for TR input Bearing, checked on an hourly basis.

Also has an electrical chip detector and 5 mag plugs on each engine

as an engineering decision, checking plugs after every flight may not be mandated, but as i said, im happy to do that personally if it helps to ease the stress on those who have to fly on them.

Geoffersincornwall

11th Apr 2009, 17:47

If a 332 pilot now gets an MGB chip light 100 miles offshore does he:-

a) Abandon the flight and land on the nearest platform
b) Abandon the flight and ditch immediately
c) Continue flight to base

Would the answer be different for each model? (L1, L2 225)

G

you want what??

11th Apr 2009, 17:52

i think i would go for A in todays climate. chip light isnt necessarily a warning of impending failure, so continuing to the nearest platform or land base might be prudent. easier to land it and get an engineer to go look at it that take the chance of continuing the flight as normal. im sure that the other engineers and dare i say it? the armchair engineers on this thread might disagree!!! but i suppose discussion is healthy is it not?

since failure of the epycyclic gearing is thought to be the cause, but how did the head separate when it is held to the gearbox by a ring of bolts, and also held to aircraft by three suspension bars? must have been an incredably violent torque to have ripped the lot off?

Scotsheli

11th Apr 2009, 18:53

or d) do exactly what it says in the FM perhaps!

Flap 5

11th Apr 2009, 19:10

For mckeg4's benefit I would ask how many main gear box failures have there been? And just think of how many flights there are on the North Sea and around the world. Yes there have been cases of gear boxes 'making metal', but catastrophic failures like this are extremely rare. The only one that comes to my mind at the moment is the Bristow's Puma 9M-SSC out of Lutong, Sarawak back in December 1980. There may have been others, but I can't think of any at the moment. Generally more frequent (but still rare) incidents are with tailrotor or other failures which are surviveable.

STANDTO

11th Apr 2009, 21:10

Two questions:

What is the all up weight of a north sea puma?

What alt would this a/c have been at this stage of the flight?

I've a couple of laymans thoughts, but don't want to post them until I'm sure of my facts. wholly inappropriate to do otherwise.

Oldlae

11th Apr 2009, 21:27

With regards to the daily inspection of the epicyclic magnetic chip detectors were the the chip detectors tested at the same time? The PT6 engine and cgb magnetic detectors on the Bell 212 had to be checked at regular intervals by holding a certain weight of metal, I forget the actual weight but it was considerably above a few chips.
This problem may result in Eurocopter in supplying replacement MGB's equipped with tested epicyclic gearing hopefully free of charge.

206Fan

11th Apr 2009, 21:35

From the AAIB report.

Recorded radar information showed the aircraft flying inbound towards Aberdeen at 2,000 ft,
climbing momentarily to 2,200 ft and then turning right and descending rapidly.

http://www.aaib.gov.uk/cms_resources/G-REDL%20-%20Initial%20AAIB%20Report.pdf

Dave

What-ho Squiffy!

12th Apr 2009, 00:11

I have had two MRGB chips offshore in Puma. One was shortly after the box produced some fine chips in a previous flight. Thankfully not too far offshore, turned around. Second was waaaaay offshore and out of the blue. Landed on a ship, where upon investigation, some decent chips were found. Hover checked and found some more. Left the machine there and picked up to gladly go back to shore.

Both of those boxes were replaced.

In my experience, and most importantly from what I have been told by olds-and-bolds, is that French machines don't produce chips unless there is something wrong (unlike Yank machines). If there is a chip-trend on a French machine (i.e. another indication after cleaning the plug), I wouldn't be taking it offshore. They can sack me, but there's no way I would do it. Call me a chicken, but that's just my policy (before the latest event).

Just sayin...

The Sultan

12th Apr 2009, 00:36

What-ho

Early Bristow Pumas had an, then, Aerospat team on site changing transmissions daily due to chips.

In 2003 I was told by the OGP that the 155 transmission never made it pass about 1500 hours before removal. Why? Chips.

At a CAA meeting Helikopter Service reported bearing problems on the latest Pumas where chips from an accessory gearbox could contaminate the main xmsn. They were changing boxes every 130 hours or so. Kind of like Bristow experience with early Pumas.

Makes American transmissions look pretty good.

The Sultan

rapman

12th Apr 2009, 01:29

You want what

As a fellow engineer, i have seen first hand, a gearbox complete with gearbox suspension bars,head and blades ripped out from the box structure Download report:
http://www.aaib.gov.uk/sites/maib/_shared/ico_pdf.gif AS355F1, G-XCEL 07-06.pdf (http://www.aaib.gov.uk/cms_resources/AS355F1,%20G-XCEL%2007-06.pdf) (888.58 kb) the forces involved are incredibly high.

It is only my supposition, looking from the photo's of the wreckage, that the head separated at the ring gear casing (conical housing) to main gearbox casing.

With regard to the inspection of the gearboxes would it not have been prudent of the authorities to ground these machines, until a visual inspection of the epicyclic gears has been carried out?

heli1

12th Apr 2009, 09:21

...So much maligned JF was right after all.The tail did separate and the tail rotor was not under power when it hit the water.
That and the fact that the MRH had clearly separated from the MGB was pretty obvious to any layman with a basic knowledge of helicopters looking at the recovery pictures.
His mistake was saying so ?

dieseldo

12th Apr 2009, 11:14

RAPMAN, I think that report shows up well the stresses involved. Given that this was caused by just freewheel slippage. Very sad to see it as 2 engineers were killed on that airtest. NM who I worked with and the son of JGS another engineer from the old days, who had himself died from cancer the previous year.

dieseldo

12th Apr 2009, 11:21

Oldlae, Exactly same problem with the BO105 chip plugs. You checked for loss of magnetism by using specific weight ball bearings.

batboy1970

13th Apr 2009, 18:42

I am another offshore worker with aviation connections in my job offshore who has taken great comfort from the reassurance offered from pilots on this thread, i deal with pilots on a daily basis out there and have a huge respect for them, i am equally devastated by the the loss of so many of my fellow o/s workers and the chopper crew recently.
The question i have however is this, when is the line drawn or the decision made that a flight should not be made,is there different paramaters or mindset from pilot to pilot, is a gut feel enough (for want of a better phrase) or must there be conformation of a problem from instrumentation or visual impairment of the chopper. I ask because i along with 15 other passengers had a very frightning and never explained expierience on an inbound L1 flight from a field NE of Shetland. In October 2006 G-TIGG landed on our deck, it then proceeded to offload all passengers as oil was being lost from the engine area and was coating the side of the airframe. Several hours later a Bristows engineer was delivered to us from a neighbouring platform he had been called to, a repair was effected (replaced O ring) oil topped up and we were loaded onboard. The route was that we had 2 stops at sister platforms then off to Scatsta, however after the last lift en route home during our ascent a horrible, memorable and frightning bang was heard from the engine compartment, main rotor area, this was followed by a quite horriffic vibration throughout the chopper which caused a pan pan to be sent an immediate controlled loss of altitude and a memorable Bristows engineer (sharing comms with the pilot) that we were giving a lift home to franticlay tightning his seat belt.
We were only a short distance out so returned to the platform of departure landed and were happily decanted to stand in the heli-wells. The engineer then opened up engine cowlings, gave the stabiliser a shake etc etc. nothing was found a quick air test was performed, we were then to our disbelief loaded on again and flown into Shetland, again on inbound flight this vibration could be felt. This incident is spoken about to this day yet and to a certain degree made for some of us the arrival of the new 92s the most welcome sight ever........... i apologise for the long winded speil but give the facts and ask how after such a defined event as this with no evidence to the cause at the time and on the tail end of a burst engine o ring initially was it deemed safe to fly us in this aircraft, we trust the pilots and their professionalisim to the absoloute end but still things like this raise an eyebrow.
I have probalbly opened myself up for endless abuse but the question and facts are genuine and as a very concerned oil worker who has sat on a chopper with what seemed a serious problem would appreciate any comments from the professional pilots/engineers out there. Even better does anybody know of this incident as i would expect that it must have been reported and tell me exactly what the cause of this was, i do know that GG featured quite regularly in the AAIB monthly reports so it may be listed there.

NorthSeaTiger

13th Apr 2009, 18:56

Who provides repair and overhaul for Bond's transmissions ? Do they have their own workshops or is it Eurocopter or some 3rd party company ?

NST

sox6

13th Apr 2009, 19:08

batboy

Ever thought of calling the helicopter company and asking for more information?

serf

13th Apr 2009, 21:19

What is happening at Bond at the moment? the online flight centre shows only 1 flight this week.

Flap 5

13th Apr 2009, 22:21

batboy,

One of the best ways to ensure a helicopter is fixed properly is to have the engineer who did it on board with you afterwards! They don't tend to come on airtests! However, in this case, it would appear even that assurance to the pilot was a bit off the mark.

technoprat

14th Apr 2009, 00:10

Flap 5,

"they [engineers] dont tend to come on airtests !"

I find that hard to swallow, every company I worked for, if an airtest is required for engineering reasons, the engineer flies in it.

"one of the best ways to ensure a helicopter is fixed properly is to have the engineer who did it onboard with you afterwards"

Pilots do not tell engineers what to do.
Most engineers I know (including me) fly in every aircraft we fix out of professionalism & faith in our work.

Your comments are insulting.

Training Centre

14th Apr 2009, 05:49

Technoprat

His comments are not insulting, just statements of fact. I fly for the largest helicopter company in the world and I am almost never accompanied by an Engineer on a flight test - not because they are unwilling to come along, but because they are too busy. Our Engineers are all Professionals and they care about their work, but when I am doing an airtest they are fixing something else.

DOUBLE BOGEY

14th Apr 2009, 07:50

BATBOY, I am a North Sea pilot flying L2s at the moment.

The Incident as you have described, taken at face value, it is quite possibly the worst ever example of CREW/PAX liason I have ever heard.

I suspect that what happened to the helicopter after the "O" ring was changed was some kind of engine surge or "POP" stalling associated with disruption of the mass airflow through the engine which is unusual when the engine is under high load. (Normally happens when we lower the lever and the nose comes up slithgly as we start a descent).

The crew appear to have acted quite correctly in electing to return to the platform and have the incident investigated by the Engineer. If as you say a "PAN" call was made, then the crew would have felt at the time that more than "Pop" stalling was occurring as most Puma pilots are fully familiar with this problem.

What leaves me speechless is the apparent lack of explanation following the incident, and then the airtest, to try to convince you guys that all is safe and well. The crew of course being at that time in hands of the engineer who ordered the airtest.

As regards the wider points of your questions...when and how to do we assess the serviceability of the helicopter.

Well the short answer, is that as pilots, we are not authorised to declare a helicopter serviceable. We can only place the machine unserviceable.

If we were offshore the normal process, following a snag, is to contact our engineering departments and in the first instance, fully explain the nature of the problem. Engineering have a number of approved and acceptable protocols available to them based on the nature of the snag.

These may range from:

1. Flying back without PAX.

2. Remaining grounded until and engineer arrives to either further assess, or indeed fix the snag.

3. In cases where the snag is covered by the terms and conditions of the Helicopter Minimum Equipment Lists (MEL) - (The MEL is a list of helicopter systems and items that may be unserviceable for a flight, or a series of flights prior to the defect being rectified. The MEL is recomended by the manufacturer and approved by the CAA).

4. In cases where the snag is not convered by the MEL, and situation warrants such action, the Engineers can seek further guidance and if necessary approval from the manfacturer and the CAA to fly it back to base. This would only ever be granted for flight without PAX.

BATBOY, having said all the above, it does not matter a jot if the Engineers, the Manufacturer and the CAA all agree and approve the flight (either by MEL or otherwise), the ultimate final decision on whether to actually fly...rests with the helicopoter Commander.

So you see, the helicopter Commander really should not play any part in the decision to assess the serviceability of the machine, BUT definitley has the authority and right to refuse the flight if authorisation is granted.

This principle holds true for all daily operations with helicopters that may be carrying defects that are acceptable within the MEL. The Commander must formally accept the helicopter with its snags in his pre-flight signature and ALWAYS has the right to refuse to do so.

I hope what I have explained to you gives you some reassurance of the depth and nature of the decisions that are taken to determine the serviceability of a machine when it is away from base and removed the impression you were given during you experience, that we just "wing it" sometimes.

Finally, the issue of liaison with the PAX. There are differing points of view and I have to say, no real clearly defined policy for how we deal with you pesky PAX when we are about to "carry on" after a snag has occured.

My view, is that if I were a PAX, I would want to know everything!!. I also realise that we are not flying lager silling f***wits to Ibiza and that you guys possess more than the average standard of engineering knowledge which in most cases, surpasses my own.

Therefore I try not to bull**** the PAX. I give them the facts of what has happened, what we have done about it and then actually afford them the same priveledges that I have as the AC Commander. I simply say, "Thats the situation, are you happy with it and do you want me to take you home now".

The ability of the Commander to deliver a sound, unbiased, confident brief varies widley and is highly subjective to the Commanders age, experience and qualities as an orator.

My advice to you for the future, is that if faced with a similar situation, accept that the crew and the engineers will be doing everything in their power to get you home safely. However, in doing so accept that they may forget the equally important part of the job, keeping you informed and happy. So get thePAX together, elect a spokesman, and ask to speak to the crew/engineers before the flight takes place.

In that meeting gently ask them what has happened, what has been done about it and any other questions you may have. You should find even the most shy and reticent crew/engineers will respond if the questions are put to them in a posiitve manner.

BATBOY, do not automatically accept that we as crew and engineers are infallable. If I was the Commander I would welcome any questions that you felt you needed to ask.

This thing that we do, aviating, it is not without risk. Events have just dramatically and graphically demonstrated this to us again. However, all of us involved, Pilots, Engineers, Managers and Regulators are trying our utmost to reduce those risks to almost zero. Somethimes, as an industry we fall short of the mark!!

Hope this helped.

Sir Niall Dementia

14th Apr 2009, 07:55

Technoprat;

In my experience engineers love to come for a post maintainence test flight. They just don't have time. I worked for the same company as Training Centre and sometimes we could tell the supervisor we wanted the boys along to discuss any problems as they occured, rather than trying to describe them later.

I think you will find that Flap 5 is making a very tongue in cheek comment. I have had an engineer say to me "fly in that? after what we've just done to it? No chance matey!" The truth was he had 2 more aircraft he was supervising at the time and couldn't leave, but the banter was fun.

helimutt

14th Apr 2009, 08:00

The comments made are not insulting. In our company, most times when we have airtests to carry out, the engineers don't accompany us, ie on an eng test after change out etc. During the day, there are two engineers on duty, so they are usually busy doing other things. We don't have the luxury of excess numbers of engineers.
Batboy, i'm sorry to hear that you weren't happy during a flight. Although it was one of 'the competition', we're all involved in the same game, and it's preferable for the pax to be happy. I'm very surprised that the a/c continued flying with pax, even though that vibration was still apparent. I doubt very much that anyone would agree to fly if the same thing happened again. I guess if you all speak up and make it known you're not happy to fly then another a/c may become available for task.
As a passenger please remember one thing. When we're sitting up front, we wouldn't be flying unless we thought it was safe to do so. Stable Extrovert does not equal Suicidal Tendencies. Not always anyway!:E and I don't know anyone I fly with who would fly an aircraft which they thought wasn't safe.
We understand the passengers concerns, only last weekend we had a pax decide he wasn't happy to fly, and he was disembarked just before departure. Just remember in a day, we could do as many as 20 trips to your one. Hope that helps to allay some fears. Ask any question you like on here, i'm sure we all don't mind putting your mind at ease.

Just as an aside, any aircraft has an MEL (Minimum Equipment List) If something is unserviceable in the aircraft, it may just be that the helicopter can still fly, but with a restriction, and we refer to the MEL to check this.
If it says we can't fly, then we don't.

212man

14th Apr 2009, 08:12

Flying back without PAX.

Really? How does that work from an airworthines perspective then?

DOUBLE BOGEY

14th Apr 2009, 09:07

212, Airworthiness is essentially either:

1. Complaince with the Manufacturers Guidelines and Adherence to the Limitations in the Rotorcraft Flight Manual, OR

2. A limited approval to not be compliant granted by the Competent Authority following a submission and justification.

The business is risk mitigation. It may be deemed acceptable to RTB the AC without PAX. As crew we always have the right to decline the invitation.

HeliComparator

14th Apr 2009, 09:08

Batboy

I checked our Safety Report database and found the incidents to which you refer. The oil leak was caused by the seal of the MGB oil filler cap coming off. After takeoff there was a sudden lateral vibration and flickering COWLS light, but on return to the platform nothing was found amiss, and indeed no further maintenance actions were taken after return to the beach, and there was no recurrence of the problem.

So was it safe to make the flight back to the beach - absolutely! Perhaps the vibration was the result of turbulence or some other strange meteorological phenomena, we will never know.

But, if your account is correct, did we handle the passenger relations aspect well? - absolutely not, to put it mildly! Even though it was not my base nor my fleet, on behalf of Bristow I would like to apologise. Next time can I suggest that you raise that sort of thing with your safety reps - we sometimes get questions from concerned passengers routed via their safety reps and are always happy to answer them. Sometimes the questions are ridiculous (ie from people with no idea about aviation) but a question from you on this incident would have been totally justified. We would certainly rather receive the question and be able to answer it, that to have our passengers harbouring the long-term mistrust in our professionalism that this sort of incident can engender.

Since 2006 we have paid more attention to "public relations" ie passenger concerns, and we now have full time staff to ensure its dealt with better. If you PM me, I will give you the name of the lady who is in charge of that department - its never too late to ask!

HC

dieseldo

14th Apr 2009, 10:41

I also find some of the comments regarding engineers and airtests as grossly insulting. Especially to the memory of the two engineers killed on the twin squirrel airtest in Gloucestershire one who was a friend . Engineers go on airtest as part of the job. It is less common than it used to be due to the fact that most aircraft have to be flown two crew and there is not much point in joy riding for the hell of it if you can't contribute to the flight. Airtests are supposed to be operating crew only, so sitting in the back finger up your ar*e doesn't count.

dieseldo

14th Apr 2009, 10:49

On a more personal note in 35 years I have been on hundreds of airtests and refused to go on two.One because the pilot tried to kill me on a previous airtest by exceeding VNE in a dive after flying into cloud and panicking.The second because the company had used unskilled staff stripping and reassembling a main gearbox. They also got my resignation!!!!!!

connel flyer

14th Apr 2009, 10:50

Double Bogey

I have one question. What are the company's doing different this week regarding checks to MGB etc that they were'nt doing before the accident?
Have all the recomondations been put in place and do you think it's enough? There has been no information fed back to the offshore workers at a formal level i know the investigation is still young but Pilots/Offshore workers need some reasurance.

Thanks

CF

batboy1970

14th Apr 2009, 11:24

Gents

please let me take this opportunity to thank you for the prompt, detailed, reassuring and genuine responses to my post. It must be quite common to encounter questions seeking reassurrance like this, you have a specialist trade and its fare to say that in this case here that an incident or occurrence that i was involved in is nothing to some people in the tade but something to a nobody who is not in your trade so i appreciate your responses greatly.

HC

This is the first official mention of this i have ever heard so thanks to you for that, again i thought i should have seen this as my position is in rig management/safety offshore.

The report which appears quite non eventful and dilute when the written word is read left me with only 3 questions

a) Why did this lateral vibration occur was it a product of the earlier repair
b) Although it did not show its self again a vibration was felt inbound albeit to a lesser degree (trust me)
c) If it had reocurred to its full extent again, lets say half way home what could have been the outcome, was it serious enough to warrant emergency action or would we just have rattled home.

Never will i doubt what im told by gents like yourselves but a picture paints a thousand words and there were 15 faces on that a/c that were a picture (engineer included)

Thanks again for your help and the sheer professionalisim that you provide us with every day.................

rapman

14th Apr 2009, 11:40

Engineers tend to go on test flights when there is requirement to ie. tracking and balancing or a specific problem that needs to be understood/helped/solved by them. Engineers are usaully busy with many aircraft and when a single/dual pilot udertakes an airtest, it is usually because of this. Afterall, flying these machines is what the pilot is paid for.

Before an aircraft even leaves the hangar, especially after a major component change or servicing, it is subject to a lot of detailed inspections. These include duplicate and full and free functional checks and a lot of paperwork. Once outside it is subject to ground runs for leak and functional checks of the systems. When and only when it's serviceability has been proven, will the aircarft be released to service or a subsequent air test. This is what an engineer is paid for and rest assured you are well looked after.

It takes many years of dedication and training to produce a competant engineer, good pilots know their worth. Sadly, some company's don't :( ..apprenticeships anyone?

In general,engineers and pilots have a good working relationship and a mutual respect for one another, i enjoy the banter with them. Human factors can bite at anytime, be it in the form of pilot error, maintenance error or a manufacturers error. It is what the industry learns from these terrible accidents and what steps it is prepared to make in preventing them, that i find more concerning.

SASless

14th Apr 2009, 11:54

Helimutt,

Your statement.....

I don't know anyone I fly with who would fly an aircraft which they thought wasn't safe.

should have read.....

I don't know anyone I fly with who would knowingly fly an aircraft which they thought wasn't safe.

DOUBLE BOGEY

14th Apr 2009, 12:22

I will try to answer your question as best I can.

The AAIB has made reccomendations in its interim report and EASA have issued an AD, I believe to increase the frequency of the mag plug checks in the epicycil MGB module.

I fly an L2 and you might feel it is a bit strange that I have not paid too much attention to the actual actions taken by the engineering staff.

This is because I know that my Company have an EASA approved Continuining Airworthiness Department who I trust completely to carry out all necessary actions required not only by the regulations but also their own internal monitoring functions and any increased actions that department feel is necessary until the full report and investigation is complete.

I have 100% faith in the engineers who service the machines I fly because if I did not...I would not fly them.

I like to feel that I have some experise in the operation of the helicopter and I know that my engineers have an expertise in maintaining them. I feel we shopuld be a little careful not to "cross-over" into areas that neither party have the depth of knowledge or experience to comment on as it not helpful and sometimes damn-right misleading.

It is tempting to want to pester the engineers to know what they are doing, have done, but in essence nothing has really changed procedurally because the procedures in place are there to assess, implement and review maintenance in the aftermath of an incident just as they always have been.

Having said all that, the jury really is out on the accident and until they return with a more detailed "verdict" I will remain positive and confident in the L2 machine.

Flying is, and has always been, subject to certain risks. Normally these are assessed, calculated and thereafter controlled. In essence thats exactly what a system of continued airworthiness strives to achieve.

When something like this happens it is easy to jump to the conclusion that the machine or the system is not safe. The truth is that safety is a concept and not an absolute and that the real mechanism employed is the management of risk.

Sometimes the risk is not managed correctly. Who knows that may be the case here. Or sometimes the risk factors (million-to-one-chance) actually occur ie...it was a chance in a million failure. Who knows..that might be the case here.

Suffice to say that taking the performance of the L2 fleet worldwide as a whole, supported by the many 1000s of hours of trouble free operation in my logbook...I, like many of my collegues temper our response proportionally.

This incident was very close to home...same fleet...same type of ops...same hemisphere...same airspace. This does not change the fact that it is the risk factors invloved that will ultimatley have caused the accident...one way or the other.

Hope that helps!!

ppng

14th Apr 2009, 16:33

OK, for our "nervous offshore workers", let's tell it like it is.

We don't have the details yet but everyone believes that the mechanical failure in this case was the Main Gearbox (MGB) and it is fairly obvious that the situation was never going to be survivable, for anyone.

Could it happen again? - Yes.
Could the wing fall off your 747 when you go on holiday? Yes.
Could your oil rig/platform collapse into the sea while you're asleep? Yes.
Could a drug-crazed maniac burst into your house and massacre your family? Yes.
Is it likely? Statistically it is neither more likely nor less than it was before.

As I see it there are four major considerations for any mechanical failure - Design, Construction, Maintenance and Operation:

Design: The MGB design has not changed much since the Super Puma was first put into service. The L, L2 and 225 are all pretty much the same and this design has "gazillions" of hours without significant problems - there is nothing wrong here.

Construction: Yes, they are manufactured differently, and so they should be. Technology has moved on and so has the way these things are made. I am fairly sure that Eurocopter do not source their metal from different suppliers according to which aircraft they are going to build. I am also sure that when they manufacture the individual gear wheels in the factory they do not assign any particular individual to each fleet. The worldwide fleet is large and mature, so if this was an issue we could expect to have had some indication of problems before this.

Maintenance: I don't care what colour t-shirt they wear or what shape logo is embroidered on their t-shirt, Aircraft Engineers are Professionals. If this turns out to be a result of maintenance error, then that's just it - a tragic error. If it is, then we should all remember that all companies rely on outside agencies to do complex work - it does not necessarily stop at the door of the Operator.

Operation: Pilots are also Professionals - although it has happened that a pilot has decided to commit suicide and take his entire aircraft with him, let's be frank, unless the rest of the workforce is also nuts there is not much chance of it happening again.

Fly relaxed (or don't fly at all) - it was a freak accident - they happen.

Of course, we need to find out why it happened and try to make sure this particular freak can't happen again.

What Limits

14th Apr 2009, 18:00

Construction: Yes, they are manufactured differently, and so they should be. Technology has moved on and so has the way these things are made. I am fairly sure that Eurocopter do not source their metal from different suppliers according to which aircraft they are going to build. I am also sure that when they manufacture the individual gear wheels in the factory they do not assign any particular individual to each fleet. The worldwide fleet is large and mature, so if this was an issue we could expect to have had some indication of problems before this.

Our experience with another unrelated manufacturer is that the vendor, the design and the material specification of a component, may change several times during the life-span of an aircraft type.

connel flyer

14th Apr 2009, 21:03

Double Bogey

Thanks for that :ok:

CF

you want what??

14th Apr 2009, 23:42

As far as the construction of the MGB's is concerned, while the design may be similar between types, infact, all eurocopter types, the 225 will undoubtedly be different in construction. the MGB was one of the big problems encountered when developing the aircraft. i have heard, though cannot confirm, that is why the L2 came out as an iterim measure, till these problems were overcome. The 225 has a 5 bladed head and a significantly more powerful pair of engines, so the main gearbox will have been beefed up to handle the extra torque from the engines and the load from the head. And of course has an emergency glycol lube system, as has been talked about alot after the S92 crash

incidently, the lateral vibe that our offshore friend was talking about, sounds more like a main rotor imbalance. maybe just needed a bit of tuning?

technoprat

15th Apr 2009, 03:10

I offer my apologies to Flaps 5.

I thought you were inferring that the engineers were unwilling to fly on test flights.
In 22 yrs as a mechanic & engineer I have never released a helicopter to service after a major component change/disturbance without flying (myself or another engineer involved in the work) on the required check ride.
I feel it is my professional duty.

However, I accept that if 3 or 4 people say they work in companys where this is normal, then it must be true.

As for the luxury of manpower, I have regularly been the only licenced engineer on duty with 8 clunky workhorses to supervise.
If there's more work than I can handle, some of the machines stay U/S until I'm ready. Airtest req'd or not.

Treat you engineers with respect & they'll treat you likewise.

helimutt

15th Apr 2009, 07:58

technoprat, i'm beginning to wonder if you post to wind some people up. Treat you engineers with respect & they'll treat you likewise

exlatccatsa

15th Apr 2009, 11:51

"Split Torque Epicyclic Helicopter Gearing
ivor the driver "

Sorry should have written this a couple of days ago.
I'm no engineer, as you can tell from my title, I was looking at the above link posted by ivor the driver a few days ago trying to understand how the 332 gearbox works. I coudn't help thinking that there's something wrong with the drawing, specifically the rotation.
The main shaft seems to be rotating against the rest of the gearing.. and comparing it against the rotation of an L2 the shaft in the drawing seems to rotate the wrong way??

farsouth

15th Apr 2009, 13:42

ExLatcc - Think you will find that is just a "generic" view of an epicyclic geartrain, it certainly looks very little like the AS332(L1) main box in my course notes, and as you suggested, some of the rotation directions do not add up, for instance shaft 28 and 30 are shown turning in opposite directions while driving the same gear ring.

Exmek

15th Apr 2009, 17:34

Here is a link to a simplified diagram of an epicyclic.

Epicyclic gearing - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Epicyclic_gearbox)

In a chopper the yellow sun gear shaft would be on the opposite side to the green planet gear carrier. The sun gear shaft would of course be vertical, driven by the input bevel gear, and the green shaft would drive the rotor mast, (or another epicyclic stage and then the rotor mast). The red ring gear is fixed to the gearbox casing.

exlatccatsa

15th Apr 2009, 18:57

Thanks for that farsouth I had assumed that input 28 was driving the upper gear and 30 was driving the bottom.
It always struck me looking down on the engineers when the cowls are open, just how small the engines and gearbox are and what a huge load is going through them.
Its certainly very interesting to learn just how the power is transferred into the rotor.
Shame the authorities couldn'd see this a few years back when Bill Lear was trying to certify his Learfan.

dipperm0

15th Apr 2009, 19:10

If it could help, it is a Super Puma Main Gear Box drawing

http://img7.imageshack.us/img7/1530/imagebtpcougarh.png

littlewing

15th Apr 2009, 19:28

When did all the happen? Do you mean CHC as in Canada Helicopter Company? :confused:

HeliComparator

15th Apr 2009, 19:39

dipperm0 - good diagram of the MGB (from the THM I think?) but just to point out that it only shows 1 planet gear on each epicyclic stage, when in fact there are a number (not sure how many).

HC

dipperm0

15th Apr 2009, 19:47

@ helicomparator

You are right. Checked in the THM but no numbers in it. Think it's 3, from my memory.

D0

widgeon

15th Apr 2009, 20:51

Where the freewheel units on this diagram ?.

HeliComparator

15th Apr 2009, 21:07

widgeon

If you look to the left of where it says "LH Accessories" you will see a blue shaft, where that gets fat and meshes with the pink tail rotor drive shaft, is the torque sensor (measures twist in the solid-looking inner shaft), keep going left and where it thins out again looking a bit like a splined coupling is the freewheel - a bit to the right of the 8011 rpm callout. Same place for the other engine obviously.

HC

Training Centre

16th Apr 2009, 10:31

In the 225 there are 8 first-stage and 8 second-stage planetary gears in the epicyclic module. I imagine the L2 is the same.

So what?

heli-cal

16th Apr 2009, 22:11

It was announced that the AAIB have said that they are still unsure as to the failure and damage sequence which occured within the gearbox, and due to the nature and extent of the damage (the gearbox broke apart) it may not be possible to find out!

This would leave questions and doubts unanswered and unresolved!

widgeon

16th Apr 2009, 22:41

Thanks HC so the gear that drives the Bevel is on the fwd end of the pink shaft. If I am not mistaken on the H-60 ( s92 ?) the freewheel function is in the input modules

HeliComparator

16th Apr 2009, 23:03

widgeon

Yes (to the bevel drive). On the Super Puma family the freewheel is after 1 stage of reduction - not sure if this is a good or bad thing.

Training Centre, thanks for the 8 - it was just that someone might be confused looking at the diagram if they thought there was only 1 planet gear.

HC

dipperm0

17th Apr 2009, 05:23

About 10 years ago, an Alouette II crashed in a similar way: rotor went away from gear box on final = 4 fatals.

On the Al II, the rotor is secured on the rotor mast by a nut. During overall maintenance, a technician used an AL III nut to secure it instead of the AL II one which is slightly different. Later on, it has been found 6 or 7 AL II flying around the world with similar error...

Could it be a problem of screw and nuts ?

AAKEE

17th Apr 2009, 07:18

Do we know if all parts from MGB, rotor hub etc was recovered from the sea, or are important parts still missing ?

NorthSeaTiger

17th Apr 2009, 08:38

From BBC News :

Investigators have said it is proving difficult to establish what caused the gearbox on the helicopter that crashed in the North Sea to fail.

The Air Accidents Investigation Branch said metal debris was carried through the gearbox, causing it to burst apart.

But it said the extent of the secondary damage could mask the initial cause of the tragedy.

NST

MoodyMan

17th Apr 2009, 12:03

Initial Report #2

http://www.aaib.gov.uk/cms_resources/G%2DREDL%20%2D%20Initial%20Report%202%2Epdf

Does not make pleasant reading...

Although two Alert Service Bulletins issued by Eurocopter have been mandated by EASA (Emergency Airworthiness Directive 2009-0087-E, dated 11 April 2009), which requires an enhanced monitoring procedure relating to the magnetic plug of the main rotor gearbox epicyclic reduction gear module, this procedure was in effect being carried out on the helicopter involved in the accident. This resulted from the discovery of a small chip of metallic debris on the epicyclic gearbox module chip detector some 34 flying hours before the failure. However, during the period between the discovery of the chip and the accident, no signs of an incipient gearbox failure were detected.

HeliCraig

17th Apr 2009, 14:34

BBC News 24 are reporting that EASA has issued an EAD mandating inspection of MGB within 1 week & that they contemplated the grounded of the fleet until this had been done.

They are reporting two types of Super Puma, although not which ones. I would assume L2 & 225 based on Initial Report 2's Safety Reccomendation... but assumption is the mother of all *** ups!

Can't find anything immediately to hand on EASA's website - and the journo on TV did say they had it before it was formally released, although I believe he had a statement from Bristow (but he was interrupted by other breaking news).

HeliCraig

17th Apr 2009, 14:46

Link to BBC article - which quotes EASA. Here (http://news.bbc.co.uk/1/hi/scotland/north_east/8004382.stm).

malabo

17th Apr 2009, 17:41

EASA (Emergency Airworthiness Directive 2009-0087-E, dated 11 April 2009) (http://ad.easa.europa.eu/blob/easa_ad_2009_0087_E.pdf)

Check the epicyclic mag chip plug daily on the L2. I think you need a 19mm wrench to do this. The 225 has it wired to a caution message/light so you don't have to wrench anything on it, just monitor.

On the 225 and L2 if you get a chip or have had a chip in the last 200 flight hours on the epicyclic, the tranny has to be disassembled and inspected, not the whole thing, maybe just the top half holding the epicylic. I don't have the quoted maintenance procedure at hand. "maintenance Work Card (WC) 60.00.00.212.001:"

Any engineers that can confirm this? - I'm just a white shirt pilot.

nodrama

17th Apr 2009, 18:22

Latest.....

Air Accidents Investigation: Initial Report 2 - Super Puma accident (http://www.aaib.gov.uk/latest_news/initial_report_2___super_puma_accident.cfm)

twang53

17th Apr 2009, 18:57

I'm just a dull old avionics engineer but I recall reading a previous AAIB Bulletin No: 8/2004 Ref: EW/C2003/02/06 Eurocopter AS332-L2, Super Puma, G-JSAR
The following are quotes from 8/2004:
Quote 1:
"Oil cooler drive shaft and gear wheel fractured. Bearing housing fractured"
Quote 2:
"The left hand accessory module was removed from the MGB and an internal examination revealed that the intermediate gear wheel had fractured from the bearing at the centre to the outer edge of the gear. Its bearing housing was also fractured through one of the three attachment lugs. The remaining two attachment lug bolts were found fully torque tightened. The detached portion of the failed lug was found lying loose within the module housing."
Quote 3:
"A similar incident occurred to another operator's AS332-L2, G-PUMS, on 21 November 2002, when an amber MGB oil pressure caption illuminated when the aircraft was on the ground following flight. On the subsequent ground run, the accessory gearbox seized, followed by the shearing of the oil cooling fan drive shaft. A large amount of debris was found on the MGB magnetic plug. Investigation of the left hand accessory module revealed that the intermediate gear had fractured into two pieces. In addition, there was associated damage to the internal surfaces of the casing. A photograph of the internal components of the module is shown at Figure 3."
Quote 4:
"Although neither of the two incidents described here occurred in the cruise, had they done so, the ability for continued safe flight was considered not to be compromised. Nevertheless, the fact that the MGB and the accessory modules share the same oil system could result in potentially serious contamination problems, thereby constituting a flight safety hazard."
http://www.aaib.gov.uk/cms_resources/dft_avsafety_pdf_030207.pdf

Special 25

17th Apr 2009, 19:31

BBC Reports

Two models of Super Puma helicopter have been grounded for 48 hours after the latest report on the North Sea crash, which claimed 16 lives.
Industry body Oil and Gas UK said 25 helicopters in the UK offshore fleet would be affected.
Earlier the Air Accidents Investigation Branch (AAIB) said gearboxes must be inspected to check internal components.
Industry officials will meet helicopter operators on Sunday to review the situation pending new safety advice.
The grounding affects AS33L2 Super Pumas - the type which crashed on 1 April killing all on board - and the EC225LP Super Puma, which ditched in the North Sea on 18 February with no loss of life.
The decision, taken voluntarily by operators, leaves about half the total helicopters available to the North Sea industry out of action.

Full story at BBC NEWS | Scotland | North East/N Isles | Helicopters grounded for 48 hours (http://news.bbc.co.uk/1/hi/scotland/north_east/8004382.stm)

This would appear to be in response to an Oil & Gas UK request, but I guess all the operators were struggling to justify flying in the shadow of an urgent request from the AAIB to carry out these inspections.

wigwam11

17th Apr 2009, 19:50

I have been reading this thread with interest over the last few nights. I have worked offshore all over the world for over 20 years and have been a nervous flyer for all of them. This last week however I am seriously considering giving up offshore travel. I have just read that the L2 and 225 have been grounded for 48 hours, over the weekend when there are next to no flights scheduled. A very similar situation afew weeks ago when the S-92S at Scatsta were grounded to have the titanium studs on the MGB filter bowl? changed out for steel. Again the grounding happened at the weekend. I just wonder how much of this is driven by the Oil companies and the effect that a fleet grounding would have on North Sea production. I also read with interest that the AAIB are having trouble identifying the exact cause of gearbox failure or indeed seaquence of events that caused G-REDL to crash. Surely the fleet should be grounded untill the cause is identified? There are many many offshore workers who are in my current frame of mind and I reckon one more incident on a UK chopper would see a mass exodus of workers who feel it is not worth the risk anymore.
Should we be concerned and do the professionals amoungst you consider the AAIB mandatory inspections a good idea bearing in mind the chopper that crashed was undergoing these checks at the time of the accident.

VeeAny

17th Apr 2009, 20:15

Wigwam

This post is intended just to respond to you and your concerns, and not the rest of this thread.

As I interpret the AAIB reports and the EASA AD we can see and the seemingly voluntary action in the face of another EASA AD.

The AAIB made 3 recommendations last week based on what they knew then, and EASA responded by doing something, it seems that the AAIB have quite rightly reached the conclusion that whatever monitoring was being done on the gearbox in question did not prevent the accident, so mandating what amounts to the same level of monitoring will probably not find what caused this incident.

The AAIB have not specified what they would like EASA to mandate and left that to the manufacturer to specify (they do know their own product best), I don't believe the AAIB can mandate things, but it would be a brave man who in the light of recent events decided to ignore their recommendations.

It seems the North Sea Operators have decided to take action which may not yet have been mandated, and if thats the case then good on them, once again a brave man who decided to keep flying in light of the AAIB's recommendations.

I hope you make the right decision for you, and only you will know what that is.

GS

HeliComparator

17th Apr 2009, 21:23

twang

The old L2 LH accessory module problem has long since been cured (though not without some difficulties along the way - I think it was the 3rd mod that was finally successful). A LH accessory module failure in flight gives you loss of LH Alternator, LH hydraulic pump and oil cooler fan. Even though I suppose its possible that after a long period of flight with this failure some contamination of the gearbox could occur, in the case of REDL is was a matter of seconds from fat, dumb and happy to disaster. No way was that a LH accessory module failure.

Although I suppose the latest actions are a good thing for PR and even possibly flight safety, personally I would (and just have done) fly the 225 without the extra inspections, based on the long history of the L, L2 and 225 marques without a catastrophic failure. All flying machines can kill you, especially vtol ones, the L2 and 225 are no worse than any others, and certainly better than some.

There is an element of the Princess Diana syndrome about all this and I suspect the Operators are doing what they are doing largely for the PR. I am sure that if there was a bus crash that killed 16, there wouldn't be cries to stop the busses running - it would barely make the papers, despite the fact that for those directly affected, it would be no less dreadful than REDL.

Wigwam, I am quite sure that its no co-incidence that the voluntary "24 hr grounding" aka extra maintenance checks are over the weekend. Since they have not been deemed necessary since the inception of the L2 in 1992, 17years ago its hard to see how a few extra days to move it to the weekend to minimise the impact not only on you going offshore, but also your colleagues stuck offshore, could make any difference.

I'm sorry that your confidence in helicopter transport is shaken, but its still far safer to be in the helicopter than it is to be on an offshore installation (perhaps not per hour, but certainly per trip). We take many risks in life from smoking to crossing the road when drunk to driving too fast etc, but we are very bad at assessing the actual risk of each of these activities.

If you want to give up offshore work because you are a nervous flyer, that's fine and your decision. But don't give it up because you think that the helicopter travel is the most dangerous aspect of your life - you would just be kidding yourself.

HC

Camper Van Basten

18th Apr 2009, 00:06

For HC's post above...:D

I would happily fly in the L2 or indeed the 225 during every working day for the remainder of my career. If this accident necessitates additional inspections to regain the confidence of the paying customers, so be it. I'll be amazed if any further defects are found, and these machines will be back flying regular as clockwork whether the offshore workforce like it or not.

I can see no alternative, or indeed any need for one.

drop lead

18th Apr 2009, 02:44

This AD has been issued requiring removal and inspection of all epicyclic modules on AS332L2 and EC225 modules before next flight aftte 18 April 2009.
A busy few days for all the engineers, good luck guys.

EASA Airworthiness Directives Publishing Tool (http://ad.easa.europa.eu/ad/2009-0095-E)

malabo

18th Apr 2009, 03:32

The EC225LP is grounded only in EASA world (for now).

The latest FAA AD 2009-09-51 is based on the Eurocopter France Emergency Directorate 2009-SW-16-AD. This AD sort of matches the previous EASA Emergency Airworthiness Directive 2009-0087-E, dated 11 April 2009 calling for an inspection only if an epicyclic chip manifested itself in the previous 200 hours that the "fuzz burn off" couldn't burn off.

Sounds like EASA is jumping the gun a little here with their -095E AD. Smells a little of political pressure.

I wonder what other countries with 225's like Nigeria are doing - following EASA or the FAA?

drop lead

18th Apr 2009, 04:05

I would suggest safety is paramount with a potentially critical area such as this. You would have to be a brave operator to say “yes we know about this, but as (by the letter of the law) we are not required to carry this out”.
Even though the probability of finding a fault is low, it’s something that should be done!

the beater

18th Apr 2009, 06:27

malabo

is it possible to burn off a chip from the epicyclic magnetic plug?
I thought it was only possible with the chip detector fitted at the bottom of the gearbox.

Sailor Vee

18th Apr 2009, 09:04

I wonder what other countries with 225'sCertainly grounded in the ME.

twang53

18th Apr 2009, 10:22

I am indebted to HC for the information that the LH accessory gearbox problem is fixed. But careful reading of AAIB Bulletin 8/2004 reveals that any accessory gearbox failure, left or right, can pass significant amounts of debris into the main gearbox via the common oil system. It seems unusual to permit a risk of consequential failure in a non-redundant system.

Solar

18th Apr 2009, 10:24

Not sure if it's 225's here in Vietnam but they are not grounded withSFC.

Training Centre

18th Apr 2009, 11:01

EASA Airworthiness Directives Publishing Tool (http://ad.easa.europa.eu/ad/2009-0095-E)

All EASA-certified L2s and 225s grounded until the inspection is completed

SASless

18th Apr 2009, 12:10

If one certifying agency grounds an aircraft.....why would others not do the same? Likewise....if I know of the grounding order...why would I fly my machine until it had been inspected?

This ain't like an electrical relay that might cause a loss of air conditioning or something.....or am I missing something here?

Exnomad

18th Apr 2009, 12:16

I am surprised by the rapid turn round apparently achieved for gearbox examinations.
I have not helio experience, but have designed many gear boxes over the years, some safety critical. Apart from chip examination I would expect flaw detection of shafts and gears, this is not normally a very quick process even in AOG conditions

ericferret

18th Apr 2009, 12:51

The EASA AD only grounds aircraft that have had a chip in the last 200 hours of operation.

No chip then carry on flying with a chip detector inspection every 10 hours.

This seems to be largely a tech records survey and probably wont ground many aircraft.

Does anybody know any different?

VeeAny

18th Apr 2009, 13:19

Eric

That was last weeks AD, there was another one issued yesterday Numbered 2009-0095-E.

In essence the bit of the AD that has the teeth to effectively ground the aircraft is

In order to complement measures mandated by AD 2009-0087-E, this new AD
is issued to require a one-time inspection for absence of particles in the MGB
epicyclic reduction gear module on the entire fleet.

1) Before next flight after the effective date of this AD, unless already
accomplished per the requirements of AD 2009-0087-E, remove and
inspect the MGB epicyclic reduction gear module in accordance with the
instructions of paragraph 2.B.2 of Eurocopter Alert Service Bulletin (ASB)
No. 05.00.81 initial issue (for AS332 helicopters) or ASB No. 05A017 initial
issue (for EC225 helicopters).

The effective date of the AD is today 18th April 2009.

Gotta rush out, but hope this helps.

GS

Oldlae

18th Apr 2009, 17:51

I am out of the loop now but I imagine that each operator would have one or two zero timed MGB's ready to replace the initial units to be inspected thus minimising downtime. The gearboxes are not sealed units but can easily be dismantled in a workshop, I would think that Eurocopter engineers are on hand at the major operators to check out the epicyclics.
Has anyone got a copy of the 332 ASB 05-00-81?

bumpthump

19th Apr 2009, 13:42

I am sure that if there was a bus crash that killed 16, there wouldn't be cries to stop the busses running - it would barely make the papers, despite the fact that for those directly affected, it would be no less dreadful than REDL.

Such an MGB failure consigns those on board to certain death. If a bus type were on the road and demonstrated a component failure mode (not a gearbox failure in terms of a bus) whereby the outcome was near enough certain to be significant loss of life, then that model of bus would very quickly disappear from service (and it would make the papers big time). Just look back in ye olde days for coverage of the Ford Pinto fuel tanks. I'm not a pilot, just an ex N Sea oil chap who worked there from 77 thro to 96. Obviously, most of my time travelling back on forth was on 61Ns (Bristow, B Cal and if my memory serves me correctly BA), a year or so on B Cal 214s (yuk), and the last four or five years on Super Pumas.
N Sea workers are gravitating to this site because they are looking for comment (and probably comfort) beyond what is available in the Red Tops. For people to read that you believe this to be a PR exercise will do little to allay their fears. Many have learnt here that cracks are not necessarily accompanied by chips, therefore chip monitoring will not necessarily warn of cracks. I have to assume that the inspections mandate a minimum of CVI or MPI, or radiography for a more complete picture of what is going on today inside those gearboxes. Some of this has to be hugely time consuming (service to service) unless you have a significant stock of spare MGBs kicking around your storeroom.......not likely. REDL has a root cause. Until it is determined and eliminated, then it's difficult to think of a MGB inspection programme intended to provide assurance that there aren't undetected cracks propogating in key components as a "PR exercise",.It's sound engineering practice is it not?

HeliComparator

19th Apr 2009, 16:17

bumpthump - PR was my feeling on Friday, but now the Manufacturer has modified its Alert Service Bulletin making further work mandatory. It seems that the manufacturer has an idea of how to improve fault detection within the epicyclic and want to implement it asap.

Regarding the point about the busses, what about a bus that crashed because its brakes failed - would the model be "grounded" in a flurry of prime time TV news and newspaper headlines? I somehow doubt it, because our perception of acceptable risk for road transport is quite different from our perception of that for air travel.

In the case of the Ford Pinto, there was certainly a fundamental design flaw and many burst into flames after a minor shunt. In the case of the L2/225 we have had one catastrophic failure in tens of millions of fleet hours over 17 years - hardly a fundamental design flaw.

This latest maintenance intervention does seem to be a good idea, but we have to be careful not to over-maintain since every maintenance intervention carries a potential hazard of human error etc.

HC

robdean

19th Apr 2009, 18:03

RN,
it's inevitable that some remote possibilities will eventuate - but most will not. On this occasion it appears one has done so - as HC reiterates excellently above. To put it another way, it's very unlikely you'll be hit by lightning in the next 24 hours, but good odds it will happen to somebody somewhere. When it happens and is on the news, it doesn't make it any more likely it will happen to you or anyone else, nor does it mean we need to start an inquiry as to why we'd not all been warned to wear fireproof dielectric hats.

JimL

19th Apr 2009, 18:31

It would appear that the clue is in the absence of precursors (just the one chip 34 hours before the failure). G-REDL was on heightened observation after this single precursor and, if there was to be an impending failure, more metal would have been anticipated - in the event, no more metal showed. Under normal circumstances that might have indicated that this metal could have been manufacturing swarf (realtively common in new gearboxes I am told).

In the EASA AD there was a hint that there might have been a reason that the mag-plug had not shown metal, hence the instruction to strip the epicyclic module and check for signs of MGB contamination (not check each gear for damage). The two ASBs from EC (one each for the EC225 and AS332L2) address the issue of absence of contamination and provide "enhancement of the means for detection of MGB contamination" by seeking to eliminate design features that could have resulted in the contamination being diverted away from the mag-plugs.

While the investigation is ongoing, it was absolutely necessary to ensure that there was no contamination in the gearboxes on other aircraft. It was also necessary to understand and address the issue of lack of precursors. EC and EASA appear to think they have found the reason (not the cause of the failure, but the inability to detect incipient failure).

Ramen - clearly it would be unlikely that any gearbox element could last for 10^9 flying hours. Achieving the extremely remote failure standard can therefore only be achieved by setting the inspection and overhaul periodicity and providing monitoring in the form of SOAP, mag-plugs and HUMS (I'm sure there are others - I'm not an engineer).

As 'The Sultan' pointed out to us several pages back, contamination detection is one of the principles tools for establishing the continuing health of rotating parts (as is HUMS). Normally, there is no failure without the precursors being seen and being confirmed by alternative monitoring methods. If, for some reason, the mag-plugs were not seeing metal (but it was being made) how much trust would have been placed in the alternative monitoring methods without this confirmation?

Jim

twang53

19th Apr 2009, 19:27

Not all metals are magnetic.

bumpthump

19th Apr 2009, 19:28

The lottery is an interesting comparison, but its reverse thinking. The lottery win is a forced, desired outcome. It's engineered to be that way. If the powers that be wanted it not to happen, and push out the likelihood of an occurance to the point where such an outcome could be considered nebulus, then there would be more than 49 numbers! In the case of MGBs, I'm pretty sure that passengers and crew alike want a repeat to be statistically speaking, as near as dammit, impossible. If the bus brakes failed because of an inherent design flaw, I reckon they'd be modified, and all types subject to a recall. I guess aviation is so exacting (and emotionally charged) simply because of the stark consequences in the event of something like an MGB failure. HUMS was being introduced jsut as I was leaving the N Sea. Doubtless a useful piece of kit, but equally, it has been shown to be not too smart (or perhaps the interpretation of its data) in the case of REDL. I guess only time will tell. Having worked in RBI and CBM for a good number of years, I have to agree with the concept of "the less intrusive maintenance the better". Bitter experience in rotating equipment (turbines and the likes) has shown a significant number of failures post intrusive maintenance were actually tied back to errors in the maintenance itself. Every time we take a wrench or screwdriver to a piece of healthy machinary, we introduce a risk that we can leave it in a worse (or potentially worse) state than we found it.
JimL, you have clarified something for me, in that you state that the inspections were to provide assurance that there was no contamination within the MGBs, as opposed to the component parts of the gearboxes.....is that correct? That would certainly make the inspections a whole lot less onerous than every cog in every box. I had assumed that there was a concern over cracks that may have preceded the catastrophic failure. A wrong assumption on my part.

Sailor Vee

19th Apr 2009, 19:31

It 'appears' that part of the epicyclic gearing of the L2 and the 225 is 'potentially' magnetic, therefore there could be a case of 'metal making' being masked by this, rumours are that these components will be changed during the 'inspections' currently being conducted.

leading edge

20th Apr 2009, 02:34

Byte Jockey

Whether or not the box had been in another L2, I couldn't comment on but TIGF is an old 332L and as such has a earlier gearbox with different part number, not interchangeable with the L2 or 225.

HC

Tens of millions of fleet hours? Methinks you exaggerate somewhat. Even if you included the L and L1, (as well as the L2 and 225) I doubt that the Super Puma fleet hours would quite total "tens of millions"

SASless

20th Apr 2009, 02:40

Mark Twain, a great many years ago wrote an article that could very well apply to our situation today in regard the statistics and risk of flying out to the Rigs by helicopter.

The Danger Of Lying In Bed - Story by Mark Twain (http://www.mtwain.com/The_Danger_Of_Lying_In_Bed/0.html)

Horror box

20th Apr 2009, 09:09

Mark Twain, a great many years ago wrote an article that could very well apply to our situation today in regard the statistics and risk of flying out to the Rigs by helicopter.

The Danger Of Lying In Bed - Story by Mark Twain

Very true - especially if you are staying in the hotel I am staying in right now. If you really want to run the gauntlet - you can try eating in the restaurant as well.

Geoffersincornwall

20th Apr 2009, 12:30

If a 332 pilot now gets an MGB chip light 100 miles offshore does he:-

a) Abandon the flight and land on the nearest platform
b) Abandon the flight and ditch immediately
c) Continue flight to base

Scotsheli - reference my earlier post (above) and your reply inviting the use of the RFM procedure as a preferred alternative. Will that RFM procedure now change ?

G

twang53

20th Apr 2009, 13:55

Civil helicoper design engineers have an additional constraint, the need to reduce passenger exposure to noise. There is very low frequency noise from the rotorblades and intrusive mid-band audible noise from the MGB right above the passenger cabin. Noise is addressed in several ways including rotor tip upturn, active noise supression, sound proofing, different materials and different tooth profiles in the MGB.

HUMS used to stand for Health and Usage Monitoring System but Smiths say the M now stands for Management. This is indicative of a change in design and usage philosophy.

Nothing's New 1: Magnetic chip detectors featured in Austin and Morris Minis where the gearbox shared the same oil as the engine. BMC fitted a magnet to the sump drain plug so that mechanics could check for chips.

Nothing's New 2: HUMS was used in the clock and watch industry. In 1967 we had an instrument that monitored the geartrain and plotted out a strip chart on which we could see the shape and periodicity of any discrepancy and deduce which gear set was causing any problem and what sort of problem it was. This was at Smiths Clock and Watch Division, which shared the Bishops Cleeve, Cheltenham site with Smiths Aviation Divison, later to develop HUMS for aircraft.

Scotsheli

20th Apr 2009, 17:55

Probably too early to say; any revisions would only be decided upon once some firm root causes were established. It will be interesting to see.

212man

20th Apr 2009, 23:16

a) Abandon the flight and land on the nearest platform
b) Abandon the flight and ditch immediately
c) Continue flight to base

Whether the RFM changes will depend on what it currently says!

a) is LAND AS SOON AS POSSIBLE, which I assume is the current guidance
b) is clearly a nonsense and will never appear in an RFM (would make fitting new gearboxes a risky activity!)
c) is LAND AS SOON AS PRACTICAL and is not the normal guidance for an MGB CHIP

If EC suggest 'PRACTICAL' rather than 'POSSIBLE' then probably it will change.

(of course, entirely irrelevant to the accident in question, as the poor crew had no opportunity to choose their options)

ElcRico

21st Apr 2009, 01:41

Out of the loop...

What does the latest Alert Service Bulletin say? Could someone post it or a link.

Thanks

malabo

21st Apr 2009, 04:06

Latest FAA at Airworthiness Directives (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/MainFrame?OpenFrameSet)

Latest EASA at EASA Airworthiness Directives Publishing Tool (http://ad.easa.europa.eu/)

Not sure why there should be a difference between them; isn't the 225 certification in any jurisdiction based on EASA?

212man

21st Apr 2009, 05:02

Not sure why there should be a difference between them; isn't the 225 certification in any jurisdiction based on EASA?

No, it could be FAA, TC or CASA, for example. In general the standards are harmonised - a stand alone document for EASA (CS29) or simply a single page that refers to FAR Part 29 (CASR 29,) but the authority that issue sthe type certificate is the one that issues the AD, and they may vary slightly, as we see in this example.

G-CPTN

21st Apr 2009, 18:10

Just heard on the Beeb that one of the newly-inspected machines had to return to base after an oil-warning . . .

206Fan

21st Apr 2009, 18:27

Heard the same aswel on the news!

BBC NEWS | Scotland | North East/N Isles | Super Puma grounded after alert (http://news.bbc.co.uk/1/hi/scotland/north_east/8010625.stm)

wigwam11

21st Apr 2009, 18:50

Local radio 5.30pm in Aberdeen stated gearbox problem was the reason for return to the Alwyn.

twang53

21st Apr 2009, 19:40

I think I prefer the FAA Airworthiness Directive.

pumaboy

21st Apr 2009, 20:55

I'm getting concerned that the media are now out to hunt and capture anything that now happens to any Super Puma Helicopter that flies the North Sea.

Are they not aware what they are doing to this industry and not only this but what they are doing to families and people who have to travel on these helicopters.

Is not only media who are involved in the discussions about the saftey levels relating to the Super puma but also Unions and Politicians.

Are they not aware how many hours these helicopters have flown but also how many of these machines are our skies.

It would make a difference if these people knew what they were speaking about 9 times out of 10 they don't and this p..... me of so much.

I have read that the BBC have picked up that an AS332L2 had to make an emergency landing this morning on the Alwyn North how on earth do they get this infomation and how quickly they can get this information this type of information is damaging the industry because before long people start to loose faith in the machines.

I have heard that they are guys and girls offshore writing out wills before they travel home or away does sound like information we want to give out to our customers every little thing that goes wrong.

If the media are going to write or report on a incident can they not limit what they report or what they write or don't write it and think about the people it affects in our every day and the people that have to travel.

wigwam11

21st Apr 2009, 21:49

I disagree. Why should the media limit news such as this. People who travel on these aircraft have a right to know every time there is a problem, covering it up wont help anyone. As to how the BBC found out, well most of the offshore workforce in Aberdeen probably knew this morning before CHC did. The news came straight from the rig.

pumaboy

21st Apr 2009, 22:12

Wigwam

then if we can not limit what is written in the media, All that is being acheived is scaring the people who have to travel in these machines.

There are people who are actually giving life offshore up and those that are left are writing wills before flying how can you explain this

Does this sound like the bears have convidence in the machines they fly no matter how much we tell them it is the safest form of transport offshore.

Every machine has had it its problems but this does not need the media hanging over and writing for every small incident that crops up it is not helping the industry and especially people who have to fly in these machines

The media don't care what they write as long as they get what they want no matter who the hurt this is wrong and should be more controlled and limit the information

PoloJamie

21st Apr 2009, 23:29

I'm not an offshore helicopter pilot, nor do I work on offshore rigs, so in a way my input is somewhat limited. However, I see both sides of the arguement. I agree with Pumaboy in the sense that the media are in any effect doing what they are best at, especially in light of REDL's tragic accident, and that's sensationalising small "news" so that they'll sell. They're using their typical journalism to get people worried and hyped up about the subsequent events in the North Sea. To the line though, all the BBC are in effect doing is providing information, different people will interpet it in different ways. Using scaremongery on the guys and girls who fly North sea choppers isn't healthy.

These events (precautionary landings) etc aren't uncommon so I can see why some people may not see the need for the media to tell anyone about it. Everyone has a right to know about something that affects them, especially when it involves something as prudent as this. No technical defect affecting the AS332 or EC225 has been offically prooved, and if something finally is, the AAIB report will tell us.

heli-cal

21st Apr 2009, 23:55

There are people who are actually giving life offshore up and those that are left are writing wills before flying how can you explain this

Perhaps this can be explained by the crew of one helicopter flying their aircraft into the sea, closely followed by a second helicopter of the same generic type suffering a sudden, catastrophic, unrecoverable failure which cost the crew and passengers their lives.

The very fact that the AAIB cannot offer any solid basis for what may have initiated the sequence of mechanical failure which in turn created the damage sequence leading to the MGB housing breaking apart, causing the loss of the entire rotor head would also perhaps explain this.

People work offshore to pay for their families, not their funerals, and there does not appear to be a great deal of confidence in the aircraft type when people give up their jobs or write out their wills before flying, hopefully, this will change by the publication of the cause of this tragedy, and the implementation of whatever it takes to prevent a re-occurrence.

SASless

22nd Apr 2009, 00:46

Anyone in this day and time without a Will is not paying attention to his personal business....and that includes all you young whipper snappers....single, childless, everyone needs a Will or the equivalent.

You never know....the 416 bus might chunk a wheel and it strikes you down on the way across the street from the Pub to the Chippy one night.

Camper Van Basten

22nd Apr 2009, 01:16

We're getting reports that a Bristow engineer may have farted in the Hangar this afternoon. No news on casualties thus far, but one report suggests the engineer in question made a precautionary trip to the gents toilet to carry out further inspections.

Aviation expert Jim Ferguson refused to comment on the incident until the full findings are made public.

pumaboy

22nd Apr 2009, 07:05

I would like to thank all of those who replied to my post of the media damaging the industry at a time the accident to REDL has shocked me and connot believe such a tragic accident has happend.

I would like to pass on my condolences to all involved in this tragic accident

RIP all aboard 85N

Staticdroop

22nd Apr 2009, 07:26

Camper,
That sums it up perfectly:ok:

helimutt

22nd Apr 2009, 07:27

Pumabog: This is not the condolences thread!

Many people talk of the impact these accidents have on the offshore rig workers and their families.
How about the guys who fly offshore day in day out. So a rig worker does one trip every two weeks or so, the guys flying them do numerous trips a day! More so in the Southern North Sea as we fly intervention teams, daily maintenance teams etc so these guys fly twice a day for two weeks or whatever it is. They then get three weeks off I think. We don't get that luxury of two or three weeks off at once. Our terms and conditions are under threat right now to actually get us to fly more! How do you think that makes us feel? Slightly more stressed?

We can, and do, fly up to 10-20 sectors a day offshore, more so if you are an offshore based pilot.
Spare a thought for our families. The reason? Our wives and children may not say it sometimes but I know for a fact, speaking to people recently, that quite rightly, the families of those of us doing this job do worry quite a bit but don't tell us.

Yes have a will sorted out. Especially if you're not married and have children etc. It's amazing how a death and money can blur the lines between common sense, reason and greed.

This incident on the Alwyn yesterday just proves how the media sensationalise things going on now. Until the actual facts of the incident come out why dwell on it. How many precautionary landings have been made throughout the world? If it turns out the cause was due to recent events then ok, systems need to be looked at.

Get a grip people. We do this job through choice. If people don't like it, move on, give someone else a break. There are risks in everything you do. I thought I was safe working on a 330,000tonne tanker sailing the worlds oceans. Unfortunately, the 475,000tonne tanker that smacked into the side of us didn't see us until it was too late. :hmm:Accidents happen.
They are far and few between in the offshore helicopter industry.

gasax

22nd Apr 2009, 07:34

I do occasionally work offshore and for my day job I'm involved in risk assessment of offshore platforms and the activities on their (and getting to and from them).

The overall accident rate had been showing a gradual reduction in fatal accident rate. I used to be an engineer and actual find the level of that reduction disappointing - given the original accident rates ame from machines designed in the early days of helicopter flight (Wessex etc).

The more recent crashes have changed that rate significantly, but the critical point for pumaboy and others to remember is that the offshore workforce does not get to choose its 'flight provider' or aircraft type. They are captive to whatever arrangements the platform operators have devided. To say this makes them a little sensitive to these events completely understands things.

The vast majority of the workforce would choose not to fly if that were possible add in being told where and when and on what and yes it results in a very nervous workforce.

The overall record of the 332 causes me no issues and the recent MGB failure surprised me as I'm sure it did many others. The results from the AD inspections may show that debris is accumulating in 'other places' and so the issue can be 'fixed' reasonably easily.

On the other hand the S-92 failure very much disappointed me - decent engineering should mean these failures should not be occuring. The element of double speak between a 30 minutes run dry capability and assessing the likelihood as 'extremely unlikely' looks like a classic bean counting decision which should result in the type certificate being pulled.

But if you are worried about the 'damage' being done to the 332 reputation or the aircraft operators' reputations - just try surpressing the information and pretending all is well. The information will get out - the workforce will ensure that and if necesssary then risk dismissal by refusing to fly - remember the Chinooks?

Geoffersincornwall

22nd Apr 2009, 07:45

The fact that our European offshore helicopter ops must all comply with the rigours of JAROPS 3 should be a comfort. These regs put such ops on a par with the airlines. In the US the offshore ops are categorised as 'charter flights' and work to a much lower set of standards (FAR 135) - nothing like the US airline standards. I feel for the guys that have to travel with the operators over there. I know there are some good companies in the US and they are doing what they see as their best but poor regulation equals poor oversight and therein lies the rub!

G
:ok:

helimutt

22nd Apr 2009, 07:57

gasax, I agree and would just say, there is a need for truthful, open information sharing in this industry. If everyone knows the 'facts' and not spurious ridiculous gossip at every caution light. Tell someone the truth, and with common sense, can make their own decision if flying offshore is for them or not.

NorthSeaTiger

22nd Apr 2009, 09:53

A super puma helicopter like the one involved in this months north sea tradgedy has been taken out of service after making a precautianary landing.

In the latest incident the aircraft had just taken off when the crew were alerted to an oil related issue .

Any more info ?

NST

Camper Van Basten

22nd Apr 2009, 10:02

I'm guessing it's a tiny bit of residual oil which came out from under a trim panel. Hardly surprising considering the major disruption in that area while carrying out the mods, and the associated multiple drainings / refilling of the MGB.

Like I say, only guessing.

gasax

22nd Apr 2009, 11:49

Geoffers has a point but it certainly is not a unique selling point. The 'rigours' of JAR OPS3 have not stopped the last 2 CFIT(W). But initiative such as that from DB may - if they gain industry acceptance.

The 'rigours' of JAR OPS3 still give us fatal accident rates for commerical helicopters which depending on how you slice the data are from 10 to about 100 times more dangerous than fixed wing operations - by sector or hour.

It is not all gloom - the industry is beginning to think in risk management terms and spokespeople such as Nick Lappos have presented the 'obvious' way forward for rotary flight but there is a long way to go from where we are today.

As far as risk perception is concerned (offshore workers smoking, helicopter plots flying) - never expect the decisions to be completely rational!

databoy

22nd Apr 2009, 18:36

Dear ppruners: I've looked back through the thread and been to Eurocopter's website, can anyone (in the know, not wikipedia-based research please !) tell me how many:

332Ls ?
332L2s ?
& EC225s ?

Are actually currently in service in offshore configuration around the world ?

Many thanks.

skydriller

24th Apr 2009, 16:33

I have just recieved a 'Workforce Helicopter Briefing' via my company's HSE Director, which I believe has been sent out to all Offshore personnel, but just in case it doesnt reach everyone, I know several offshore guys have been keeping an eye on this thread, so I will post it below.

I would also be interested in any comments you guys flying us offshore may like to make about it.

Regards, SD..

Workforce Helicopter Briefing - Q&A

This briefing is designed to update workers on the recent issues raised surrounding offshore helicopter travel, including the temporary suspension of some flights.

Which flights were suspended?
The two types of aircraft affected were the AS332 L2 and the EC225, both belonging to the Super Puma family and manufactured by Eurocopter. The Super Puma family of helicopters is used by more than 100 operators in 50 countries. 640 aircraft of the Super Puma family are currently in service around the globe, in both the civil and military sectors.

Why were the flights suspended?
The flights were suspended following the publication of a second Air Accident Investigation Branch initial report, and subsequent Alert Service Bulletins from Eurocopter and an Air worthiness Directive from EASA (European Aviation Safety Agency)

Who made the decision to suspend the flights?
An EASA Airworthiness Directive (AD) required an immediate internal inspection of the gearbox and this work was done in conjunction with a modification which is discussed later. The decision to carry out this work concurrently was made voluntarily by the UK helicopter operators to eliminate one unnecessary maintenance intervention, and that was supported by the oil and gas industry.

Who are the authorities involved?
There are a number of authorities involved in the recent investigation and subsequent recommendations and directives. These are:
 AAIB (Air Accident Investigation Branch) – The body responsible for investigating the causes of aviation accidents. The AAIB issue reports which contain recommendations, based on their findings, which are designed to correct or improve safety issues in light of the incident they are investigating.

 EASA (European Aviation Safety Agency) – The aviation regulator within Europe. EASA considers recommendations from the AAIB reports and, in conjunction with the manufacturer of the helicopter, may develop an Airworthiness Directives (AD) to mandate the maintenance requirement. EASA regulates compliance with these AD’s.

 CAA (Civil Aviation Authority) – The UK aviation regulator which enforces EASA directives within the UK.

 Eurocopter – As the manufacturer of the Super Puma aircraft, Eurocopter issues Alert Service Bulletins (ASB) based on the recommendations from AAIB. these ASB’s are passed on to the helicopter operators and prescribe the technical instructions. EASA then mandates that ASB with an AD
Please note that any AD issued by EASA is European specific but is normally adopted by all other aviation regulators, globally. An ASB issued by Eurocopter applies to all helicopters of that type across the globe.

What is the timeline for the various reports and requirements issued by these bodies?

1st April 2009 The AS332L2, G-REDL, crashes off the coast of Peterhead. The AAIB begin their investigation

10th April 2009 AAIB issue their Initial Report. The report contains 3 recommendations:

1. Eurocopter issue an Alert Service Bulletin to require all operators of AS332L2 helicopters to implement a regime of additional inspections and enhanced monitoring to ensure the continued airworthiness of the main rotor gearbox epicyclic module.
2. European Aviation Safety Agency (EASA) evaluate the efficacy of the Eurocopter programme of additional inspections and enhanced monitoring and, when satisfied, make the Eurocopter Alert Service Bulletin mandatory by issuing an Airworthiness Directive with immediate effect.
3. Eurocopter improve the gearbox monitoring and warning systems on the AS332L2 helicopter so as to identify degradation and provide adequate alerts. (longer term)

10th April 2009 Simultaneous to the AAIB Report being issued, Eurocopter issued their ASB and EASA their AD as per the AAIB recommendations

17th April 2009 AAIB issue their second Initial Report. The report contains one recommendation:

1. Eurocopter, along with EASA, to develop and implement an inspection of the internal components of the main rotor gearbox epicyclic module for all AS332L2 and EC225LP helicopters as a matter of urgency. This inspection is in addition to that specified in the original EASA AD, and should be made mandatory with immediate effect by an additional EASA AD.

17th April 2009 EASA issue an AD as per the recommendation in the second AAIB report for a one-time inspection of the epicyclic module (by removal and inspection) in accordance with existing Eurocopter technical instructions.

18th April 2009 Eurocopter issue an ASB detailing a modification to the gearbox as per the 3rd recommendation of the first AAIB report. As yet, EASA has still to mandate this work but, importantly, the helicopter operators will embody the modification before each helicopter returns to service.

What exactly will the inspections and modifications entail?
These recommendations resulted in Alert Service Bulletins being issued by Eurocopter which implemented the following precautionary measures:

1) The inspection frequency of the magnetic plug of the epicyclic stage be increased from every 25 flight hours to every 10 flight hours on the AS332L2. The EC225 magnetic plug is connected directly to a warning caption in the cockpit.

2) A one time inspection to be carried out on the epicyclic module which required physically opening the gearbox to check for loose particles. (Applicable to both the AS332L2 and the EC225)

3) The magnetic elements installed on the chip collector and the flanged edge from the chip collector to be removed in order to improve the flow of particles towards the magnetic plug detection devices which are located in the gearbox sump and epicyclic module (Applicable to both the AS332L2 and the EC225)

Where is the epicyclic module? (Schematic Attached)
The gearboxes within the AS332L2 and EC225 Super Puma’s are made up of two modules – the main module and the epicyclic module. The epicyclic module is equipped with 25 magnets and 1 magnetic chip detector; although a total of 3 detectors monitor the gearbox. The magnetic chip detector (like the magnets) is designed to catch any metal particles within the gearbox. When a metal particle is caught by the detector within the epicyclic module, an alert will trigger within the HUMS and, in the case of the EC225, an automatic warning in the cockpit will also be activated.

When will these inspections/modifications have to be completed?
The new inspection frequency was put into effect immediately on 11th April, so any of the affected aircraft flying from that date will have complied with these measures.
Although the regulator allowed an extended period over which to complete the modification, helicopter operators and the oil industry felt it was important to combine the one time inspection and modification steps and carry them both out before any aircraft flew again. This is why the use of these aircraft has been temporarily suspended and they are being returned to use progressively as the work is completed.

What is thought to have caused the 1st April accident?
Whilst it is apparent that a gearbox failure occurred during the accident, and a metal chip had been detected a week previously on the aircraft, it is not yet known whether these two factors are linked or what the exact cause of the accident was. The AAIB has said that the way in which the gearbox failed may mask the initial failure mechanism and make it more difficult to identify the actual cause.

Are gearbox failures common in Super Puma’s?
The Super Puma family has more than 3.7 million flight hours flown around the world over the last three decades, and this is the first gearbox failure which has been experienced. The L2 model alone has been in use for 15 years with just under half a million flight hours flown.

Did the recent Canadian accident involve the same issue as the 1st April accident?
The investigation into the Canadian Sikorsky S92 accident in February also centres on a potential gearbox failure. Whilst the investigation is continuing, the cause in this case appears to have been a loss of oil from the gearbox, possibly linked to the failure of titanium studs on an oil filter bowl. These titanium studs have now been replaced by steel studs on all aircraft flying within the UK, in accordance with an ASB issued by Sikorsky which is the helicopter manufacturer in this case. The two accidents therefore have different causation and the two aircraft concerned were different types from different manufacturers.

WAH

24th Apr 2009, 20:45

As far as im aware from reading through the ASB is that the actual epicyclic module is NOT inspected.

The epicyclic module is removed as a 'sealed' unit on the L2's and the bottom portion of the gearbox is where the magnets are housed. All the work is being done here on removal of the magnets and modification to the oil collector plate to allow oil to fall down back into the sump to be picked up by the magnetic plug.

It's a strange move as the AAIB have stated that there was a failure within the epicyclic module but yet this ASB does not focus its attention around that? (i.e a direct detailed inspection of all the gears and bearings)

To put into summary, if there is a flaw with the upper planet gears/bearings, upper sun/ring gear, then they would not be picked up by this inspection.

Something in the epicyclic part failed in G-REDL and this inspection as far as i am aware is doing nothing to stop it from happening again. The removal of the magnets will allow more metal particles to be picked up by the plug BUT what if its a crack in 1 of the gears or a bearing that gives off little or no material?

Can any other engineers or pilots in the know comment on this inspection and confirm or deny if my understanding of the procedure is correct?

WAH

widgeon

25th Apr 2009, 15:05

OWNER 332C 332L 332L1 332L2 EC225
BOND 0 0 0 7 3
BRIST 0 24 1 1 9
CHCI 1 15 4 16 6
LLOY 0 3 4 0 0
NORS 0 0 1 2 0

Data boy as close as I can see this is the distribution of offshore operators.

There may be a few I have missed.

WaveWarrior

25th Apr 2009, 21:57

Yesterday I was looking at the epicyclic module and oil collector plate of an EC225 gearbox which had been removed from the aircraft for inspection. My understanding is that a detailed physical inspection of the whole module is required as well as the removal of the magnets on the collector plate.

databoy

26th Apr 2009, 15:40

Widgeon, Many thanks for the numbers.

js0987

26th Apr 2009, 17:04

Does the "physical inspection" require magnafluxing or xraying or is it just a visual inspection?

you want what??

27th Apr 2009, 20:38

widgeon,

Bond, according to G-INFO database, was 8 and 3 now 7 L2's and 2 EC225's just for the sake of accuracy (also operate L2 for JIGSAW)

As for the inspection of the epicyclic, when ever we take something apart, no matter what it is, we usually inspect everything with a fairly detailed visual inspection anyway, weather mandated by the maintenace procedure or not. its just good engineering practice.

HeliComparator

27th Apr 2009, 21:18

just for the sake of accuracy (also operate L2 G-JSAR (JIGSAW))

Just for the sake of accuracy, G-JSAR was operated by Bristow until it ditched off Den Helder in 2006 and was eventually declared an insurance write-off.

HC

drop lead

1st May 2009, 10:22

By now I would guess most of the L2's and 225's have had the epicyclic modules inspected?
Does anyone know if any additional problems have been found?

L2driver

1st May 2009, 12:35

Nothing is found so far , and that is a bit scary

JimL

1st May 2009, 13:37

L2driver,

That is exactly what you should have expected; to think otherwise would be to anticipate that there is a fatal flaw in this type of gearbox. Clearly that is not true otherwise the record of reliability in the life of the L2 and 225 gearboxes would look somewhat different.

Those who have seen the debris trays and looked at the (now removed) magnets, have remarked on the lack of deposits; at the most, on a near term gearbox, a mere smear of substance (not even enough to excite a fuzz-burner).

As was said previously, we will have to rely upon what can be deduced from the intact data collected in the VHM/HUMS system.

Jim

SASless

1st May 2009, 23:40

JimL,

There is at least one fatal flaw!

Whether it is design, manufacturing, engineering, or material failure is yet to be decided.

Brian Abraham

2nd May 2009, 01:33

Jim, do you know if they have a "complete" gear box, or might the offending piece have been ejected in the break up and lying some where on the sea bed?

ppng

2nd May 2009, 08:54

They only have about 20% of the epicyclic module, which is where the failure is believed to have started

you want what??

4th May 2009, 02:29

i knew JSAR was a Bristow Aircraft, dont know why i put that down!!! must have been the same black and yellow paint jobs!!

DOUBLE BOGEY

11th Jun 2009, 08:30

It was explained to me (by the Eurocopter MGB Overhual Specialist) that the magnets on the oil distribution plate were designed into the system to protect the lower part of the MGB suffering from a detrioration of the epicyclic module.

I guess in their design analysis they never expected a catastrophic breakdown of the epicyclic module, which in hindsight, probably renders the lower part of the MGB redundant for purpose.

My understanding of the situation so far, is there was very little HUMs evidence, leading up to, and immediatley prior, to the catastrophic event.

Rumour mill tells us that only 20% of the box and its components have been recovered.

There have been no significant findings in any other gearboxes during the AD inspections. Some MGBs have been rejected in the process, but not due to any conculisve evidence of impending failure. Some have made metal immediatley after the stripdown and they too have been rejected.

Given all the available information I summise that the AIB have made a "Best Guess" that the event was precipitated by the failure of the epicyclic module. This summation may not be correct.

What we do know is that the MGB casing was compromised leading to a significant reduction in rigidity between the barbecue plate and the MGB suspension bars, thus allowing the top portion of the box to rotate under load causing seperation of the MRH and blades.

The exact sequence of events may never be understood which is a great pity because without knowing this sequence we remain unsure what component was at fault.

MGB stripdown evidence, previous reliability, lack of discernable HUMs data in the accident AC, creates trends that point away from the epicyclic module.

It cannot be overstated that the helicopter was cruising at a mass significantly lower than its permitted MTOM. The MGB being subjected at this time to approximatley 60% of the engine power it is certified to recieve. I struggle to accept that an epicyclic would let go under such conditions when the machine has been flying for 4 hours already that day.

My greatest worry is that over focusing on the epicyclic module may lead to overlooking the root cause of the problem!!!!

DB

HeliCraig

22nd Jun 2009, 13:42

Not sure if anyone saw this press release from the CAA last week:
UK CAA hosts successful meeting on equipment needs of search and rescue for offshore helicopters | CAA News | CAA (http://www.caa.co.uk/application.aspx?catid=14&pagetype=65&appid=7&mode=detail&nid=1765)

UK CAA hosts successful meeting on equipment needs of search and rescue for offshore helicopters

http://www.pprune.org/applicationimages/whitespace.gif http://www.pprune.org/applicationimages/whitespace.gif Date: 19 June 2009 http://www.pprune.org/applicationimages/whitespace.gif
http://www.pprune.org/applicationimages/whitespace.gif
Key organisations involved in the operation and regulation of offshore helicopter operations met with representatives from the UK’s search and rescue services yesterday at a meeting initiated by the UK Civil Aviation Authority (CAA) to discuss the operational needs of search and rescue organisations, and the role of Personal Locator Beacons (PLB) and Emergency Locator Transmitters (ELT).

In a search and rescue situation it is important that all emergency locator transmitting devices work successfully without compromising the safe operation of the helicopter in which they are carried.

Following the Super Puma accident in February of this year, it was suspected that PLBs issued to passengers interfered with the primary Emergency Locator Transmitter (ELT) fitted to the helicopter and liferafts. As a result, the carriage of PLBs was restricted.

Following yesterday's very constructive meeting, a way to progress the re-instatement of PLBs in offshore helicopters was agreed.

For more information please contact the CAA press office on 020 7453 6030.
Anyone know what the way to progress re-instatement was?

JimL

22nd Jun 2009, 14:48

There has been discussion of a change in the technical standard of the PLBs to avoid unwanted activation as well as interferrence with the ELT.

These were not an unknown features of PLBs so a solution was probably already on the cards.

Jim

VeeAny

16th Jul 2009, 14:08

The AAIB have just issued a special bulletin on the G-REDL Crash

Air Accidents Investigation: Special Bulletin S5/2009 (http://www.aaib.gov.uk/latest_news/special_bulletin_s5_2009.cfm)

TiPwEiGhT

16th Jul 2009, 14:35

Having not flown the 332 series I have a question:

In the report it details that the HUMS had detected the chip in the epicyclic module and does not produce a caution/warning in the cockpit. Would HUMS on the L2 flag up a caution after shutdown?

Should it not be the case with such a system like HUMS it should create a cockpit warning for any form of MGB chip?

TiP

Special 25

16th Jul 2009, 18:33

As stated above, what is the response to a Chip Warning in the cockpit, other than to try and burn it, and if that fails, just hope it is on an 'unburnable' chip detector and continue flying.

I am curious how the chip detector was able to flag one chip, and then subsequently three more. Once a magnetic particle has bridged the contacts, how can it then detect additional debris ? That would certainly be a useful piece of information for pilots, indicating that they don't just have a single chip, but a series of fragments indicating gears breaking down.

outhouse

17th Jul 2009, 08:29

I have not viewed this thread for some time and have not had the opportunity to go back and go through the past entries however:
Mitchaa comments regarding an inferred non compliance to a MM procedure, by the operator, Is this identified in the report or is it an assumption based on the interpretation of the report wording. In my experience engineering will always follow the requirements of the MM or when required take advisories/instruction from the manufacture in writing regarding maintenance actions. Any clarification available please,
Outhouse.

Oilandgasman

17th Jul 2009, 10:10

Re an inferred non compliance with the MM procedures the report states "It was concluded, at that time, that the particle was of a type that did not require further investigation of the epicyclic module. In addition, the operator drained the MRG oil system and, after filtering the oil and examining the filters, identified no other contamination." The procedure used was text only and there is an action on the Manufacturer to include images of gearbox chips to assist in the identification of these and presumably highlighting those that are significant.
In the same report on page 5 there is a picture of "A typical epicyclic gearbox" If this is typical then it is no wonder that chips are generated. Six out of the seven gears which are visible appear to have had a stressful overheated life.
I look forward to the outcome of the review of this gearbox design.

SafetyCase

17th Jul 2009, 10:41

I think you might be jumping to conclusions here, the caption to the small picture in the report does not say "A typical epicyclic gearbox". It says "Typical epicyclic gearbox layout".

It might not be from an L2 at all, and it is clearly a training aid to visualize the inner workings of an epicyclic gearbox. You can see the the gearbox walls are cut away. It might even never have been used in a flying helicopter. For all we know, it might have been used by the manufacturer for stress testing purposes before it became a training aid.

I wouldn't draw any conclusions based on this picture.

Oilandgasman

17th Jul 2009, 14:58

Point taken SafetyCase, where ever it came from it is not in pristine condition.

SafetyCase

17th Jul 2009, 15:05

Yes , I agree, it does not look good

332mistress

17th Jul 2009, 16:59

Oilandgasman

In the aviation industry most cut-away components used in classrooms are time expired or u/s for one reason or another so I would expect them to show either wear and tear or damage. It is too expensive and wasteful to use a new component.

A chip found on a mag plug can range from a tiny sliver of metal to more chunky pieces so your idea-

The procedure used was text only and there is an action on the Manufacturer to include images of gearbox chips to assist in the identification of these and presumably highlighting those that are significant.

is not practical as in my experience if you can recognise the chip and where it comes from, either from a photo or experience, then the component will nearly always be rejected.

In this case there was no further contamination of the removable mag plug so maybe a very understandable false sense of the integrity of the gearbox was assumed.

The fixed magnets, which I believe have now been removed, also seem to have maybe masked events as they possibly prevented further chips making it to the mag plugs.

Whatever the outcome of the investigation it is still a tragic accident but it has to be put into the context of thousands of hours flown with that type of gearbox without incident.

I fly with a very similar gearbox keeping me aloft and have every confidence in it and the very professional engineers who maintain it.

332M

Morane

17th Jul 2009, 19:23

@Mitchaa

2nd stage is downstream 1st stage.

scorchboy

11th Jan 2010, 14:37

I write this having, since April scoured the internet for information/news/anything that will allow us as family and friends of the captain, Paul Burnham and all those others on board, to find some way of directing our anger/sadness/emptiness. Since the accident every day has had a tear and every helicopter that flies overhead, especially a Bond helicopter, raises the question why? To date we have no answers. Rumours of a misdiagnosis of the magnetic chips found circulate. Blame is going to pass between Bond and Eurocopter relentlessly and the dread of its longevity lives with us every day. The fear of the 1st April 2010 arriving has been there, in the back of our and the other families' minds since the memorial. It marks the day when everyone will remember - and then forget agin. Not for us. To us 1st April 2010 will be the last time we will ever be able to say, "this time last year...." Every day is a grab for some memory, everyday is a stab through the heart, everyday is an ache and the searing question, when will it stop.

I read this forum and am glad for the support shown. I cry with bitterness everyday at the lack of support shown by Bond towards the families. Not even assistance with funeral/repatriation costs. No assistance with flying families up to Aberdeen after the accident. Contact with the families subsequently has been non-existant, a token, uncomfortable, appearance at the funeral - that's it. The overwhelming impression that they wanted to wash their hands of this "dirty mess". That hurts more than anything.

Paul loved flying, he gave up everything to do it and he would never have played the blame game. But, Paul isn't here, his family and friends are. Everyday we look for more information, it's what gets you through the day. Please, don't knock each other for the comments. Everyone of them is a sign of maintained interest, it keeps the issue alive and in so doing hopefully spare anyone the pain of hanging on to the smallest item to try and keep that person alive in your life.

Thank you, to all those out there who know this is important.

Tuckunder

12th Jan 2010, 13:08

Scorchboy, a moving post. It is sad that you feel support from Bond towards the friends / relatives of all the occupants of G-REDL is less than it should be. Rest assured that this accident is still foremost in our (North Sea Operators) minds and that you, the friends and relatives, are thought of regularly. I work for one the oposition but am very reluctant to think that Bond engineering did anything so terribly different to how the other two operators would have conducted themselves.

There are unanswered questions such as the design change in drained oil and the fact that the oil drain ring could be removed along with its magnets as a post accident mod. This raises the inevitable question why the mod in the first place and perhaps more emphasis from the manufacturer on the implications of this mod should have been given to the operators both engineers and pilots. However we have one of the best accident investigation branches in the world looking at it and I am of the opinion that the final report will answer those questions. In the meantime friends and family are in my mind and best wishes to you all.

WAH

12th Jan 2010, 20:39

Scorchboy, I agree with the above, a moving post and just to assure you, it still is in the thoughts of everyone in the offshore business.

It's only human nature to point the finger of blame in situations like these. Sure, it was a catastrophic accident, but the question is, was it a preventable accident?

To me anyway, I echo what Mitchaa states a few posts up. A few things stick out that raise question marks.

There WAS a pre emptive warning in regards to the chip.
The AAIB have not released any information regarding what the HUMS system was showing which I find a little strange 9 months on.

Reference the first point, I would definitely be checking to see what the Eurocopter maintenance manual states in regards to a chip being found. If the maintenance manual states that the epicyclic should have been inspected and Bond chose to ignore this action then well I dont need to tell you much more. The accident would have been preventable and there is a definite blame for negligence.

As to the 2nd point, why have the AAIB not released any information in regards to what the HUMS system was doing? I know that Bristows and CHC have dedicated HUMS departments looking at their gearboxes daily, but I am unsure as to what Bond have/had in place.

HUMS if you are unfamiliar with the term, is a system that is used to monitor the internal components of the gearboxes. High speed rotating shafts/bearings and quite a few other things like main and tail rotor balancing. The data is downloaded after every flight and is plotted in graphs to which experts look at the data to check for any abnormalities/trending in the data. I do believe the engineers were alerted to the initial chip through a warning generated on the HUMS system that then prompted them to look at the probes. From memory of reading the AAIB report, it would appear a further few HUMS warnings were generated just before the gearbox failed. Of course though, unfortunately there was no way for these warnings to have been acknowledged.

In this case it looks like some kind of planet gear failure, perhaps a bearing in the outer race. Just what were the graphs showing? Why no information from EC/AAIB?

Have any familes started any legal proceedings? Is there negligible blame?

Im sorry for your loss.

Woolf

12th Jan 2010, 23:06

Scorchboy, I can only echo Tuckunders lines and assure you that this accident is still very fresh in everyone’s minds. It is very frustrating not to have the answers to the questions you ask and I sincerely hope for everyone involved that the exact cause of this tragedy can be established as soon as possible.

As demonstrated by WAH’s post you will not find any meaningful answers here if you are looking for more than speculation. The UK AAIB is the only source with enough information to attempt an explanation. They do not work quickly. They are however very thorough and most importantly impartial. Let’s hope they have enough pieces of the jigsaw to guess the picture. I truly hope you can put your trust in them as I do – I don’t think there is anything else.

Our friends are not forgotten! :(

Aser

15th Sep 2010, 11:01

BBC News - Offshore helicopter advances to be analysed (http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-11295854)

The latest advances in offshore helicopter safety are to be discussed at an aviation seminar.
Delegates will hear about the achievements of the helicopter task group, set up after 16 men died when a Super Puma crashed in April last year.
The event, organised by industry body Oil and Gas UK, is at Aberdeen Exhibition and Conference Centre.
Oil and Gas UK's Robert Paterson said: "This will help inform the industry about future safety developments."
Representatives from the offshore industry and the Air Accidents Investigation Branch (AAIB) will also be attending.
The 14 passengers and two crew on board the Bond helicopter lost their lives on 1 April last year when it came down in the North Sea.
Eight of the victims came from the north east of Scotland, seven from the rest of the UK, and one from Latvia.
The initial report into the crash found that the aircraft suffered a "catastrophic gearbox failure", resulting in "detachment of the main rotor assembly".
The AAIB has said it anticipates that a final report will be published towards the end of 2010.

Best regards
Aser

Staticdroop

8th Jan 2011, 10:39

Anybody heard if the AAIB report is due soon, for either of the 2 incidents with Bond that year?

VeeAny

24th Nov 2011, 03:03

The long awaited accident report concerning G-REDL is published today.

Air Accidents Investigation: Formal Report 2/2011 published (http://www.aaib.gov.uk/latest_news/formal_report_2_2011_published.cfm)

The document itself is located at http://www.aaib.gov.uk/cms_resources.cfm?file=/2-2011%20G-REDL.pdf

SASless

25th Nov 2011, 01:08

Why the silence?

The Conclusions section raises some very interesting questions re certification and design assumptions.

Some topics that jumped out at me had to do with the location and operation of the Magnetic Chip Detectors....and the EC Engineering assumption that gearbox failures would always produce spalling.

Also interesting is the note about the decision to end Oil Sampling and analysis of the samples back in the mid-80's....or did I misunderstand what that reference was all about?

It is interesting that the FAR's get referenced....for a EC product.

HeliComparator

25th Nov 2011, 10:59

Yes does seem a bit quiet. I suppose one would not like to be in the engineering team that were dealing with the chip issue, perhaps there is some desire not to give them a harder time than they will already be having.

The reason for the FAR references I suppose is that FAR29 and CS29 are virtually identical so no point in trying to change one without the other. There are of course a few FAA certified EC225s (but no L2s as far as I know) around.

One thing that did not get a mention (unless I missed it) is the language issue. EC of course have very much better English than we do French, however I routinely see misinterpretations on both sides. One only has to read EC's documentation to realise that it is not written by someone who has English as their first language.

At present all the documentation is written by the specialists in French, then translated into English, perhaps by someone who is a translator, not a technical specialist. Thereby creating the potential for misinterpretation etc. Interestingly we did receive a visit from the EC guy in charge of Flight Manuals a year or so ago - he said that the longer term plan was to have all the documents written originally in English, then translated into French as required. Sounds like a good plan but then he was English, so not sure how easy it will be for him to achieve that!

The language issue is surely good grounds for having solid and written dialogue with the manufacturer on critical issues. Yes as I said the written word can be ambiguous but it is surely better than the spoken word!

If fingers are pointed at the individual engineers concerned, that will be unfortunate because just like so many aviation accidents, the root cause is not the momentary action by the indivdual, rather the failure by the company's managers to ensure robust procedures and systems are in place with adequate monitoring for compliance.

Droopy

25th Nov 2011, 12:30

ISTR the "similar accident" referred to in the report was SA330J 9M-SSC in Miri where the language barrier blurred the interpretation of debris amounting to 50mm2 was an issue - ie/ was it 5 x 10mm or 50 x 50mm.

SASless

25th Nov 2011, 12:41

HC,

It not just French/English conversions where language lets us down but also in English/English (in this case English/American).

My use of the word "Engineer" is in the American usage....as in Design Engineers and not the British usage which in American is "Mechanic"....those that use hand tools etc...in the maintenance and repair of things.

I particularly note the issues raised about the assumptions all serious MGB failures would produce "spalling", that there would be adequate oil flow to move any foreign matter in the oil within reach of magnetic sensors, and the decision that oil sampling was no longer necessary.

We are talking about possibly the most important component of a helicopter when we talk of Main Gear Boxes....yet we are confronted with decisions and designs that fail to meet all contingencies.

How many times we heard that kind of comment about the S-92 MGB design?

All I am looking for here is the exact same kind of analysis by those that are so critical of the Sikorsky S-92 and its Engineers. No one gave a damn about their feelings....why should we treat the French Engineers any differently?

The discussion is all about the design, its flaws, and how to correct them and the certification system so we have "safe" aircraft to fly.

IMHO.....until the Gearboxes in question are re-designed to correct their shortcoming in detecting such failures...identify all foreign objects in the oil the come from gear/bearing/race wear and cracking....and oil analysis is re-instituted as a standard practice...and less reliance on HUMs as the main Gearbox Health measure is a standard engineering practice, I would suggest the industry has not adequately addressed the situation.

Now HC....care to discuss the technical issues raised in the Report?

In your view...what do they tell us about the current state of EC MGB design and safety monitoring of the gearboxes by flight crews, maintenance crews, and the Manufactuer?

Where do we go from here to improve the situation?

As to worrying about the feelings of people....how about we get concerned about the feelings of the next of kin of those that get killed in a second occurrence of this kind of failure.....or will it be the third occurrence if we accept the Report's findings?

JimL

25th Nov 2011, 14:08

From the point of view of a pilot and not an engineer:

I was heartened by the quality of the AAIB's forensic investigation that permitted establishment the point of failure to (part of) a specific second stage planetary gear in the epicyclic module. Further that the chip, collected on the 25th March, was from a 'second stage planet gear' - concluded, not just from its metallurgical composition but from the marks made during 'honing' process - was astonishing.

I was also astounded by the further analysis of that chip which appeared to indicate that the source of the stress leading to the fatigue cracks was some foreign agent whose indent could still be seen. Although not making any conclusive statements, there was a hint that the introduction of this foreign object could have resulted from the previous conical housing/rotor head replacement on the 1st March.

I agree with HC that the assignment of blame is futile but a system where such an important precursor is permitted to be discarded because the conclusion was reached that "the particle was a piece of 'scale'" - i.e. that it was believed to be "...silver or cadmium plating, which, in accordance with MTC 20.08.01.601, was '...unimportant...'" should be a wake-up call for management everywhere. Perhaps such areas of critical judgement should have far tighter control mechanisms if so many actions and consequences are likely to stem from them.

We have previously discussed the placement of the magnets on the epicyclic module separator plates (since rectified) - which might have captured debris from the stressed gear and thus prevented them from reaching the chip detector. Surely another failure of FMECA in the design process.

The reference to FARs (as opposed to JARs or EASA CS) is because the 332 was certificated to FARs (JARs were not in yet in place) and, specifically to amendment 24 of FARs. As you should be aware, the certification basis for an aircraft is frozen at a particular amendment version - which is why the FAA regulatory library has to provide all previous version on their regulatory web site.

Like others, I was disappointed with the failure of HUMS to provide adequate warning of failure (which confirmed experience from previous planetary gear failures in the S61); further, that it might never be an effective detector of bearing wear/failure in the epicyclic module (even with AAD). Clearly, we have to move back to debris monitoring using old and proven methods such as SOAP and other oil analysis techniques as is recommended in the report.

All-in-all a fascinating report and one which, if it is extensively studied, will add to the knowledge of helicopter professionals everywhere.

Jim

SASless

25th Nov 2011, 14:58

Assignment of blame is not the objective.....finding an effective solution to the problems is the exact goal.

Did we rely on advanced technology, caste off proven techniques in the process, and by doing so....set ourselves up for failure?

As you correctly note JimL....the investigation begs questions whose answers are very important if they can be determined.

Every time we open up something as complex as a Gearbox....or dissasemble an aircraft's components to "inspect"....do we not introduce the possibility of contamination that can lead to failures shortly after the "satisfactory" inspection of the component?

Where do we draw the line between "inspecting" and "monitoring" to ensure a component remains "safe and serviceable" until TBO?

donkyoatie

25th Nov 2011, 18:58

Ref - AAIB Report page 130 Aircraft Maintenance Manual AS332 MK 2 Sub task 60-00-00-212-001 Para 3.1.1 Examination of the magnetic element.

If particles are found open the epicyclic module

Remove the epicyclic module.as per 63-22-00-021

Use a magnet to recover all the particles which you find on the magnets (3) of the collector.

There is no evidence in the report that this maintenance instruction was followed.

Whilst it is true to say “ The ring of magnets installed on the AS332 L2 and EC225 main rotor gearboxes reduced the probability of detecting released debris from the epicyclic module,” having had a detection the next maintenance action intended by the Design Engineers to assure airworthiness does not appear for what ever reason to have been taken.

It is notable that the report 2.7.3 Maintenance actions states “Had the magnetic particle recovered from the epicyclic chip detector been found in isolation, it is probable that the appropriate maintenance manual tasks would have been applied without consulting the helicopter manufacturer.” and “Since the accident the operator has completed a review of its maintenance practices and procedures and has measures in place to ensure that reference is made to the approved documentation when completing maintenance tasks.”

The AAIB report is an excellent illustration of how what at the time could be claimed to be unforseen is now blindingly obvious.

Brian Abraham

25th Nov 2011, 22:17

I was disappointed with the failure of HUMS to provide adequate warning of failureThe 1,022 vibe was interesting in that its source could not be ascertained and one wonders if it was a red flag being waved. Seems to have provided plenty of warning if such was the case, and if we had the technology and necessary knowledge to understand what it all meant was available.

HeliComparator

25th Nov 2011, 22:51

Hi SAS

My sympathy for the maintenance guys was aimed at those working for Bond, not for EC.

Regarding your defensiveness of the 92 there are a couple of differences between it and the L2 - the first being that unlike the 92 they were not marketed as being the safest heli on the planet (ie expectations of the 92 were high) and that gearbox has been flying a lot longer than the 92's one with only 1 failure so far. That failure probably wouldn't have happened if the manufacturer's procedure had been applied as intended.

In its relatively short career, the 92 has killed a few and scared a whole lot more with a number of "near misses" whilst the similar number of 225s in service haven't much scared anyone (yet!).

On the subject of detecting transmission failures, HUMS and debris monitoring are complimentary techniques each with their areas of effectiveness. Because the planet gears are passing around the sun gear as well as rotating, the energy of their vibration signature, even after signal averaging, seems to be too weak for current technology.

I do feel that HUMS technology has stagnated a bit, even though AAD is a great advance it is only applied to the existing HUMS analysis and that has not really advanced since its inception as far as I can tell. The long standing flaws in the software mentioned in the report are an indication that there is insufficient investment in the technology (in terms of both time and money) which is unfortunately so typical of that sort of thing these days - once the push to get new stuff in place dies down a bit, compliance with such "good ideas" is checked by people who don't really understand the sharp end of it and just want to tick the box to keep the client/Authority happy. The full value and potential is never realised.

HUMS will never be perfect, nor will debris monitoring (and SOAP only works for microscopic-sized debris, not chips) and neither will transmission. Of course transmissions don't have to be perfect, the certification rules don't require zero failure rate, just one low enough so that those designing and certifying it will have likely retired before the first failure occurs!

HeliComparator

26th Nov 2011, 00:12

Just thought I would expand on the SOAP thing. SOAP is not the solution:

SOAP uses spectrography to detect microscopic metallic particles such as are produced by general wear, plain bearing degradation etc

In the REDL case, the problem seems to be that a chunk of roller bearing raceway surface broke away due to spalling. This left a pit which was the likely start of a fatigue crack. Neither the chunk, or the fatigue crack, released any microscopic wear particles, so there would be nothing for SOAP to detect.

Therefore SOAP or its ilk would not have shown any problem prior to the accident, and in this respect unfortunately the otherwise good AAIB report is misleading (aka incorrect).

Chip detection is the only current means to detect this type of failure. It did of course work correctly, but unfortunately the implications of the chip were not correctly grasped by the maintenance guys and the accident happened. Silver and cadmium are non-magnetic so it seems pretty unlikely to me that they would be stuck to magnetic chip detector!

SASless

26th Nov 2011, 00:13

transmissions don't have to be perfect, the certification rules don't require zero failure rate, just one low enough so that those designing and certifying it will have likely retired before the first failure occurs

What repercussions are there for some "Crat" in a Government Certification Agency that signs off on a bad design? Did anyone jump out of a hi-rise window over the Comet, the DC-10, Air Bus Pitot tubes, the 92 Gearbox?

Any ritual suicides anywhere we haven't heard of?

At best they retire with a full pension....worse case they stay on to commit more murders....then retire with that fat pension.

industry insider

26th Nov 2011, 03:07

While SOAP may not have shown any pre cursor to this accident, it is very good general practice and should be routinely re introduced.

Brian Abraham also raises a point which jumped out at me when I read the report. The 1,022 HZ noise, not being type typical may, with hindsight have been a possible indicator. Should operators and manufacturers consider adding audio to one of the regularly monitored HUMS parameters?

squib66

26th Nov 2011, 07:20

While I would not want to stifle any well intentioned creative thinking about possible indicators like acoustic signatures, they perhaps border on being a red herring here.

The elephant in the room is the AS332L2 was certified with magnets to catch epicyclic debris such as spalling, and the Maintenance Manual (see AAIB report App C2) called for them to be examined after any chip indication on the epicyclic mag plug. The mag plug and the magnets were specifically fitted to give early warning of failures.

According to AAIB they were never examined on G-REDL, on 25 March 2009 or subsequently.

obnoxio f*ckwit

26th Nov 2011, 11:11

In a similar vein to SASless's post above, a Puma had just taken off from Pau to go mountain flying a few years ago, the crewman decided that there was an unusual noise coming from down the tail. The rest of the crew couldnt hear it but took the crewman at his word and returned to base. Eng removed the mag plug (from IIRC the intermediate g/b) and it looked like a golf ball of chips and dust; and a very short way from letting go completely. It's not usually the noise that's important, but the change in noise.

Or indeed SASless's post below now. What is going on with the posting order recently?

bolkow

26th Nov 2011, 11:49

Arnie Madsen, I agree. On one occasion where I was in a situation that could have resulted in multiply deaths (only one died as a result) my expletive to emergency services was exactly the same, the only difference I remember was that I used it about eleven times in a three minute exchange with an operator who was askign mostly irrelevant questions, thats stress for you.
My ealrier comment about multiple incidetns with this aircraft, just to acknowledge that yes, I am not aware the cougar incident was a different aircraft as was one other.

SASless

26th Nov 2011, 12:03

Sound does very much play a role in Gearboxes or any other bearing function.

How many of us (who drive the same car or light truck for multiple hundreds of thousands of miles) have not at some point heard the "rum...rum...rum...rum" sound of a bad wheel bearing or universal joint?

While flying a corporate MD-500E....I began to complain the MGB just did not sound right....it had changed noticeably to me over the time I had been flying it. For the longest time the CP and Mechanic/Engineer treated me like I was merely going mad. I finally forced the issue and refused to fly the machine unless we pulled the gearbox and did a split case inspection.

Good thing we did....it was in the process of losing some bolts that retained one of the gears. One bolt had worked completely loose and found its way into the sump....without fouling anything, no spalling, no chip detector...just a change in the sound of the gearbox and I am sure a change in its vibration pattern but without HUMs who would have known.

The question I would have on adding a "sound channel" to HUMs....how would one arrive at a "normal standard" for comparison over time? What would be a "significant variation" that would trigger a maintenance action?

zalt

26th Nov 2011, 14:32

Geoff

You ask
Does anyone know if EC had a Tech Rep for the 332 in UK/ADN and if so was he consulted? Sometimes a good Tech Rep will be a mine of information that can help hard pushed and shift-working maintenance personnel to react appropriately to the first signs of a major defect.

According to the AAIB:

a manufacturer’s technical representative is based in Aberdeen to provide direct support to local operators. This representative was not available in Aberdeen on 25 March 2009 due to a pre-planned commitment.

The AMM however was available and required the epicyclic module to be opened and inspected (squib's 'elephant').

HeliComparator

26th Nov 2011, 14:44

II / SAS

I very much doubt that the 1022 hz tone was relevant. That frequency corresponds to a rotational speed of 61,320 rpm or for say a gear with 30 teeth, gear meshing frequency at 2044 rpm which I think is much faster than the upper epicyclic planets are going. It is more likely to be an avionics cooling fan or even electrical (not sound) interference picked up on the microphone leads.
Interesting but one could spend one's life chasing sounds that are not related to the transmission.

henra

26th Nov 2011, 17:41

II / SAS
That frequency corresponds to a rotational speed of 61,320 rpm or for say a gear with 30 teeth, gear meshing frequency at 2044 rpm which I think is much faster than the upper epicyclic planets are going.

Maybe it could still be linked to the Gear Box.

There are 14 Rollers in the bearing. Turning at twice the RPM than the Rotorshaft. means 2190/min. common denominator between roller position ans Gear Mesh would be 1/15th.
Would be 146/min. Still no match but you get the picture.
You can get resonances from weird combinations...

I wouldn't rule it out completely.

JohnDixson

26th Nov 2011, 20:26

Henra makes a valid observation.

Anecdotally: The CH-47A production prototypes that we had at the Aviation Test Board in 1963 had developed a problem in the engine nose gearboxes that exhibited itself thru the disturbing propensity of literally exploding in flight, with the resultant debris being ingested into that engine, causing it to fail in a noisy manner. The "Captains and Majors, and Light Colonels too", started shunning the machine and that's how a junior Lt ( me ) got to fly them, tho' I was two weeks out of flight school.

Anyhow, the cause of failure was exactly what Henra referred to, a resonance within the box. Boeing couldn't redesign the box overnight, so the operating Nr was shifted from 204 to 230. Far enough away to keep us off the problem. And doing that, we nor the 11th Air Assault Div ( soon the 1st Air Cav ) CH-47 drivers had any further events due to that cause, as I recall.

In rotary wing machines, its not just the component natural frequencies that can create larger issues.

Thanks,
John Dixson

Geoffersincornwall

26th Nov 2011, 20:36

Just for the record the Comet debacle (wing-stall on rotation during take-off) was a problem that had its root in the lack of development via prototype and was covered up not only by the manufacturer but by the UK aviation authority, the accident investigators and the airline (see David Beaty's excellent book The Naked Pilot).

Reading about that incident was for me a life-changing experience for ever since I have never been able to trust anyone in authority to deliver 100% of the truth and have frequently found this approach to be justified. It is a sad indictment of our world. The AAIB was, I believe, formed after the Comet debacle as independent accident investigators and they at least appear to be up to the task. Anyone who believes that everyone in aviation is pure of heart, honest and upstanding needs a reality check.

Does anyone know if EC had a Tech Rep for the 332 in UK/ADN and if so was he consulted? Sometimes a good Tech Rep will be a mine of information that can help hard pushed and shift-working maintenance personnel to react appropriately to the first signs of a major defect.

G.

SASless

26th Nov 2011, 21:36

Geoffers....I was referring to the depressurizations caused by airframe cracks...that resulted in several mid-air breakups fatal to all aboard. That engineering failure led to the Boeing 707 and Douglas DC-8 being the Jets of choice during the early years.

John.....ah yes....Nose Boxes....and how they could liven up a dull day!

Then that takes us to podded engines the British like so much. One dies...pukes up its innards and its next door neighbor gets a terminal dose of FOD. Aircraft like the B-52 and B-47 had that similarity.

I always wondered about the Puma series....except helicopters tend to have very good inlet screeens which cures that problem. Granted two engines being nestled like lovers sets one up for an interesting day if one shucks a turbine wheel and kills the other.

Is there a book somewhere that Design Engineers should refer to when drawing up a new design....to see what ideas from the past did not work out well?

Geoffersincornwall

26th Nov 2011, 22:19

Yes It's called the HARP report. (Helicopter Airworthiness Review Panel).

G. :}

zalt

26th Nov 2011, 22:22

Geoff

According to the AAIB:

a manufacturer’s technical representative is based in Aberdeen to provide direct support to local operators. This representative was not available in Aberdeen on 25 March 2009 due to a pre-planned commitment.

The AMM however was available and required the epicyclic module to be opened and inspected (squib's 'elephant').

Brian Abraham

26th Nov 2011, 22:55

the cause of failure was exactly what Henra referred to, a resonance within the boxJust a comment on how things can strike out of left field. The F-14 was suffering a spate of CSD failures. Investigation found it was only occurring on one particular ship. Cause - the deck had been painted with a previously unused type. The changed nature of the wheel spin up on touch down excited the CSD's natural frequency and caused the failure. Changed paint, job fixed.
Granted two engines being nestled like lovers sets one up for an interesting day if one shucks a turbine wheel and kills the other.Shades of S-76 and BBQ plates. Bit difficult for an alternative arrangement on helos though SAS.

n305fa

27th Nov 2011, 10:19

After reading the report a couple of times, I would like to throw the following comments up for consideration.

1/ during design, the primary failure mode of the gears was considered to be spalling and all of the maintenance and monitoring tasks were tailored to identify this type of failure, e.g a failure that generates a load of metallic particles.

2/ The AAIB state that the failure of the 2nd stage gear was not consistent with spalling alone, so there may not have been as much metal generated as with a pure spalling failure. In view of this, even had the gearbox been opened there was the possibility that there would not have been enough material to declare the MGB unserviceable. The actual ammount of particles released will never be known as the MGB was not opened.

3/After 25/3 there were no more indications of degradation in the MGB despite the additional monitoring. Failure of a critical component should be preceeded by more than one sign of degradation.

4/ The use of MCD's as the primary method of detecting epicyclic gear deterioration appears to have limited ability to detect a rapid (non-spalling) failure of a gear.

HeliComparator

27th Nov 2011, 18:02

n305 you raise some interesting points, though I would say that you comment in 1/ about "a load of metallic particles" is perhaps a slight exaggeration.

Really we have only two non-invasive technologies for detecting incipient transmission failure - debris monitoring and HUMS (or VHM if you want to be trendy).

Tradionally VHM's strong point has been gear crack detection since a fatigue crack can occur and propagate to near-failure without much or any debris being released. Other types of impending failure such as bearing or spline disintegration are better detected by debris monitoring.

Unfortunately the path of a planet gear's tooth around the sun and ring gears is a little complex and seems to be beyond current VHM implementation's ability to detect cracks. Thus whilst many other elements of the transmission are "protected" by either debris monitoring or VHM, the epicyclic seems to fall between the two of them.

There is a view in the industry that monitoring planet gears is beyond VMH, without rather drastic steps such as fitting sensors onto the rotating planet gear carrier and somehow remotely powering and recovering the signal. I don't really like this idea because adding "stuff" inside the gearbox bolted onto gears seems likely to introduce new hazards when it falls off, disintegrates etc.

Personally I remain to be convinced why current hardware cannot be used to adequately recover gear tooth vibration signal from rotating planet gears. Although each tooth only meshes with a specific location on the ring gear after many rotations, surely the time interval between each occurance is predictable and therefore current techniques of signal averaging could be used to recover an adequate signal for processing in the VMH system. The downside would be that it would take a relatively long time for the acquisition, and one of the goals of VHM system design is to not require too long "on condition" since the aircraft may not be in cruising flight for long (this can be a problem for example on SAR aircraft). However, being selfish about it, oil and gas operations at least in the Northern N Sea tend to spend quite a long time in the cruise and so the time issue is less relevant. Our current VHM systems spend a long time in the cruise doing nothing.

I would like to see more research into this issue, something that unfortunately is not specifically suggested in the report. As I mentioned before, with the exception of AAD, HUMS technology has been resting on its laurels for a long time now, time for some progress! CAA Research Dept, this would be a good one for you!

HC

Edited to say that the report does in a roundabout way recommend further research into VHM for epicyclic, but directs this at EASA who have no track record in VHM research. No doubt putting politics ahead of the optimum. I suppose that in the fullness of the time associated with EASA beaurocracy, the recommendation might wend its way to the UK CAA eventually!

maxwelg2

27th Nov 2011, 20:21

Silver and cadmium are non-magnetic so it seems pretty unlikely to me that they would be stuck to magnetic chip detector

Wrt. HC's comment IMHO this was a major point of the AAIB report i.e. the chip found must have been magnetic to be found on the plug, so why would Bond incorrectly identify this chip as non-magnetic material? The mis-communication between Bond and EC was also IMO a serious breakdown. Hopefully the improved procedures on chip identification and documented correspondence will address these base errors.

Wrt. the 1,022 Hz anomaly picked up in the acoustical analysis (ref report section 2.5), perhaps this could be a resonant harmonic from a change in the epicyclic module cruise mode signature. Without the missing section of the second stage planet gear it will never be known if this part of the MRGB was the generator of this harmonic. Hopefully the recommendation to further enhance HUMS will look at the addition of acoustical signatures in this specific frequency range.

As with Cougar 491 the key point is that we all learn from these tragedies and improve helo safety for all by negating mis-information and having effective communication protocols.

Safe flying

Max

pasptoo

27th Nov 2011, 20:56

Maxwelg2,

WRT your comment Without the missing section of the second stage planet gear it will never be known if this part of the MRGB was the generator of this harmonic

EC will have to capability to produce an acoustic analysis from the known design parameters. It will have been analysed over and over for all known harmonics, especially those which would interfere with all major rotating frequencies (of which there are many in a helicopter).

Whether or not a section of the gearbox is missing or not, a modal/rotor dynamic analysis will produce all possible amplitudes.

Pas.

maxwelg2

27th Nov 2011, 21:31

Hi Pas

Perhaps my syntax wasn't too clear, I was referring more to the point that it would appear that to date nobody has ascertained the root cause of the 1,022 Hz signature and without knowing exactly what the structure of the missing section of gear had and no epicyclic inspection performed post-magnetic plug contamination it is still unclear what the root cause for this harmonic was. Additionally report section 1.11.6 states that this harmonic was not found present in other AS332L2 MRGB acoustic signatures, so it can be assumed that it was specifically related to the condition of the installed G-REDL MRGB.

Safe flying

Max

HeliComparator

27th Nov 2011, 21:54

The report does say that the frequency varied with the Nr so it was something connected to the transmission, but there is an awful lot that it could have been - something on an engine Nf shaft, oil cooler fan, accessories such as alternator / hydraulic pump, tail rotor drive or an ac electrical noise (frequency linked to rotational speed of the alternators). I really think it is highly unlikely to be coming from the epicyclic. We would on the one hand be saying that sensitive accelerometers mounted on the transmission are not thought able to pick up anomalous vibration relating to planet gears even after augmentation from say 100 cycles of signal averaging, on the other that it could be heard above the general din in the cockpit, a very long way away from the epicyclic. Sorry but it doesn't add up for me. A red herring.

kennethr

29th Nov 2011, 17:16

This is an exhaustive report and there are many contributing factors, mis communication being a prime example but in conclusion it was a failure of a component that the systems failed to recognise or identify, not an ommision by an engineer or any other individual,,,,,All recommendations and conclusions are pointed towards failures or short comings either by the manufacturer or by EASA

No need to point fingers and blame the staff or the operator

The conclusions of the report say it all, Eurocopter and EASA need to sort this out , from design failures and manufacturing process to procedures and clear and concise communication methods!:ugh:

SASless

29th Nov 2011, 17:25

No need to point fingers and blame the staff or the operator

How does one analyze the chain of events that led to the crash, do so rationally and fairly, without pointing out all of the factors that played a role in the sequence of events?

That is not finger pointing or laying blame in my view but rather taking an impartial view towards improving the situation we all face on a daily basis.

Humans are not perfect and unfortunately machines are not either.

We have to be willing to examine all the links in the chain....if we have any hope of improving the system from design concept to operation by the end user.

To do anything less is a failure in and of itself.....and is this not all about finding out how the system failed and resulted in the loss of precious human lives?

henra

29th Nov 2011, 20:42

The conclusions of the report say it all, Eurocopter and EASA need to sort this out , from design failures and manufacturing process to procedures and clear and concise communication methods!:ugh:

Are we all talking about the same report ? :confused:
The one I read was a very detailed and thourough one looking into many aspects that contributed to this tragic accident.
And this also -besides the things you mentioned- included the fact that the epicyclic module was not removed and the magnet ring was not inspected and the misunderstanding with the EC staff on this topic both of which might have broken the chain leading ultimately to the accident.

SASless

29th Nov 2011, 22:41

Mars

30th Nov 2011, 07:13

Although there is a need to avoid a blame culture if we are to ensure transparency in operations, it was somewhat surprising to see the following excerpt from the recent statement from "Oil & Gas UK":

While the AAIB report confirms that neither the actions of the crew nor the weather were factors in the accident and that the helicopter maintenance regime satisfactorily complied with existing regulations, it does make 17 recommendations

It would be interesting to hear other's views of how the underlined statement resonates with the following 'Conclusions, Finding' contained in the AAIB report:

37. The maintenance recommendations provided by the helicopter manufacturer were based on their belief that small particles had been found on the main module chip detector and that the maintenance actions contained in AMM task 60.00.00.212 had already been completed.

38. The maintenance task to remove the epicyclic module and examine the ring of magnets on the oil separator plates, contained in AMM task 60.00.00.212.001, was not carried out.

39. The standard practices procedure used to identify the origin of metallic particles within the MGB was generic and open to interpretation.

40. The particle discovered on 25 March 2009, from visual examination, was identified as ‘scale’, but the material was misidentified as being silver or cadmium plating.
Although all of us welcome the intent of the Oil & Gas UK to restore calm - following a very technical but thorough report, this should not be done by spinning the information.

For the same reason, I find the statement made by 'kennethr' - putting the focus upon EASA and the manufacturer - somewhat misplaced.

Safety depends upon all of us taking responsibility for our actions. Yes, from the outside the system appeared to be complex and lacking in sufficient control and oversight; however, all systems are ultimately dependent upon all of us 'playing our part' and doing what is documented and/or expected. This unfortunate accident emphasizes the fact that 'critical elements' of a system have to have checks and balances.

We will never know whether this chip was shed in isolation; however confirmation of this, by examining the ting of magnets on the oil separator plates, contained in the AMM task 60.00.00.212.001, was not achieved.

As 'Geoffers' has pointed out in a number of posts, the respected HARP report recognised that complexity in the MGB makes eradication of all failures difficult to achieve. For this reason, it is imperative for us to ensure that the tools that we do have are employed effectively. It is the system that has to be made more effective, not the airworthiness code.

Leaving aside the flawed interpretation of FAR 29.927, it was largely the system that was at fault (both manufacturer's and operator's) in the S92 accident; these permitted the somewhat innocuous incident at Broome to turn into the tragic accident at Newfoundland.

SASless

30th Nov 2011, 12:04

The AAIB report wording is way too polite in some areas....and leaves the interpetation up to the reader when it should be quite specific and point out the magnitude of the action or in-action of various parties.

Having been an Investigator in other fields in the past....I see several "Leads" that are left unanswered and un-explored.

Granted the AAIB is more a technical investigative operation but there are times getting into the "Why" something was done or not-done becomes very important to understanding the overall chain of events.

The important issue to me....due to my background....is "Who" made the decisions, "Why" they decided what they did...."What" they decided...."When" (in the sequence of events) they made the decisions they did...."Where" they made the decision....and "How" they made the decision.

In a Criminal or Civil prosecution...this becomes very important but is just as important in any aircraft accident investigation. Bottomline analysis of any event....it comes down to figuring out "How" something happened once "What" happened is determined.

No one set out to destroy this aircraft and kill the occupants....but that is what happened. What turned the "system" into a killer?

Just as we look back now for indicators that should have warned us about the health of the Gearbox....where are the indicators the system itself was failing?

Perhaps we need to learn from this tragedy and examine our own operations with a critical eye. A proper Safety Program would do so...and do so with a very sharp eye.

As we reflect upon the 92 Gearbox problems....and now the EC gearbox problem...perhaps we can all agree it is a general industry wide problem we confront and that it is not limited to just one builder of aircraft.

Are we not seeing a problem in the design, certification and oversight of maintenance of helicopters within the world-wide Helicopter Industry?

It is not a perfect World we live in....but I firmly believe we can do better....if we don't...how many of us are we willing to write off to that failure to strive for perfection?

Shell Management

30th Nov 2011, 17:14

henra

Spot on.

Mitchaa

I agree with you on counts 2 and 3 and also that this WAS preventable.

On count 1 you are wrong. :uhoh: One of two accerometers (the one on the lower epicyclic) was moved. The one on the upper (where the failure was occuring) remained.

Mars

I agree totally.

Compliance monitoring of maintenace staffs is what is required.

It was Shell who funded HUMS after the HARP report.

The IHST Maintenance Toolkit give plenty of guidance on using HUMS.

It is sad that Oil and Gas UK made their press release without consulting professional aviation advice, which certain of their members could have given.

One can only assume the AAIB has left the detemination on the maintenance errors to the Scottish Proscurator Fiscle under the UK's Corporate Killing law.

Sasless

While your last post is well written, your appear to be trying to stimulate a particular reaction :mad: for reasons unrelated to this accident and also do not align with your comments on the pilots and their delayed ditching in Canada.:suspect:

You have also failed :ugh:to take into account that the AAIB recommendation related to not only assessing the EC products against the latest requirement but also a Notice of Proposed amendment that is not yet a rule!

In comparison, one question about the S-92 relate to wether it actually really complies with the certification standards that were current back when Sikorsky applied for certification.

This is made significant as as an unconventional means of compliance was used when the conventionally done test failed.

The other is wether the action Sikorsky took after Broome was sufficiently prompt for a failure Sikorsky had already said would be extremely remote occurred to simple, non moving componets after about 100000 flight hours. :ugh:

The AAIB report deals with a type with 6 million flying hours, that had a failure in a complex rotating component, that AAIB still don't understand, and propagated to fatal failure after the operator neglected to follow a key step in the maintenance process.

HeliComparator

30th Nov 2011, 17:25

Safety Recommendation 2011-036
It is recommended that the European Aviation Safety Agency (EASA) re-evaluate the continued airworthiness of the main rotor gearbox fitted to the AS332 L2 and EC225 helicopters to ensure that it satisfies the requirements of Certification Specification (CS) 29.571 and EASA Notice of Proposed Amendment 2010-06.

What reaction has that provoked? Would EASA remove the Airworthiness Certification of the MGB and force Eurocopter to redesign that component, to include the cockpit warning systems for chip detectors in the Epicyclic module and improve the oil system to better expose oil borne chips to those new detection systems?

It sounds like this situation is not all that different than the Sikorsky S-92 gearbox problems....different symptoms but pretty much a common problem in that the certification standards left users vulnerable to fatal flaws

I could be wrong here but I think the report means that the L2 gearbox met the certification requirements at the time, things have moved on and the current certification requirements may no longer be met. There is nothing wrong with AAIB trying to raise the game a bit, but in terms of the "rules" an aircraft and its systems have to meet the certification requirements in force at the time. When these change, they cannot be retrospective to existing types. So whilst complying with the current standards must be a "good thing", there could surely be no possibility to enforce that and/or remove the certification if it were not done?.

In terms of the epicyclic chip detector on the L2, it would seem fairly easy to install a cockpit warning light, as there is in the 225, since most of the infrastructure is already there.

By contrast, the basis for the S92's gearbox certification to the standard in force at the time of original certification, seems hard to justify.

HC

Edited to say - cross posted with SM

victor papa

30th Nov 2011, 18:41

I am reluctant to post here. Been on the L2 and now the smaller versions. I do not critisize, point finger or wanna upset anyone here. Yes, EC could have designed a even better gearbox that took more than the current fleet hours before this tragedy occured and yes the certification for gearboxes could have been more stringent. If this is referred to a court regarding the engineering action taken or not taken it will make the current sickness in aviation worse! All humans make errors-engineers, pilots, designers, etc. That is why we have systems. My issue is that in one of my fields which is training I more and more see the sickness from all trades of "as long as i can't be blamed"! This results in no decision making, accountability etc and all due possible future prosecution. So we end up in meeting after meeting after meeting resulting in commercial/HR/safety/who ever joining before a decision is made and if ever made it is vague and non-committal. Been there and done that in the offshore industry where a simple decision can have a huge commercial consequence-the question comes back to why is that enforced and allowed to be enforced down to the engineer and/or pilot who has to go to court for their decision when we are no longer in a culture of decisions without meetings. The fact that the gearbox had so many chips is maybe what made the engineer decide what is one more chip-complacency? Human nature? This is a system failure as more than 1 engineer is normally involved in HUMS, chip warnings, correspondence with a OEM etc so who exactly is to blame? How do we select? Blame EC? Blame Bond? Blame the last signature? I dont know Bond procedures but normally a team is involved.

I learned to respect chip warnings. I learned to forget the old school thought of if no part number it is ok to continue. I learned that what becomes the usual will lead to disaster. I learned to respect epicyclics and why EC made that top chip detector on the 350 engineer only territory! I learned to know my type and my types don't have chip warnings unless something is seriously wrong!!!!

Shell Management

30th Nov 2011, 18:55

Yes! Respect chip warnings and respect the manuals!

SASless

30th Nov 2011, 19:43

HC,

The common denominator in the EC/SK MGB issues is the Certifying Authority for each type signed off on the aircraft design. Neither EC or SK could have put the aircraft into production without those approvals.

I am not defending SK or impugning EC when I challenge the criteria used to approve both of the Gearbox designs....but I am definitely challenging the criteria and process that let both be certified.

Then in a similar view....I challenge the systems that allowed each of the accidents to occur. That cuts across multi-national and multi-operator actions and in-actions....and accuses the helicopter Industry (including certifying authorities) of failing itself in the manner in which business is being done currently.

The question I posed...."cancelling the Type Certificate or Approval of the Gearbox" is valid. I know the Rule is as you state...."certified to the standard then existing"...but at some point does not new data and circumstances demand rethinking that Rule and existing Certifications?

If we accept the AAIB findings but do not require EC to make the needed improvements....are we not ensuring another tragedy at some point in the future? The same goes for SK and the Canadian Investigation.

Do you want to climb into an aircraft with the same deficencies as discovered by the AAIB investigation or the Canadian investigation into the 92 crash and do so because they are both legally certified by the government authority?

Of course not.....otherwise why even investigate an accident at all.

Once we identify "bad" designs, bad engineering, inadequate procedures and policies....certainly corrective actions must be demanded.

How we accomplish that is the question....but what is the answer?

Shell Management

30th Nov 2011, 19:53

The common denominator in the EC/SK MGB issues is the Certifying Authority for each type signed off on the aircraft design.

In fact a common denominator of all aircraft is the Certifying Authority for each type signed off on the design.

Though only one Certifying Authority also promotes the industry it regulates. The FAA.

HeliComparator

30th Nov 2011, 20:21

The question I posed...."cancelling the Type Certificate or Approval of the Gearbox" is valid. I know the Rule is as you state...."certified to the standard then existing"...but at some point does not new data and circumstances demand rethinking that Rule and existing Certifications?

If we accept the AAIB findings but do not require EC to make the needed improvements....are we not ensuring another tragedy at some point in the future? The same goes for SK and the Canadian Investigation.

Do you want to climb into an aircraft with the same deficencies as discovered by the AAIB investigation or the Canadian investigation into the 92 crash and do so because they are both legally certified by the government authority?

SAS, I get the feeling that what you are saying is that whenever there is an accident caused by technical failure, the type should have its Type Certificate pulled until the design is modified to a new standard that guarantees the type will never crash again due to that failure.

In an ideal world that might work, but in the current world it would just mean that we take the safest option - ie never fly again.

The certification rules can never require a 100% guarantee that a part cannot fail to cause a catastrophy - only that it is "extremely remote" etc so I am afraid there will always be accidents, just like thousand of times more people will die on the roads, from cancer etc. We are kidding ourselves if we think we should have a society where untimely death is an impossibility.

Of course we should do what we can to reduce such events to "as low as reasonably practicable" but to go any lower starves the human race of any progress or production.

It has to be said that in both of the accidents cropping up in this thread, the accident could probably have been avoided if the existing systems and procedures had been followed correctly, ie as intended by the author. In the case of the L2 by following the correct maintenance procedure, and in the case of the 92 by the crew following the emergency checklist.

It is when you look at the reasons why these actions did not take place correctly, that it gets interesting. It is very hard to pin down onto 1 person (and who would want to do that anyway) since the failings are intrinsic to our current society's values and ways of behaving.

Just like pilots, helicopters invent new ways to crash from time to time. The certification rules help for those accidents we have already thought of (especially if they are properly followed and enforced) but there will always be new accidents (until we invent anti-gravity!), our only realistic goal is to try to prevent the most obvious, predictable and stupid ones!

HC

SASless

30th Nov 2011, 20:54

HC,

You read more into my comment than perhaps you should. I am not saying each time there is an accident, the Type Certificate should be yanked....just when there is discovered clear evidence the existing design is proven to be deficient even if "properly certified" at the time of the issuance of the Type Certificate.

If the standards under which the Type Certificate was issued are insufficient there is no reason why the Certificate should stand.

The critics of the 92 Gearbox are saying exactly the same thing I am....but using different words. They question the criteria and submissions by Sikorsky in meeting the FAA's requirements. Yet....the 92 received its Type Certificate and maintains it yet today despite the events that led up to the Newfoundland crash.

We can agree, I think, that just because a Type Certificate is issued it does not become etched in stone and cannot be withdrawn.

The problem with that, is it will require Certifying Authorities to admit publically they made a mistake by issuing the Type Certiicate in the first place. They may have met the letter of their rules and requirements but at the same time have been in error by missing some critical flaw in the design or method of acheiving approval.

Government never wants to admit a mistake....even when it is patently clear to everyone involved.

maxwelg2

1st Dec 2011, 00:38

Government never wants to admit a mistake....even when it is patently clear to everyone involved.

For me this is a key issue, how many times has there been an engineering oversight e.g. Ford Pinto fuel tanks exploding in crashes that lead to legal action and eventually design improvements? When did the government step in?

If we don't learn from our mistakes we will never move forward. It won't bring back our lost colleagues but at least they won't have died completely in vain.

People need to be held accountable and we need to move on. We should learn from our mistakes otherwise they will happen again.

If legal action is the only way these days we can painfully slowly move design/operational issues forward then the world is truly a very sad place. Whatever happened to pride in building the best machines possible and with enough inherent safety factors & procedures to allow a solid reputation to be established?

Do we need to start enforcing more independent audits to ensure standards & procedures are maintained, IMO this is definitely something that should be looked at. Who audits the auditors?

IMO it's all about cost-effectiveness and the inherent compromise on safety, not enough due diligence by all disciplines.

It's also about all involved in this industry to stand up and voice their concerns collectively so that everybody in the industry is informed of the issues. Reports such as the TSB and AAIB should be the official ammunition to expedite pro-active solutions/improvements. Governments and their regulating bodies need to get with the programme and not just look for more votes at the next election as we have here in Canada right now.

They say that there is no price on safety, I say that's a load of bollocks, there's a price on everything, even people's lives...that's where the as low as reasonably practicable statement comes from, not just from the bounds of current technology.

As technology moves forward so should engineering safety design, not the opposite...

Safe flying

Max

Hilico

10th Apr 2012, 20:21

Friends and colleagues:

Report into G-REDL accident from the AAIB (http://www.aaib.gov.uk/publications/formal_reports/2_2011_g_redl.cfm)

HeliComparator

10th Apr 2012, 21:19

Err, published last November I think you will find?

Hilico

10th Apr 2012, 22:17

My most embarrassed apologies - the date at the top right of that page is today's...and tomorrow, it will be tomorrow's...

jimf671

7th Oct 2013, 16:24

CROWN OFFICE Website.

G-REDL FAI: 6 January 2014

"February 2013 – Contact with Sheriff Principal of Grampian Highland and Islands identifies 28 October 2013 as the date to hold FAI in the council Chambers fixed for the hearing of the FAI. Responsibility for the date and venue of the FAI rests with the Sheriff Principal.

However in June SCS advised they were unable to source suitable accommodation in Aberdeen for an FAI of this magnitude at that time. A new date has now been scheduled for the FAI of 6 January 2014 and it will take place in Aberdeen."

Oldlae

12th Jan 2014, 08:12

Is anyone keeping track of the FAI?

HeliComparator

12th Jan 2014, 16:03

Yes there is a summary in the P&J each day. Nothing too startling yet. The lawyer for the victims families wanted to "fishing trip" by asking to see all tech logs for all Bond's helis but it was declined. I wouldn't like to be the Bond engineers having to account for their decisions.

RByrne

12th Jan 2014, 19:37

STV news have reported on it most days as well.

Engineering 'anomaly' reported in 2009 helicopter crash inquiry | Aberdeen & North | News | STV (http://news.stv.tv/north/259720-engineering-anomaly-reported-in-2009-helicopter-crash-inquiry/)

There are related articles underneath where anyone can catch up with what happened during the first week.

Apparently due to last 6 weeks.

jimf671

13th Jan 2014, 10:22

A few words about FAI.

Here is where the determination will eventually appear.
Sheriff Court (http://www.scotcourts.gov.uk/search-judgments/sheriff-court?type=structured)

This is the guy that will write it.
http://img.thesun.co.uk/aidemitlum/archive/00619/SNA172111-280_619259a.jpg
Known for his abilityto get into the detail. Originally a corporate and commercial solicitor. Sheriff Principal in the North since June 2012.

The investigation is a Crown Office one. Here is what they have to say about their role.
Our role in Investigating Deaths (http://www.copfs.gov.uk/investigating-deaths/our-role-in-investigating-deaths)

The principal players in the Inquiry are the Sheriff, the Procurator fiscal and the Interested Parties. The PF has a lot of control over the format of the Inquiry because the results of the COPFS investigation dictate it. Though the role of the Interested Parties is in some ways limited, any of them may end up uncovering important matters not revealed by the COPFS.

The Sheriff will write the Determination which provides the information required by the Act. It is important to realise that the information in the Determination is restricted to tightly defined results. Much more than this will come out during the course of the presentation of evidence at the FAI.

Fatal Accidents and Sudden Deaths Inquiry (Scotland) Act 1976 (http://www.legislation.gov.uk/ukpga/1976/14/contents)

6 Sheriff’s determination etc.
(1)
(a) where and when the death and any accident resulting in the death took place;
(b) the cause or causes of such death and any accident resulting in the death;
(c) the reasonable precautions, if any, whereby the death and any accident resulting in the death might have been avoided;
(d) the defects, if any, in any system of working which contributed to the death or any accident resulting in the death; and
(e) any other facts which are relevant to the circumstances of the death.