Bristow S76 down in Lagos discussion (Not condolences)

[unstable load]

Reports coming in of a Bristow S76 crash in Lagos, some survivors and some fatals, apparently.

[212man]

Sad news: Helicopter Crashes Into Oworonsoki End Of Lagos Lagoon - Channels Television (http://www.channelstv.com/2015/08/12/helicopter-crashes-into-oworonsoki-end-of-lagos-lagoon/)

[finalchecksplease]

More details here: Four die, two missing in Lagos helicopter crash (https://shar.es/1tlW5v)

[xtremalsound]

Very sad news, There were ten passengers plus two pilots. It looks like a least six dead.... I heard them this morning on the radio going to offshore ....

[UPDATED+Videos] Four die, two missing in Lagos helicopter crash (http://www.punchng.com/news/helicopter-crashes-into-lagos-lagoon/)

[before landing check list]

Do you know who the pilots were?

[tgvbhy15]

Does anybody know who the crew were?
RIP

[SICKorSKI]

http://prod-app-01.bristowgroup.com/_assets/filer/2015/08/12/news_release_2_update_bristow_helicopter_involved_in_acciden t.pdf

[Senior Pilot]

Whilst we all are concerned at the news that the crew perished in this accident, please refrain from speculating with the identities of those who have died until officially released.

The family should be informed first, and not hear via PPRuNe.

[pilot and apprentice]

Agreed SP

Up to now, I have seen no official word about the crew, and continue to hope for the best. Many good friends still there, both P1 and P2.

Just standing by......

[alouette]

Any word about the crew...? Not a good day...:sad:

[DonQuixote23]

Rescue personnel say that they have recovered an additional two bodies bringing the total number to twelve.


Desperately sad news.

[Nescafe]

The crew names have been released. Sad day for all.

Everyone,

It is with tremendous sadness that we now confirm our crew as being among the fatalities from yesterday’s tragic accident.

The crew were Captain Joseph “Jay” Wyatt, age 37, of Oklahoma, and First Officer Peter Bello, age 26, of Nigeria.

Captain Wyatt joined Bristow in 2006 and has spent his entire career flying with Bristow Helicopters out of Africa. First Officer Peter Bello joined Bristow in 2014 after graduating from Bristow Academy’s helicopter flight school. Both were highly respected members of the Bristow family. Their families have been informed and are receiving our fullest support.

We all remain shaken and deeply saddened by this tragic event and our thoughts and prayers go out to the families of all of those on board.

I am so sorry to be the bearer of this news. We will continue to keep you informed as news becomes available.

Kind regards,

Duncan Moore
Regional Director, Africa & Middle East
Bristow Group Inc.


Confidence in flight. Worldwide

[212man]

At least we know the cause now:

According to Vanguard, the Traditional ruler of Oworonsoki, Oba Basiru Oloruntoyin Saliu, who spoke to Vanguard in a telephone conversation said as soon as the incident occurred, said the collapse of traditional rites in the area may be responsible for the crash. He said,


The government no longer pays attention to traditional rites which is necessary to prevent such occurrences. For instance, how many times have we appeased the goddess this year? An occurrence like this may be caused by the goddess because no human being can depict the depth of the lagoon; but if the goddess is appeased, she would have prevented such occurrence.

[Nescafe]

From Wasbu head.

Our thoughts and prayers continue to be with those most directly affected by Wednesday’s tragic events and we continue to focus our efforts on supporting the families in every way that we can.

Meantime, about 1 ½ hours ago, I can report that the cockpit voice / flight data recorder from the aircraft was recovered and handed over to the AIB for analysis.

We will continue to keep you updated as facts become available to us.

[cyclic]

My sympathies to all involved. Had this happened on the North Sea this thread would be pages long by now. I don't know what that says about us as aviators or the industry we work for.

[TIMTS]

Pretty sure the reason for the brevity of this thread is that if the ones of us who worked there, or still work there, posted what we think about what happened it would be, or already has been, banned.

This is what happens when policy and political correctness overrides common sense and learning from the past...

[DOUBLE BOGEY]

Or maybe out of respect and the postings from the Bristows Manager people are just waiting for information.

[ramos]

Some things have already been posted and deleted. I personally made a few remarks out of sadness and the loss of a good friend which were chopped and I under stand why.

It is a time to remember the guys we have lost and treat their passing with respect.

There is going to be plenty of time to point fingers, speculate, blame and so on!

As hard as I find it to hold my tongue I respect this time for my good friend! But however look forward to the fiasco that will follow this in possibly another thread.

BHNL are in the :mad::mad::mad:t and they know it.

Focker out for now!

[pilonrock]

The cause cannot be hidden. The cause will determined to be either mechanical or human error. Now if it mechanical BATS is on the hook. Do you suppose that Bristow/BATS will shove their silly little helmet rule join the rest of the world and allow pilots to pull cowling and give the thing a proper look over in the morning before strapping and in and going... I doubt it! At least there could have been a second look. Maybe something got missed.... JOIN THE HELICOPTER INDUSTRY.

Why not invite in the NTSB to have a look... what's the harm in that?

Very sad for the family, way too young to go.

[Nescafe]

Maybe the company should stop accepting flights in IMC on VFR plans/reserves?

[Copterline 103]

No surprise, it took ten years and two days from Copterline flight 103 accidents.
This did not come as a new issue after at least not to the manufacturer.
Transportation category helicopter can not come unflyable with any single failure.
This design defect is known to everyone if you just want to look the truth in the eye.
I'm sorry that once again innocent people were lost.

[before landing check list]

Piloteock, are you serious? I have never heard of that policy before. (Not being able to open cowlings) what is the reasoning behind this? Is somebody afraid that a well trained pilot does not know how to close a,cowling or is somebody afraid a pilot may find questionable practices? I too am flying in Nigeria, (does not matter where really) however I will always look. It is just the proffesional thing to do. By the way, I have been flying since 1974. I always look.

[helialan]

Does anyone have the weather from the time of the incident?

[Copterline 103]

Sa 12/08/2015 16:00-> metar dnmm 121600z 20008kt 160v250 9999 sct012 28/22 q1014 nosig=

sa 12/08/2015 15:00-> metar dnmm 121500z 21011kt 150v270 9999 bkn012 28/22 q1014 nosig=

sa 12/08/2015 14:00-> metar dnmm 121400z 20008kt 160v250 9999 bkn012 29/22 q1015 nosig=

sa 12/08/2015 13:00-> metar dnmm 121300z 20005kt 150v260 9999 bkn012 few020cb 28/23 q1016 nosig=

[TukTuk BoomBoom]

Pilonrock..
Actually it's the other way around. Most pilots couldn't be bothered looking in the cowls when I was there. I also never once saw a pilot on the cabin roof of even a 412 where there's lots of access and space to stand.
How many Bristow pilots did a walk around after the flight? None, never saw one.
It's assumed to be an engineering task
That's been my general experience too, the larger the helicopter the less pilots look it over.

[pilonrock]

I agree with Nescafe 100% this business of flying in IMC condition on a VFR flight plan must stop immediately. There is no way that this would fly in any other part of the world ! so why Nigeria?

In the morning or at shift change cowlings are left open by engineering so the pilot can climb around and have a look. then engineering can close it up . This is the way its done every other place I have worked with twins.

It is not a military operation, it is a civil operation and should begin adoptng the practices that civil operators have developed to promote safety.

There is a lot of target zero lip service but very little target zero action.

In addition a pilot should be able to land on any deck he wishes if he suspects there is a mechanical or safety issue with his aircraft.( without any repercussions) The culture now that is engrained is a fear of a wrong deck landing and loosing your job. .

After almost 28 years in this business i have never seen seen such stupidity.

2 friends gone! Action is required! the bull**** stops here!

[Copterline 103]

Pilonrock ,
The fear of the wrong deck landing and its consequences is probably due to the rig’s strict insurance policy and condition requirements. The rig’s Hull insurances are not valid if each fire fighting stations are not manned, as well as fire fighting system has not been fully pressurized for immediate fire fighting response.
If a helicopter lands on the wrong deck then immediate fire fighting and immediate rescue service does not exist. In this case, the rig’s Hull insurance coverage does not exist at all. This is the reason why this is almost larger issue than life thing. This is Underwriter’s mandatory requirement (fully established immediate fire fighting and rescue response).

[DOUBLE BOGEY]

I think you boys need to calm down. The Pilots job is to fly the helicopter not service or maintain it. With a large rotorcraft, quite apart from the risks of falling off it from a height out on the apron, there is more risk associated with a pilot leaving catches insecure than benefit to be gained from climbing all over it.

If you worry about looking under the cowling why not check torque each bolt to make sure the engineers have not made a mistake. Why not confirm every piece of wire locking? Why not check the correct oil has been used. The list is endless and far surpasses what the pilot can see during his tactile acceptance.

Bottom line, if you trust your engineers there should be very little to worry about.if you don't trust the.............reach the the torque wrench.

Pilonrock, there is a world of difference between a wrong deck landing and an emergency landing! Where are you dreaming this stuff up?

[pilonrock]

Well I'll tell ya perhaps if they could get the C check right specially bad rigging that came out of Lagos I would be less concerned . I asked to have cowls opened once . The amount of oil leaking from said component was definitely beyond limits and I have also seen lock wire out in backwards before ( wrong direction) . Trusting the engineer is one thing trusting the policy and the pushers at the top is another . There is no harm in leaving the cowls open for a little look around if even to be sure that tool control is working. When I asked why the seal wasn't replaced on said leaving component - no parts!!

As far as the human brain us concerned instilling a culture of fear can at desperate times lead to irrational decisions . Human factors muchachos!

Pilot/Engineer.

[pilonrock]

All true chopper line ! But really if I'm running out of fuel or have a concern for the AC I wouldn't think twice about landing anywhere the concerns about insurance are secondary. I just don't think Bristows attitude on many levels supports safety. One guy falls and bumps his head and sustains injury and everyone is wearing helmets ! 6 people die and instead of fast rule changes that would prevent more loss of life it will be same old same old. There will be no changes if it effects the bottom line. Let's hope it's the complete opposite and the loss of Jay and Bello and the passengers on board effects change for the betterment of safety for all future operations. I hope and pray that the mgmt in Lagos gets their head out if their ass and effects change fast!



Pilonrock ,
The fear of the wrong deck landing and its consequences is probably due to the rig’s strict insurance policy and condition requirements. The rig’s Hull insurances are not valid if each fire fighting stations are not manned, as well as fire fighting system has not been fully pressurized for immediate fire fighting response.
If a helicopter lands on the wrong deck then immediate fire fighting and immediate rescue service does not exist. In this case, the rig’s Hull insurance coverage does not exist at all. This is the reason why this is almost larger issue than life thing. This is Underwriter’s mandatory requirement (fully established immediate fire fighting and rescue response).

[Dragoon52]

You sound a bit arrogant. I used to climb every flight while I was there. Be reasonable in your comments please.

[Jimny]

I think you boys need to calm down. The Pilots job is to fly the helicopter not service or maintain it. With a large rotorcraft, quite apart from the risks of falling off it from a height out on the apron, there is more risk associated with a pilot leaving catches insecure than benefit to be gained from climbing all over it.

If you worry about looking under the cowling why not check torque each bolt to make sure the engineers have not made a mistake. Why not confirm every piece of wire locking? Why not check the correct oil has been used. The list is endless and far surpasses what the pilot can see during his tactile acceptance.

Bottom line, if you trust your engineers there should be very little to worry about.if you don't trust the.............reach the the torque wrench.Trust doesn't mean you can't double check. Engineers (and pilots) have bad days, difficult mornings and whatnot. Even on larger aircraft: why not just have a look? We're not talking about redoing the engineers' job, just making sure you're safe!
I work on a medium twin on aerial work ops and somehow the only pilots that have problems on the job are those who don't do a walk around of the AC. When they come back from the fire/sling job whatever they always blame the engineers and it always turn out that if they had had a look instead of just sitting their asses in the aircraft (not even checking oil levels, you don't need to climb anywhere for these), they'd have been alright.

It's only 5 to 15 minutes of your time, isn't it worth it? Double check the cowlings on the way down.

Hopefully lack of preflight won't be the issue here, I just read they've found the flight recorders so I guess it's just a matter of time before a report gets out.

My thoughts to those concerned, it's always a tragedy.

[tistisnot]

Jimny, I am sure DB does a walk-around every flight .... he just doesn't climb up on top to re-open cowlings that have already been opened the previous day's post flight, and again in the morning and signed for by a qualified engineer. Sounds like he was in an Air Force - you know where the orficers job was just to wiggle the sticks, don't you know!

I was a grunt and so clambered on top for years; but after quite some time in established civilian offshore companies, and with age .... I see no point in placing myself as well at risk - and have every confidence in the safety systems procedures that now permit this - whilst I am at a base with maintenance personnel.

[tgvbhy15]

May the souls of Jay, Peter and the 4 passengers rest in peace. This could not happened to a nicer couple of guys. They both were a huge asset for Bristow and, I'm sure, their families. Rest in peace.

It is nice to see a healthy discussion for a change without personal insults and attacks. The only fact I can say is that the only thing that is truly Bristow about Bristow Nigeria's operation is the colour scheme and company name on their helicopters. Everything else is pretty much different. They try to copy a few things here and there from what's done in the NS but even those are different. I have worked for Bristow in both places and I can tell you this is a fact. If you took away the common colour scheme and company name in all the helis (both in Nigeria and the NS) you definitely would not feel like you were flying for the same operator. Although Bristow's brochure says One Company One World, nothing is further from the truth. The way day to day operations are carried out in Nigeria is nothing like the way things are done in the NS.
Maybe they can use the "one world" bit in their brochure to join the Oneworld alliance. Maybe then I would be able to increase my FF miles and join the platinum card status!! 😃

[Nescafe]

The only fact I can say is that the only thing that is truly Bristow about Bristow Nigeria's operation is the colour scheme and company name on their helicopters. Everything else is pretty much different. They try to copy a few things here and there from what's done in the NS but even those are different. I have worked for Bristow in both places and I can tell you this is a fact. If you took away the common colour scheme and company name in all the helis (both in Nigeria and the NS) you definitely would not feel like you were flying for the same operator.

Bristow Nigeria summed up in one paragraph. Bravo :D

[ericferret]

I have to say that I am a little baffled by some of the comments in respect of pre flight inspections. I can't work out how they relate to the accident in question.

Sticking to the S76, what good does looking solely under the engine cowling do? The most likely area for trouble to develop that would really spoil your day would be under the main transmission fairing, after all you have two engines. A loose article in this area could be catastrophic. I would happily lend any pilot who wanted to inspect this area a screwdriver with which to take out the umpteen screws that hold the fairing providing he is going to put them all back in again. The access panels provided give a very restricted view of the area.

The dangers of climbing onto the top of the 76 should not be dismissed. The walkway areas on either side of the aircraft are small and curved, even with non slip paint they can be lethal when wet.
In recent times at least one enginer has been killed in a fall from the top of a helicopter.
Do we want to expose crews to this possibilty?

Like most things in life there has to be a balance between safety and practicality.
The pilots have a preflight inspection schedule and should stick to it. If unhappy get it changed.

As one senior member of staff was heard to say on a very foggy day with the hangar full of aircraft, "that is what I like to see 100% safety"!!!!

[DOUBLE BOGEY]

Ericferret I agree with you completely. I think we have to trust each other to do our respective roles. I have never had a engineer flying with us who has asked to check my planning.

In offshore operations the less the pilots interfere under the cowlings the better. We do a walk round which is really to check all cowlings, doors and fuel caps are secure, blanks removed and no obvious bits missing.

Climbing on top of a puma on an Aberdeen winters day is akin to mountaineering and best left to the engineers.

I am more surprised at the anger directed towards the Operator when as yet, no cause has been intimated.

[DOUBLE BOGEY]

Tistisnot - Commissioned Army Officer so I was so not nearly as bad as a Crab! We had a man to do most of the tough stuff lest we break a finger nail or miss Tiffin in the mess!

Still I was the one digging a shell scrape and sleeping under my basha while you "Grunts" cuddled up in the SQMS Four-Tonner! AAC Grunts were not like real Grunts. I standby for the incoming!

[Copterline 103]

Pilonrock,
Something has gone terribly wrong if one reason or another running out fuel threats. Running out of fuel activates “Fuel emergency” and fuel emergency radio call is needed.
There are reasons to think there is any there sense to fly IMC conditions using VMC planning and reserves?
If the case is a helicopter mechanical failure then should Mayday, Mayday message to be sent to the ATC and to inform the nearest Deck/HLO that helicopter X is going make emergency landing on your deck at xx minutes from now.
Wrong deck landing is most likely happen when crew is not following SOP’s to verify deck or vessel name before making committing call out. This is the most likely this root cause for Wrong deck landings what should be taken account company SMS and recurrent training (following SOP and usage of check lists).
You have to remember that there may be a defect that is not the company or technician known, but will lead to unpredictably situation where helicopter will come unflyable.

FAR 29 requires a Transportation Category helicopter as follows:

FAR 29.695 Power boost and power-operated control system.
(a) If a power boost or power-operated control system is used, an alternate system must be immediately available that allows continued safe flight and landing in the event of-
(1) Any single failure in the power portion of the system; or
(2) The failure of all engines.
(b) Each alternate system may be a duplicate power portion or a manually operated mechanical system. The power portion includes the power source (such as hydraulic pumps), and such items as valves, lines, and actuators.
(c) The failure of mechanical parts (such as piston rods and links), and the jamming of power cylinders must be considered unless they are extremely improbable

FAR 29.181 Dynamic stability: Category A rotorcraft.
Any short-period oscillation occurring at any speed from VY to VNE must be positively damped with the primary flight controls free and in a fixed position.

I know what I’m writing!

[tasspook]

senior management is that seem to be happy to let certain operations get run locally without too much influence from outside, something that has lead to these operations becoming insular rather than integral parts of theApologies for the slight thread drift and in no way intending to marginalize the tragic loss of life in this terrible event, the above quotation applies equally to CHC.......the utter disconnect between Dallas and say an AOC holder like the one they partner with in Thailand is just shameful. No protection for crews, be they engineering or pilots, local management wannabes running roughshod over the regulations.....the list goes on.

Hopefully those that perished in this accident were not victims of local management cutting corners.

[N Arslow]

Are people on here just looking for an excuse to vent? I would say this is the wrong thread to do so. It seems more about the loss of two well liked and respected colleagues. Speculation, however couched in a round-about fashion, seems inappropriate to this thread.

No belittling of points being made but at this stage not too many seem relevant to this sad accident, certainly at this moment. Start some other threads and get things off your chest there.

Jay will have signed out the aircraft and would have expected to sign it back in - just as most of us do each day wherever we are, and despite all the whinges posted on PPRuNe.

Rest in peace, Jay - and also to those I did not know as well.

[tasspook]

No venting going on here Mr. Arslow, just an observation of cold, hard truth and that truth is corners are cut in all too many places in the helicopter world. Ideally the investigation into this accident will be timely, thorough and devoid of meddling or undue influence from parties who may have something to hide.

[FLYDHC8]

N Arslow is spot on, nothing to show that this accident was caused by management cutting corners or anything else for that matter. Let's wait till we get to know what actually happened.

[Jimny]

Jimny, I am sure DB does a walk-around every flight .... he just doesn't climb up on top to re-open cowlings that have already been opened the previous day's post flight, and again in the morning and signed for by a qualified engineerOk fair enough, I came in a bit strong and as DB mentioned later on, I am not saying you should reopen everything again. But since I've actually seen a lot of older pilots just go straight to the pilot seat without even checking if the aircraft is still tied down I guess I'm a bit traumatised.

I have to say that I am a little baffled by some of the comments in respect of pre flight inspections. I can't work out how they relate to the accident in question.Nobody said it did, the subject wass brought up and a small discussion arose from it.

I sincerly hope they find the cause to the accident soon.

Unfortunately I lost the link to the newspapper mentioning it but there was an article about witnesses in a nearby village seing the helicopter trying to land (or at least it seemed so to them) on roof tops before opting for ditching. Don't know how reliable the info is thou.

[flyer43]

I wouldn't hold you breath regarding eye witness reports! The majority of these tend to be embelished for the media and are far from accurate representations of what actually happened.

Whilst some of the comments on this thread are worrying if they are true, let's all show respect the lives that have sadly been lost and not continue any speculation. Wait for the officical report!

[Fareastdriver]

Kick the tyres; light the fires. Worked for me for forty-eight years.

[chuks]

Nigerian eyewitness reports are only useful as a gauge of how imaginative your average Nigerian can be.

There was a report once of a missing 727 having been seen "hovering" over Murtala Muhammed Airport by some prominent God-botherer, and it was repeated so, verbatim, in the local papers. In fact, the aircraft had never got near the airport, crashing into a lagoon some miles away.

[jesusnutt]

To which Oil Co was the 76 on contract?

[HeliComparator]

Jay will have signed out the aircraft and would have expected to sign it back in

That's funny, I have been a pilot in the industry for 35 years, captain for 30, and never ever signed an aircraft out. But then I suppose I don't have "still in the military" disease.

[minigundiplomat]

Clearly not.

Just an inferiority complex.

[Copterline 103]

Given by eyewitnesses statements should be treated with caution.
Trusted from information seems to a loud bang sound and helicopter spinning before hitting the water with M/R RPM zero or almost zero..
The best source of information is the FDR which explains in detail where it all began and where it all ended.
In my assessment, the FDR will indicate that the cyclic has become fully aft position, collective has risen to max top position within one second.
No warning or caution has existed when the situation has started. The first warning probably had been a low M/R RPM. This is due to the fact that the helicopter nose will rise up to 60 degrees (stalling and making a banging sound), banking 50 degrees to the left. Cruising speed 140 kts to zero will be lost in a second. Flight controls are stuck by one servo actuator which is stuck in fully extended position. (Sikorsky’s flight controls system has mechanical mixing unit. This mixing unit will reduce pilots work load by mechanical compensation to peals when the collective will be increased or decreased). When the collective is in a fully up position the helicopter mixing unit mechanically makes compensation and will put left pedal almost max left position (causing spinning to the left after helicopter has lost its airspeed).
The reason why helicopter is losing its M/R RPM it is most likely due to collective position which remains max up position due to 3500 PSI hydraulic pressure. Even both of Turbomeca’s ARRIEL 2S1 engines are in “fly-away emergency power” but engines don’t have enough power to maintain MR RPM due to collective remains in max up position. The crew doesn’t have any possibility to fight against 3500 PSI hydraulic power which is over controlling all controls keeping cyclic in full aft, collective max up and mixing unit is compensating collective position by taking left pedal almost fully down.
All this causes the Servo Actuator piston’s chipped plasma coating what will block Servo Actuator’s C3 return port (fluid) or both of C3 return ports. Servo Actuator system or system design does not recognize that the Servo Actuator has failed and there is not any auto function which will release affected servo channel. Servo Actuator’s design can’t recognize that servo actuator has failed and the whole Servo Actuator unit (two independent Servo Actuators) is out of control. During this situation there is no any Servo related cautions or warnings. This single defect will cause that the helicopter will be immediately unflyable.
It is clear that the transportation category’s helicopter type certification requirements requires that any single defect (e.g. chipping of the plasma coating) wouldn’t drop any offshore approved transportation category helicopter down. That's what has happened to us 10th August, 2005. Our helicopter s/n was 760512 (made 28 units before that Bristow’s s/n 760540). All information what I have received are supporting theory that “the most likely” this will be also the case in Lagos.
FDR's data will tell immediately what has happened.

In our accident August 10th, 2005 we lost 14 innocent lives.

[212man]

Copterline, 'your' accident came quickly to mind when I heard of the initial witness reports, but please try and add credibility to your posts by getting the facts correct!
S76 hydraulic system is 3000psi, not 3500
The Copterline aircraft hit the water with 70+% Nr from about 5 times the altitude of 5N-BGN, so clearly this failure will not have resulted in zero Nr!


Given by eyewitnesses statements should be treated with caution.
Trusted from information seems to a loud bang sound and helicopter spinning before hitting the water with M/R RPM zero or almost zero..
The best source of information is the FDR which explains in detail where it all began and where it all ended.
In my assessment, the FDR will indicate that the cyclic has become fully aft position, collective has risen to max top position within one second.
No warning or caution has existed when the situation has started. The first warning probably had been a low M/R RPM. This is due to the fact that the helicopter nose will rise up to 60 degrees (stalling and making a banging sound), banking 50 degrees to the left. Cruising speed 140 kts to zero will be lost in a second. Flight controls are stuck by one servo actuator which is stuck in fully extended position. (Sikorsky’s flight controls system has mechanical mixing unit. This mixing unit will reduce pilots work load by mechanical compensation to peals when the collective will be increased or decreased). When the collective is in a fully up position the helicopter mixing unit mechanically makes compensation and will put left pedal almost max left position (causing spinning to the left after helicopter has lost its airspeed).
The reason why helicopter is losing its M/R RPM it is most likely due to collective position which remains max up position due to 3500 PSI hydraulic pressure. Even both of Turbomeca’s ARRIEL 2S1 engines are in “fly-away emergency power” but engines don’t have enough power to maintain MR RPM due to collective remains in max up position. The crew doesn’t have any possibility to fight against 3500 PSI hydraulic power which is over controlling all controls keeping cyclic in full aft, collective max up and mixing unit is compensating collective position by taking left pedal almost fully down.
All this causes the Servo Actuator piston’s chipped plasma coating what will block Servo Actuator’s C3 return port (fluid) or both of C3 return ports. Servo Actuator system or system design does not recognize that the Servo Actuator has failed and there is not any auto function which will release affected servo channel. Servo Actuator’s design can’t recognize that servo actuator has failed and the whole Servo Actuator unit (two independent Servo Actuators) is out of control. During this situation there is no any Servo related cautions or warnings. This single defect will cause that the helicopter will be immediately unflyable.
It is clear that the transportation category’s helicopter type certification requirements requires that any single defect (e.g. chipping of the plasma coating) wouldn’t drop any offshore approved transportation category helicopter down. That's what has happened to us 10th August, 2005. Our helicopter s/n was 760512 (made 28 units before that Bristow’s s/n 760540). All information what I have received are supporting theory that “the most likely” this will be also the case in Lagos.
FDR's data will tell immediately what has happened.

In our accident August 10th, 2005 we lost 14 innocent lives.

[cpt]

..... but if I remenber well, in the "Baltic sea case" there had been previous signs of an anomaly in the hydraulic system .... an uncommonly darker color of the hydraulic oil had been noticed, and a pilot returning from a technical flight reported having felt a very brief temporary blocking in the collective pitch without any other sign.

[n1tut]

I have only just heard of the crash from this Forum six days after the accident, and saw no mention of it on the news in the UK. I flew 17 years for Bristow on the North Sea from Aberdeen, 13 of them on the S76.

However I am now 75 and was medically retired in 1993, so none of my colleagues are still flying. Although I did not know the two pilots my thoughts go to their family and friends, I had many nasty moments myself over the years, even more so during my seven years flying in the War in Oman, so count myself fortunate to have survived to retirement.

Cheers

David Duncan

[tistisnot]

Moderators, please - Ramos has a valid point.

Is it not time to set up a public / group Facebook In Memoriam page where people could express their condolences, thoughts about crews / individuals whether death by natural causes or otherwise - instead of the families trawling through the immediate reportings and speculation here on the Rumour Network?

People would then be probably posting with their real names, instead of the anonymity many prefer here on this site?




A separate thread for condolences is here (http://www.pprune.org/rotorheads/566377-bristow-lagos-fatal-condolence-thread.html)

Splot

[Variable Load]

Until the course of the Bristow Nigeria accident is known, the Copterline accident is irrelevant to this thread and was well covered a long time ago in this forum.

Copterline 103 - if you want to discuss the OH-HCI accident please start another thread :rolleyes:

[terminus mos]

I am very sorry for everyone affected by this accident. I won't pray for anyone because it doesn't work and I am an atheist.

PPrune forums, threads and posts have always been about expressing one's sympathies if one so wishes. But they have also been about speculation and rumour. We are Pilots, we are directly linked if not directly affected. Speculation is normal, occupies many crew room conversations and will always happen.

To try to shut it down here and limit threads and posts to condolences would stop many people reading PPrune.

[Boudreaux Bob]

I distinctly recall a Bristow Pilot who always said the following Prayer just before hitting the Start Button.

"Oh Lord, Please forgive me for flying this Bell Built, Bristow Maintained, piece of ****!".

He is happily retired now.

I would suggest that is real evidence that Prayer does work.

[Grunt92]

Gentlemen, especialy, copterline 103, please do not speculate on previous accidents, after reading , Cl 103 ,s biblical speal, i realise he doesnt really know the S76 hydraulic and rigging system, leave that to the certified engineers, also please wait until the results of the invesigations are disclosed.
If at anytime , one of my pilots have wanted a cowling or panel opened I have always been willing to do this, and then ensured it was secured, as I had signed ,the pre flight inspection, and have always been part of a good and safe Flying and Engineering TEAM.
Engineers have coverals and opposing thumbs to climb around , pilots have sloppy links to fly with. Sad this has happened.
Safe landing to all.

[pilot and apprentice]

One of the concerns is that, given where the accident happened, there may never be a true and full accounting of what really happened. We will see. I hope so. Unfortunately what I have seen happen before instills little confidence. (No, not a complete stab at Nigeria. The outside parties have been just as happy to let the truth die a whimpering death as any in country)

=========

Has there been any word put out at all? Even a very basic preliminary report would normally be released by now, would it not?

[RVDT]

The assumption is that this AD is related -

FAA AD 2015-19-51

DATE: September 14, 2015 AD #: 2015-19-51
AIRWORTHINESS DIRECTIVE Aircraft Safety Alerts (http://www.faa.gov/aircraft/safety/alerts/)
www.gpoaccess.gov/fr/advanced.html
This emergency airworthiness directive (EAD) 2015-19-51 is being sent to owners and operators of Sikorsky Aircraft Corporation Model S-76A, S-76B, S-76C, and S-76D helicopters.
Background
This EAD was prompted by an accident of a Sikorsky Aircraft Corporation Model S-76C helicopter. During preliminary investigation, a failed servo input control pushrod (pushrod) assembly was identified. Separation of the pushrod tube and the control rod end with bearing was found. This EAD requires inspecting the main rotor (M/R) forward, aft, and lateral pushrod assemblies, the tail rotor (T/R) pushrod assembly, and the jamnuts, and applying slippage marks across the pushrod tubes and jamnuts. These EAD actions are intended to prevent loss of M/R or T/R flight control and subsequent loss of control of the helicopter.
FAA’s Determination
We are issuing this EAD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs.
Related Service Information
Sikorsky issued Alert Service Bulletin No. 76-67-57, Basic Issue, dated September 10, 2015 (ASB), which specifies a one-time inspection of the M/R forward, aft, and lateral pushrod assemblies, the T/R pushrod assembly, and the jamnuts for proper installation, condition, and security. If a pushrod or jamnut does not meet criteria specified in the inspection, the ASB specifies replacing the assembly. The ASB also specifies applying two slippage marks across each M/R and T/R pushrod tube and jamnut. Further, the ASB references the applicable maintenance manual for a new recurring inspection of the slippage marks.
EAD Requirements
This EAD requires, within five hours time-in-service, inspecting each M/R and T/R pushrod assembly by inspecting the position of the control rod end in the pushrod tube. If the lockwire passes through the inspection hole, this EAD requires replacing the pushrod assembly. If the lockwire does not pass through the inspection hole, this EAD requires inspecting the jamnut to determine seating position against the pushrod and whether the jamnut can be turned with finger pressure. If the jamnut is not seated against the pushrod or is loose, this EAD requires replacing the pushrod assembly. This EAD also requires, both for those pushrod assemblies that are replaced and for those that pass the inspections, applying two slippage marks across each M/R and T/R pushrod tube and jamnut.

[Copterline 103]

This was not a surprise that the Servo Actuator is once again part of the accident cause.
The next step should be that investigators will find out which is the real reason why Rod End breaks down. It’s pretty obvious that there is another reason is behind this fail of Rod End.
Most likely the failed Rod End is a consequence not a cause of the accident.

[twisted wrench]

In following the requirements of the ASB the main focus is on the jam nut that secures the rod end, inspection is to make sure is tight and if found loose. The push rod assembly is removed and replaced with a new part that is assembled correctly.


The ASB also requires the jam nuts to be marked so that on future inspection can see if the nut has slipped ( moved ) .

[Helinaut]

The preliminary inspection and in turn this Emergency Airworthiness Directive points straight to the cause of the accident and in turn to maintenance. This may sound harsh but be your own judge on this one.

The procedure to be carried out, as prescribed in the EAD is a very basic one and every aircraft mechanic is supposed to do it while checking and or making adjustments on the rod end / push rod. :ugh:

The two parts separated, so some one did not do the job. Very sad story.

[Ainippe]

It is not proven or a correct assumption some one did not do their job unless you know something you should'nt?
Conjecture is not the correct way to come to the reasons for an accident.

[Helinaut]

Ainippe

This is from the EAD;

During preliminary investigation, a failed servo input control pushrod (pushrod) assembly was identified. Separation of the pushrod tube and the control rod end with bearing was found.

This EAD requires, within five hours time-in-service, inspecting each M/R and T/R pushrod assembly by inspecting the position of the control rod end in the pushrod tube. If the lockwire passes through the inspection hole, this EAD requires replacing the pushrod assembly. If the lockwire does not pass through the inspection hole, this EAD requires inspecting the jamnut to determine seating position against the pushrod and whether the jamnut can be turned with finger pressure.

Talk to any certified engineer and he will explain to you what happened or why the separation did occur. This is not a faulty part, otherwise the parts would have to be replaced and not like in this case, inspected for correct assembly.

[Copterline 103]

Separation of the pushrod tube and the control rod end with bearing was found.

Is the bolt just disappeared or has the bolt been cut? Servo Actuator defect could make a kickback affect to all flight controls. In case of kickback 3000 PSI working pressure will moves stick full aft position and collective will come max up position. When collective is fully up position Sikorsky’s mixing unit mechanical connection will make left pedal mechanically about 50 % left down position. This left down 50 % makes left spinning after the helicopter has lost airspeed.
A possibility for the lost bolt could be this hydraulic system kickback affect which has cut the bolt which is connecting the pushrod tube and the control rod end? Any picture available?

[RVDT]

Copterline,

Go back and read the text - it has NOTHING to do with the bolt in the rod end.

Show us where a bolt is mentioned.

The rod end has separated from the control rod.

[Ainippe]

Dear Helinaut,

be careful what you say - I have been a licensed S76 engineer since 1994 and a practising LAE since 1980, I do not need lessons from you on how to read an incident report.

Has the item you are referring to actually been identified and confirmed as causing the accident?

[ericferret]

This is a emergency AD. It is early days and as it says it is interim action as the investigation is ongoing. So no defined reason for the incident and this is a holding action to ensure safety.

Possible causes could be a manufacturing issue or miss-assembly. I would wait for the final report.

[malabo]

Can someone post a picture of the rod /rod end in question.

https://c2.staticflickr.com/4/3068/3129307969_dcd291490d.jpg

[RVDT]

CAUTION: GENERIC EXAMPLE

http://apachehelicopter.tpub.com/TM-1-1520-238-23-7-1/img/TM-1-1520-238-23-7-1_40_2.jpg

Generic Installation

Adjustment.
(a)Adjust rod end bearing on rod.

(1) Hold rod end bearing in position.
(2) Hold fixed nut.
(3) Tighten nut against key washer.
(4) Ensure that rod end position has not been disturbed.

b. Check for proper thread engagement by attempting to insert wire in witness hole.

(1) If wire can be inserted in witness hole, thread engagement is not correct. Use wire.
(2) Check for correct parts and adjust push-pullrod during rigging procedure.
(3) If wire cannot be inserted in witness hole, thread engagement is correct.
(4) Lockwire nut to keywasher
(5). Use wire.

c. Inspect (QA).

d. Perform rig check on collective, directional,lateral, or longitudinal flight control system,as required.

[S76 wizard]

If this happened in flight it is amazing there are survivors. My speculation is that when they rigged the input they misread the tape measure and made this an inch longer than it should be and then compensated by adjusting the pitch links to bring it in rig. The problem is that too much maintenance gets done to helicopters by engineers that don't have enough experience on type.

[bluesafari]

Eric, I agree with you completely.

Just some information, I read the EAD to refer to the servo input rods, both main rotor and tail servo inputs. Having looked at the S76A i.p.c. 67-15-00, it seems to me that for the adjustable rod end to disconnect from the tube one of the bolts would have to be removed, as the other rod end is rivetted to the tube. If both rod ends were threaded (l.h. and r.h. threads) and both of the lock nuts were loose and not locked then the rod could have could have lost a rod end, on the servo rods only one end is adjustable. There is, of course, a chance that the rod end itself has failed on the threaded part. I await comment from a current S76 L.A.E.

[bluesafari]

S76 Wizard,
I believe that if these rods were that far out of adjustment they could not have been fitted. The servo input rods are not very long at all, The tail rod is about 5 inches long and the mains about 7 or 8 inches, if my memory serves ! Perhaps someone current can confirm that.

[Copterline 103]

Bluesafari,

The Baltic Sea S76C+ accident factual findings were:

Due to blockage of C3 return port (by plasma flakes) the Servo Actuator came fully extended. The Control Stick came full aft and collective vent full (max) up position, right pedal vent full down.

The flight crew were able to recognize that it was an emergency situation, but could not identify what the emergency was and why the helicopter was responding the way it was.

The helicopter come unflyable but the crew tried to fight against stuck flight controls. During this 37 seconds the helicopter made 13 spirals to the right...

Finding 1.
A plastic cover for the engine power control switch had separated from pilot’s collective control handle.

Finding 2.
The rod (tube) under the cockpit floor that connected the pilot’s and the co-pilot’s cyclic controls was broken

Finding 3.
The cyclic control stick on the right side (pilot) was bent slightly forward near the floor.

I have heard more than 30 times together with the accident investigator the CVR recording of COPTERLINE 103.The crew was fighting 37 seconds against stuck flight controls.

Our crew was able to bent the cyclic control stick forward, broke the Rod Tube which is connecting pilot and co-pilot controls and the captain broke the plastic cover for pilot’s collective control handle when he was fighting against fully up standing collective.

It is possible and more likely that the Crew of Lagos S76C+ has broke this Control Rod end by the power what they had on hands and legs. The Rod tube and the Rod end should be fail safe but not designed for dying men's (the crew) adrenaline boosted fighting power.

Do not blame technicians or pilots!

[S76 wizard]

Blue safari
You might be right about not being able to fit it. I had an old style input in my tool box and the difference from the way this one came out of the aircraft and from where the rod end can come out is 1 inch. I know in the mm it says to adjust the input to a nominal length when doing a rig.

[Kor6e]

Copterline 103, can you provide more details? Why haven't the interim report finished yet?

[S76 wizard]

Blue safari
You can fit it. But it would take a lot of work to make it not right.if that makes sense. So I don't think this was the case. I guess we will find out soon.

[500e]

Kor6e
Is this what you are looking for
http://www.turvallisuustutkinta.fi/material/attachments/otkes/tutkintaselostukset/en/ilmailuonnettomuuksientutkinta/2005/b42005l_tutkintaselostus/b42005l_tutkintaselostus.pdf

[cpt]

Hello Copterline,

Is there an evidence that the control rod linking the pilot's and copilot's cyclics have actually been broken by the crew's only physical strength rather than by the force of impact ?
Couldn't this be detected on the FDR, as a discrepancy between the actions on the cyclic and the rotor (swachplate) response ? (actually, I can't check here, where the cyclic positions are recorded, maybe at the transducers ? )

[The Sultan]

Cot

On a non-fly by wire aircraft with crew linked controls you are required only to measure one control/response.

The Sultan

[Copterline 103]

cpt ,
CVR was explaining what was on going in our accident. Flight Controls were stuck and the crew was fighting and making all the efforts to get these stuck controls to move.

The crew broke the top of collective when the captain was trying to got fully (max) up position standing collective down. Also the crew was using all available hand power to move cyclic stick. Pilot’s side cyclic stick was bended forward. The connecting Rod (connecting pilot and co-pilots controls was separated (the tube and the Rod end).

The design of the flight controls tubes and rod ends are designed to be used in normal condition. In normal conditions there is no major load at all. These tubes and control Rod End are not designed to be fail safe with a power what could be used by two dying men. The basic assumption is that (FAR29) redundant Servo Actuator systems should not be stuck.

I can sent an email to you and attach NTSB’s ADAMS HYDRAULIC SIMULATION. There are scenarios where one C3 return port is blocked and the second simulation is that the both of these C3 return ports are blocked.
The scenario of one C3 is block will make Forward and Lateral Servo Actuator full extension within 3,5 seconds. If the both C3 ports are blocked then the Forward and Lateral Servo Actuators full extension will happened within 1,5 seconds.

Simulation affect (air speed 0,8 VNE and G force 1,0 cruise flight phase) is that when Servo actuator is fully extended then the helicopter will pitch up 60 degrees, banking to the left, at the beginning turning to the left which after (the collective is max up position then mixing unit will mechanically put the right pedal in fully right down position. After this helicopter will start to spiral to the right.

NTSB Servo simulation found out that Lateral Servo Actuator is under very heavy stress (load). The NTSB test report shows that, the stress force will variate between -1400 LBF to -400 LBF. This variation is very quick to fluctuate. It will fluctuate from high -1400 LBF (equal -6227 Newton) to -400 LBF (equal -1779 Newton) average 8 times every second.

If you will study an accident in Sutton, USA in 1986 the root case for accident is unknown. The S76B helicopter was cruising at 6000 ft. The crew was two Sikorsky’s test pilot and two Sikorsky’s technicians. Suddenly helicopter came unflyable. The radar recording is proving that helicopter speed, heading start to variate quickly. The helicopter was losing the speed and turning to the left. Very soon after this helicopter was starting to spiral to the right. The rate of decent was about 3000 ft/min. At time when this S76 hit to the ground the impact attitude was 12 degrees bank to the right and nose was at zero level. The Baltic Sea accident rate of decent was 3000 ft/ min and when the helicopter hit to the water it had 12 degrees right bank.

We all know the law of aerodynamics. If the conditions are same the result is always the same.

It is very interested in to see all the data from Lagos. Flight data recorder and CVR recording will tell within five minutes what this case was. ICAO ANNEX 13 procedures should bring Interim Accident Report to be published within 30 days. What is the reason for delay?

FAA has issued an EAD. My opinion is that the Jam nut is not the issue at all. It idea of Jam nut in this Control Rod tube / Rod End is only for to keep this Rod assemblies length stuck at time when the Rod assembly in not connected to the helicopter flight controls, mixing unit or the Servo Actuators. When Rod Assembly is connected by locking bolts (by each end) the Rod end is not able to rotate. If the Jam nut is totally missing or if the Jam nut is in its place with safety wiring there is no change of strength of the Rod assembly.
The other end of the Rod tube and Rod end is riveted (fix installation). Also the other Rod end is a fix installation due to the bolt connection (Servo Actuator). This makes impossible that the Rod End can be rotating (loosens or tightens).

I don’t understand how this Jam nut could be a case at all? And what is the point of this EAD?

The crew had 37 seconds time to try everything to have helicopter be a flyable helicopter. During this 37 seconds time the helicopter was spiraling to the right 13 times.
There is a procedure to get an unflyable helicopter back to flyable if this stuck controls case happen.

[terminus mos]

Preliminary report from the NAIB

AIB | News Updates (http://www.aib.gov.ng/viewentry.php?id=82)

[HeliComparator]

Copterline, I think the issue is that without the jam nut being tight, the threads of the rod and body can start to chatter, and thus wear, and thus eventually pull out - no rotation of the parts needed. This is just my guess, hopefully a technician will confirm.

[DonQuixote23]

Interesting report! The separation of the control rod was pre-impact. Not clear if it was also pre-control loss. Seeing the pictures I am surprised that anyone survived.

[cpt]

.... there's also this #2 engine uncontained failure wich is a concern. The damage seems to be aft of the armouring shield but there's obviously no apparent link with the disconnected rod wich is located much more forward. A power turbine shedding its blades here, would rather damage the tail rotor shaft.

But the point is that the similarities, with the "Baltic Sea case" are strikingly evident, at least in the first stage of the flight upset.

[Dave B]

I am very rusty now, having been retired for some years, but I was on the 76 from day one, as a senior engineer and I find this accident very strange. If the rod end was engage to past the witness hole, I cannot see why it should pull out just because the lock nut was not tight. From memory there is very little stress on these rods, hydraulics on or off, they only operate the pilot valves.
If the rod had been fitted with just a few threads engaged, then I would think it unlikely that the correct rigging figures could have been obtained. The only way I can see that the servo could have been correctly rigged like that, is for the whole system to have been miss rigged all the way back to the stick, an unlikely scenario.
The rod ends cannot rotate, so are they saying that if the nut is not tight, then chattering is enough to pull the rod apart.

[HeliComparator]

The rod ends cannot rotate, so are they saying that if the nut is not tight, then chattering is enough to pull the rod apart.

I'm sure that if we could see the actual parts, it would be obvious whether the threads had pulled out or not.

I took my Subaru in to a dealer for a 4-wheel alignment. 3 months and about 2000 miles later it was due an MOT, I gave it a quick check-over including jacking it up. I noticed detectable play in one of the front wheels. Transpired the jam nut on the track rod was backed off a couple of turns. Clearly it had never been tightened. The threads had worn sufficiently for detectable play caused mostly by a slight buckling effect even though there was lots of mating thread length.

So with that in mind I can believe that the accident helicopter's rod end could have worn and pulled out. Perhaps less force than a car's steering, but a much more rapid cycling of that force.

[cpt]

G'd evening Dave,

Do you think it could have been possible that this loose lock nut with only a few threads engaged had no consequences on the rod integrity in a normal servo valves operation, but may have allowed a separation of the rod with its body under the constrains of a struggling pilot's inputs against a frozen (jammed) servo ?

[Copterline 103]

Perhaps less force than a car's steering, but a much more rapid cycling of that force.

NTSB has a sophisticated ADAMS multi-body dynamics software and EASY5 system simulation software. In this simulation model NTSB is using “pilot’s controls have a small 5 lbf resisting force”.
The strength of the Control tubes and Rod Ends are much higher (at least 100 times higher) than this 5 lbf load.

[HeliComparator]

However that is not taking into account the very destructive effects of vibration on the masses of the parts. I'll confess to knowing nothing about the control topology of the S76 flight control system, but if you know more and can suggest an alternative explanation (other than a jack runaway, which doesn't seem to be supported by the evidence) then let's hear it please.

[Dave B]

I am not going to argue with the AIB, they are very clever people, and I have worked with some. I will however offer an alternative for discussion.
If the uncontained engine took out some hydraulic pipes, then you could lose both systems pressure, the S76 cannot fly in manual control, but you are obviously going to try to save the aircraft. Could the control rod have pulled out under severe loading.
As I said already I am rusty now, but I seem to remember that both 1&2 systems run pipes through the tail boom to the tail rotor, if I am getting confused in my dotage, then someone please correct me.

[cpt]

Yes Dave, you are right, hydraulic lines run all along the tail boom to supply the tail rotor servos, but if these lines are severed the "tail rotor shut off valve" will automatically isolate the main rotor stage 1 servos from the leak, as the hydraulic level drops. Thus, in case of a major dual system hydraulic leak aft of the the main rotor servos, control of the main rotor is normally still possible via hydraulic stage1.
....I'm not "speculating" but as a S76 flyer, it seems normal to share ideas and experiences on such a case.

For sure, investigators will soon find out what happened.

[helicopterkeys]

S76 Wizard wrote "My speculation is that when they rigged the input they misread the tape measure and made this an inch longer than it should be and then compensated by adjusting the pitch links to bring it in rig. The problem is that too much maintenance gets done to helicopters by engineers that don't have enough experience on type."
The input rods are not measured. With the controls set in a fixed position and rigging blocks installed in the servos, the inputs are adjusted to fit. Later in the process they maybe adjusted again for control clearance.

The S92 TR servo follow through linkage had a steel rod screwed into an aluminum block on early servos, with no jam nut. Vibration would cause the movement between the rod and block, steel won. No clue what that follow through linkage does, the servo will work when the steel rod falls out of the aluminum block. That steel rod augered that thing out like a drill bit, we didn't notice until it was in two pieces, we- in fact I didn't, a coworker spotted it while inspecting some unrelated work I had done. The design has been improved.
If the jam nut was loose for what ever reason, I can see the same type of wear occurring.

[S76 wizard]

Hi helicopterkeys

The report has yet to say if the rodend came out of the input or if it was hanging on by a thread. My guess is the input was hanging by a thread or we would be doing more inspections on these input threads.

[lynnx]

ASB 76-67-57.
FA EAD 2015-19-51
Sikorsky T-Rev 5-187

Prior preparation prevents speculation. :=

[Brother]

Lynnx

What is your point with the waiving finger?

Those of us in the business have all read these documents, carried out the inspections as required by the EAD and ASB and released the aircraft back to service.

[lynnx]

Brother,
My waving finger was mainly - ( though not clearly enough - obviously) -pointed at 76 Wizard and/or Copterline.
The accident report is a marvel of brevity.
It simply states that the separation was a "pre impact condition"
Nothing more.
EVERYthing on this thread other than that simple comment is therefore pure speculation as of now, and until, a further report is released.
Perhaps that is the purpose of the "Proffessional Pilots Rumour Network" ?

[SASless]

OK....we have a pre-impact failure of a rod end....and an un-contained engine failure in the same crashed aircraft. Two completely different components in two different areas of the aircraft.

Just what do we take out of that situation?

Are we overlooking something in all of the wild assed guessing that is going on about what caused the Crash?

[S76 wizard]

OK....we have a pre-impact failure of a rod end....and an un-contained engine failure in the same crashed aircraft. Two completely different components in two different areas of the aircraft.

Just what do we take out of that situation?

Are we overlooking something in all of the wild assed guessing that is going on about what caused the Crash?

The engine blowing up was most likely the result of the engine decoupling from the Mgb and overspeeding.

[twisted wrench]

SASLESS your back, I have not seen a post from you in a very long time.


Is it not possible the engine failure ( eruption) was after the aircraft impacted the water??


Looking at the pictures of the engine most if not all of the bolts that hold on the power module were gone, indicated they broke. Which could have occurred post crash.


As SAS mentions is quite hard to believe two totally different failures happen at the same time in flight.

[cpt]

Yes "twisted wrench" that's what I'm also thinking as a possibility .... I have had an uncontroled ditching once, and on impact, engines didn't immediatly stop by themselves, and instead stabilised at an intermediate regime, but the "flexible couplings" linking their power shafts to the gear box, broke .... we can imagine that this condition may, as well, have caused a sudden uncontained overspeed. Or else,as you say, the forces of impact, caused a displacement of the power turbine out of its shield while the engine was still running.

Once again, just pilots sharing ideas ! Investigators probably already have a clearer picture now.

[lynnx]

AND... there we go again.
Where, exactly, does the report even HINT at a possible engine/gearbox de-couple?

[SASless]

I would vote for the engine being a post impact event.....but that is purely an assumption.

I do wonder what the Rod End failure would have done to the controllability of the aircraft....and what that might prompt in the way of a Crew Reaction?

Perhaps we can start with a simple query....and focus upon the results of the Rod End issue rather than the "why".....and see where that leads us.

Or....let's start with the simple assumption the Engine did its thing and a crew reaction resulted in the control rod failure.

Not faulting the Crew or in any way suggesting they caused the tragedy....but as we all know our Emergency Procedure Training is for the expected and common place....and not the absolutely weird things that can happen.

[lynnx]

The weight of the servo input rod (when detached from lower rod end) is enough to ramp the servo down under static loads.
No idea what the dynamic loads would do, but the whole purpose of a servo is to isolate flight control loading from the pilot, so there cannot be much feedback.
In flight, a movement down on this servo - alone - causes right roll and nose down.
This is not what the report says happened in this case.

[SASless]

Are my tired old eyes deceiving me or does the Nigerian AIB Report's photo of the Bell Crank Assy and Rod End not show some thread defamation/wear which would suggest it had been on its way out for some time?

The Question that begs is when was the last time it was inspected as being as it should be and by whom?

[S76 wizard]

Hi lynnx;

The servo would go full extension when the input disconnected and after seeing the pictures of the mangled helicopter in the report there is a strong possibility that the engine decoupled after the crash.

[SASless]

The Engine did not seem to exhibit "Shrapnel" damage as one would expect from a genuine "Un-contained Failure".

[lynnx]

Hi Wizard,
I grant you, there may well have been a decouple following impact but the report does not state that.
A servo does not move unless there is an input - IF it is working correctly.
A servo mounted the way they are in the s76 should not go to full extension/retraction if you disconnect the imput unless the input is moved. The weight of the imput lever itself will normally ramp it down. With the control rod attached it will almost certainly ramp down under weight alone.
But thats static - with rotors running who knows.

[twisted wrench]

Lynnx you might be very correct but that only accounts for the one with the link that is disconnected there are two other servo´s that are connected and being moved by the pilot who is wondering what has happened to his controls.


So if two servo´s are moving and one is not imagine what that is doing with the swashplate and control of the helicopter?

[lynnx]

I,m trying very hard NOT to imagine !

I was exploring SASless' comment about the effect of the rod end detaching
and its consequences.

[helicopterkeys]

I did not study the picture of the engine in the report very much. The rod end is much more disturbing. My memory says the containment ring for the power turbine was deformed, and I have seen that before in an Arriel 2. A. Sudden stoppage caused a main drive shaft coupling failure, and a TR DS coupling failure, the engine did not shut down, until the fuel supply was shut off, even though the power turbine had disintegrated and departed out the exhaust. The containment ring did its job and then started to melt I guess- it was tear drop shaped by the time it was all over.
To me all evidence points to the rod end including the resulting bulletins. I'm sure a corresponding action would have been taken if the engine were thought to be a contributing cause, and as far as I know all post accident bulletis, ADs, and MM amendment.

[megan]

The Engine did not seem to exhibit "Shrapnel" damage as one would expect from a genuine "Un-contained Failure".SAS, have had two blow em up failures with this engine (same failure mode, turbine blade breaking off at root). One had shrapnel damage all over, while the other just spat it all out the exhaust.

[S76 wizard]

Hi Lynx
I'm 100% sure the servo will go to full extension when there is no input connected.

[SASless]

Why would any kind of engine failure cause the aircraft to become uncontrollable?

It is easy to accept such a control rod failure could make the aircraft uncontrollable.

If the one Servo went to full extension and could not be moved in the other direction by Flight Control Inputs....what effect would it cause?

Perhaps Brother Dixson could offer some thoughts on this?

[RVDT]

A servo does not move unless there is an input - IF it is working correctly.

Flown a Bell medium at all?

Ever thought about the weight of the disconnected parts?

[lynnx]

Hi RVDT,
Did you read past that line?
If servos moved without inputs you,d have a hard job flying.

[RVDT]

Lynnx,

I did read your comments - just having difficulty understanding them.

[lynnx]

Fair enough.

You asked about the weight of the disconnected rod?
I posted"with the control rod attached it will almost certainly ramp down under weight alone"
The rod in question had disconnected at the bottom. I,m presuming(!) that the AIB had disconnected it from the servo at the top for photo purposes - hence the "weight alone" - the remaining rod would be hanging off the servo input.

If your servo,s were moving WITHOUT an input (from the controls)then they would be continuously "running away" the whole time and the pilot would continuously fighting them the whole time!!

Does this make sense?

[JohnDixson]

SAS, RVDT and lynnx,

This is conjecture based on the quite limited information in the posted accident report, and assuming that the input rod linkage to the forward main servo has become disconnected.

If there was no pilot or AFCS input to the controls at the moment of separation, the servo would stay in place and from that point that attachment point on the swashplate becomes a fixed point, a fulcrum if you will. Some of the comments referred to the servo fully extending. That might be possible if there was an input at the moment of separation. However, if the forward servo had gone hardover ( remember, a disconnected control input means that the follow-up link would not stop the servo from moving at an intermediate point ), then the initial described aircraft reaction would have been much more violent than has been posted.

Back to the fulcrum point. With the attachment from the forward servo to the swashplate fixed in space, , then other control inputs would be affected. A collective input would then tilt the swashplate, instead of moving it up or down at whatever tilt it had. The head moment that is the moment placed on the vehicle thru tilting the control axis, is quite strong on the 76 ( some have seen the videos of the armed 76 doing rolls etc ), so the resultant unexpected cross coupling would certainly baffle the crew.

At this point, it is hard to say much more, except that the FDR analysis ought to shed more light on this aspect of the crash, and translate pure conjecture into fact. Focus has to be on the disconnect, maintenance history etc.

John

[JohnDixson]

SAS, RVDT and lynnx,

This is conjecture based on the quite limited information in the posted accident report, and assuming that the input rod linkage to the forward main servo has become disconnected.

If there was no pilot or AFCS input to the controls at the moment of separation, the servo would stay in place and from that point that attachment point on the swashplate becomes a fixed point, a fulcrum if you will. Some of the comments referred to the servo fully extending. That might be possible if there was an input at the moment of separation. However, if the forward servo had gone hardover ( full extension ) , then the initial described aircraft reaction would have been much more violent than has been posted.

Back to the fulcrum point. With the attachment from the forward servo to the swashplate fixed in space, , then other control inputs would be affected. A collective input would then tilt the swashplate, instead of moving it up or down at whatever tilt it had. The head moment that is the moment placed on the vehicle thru tilting the control axis, is quite strong on the 76 ( some have seen the videos of the armed 76 doing rolls etc ), so the resultant unexpected cross coupling would certainly baffle the crew.

At this point, it is hard to say much more, except that the FDR analysis ought to shed more light on this aspect of the crash, and translate pure conjecture into fact. Focus has to be on the disconnect, maintenance history etc.

John

[ericferret]

I believe that if the rod was totally disconnected at the lower end then the weight of the rod still attached at the upper end to the servo input under the influence of gravity would try to drive the servo to max travel. This would continue unless the rod jammed against the structure in which case the servo would stop in a random position.

[JohnDixson]

Point is valid Eric, but there is another factor, or should I mention two factors in play. The breakout force required to move the pilot valve, and the stiction of the system left after rod disconnect. If high enough, the valve could remain centered.

All this should come out in the detailed investigation, and you may be correct. As I wrote, though, if a servo went hardover ( and BTW, my recollection is anything but 100% accurate ) the servo's are typically designed for 100%/second rate, and if the servo went to full extension at that rate, the resulting initial maneuver would have been different than reported.

John

[lynnx]

Well, they say what goes around, comes around - and I,ve just had the wavy finger pointed firmly in my direction lol.
I still think that the weight of the (separated) rod attached to the input would run the the servo down (not up) but I like and appreciate the fixed fulcrum theory and the resultant confusion.
I,m leaving it to the big boys now!
Lynnx out.

[S76 wizard]

Hi Lynnx

I have never heard of a servo down in a crash report they always go hard over when separated from the input.

[Copterline 103]

It seems strange why the CVR and FDR data not yet published. All the speculations will be exhausted if this data will come public.

If the FDR data will be converted to be an animation and this animation is accompanied by the CVR audio recording, so the overall situation provides a clear picture of what really has happened.

CVR and FDR are installed in the helicopter just in the cause of the accident can be quickly and reliably verified.

What’s wrong?

[HeliComparator]

It seems strange why the CVR and FDR data not yet published.

FDR data and relevant CVR data should be published as part of the accident report. They should not be published in haste just so that armchair "investigators", pilots, passengers and the press can have their wild speculations and gossip down the pub, fed.

[Natasha02]

well my friend you never saw me cause I always looked n the roof and in the
couls may be that is why I am still here after 35 years n the air and 11 years of retirement god bell britow helis

[Copterline 103]

ASN Wiki Base Occurrence # 178588
Date: 12-AUG-2015
Time: 15:31 LT
Type: Sikorsky S-76C+
Owner/operator: Bristow Helicopters (Nigeria)
Registration: 5N-BGD C/n / msn: 76-0540
Fatalities: Fatalities: 6 / Occupants: 12
Airplane damage: Written off (damaged beyond repair)
Location: off Oworonshoki, Lagos Lagoon - Nigeria

Phase: En route
Nature: Non Scheduled Passenger
Departure airport: 'SEDCO' Offshore Drilling Rig
Destination airport: Lagos-Murtala Muhammed International Airport (LOS/DNMM)
Narrative:
A Sikorsky S-76C+, a domestic chartered flight operated by Bristow Helicopters Ltd (Nigeria), crashed into the Lagoon at Oworonshoki
area of Lagos. Visual meteorological conditions prevailed at the time and a VFR flight plan was filed. The two flight crewmembers and four of the ten passengers were fatally injured. The helicopter was destroyed and there was no fire.

Preliminary flight recorder data indicated that at 1000ft and 120Kts, the helicopter experienced sudden pitch up, and left roll with varying attitude of yaw, roll and pitch for 12 seconds until it impacted water at about 1531hrs.


Do someone knows where this FDR data is available?

1. Visual meteorological conditions prevailed
2. flight recorder data indicated that at 1000ft and 120Kts
3. sudden pitch up
4. left roll with varying attitude of yaw
5. roll and pitch for 12 seconds until it impacted water
6. the two flight crewmembers and four of the ten passengers were fatally injured
+ unofficial information that the hydraulic fluid was contaminated.


Okey, Houston, we've had a problem here!

[Copterline 103]

Three weeks to go and then we are able to see what was the case. The Final Accident Report should be published within 12 months? The report will explain e.g.!why S76C+ came suddenly unflyable and was the Hydraulic Fluid contaminated or not?

[Copterline 103]

Three weeks to go and then we are able to see what was the case. The Final Accident Report should be published within 12 months? The report will explain e.g.!why S76C+ came suddenly unflyable and was the Hydraulic Fluid contaminated or not?

The 60 days stakeholders comment period is past already (12.10.2016). This delay is supporting my theory and knowledge of the most probable cause of this accident. The reality is that the stakeholder (captain Jay's family) can't and don't have the power needed to postpone publishing of the final accident report (the truth).

In the Baltic Sea Accident one of the stakeholder was able to kept the Final Accident Report on hold position more than year until the needed changes was done (to delete some of the factual findings before publishing the report).

This Final Accident Report should be published without unnecessary delays to confirm that S76 series helicopters are safe. This information is necessary to be published to secure the safety of all crews and people who are operating S76 series helicopters. This relevant safety issue should also be carefully evaluated and to be mitigated of the president-elected, Mr. Trump's and his family's flights with three S76B helicopters what the president-elected owns.

I hope that this safety issue has already been carefully taken account by the people who are responsible of president-elected's and his family's safety.

[Copterline 103]

2418
"There was no indications of a malfunction in the aircraft systems before the aircraft loss of control occurred".


This is a Sikorsky S76C+ accident in Indonesia 21.3.2015. Most likely we will see similar flight data from Nigeria AIB's final accident report when, if ever will be officially published. Interesting to see if the hydraulic fluid will be contaminated due to sudden wear of Nylon-Teflon servo actuator piston ring?


Let's hope that everything is good and the helo type is safe to fly now and in the future.

[Cyclic Hotline]

News from Nigeria regarding this report.

AIB set to release Bristow Helicopter crash report, others - Vanguard News (http://www.vanguardngr.com/2017/07/aib-set-release-bristow-helicopter-crash-report-others/)

[Copterline 103]

This is the Sikorsky 76C+ OH-HCR (Copterline 103) FDR data after fwd servo uncommand extension due to the blockage of Servo Actuator C3 return ports.

[Copterline 103]

The truth but nothing but the truth.

[212man]

This is the Sikorsky 76C+ OH-HCR (Copterline 103) FDR data after fwd servo uncommand extension due to the blockage of Servo Actuator C3 return ports.

Just wait and see - there's more to control systems than hydraulics!

[Copterline 103]

These pictures of s/n 466 are almost identical with s/n 508 (Copterline 103). The defect of s/n 466 Servo Actuator pistons may be an airsafety issue?

[gulliBell]

From what I understand, if the after start hydraulic servo checks had been done properly in the Copterline example then that aircraft should have been grounded. The importance of doing this check as per the RFM can't be over emphasized. I see so many S76 pilots do this check incorrectly during their annual recurrent sim training.
The Indonesia accident mentioned earlier had nothing to do with hydraulic servos.

[Copterline 103]

From what I understand, if the after start hydraulic servo checks had been done properly in the Copterline example then that aircraft should have been grounded.


gulliBell:


Your theory is naive. Helicopter servos doesn’t move much while the helicopter is in the ground or the helicopter is taxing. When the autopilot is engaged the Electric Line Actuators are giving some slight control commands to the servos. When the helicopter is lifted to the hover and during the flying phase 99.99 percent of the servo's movements, loads and stress will be actualized to the Servo Actuators. In the practice the work load, aerodynamical load, vibrations to the Servo Actuators will be generated during flight phase only.

Your theory doesn’t take into account that the most likely the plasma flakes or plasma particles are chipping (remove)from the head of the Servo Actuator’s Piston during flight phase and blocks the C3 return port or C3 ports during the flight phase.

It is very unlikely that the plasma will be removing from the piston head at time when the helicopter is in the ground run or taxing. In the ground the servo actuators don’t have any moves, loads, aerodynamical loads or vibration. This all loads are mostly generated by the M/R Blades as a function of airspeed / vibration. The Servo Actuators will take on all the aerodynamic loads that the main rotor generates during the main rotor generates the lift. This aerodynamic load is very huge especially for the forward Servo Actuator. The other Servo Actuators are having much less aerodynamic load than the forward Servo Actuator.

It is possible but improbably that the Servo Actuator’s piston plasma coating chipping will happen in the ground when the Servo Actuators are almost “frozen” phase.

The helicopter will be safe if this plasma chipping or plasma flakes separation from the Piston will happen in the ground phase. The common sense is saying that the risk for chipping or plasma separation from the Piston head and that the plasma flakes will obstruct Servo Actuator’s C3 return fluid ports. The partial blockage is enough to cause the Actuator Piston Jam. When the Piston is jammed, the Servo out put will not respond to control inputs. This will lead to the Loss of the affected channel. The loss of Servo Channel will possible cause the loss of the control of entire aircraft. The consequence may most likely to be a fatal.

The S76 system design is not capable to identify Actuator Piston Jam by SER.JAM CAUTION because in case the “jam” has been caused by the blockage of the C3 return port(s). The MCV is still capable to move but the return port(s) are block. The Servo Actuator is “jammed” but with out any caution to the helicopter caution and warning system. The SER.JAM CAUTION is activated if the MCV is mechanically jammed. The flight crew don’t have any indication that the Servo Actuator has failed. When the one of the tree Servo Actuators are frozen, fully extended or not working parallel with the other the Mixing Unit will finally to mix helicopter steering logic. This will lead to the situation where the helicopter is unflyable. The problem is very well investigated and analyzed already by the end of 70’s e.g. by H-53 helicopters accident investigations.

Looking forward to see Bristow Helicopter’s accident 12th of August, 2015 accident report why the S76C+ was spiraling and acting precisely like COPTERLINE 103 and what was the reason for the second accident when Bristow Helicopter S76 become unflyable 3rd of February, 2015.

[gulliBell]

gulliBell:


Your theory is naive.....

You're barking up the wrong tree. The pilots didn't do the RFM mandatory after-start hydraulic checks ELEVEN TIMES in the previous 14 engine starts. Pilots who don't do the required flight critical checks, or who do them but don't understand what they are doing or why, are the naive ones. Not me. Whilst the stick jump check, even if done properly, might not have revealed the leaking hydraulic actuator immediately prior to the accident flight (because both sides of the faulty servo were leaking about equally), by not doing the check they certainly missed an opportunity to discover the problem. And through the history of that servo being installed on that aircraft, I find it impossible to believe that at some point in the past, as the servo condition deteriorated over time, that not a single after-start hydraulic check revealed any problem. That servo had been leaking for a long time, the hydraulic fluid had been contaminated for a long time, yet nobody knew. All because proper procedure hadn't been followed.

[212man]

Looking forward to see Bristow Helicopter’s accident 12th of August, 2015 accident report why the S76C+ was spiraling and acting precisely like COPTERLINE 103 and what was the reason for the second accident when Bristow Helicopter S76 become unflyable 3rd of February, 2015.

There are some people who know what they are talking about, and some relevant facts, and some that don't - I'm afraid you fall into the latter category.

[Helinaut]

Copterline 103
I was in Nigeria on February 5, 2015. What “accident” with a 76 happened at that date?

[Nescafe]

Link (https://www.pprune.org/rotorheads/574171-bristow-s76-ditched-nigeria-today-feb-3-2016-a.html?highlight=Lagos+76)

I think he means the “water landing.”

[gulliBell]

I think he means the “water landing.”

....good grief, ditching because of an AFCS problem....lucky they had a hero pilot to save the day.

[Copterline 103]

You're barking up the wrong tree. The pilots didn't do the RFM mandatory after-start hydraulic checks ELEVEN TIMES in the previous 14 engine starts. Pilots who don't do the required flight critical checks, or who do them but don't understand what they are doing or why, are the naive ones..
Dear gulliBell,

First of the all I would like remind you that we had met September 13th, 2006 at Sikorsky S-76 Operators Conference. I know your identity and to whom you are working for. I’m the guy who has been able to see behind to the curtains by reading thousands and thousands Sikorsky’s internal documents related to the S-76 Servo Actuator. In addition, I have had an opportunity to read thousands and thousands of internal Sikorsky’s emails, emails between HR, FAA, NTSB etc. In these emails you have been partly involved as a receiver, sender of by cc. For example, I have seen 1445 different emails to and from FAA’s Kirk G. between SIK, HR, NTSB and FAA. It might be that I’m not barking up the wrong tree?

You should be more precise about Copterline 103’s mandatory after-start hydraulic checks allegation. The truth is that you should separate engine starts and actual number of flights where the engines have been running after 18 to 20 minutes flights. During these 14 flight sequences there has been three engines start-ups. The S-76 RFM mandatory after-start hydraulic checks are related only to the engines starts, not to the flight sequences where the engines will be ground idle during the helicopter ground time. The Copterline 103 Commander was type trained by Flight Safety West Palm Beach, with an earlier significant experience as an Bell 412 EP Commander of Finnish Border Guard Search and Rescue unit.

What about your reference to all proper procedure hadn’t been followed. Your arguments about missed after-start hydraulic checks, stick jump tests are improper and prejudiced to reach your intention and leads the dogs barking the wrong tree.

About your argument of “all proper procedure hadn’t been followed”. The Servo Actuator piston rework in Plasma Tech Inc. didn’t follow the FAA accepted overhaul instructions. The composition of the plasma that was used in Copterline 103 Servo Piston’s overhaul was wrong. The overhaul instructions which were used issued by HR was never accepted by the FAA. The maximum accepted thickness of plasma coating clearly exceeded the maximum approved by FAA. Servo Actuator design in late 70’s didn’t take into account the oversized plasma thickness, didn’t take into account that the plasma’s aluminiun composition is less than accepted 20 % (accident servo piston’s plasma had only 10 % composition of aluminiun) and Servo Design allows a malfunction which will block the MCV’s return ports (C3 ports) and the helicopter caution and warning system doesn’t detect any defect. This malfunction will lead to the situation where the helicopter will become suddenly unflyable….

This all was informed to Lockheed Martin Corporation at time when the acquisition process to acquire Sikorsky (due diligence) was still pending. The listed company Lockheed Martin Corporation’s highest level was informed for this possible flight safety concern which may have a type certification consequence. After evaluation where you have very likely participated, Lockheed Martin Corporation decided to proceed with the acquisition of Sikorsky Aircraft Corporation from United Technologies (UTC).

It looks that Sikorsky has passed the point of no return already on 25th of May, 1978 when the Servo Jam defect due to the plasma flakes was evidently detected by SIK. Also the consequences were evidently understood (loss of control of aircraft and fatal accident). If I’m right and if all the documents what I have been able to see are correct it might be that quite many involved entity have past the point of no return, not limited only present owner of the Sikorsky, Lockheed Martin Corporation and its shareholders. It looks that there is a high possibility that we are not far away from the time when the **** will hit the rotor. If this will make the helicopter industry to be more focused for aircraft safety and be more creditable. This will not be bad at all.

The documentation what I have been able to see is the ground of the origin of my thoughts. :ok:

[gulliBell]

...You should be more precise about Copterline 103’s mandatory after-start hydraulic checks allegation. The truth is ...

The truth is as per what was written in the accident report, which you've no doubt read. I've attached the relevant finding here, for those not familiar with it. Pilots must do the after-start hydraulics check, it's probably the most important check in the book. The accident report says it was only performed 3 times in the previous 14 engine starts.

And when you speculate about other S76 accidents that you suspect might be servo related (Nigeria, Indonesia), which everybody else knows had nothing to do with servo, just emphasizes my point. Barking up the wrong tree.

Guys, do your checks by the book, understand what you're doing, and why! In my experience teaching recurrent trainees, the knowledge level on this aspect is generally south of where it should be....I find it impossible to believe that after-start hydraulic checks would not have revealed the problematic servo in the accident aircraft at some point after it was first installed.

[Mast Bumper]

GulliBell, can you post a better picture of the section of the report you are referencing? I can't read what you posted. Thanks.

[GoodGrief]

It's a thumbnail. Click it.

[gulliBell]

GulliBell, can you post a better picture of the section of the report you are referencing? I can't read what you posted. Thanks.

Yeah, it's a thumbnail. Click it and it goes full screen.

[HeliComparator]

I find it impossible to believe that after-start hydraulic checks would not have revealed the problematic servo in the accident aircraft at some point after it was first installed.

The last sentence of the report section you’ve published, seems to disagree with you.

[gulliBell]

The last sentence of the report section you’ve published, seems to disagree with you.

No it doesn't.

That is specifically referring to the state of the servo at the time of the accident, because both sides were leaking about equally at that time. That faulty servo was on the aircraft for a long time, and over that time, with variance of wear in service and the rest of it, I seriously doubt that at all times during its in-service history that both sides were always leaking equally. Hence the after-start servo checks should have revealed a discrepancy at some point in the past.

[Copterline 103]

Dear gulliBell,

Let's go back to the right tree. How can you explain the attached images of the Servo Actuator's pistons? How long do you believe the Plasma Flakes has been in C3 port? How do you explain that some of the plasma flakes have gone through the C3 port?

Just memorizing you..,.. you should be familiar with the following text:

“As indicated, we are aware of only four totalinstances of the defined failure mode. The summary of these pistons is asfollows (please note the first item listed was NOT chipped, however, it wasre-plasma sprayed in the same overhaul lot of 29 pieces that the second and thirdlisted items were also a part of – this is listed to show that we do no necessarilyhave an obvious lot problem – however,we may have a process related failure mode):”

These 29 reworked pistons went to the market 2003, with loss of Piston’s S/N because the original S/N of Piston was over coated by the plasma spray. This may be the reason why SIK can’t anymore identify and locate where these “failure mode piston are installed today”.

[RVDT]

I seriously doubt that at all times during its in-service history that both sides were always leaking equally.

No doubt - but does it not expose the possibility that the test is not without fault?

[gulliBell]

No doubt - but does it not expose the possibility that the test is not without fault?

If the pilots were only occasionally doing the required mandatory servo check - 3 times in the last 14 starts when the RFM says it must be done after every start - is indicative to me either of a lax attitude, or appalling lack of knowledge. There is no other way to dice it. One or the other being self evident lends the idea that when the check was actually done it may not have been done properly. I'd like to see the FDR data points on those 3 occasions captured when the check was done (if I recall, the resolution of the cyclic/collective position data is 4 samples/sec, which should be sufficient to confirm whether there was no delay between applying control inputs and isolating each hydraulic system).

There is no point doing the check if you don't do it properly. So do it properly. Don't invent your own way of doing it. The test is not at fault here.

[gulliBell]

Dear gulliBell,

Let's go back to the right tree. How can you explain the attached images of the Servo Actuator's pistons?...

I don't care about the photos. A bad servo was fitted to the aircraft, we know that. It shouldn't have gone undetected for that long. There were missed opportunities for finding it before it caused the accident. If the proper maintenance procedures were followed, and if the proper system checks were performed by the operating crews, then maybe we wouldn't be having this discussion.

[Mast Bumper]

It's a thumbnail. Click it.

Ahh, got it, thanks.

[Copterline 103]

I don't care about the photos. A bad servo was fitted to the aircraft, we know that.


Dear gulliBell,


I have learn that you don't care about the photos. You remember well as you refused to see "erecting plasma flake in the C3 return port". You told me that you can't see anything wrong or anything unusual in the erecting plama flake in the picture. Do you still concur?


Servo Actuator was a good one but SIK was saving money by using old reworked pistons. The rework process was not at all a proper overhaul process. The SIK failed to follow FAA's approved overhaul instructions. The old plasma was stripped away by using a mechanical process despite of the approved chemical stripping process. This unapproved overhaul practice lead to the consequences where the diameter of origin of the piston became smaller and smaller after each rework turnaround. The accident servo actuators piston has been 9 times been reworked. The diameter of the origin of the piston was clearly less than the minimum diameter accepted by the FAA approved overhaul instructions.


This recycling of the used piston up to 9 times lead to the demand where the thickness of the plasma needed to be increased to reach the required final diameter of the piston.


The used plasma composition was not a proper and not as accepted by FAA's approved maintenance instructions. The approved composition should have been 80 % copper and 20 % aluminiun. The accident pistons and the whole patch of reworked pistons (which may still be in use and most likely are in daily flight operation) composition was 90 % of copper and 9,6 % aluminiun and 0,4 % titanium.


During the rework process the original S/N of the piston was over sprayed and due to this the mandatory requirement of Airworthiness which insists that aircrafts each component's or spare part's maintenance history must be reliably documented. Despite of the loss of this mandatory identification and tracking requirement all of the defected pistons patch were returned to the market by violating the mandatory airworthiness requirement.


SIK has had the knowledge of this serious flight safety issue already since late 70's but SIK decided to continue forward by passing the point of no return. SIK has had the knowledge that there has been "process related failure mode" during the overhaul process of the Servo Actuator Pistons.

FAA has this knowledge that accident helicopter servo actuator's pistons has been overhauled by violating the approved overhaul instructions. Also FAA has a knowledge of this piston's overhaul process has violated the approved instructions.


It is sad that the safety doesn't matter at all and everything will be hidden.


I have a capacity to prove the SIK knowledge. At the moment this issue is not only an issue of Sikorsky, it's now the issue of the owner of the SIK, the Lockheed Martin Corporation. My opinion is that Lockheed Martin's corporate culture derivates from past time Sikorsky's culture.


Every entity involved for the air safety, airworthiness has the proven knowledge of this above. I can now just wonder the consequences when the **** hits the rotor. It will bring up the question why the authorities let this going on. How many other lives must be lost?


Improper maintenance? What do you gullBell think about this Servo Actuator's overhaul process and SIK's violating of the mandatory FAA's overhaul instructions?

[Copterline 103]

I have open my files. One correction must be done:

The FAA approved overhaul instruction requires that the Plasma coating material should be Metco 445 (85 % copper and 15 % aluminiun).

The Tallinn University of Technology and NTSB came up with the same results of SIK used plasma composition. The accident servo piston plasma composition was Cu 98 %, Al 1,5 % and Ti 0,3 %. The other finding was that due to wrong plasma composition the plasma flakes doesn't decompose to the smaller pieces as planned.

By using the right material (Metco 445) the removing plasma flakes should not maintain the present size and the plasma flakes should be decomposed to the smaller and smaller pieces to avoid the C3 port obstructions. This is the knowledge what I, NTSB, FAA and SIK are sharing. This in no new news for any stakeholder.

SIK S76 HRT Servo Reliability Improvement Plan meeting on 15th Sep, 2006 has agreed that: "Chips/flakes have low likelihood of creating significant (>75%) blockage during 3000 TSO".

The type certification requirements requires instead of "low likelihood" to be "extremely improbable". This is an issue what Lockheed Martin Corporation is nowadays accountable as the TC Holder of S-76.

If more detailed information or evidences are needed, I'm more than pleased to show and provide it.

Please see the attached pictures of the plasma and plasma composition as an evidence of improper maintenance.

[212man]

All great and I admire your devotion, but totally irrelevant to the BHL incident in this thread and the HL one in Indonesia - I assure you!

[gulliBell]

..You told me that you can't see anything wrong or anything unusual in the erecting plama flake in the picture. Do you still concur?


I never said that. I said, I don't care about the photo. What I care about is that routine maintenance didn't detect the internal leak in the faulty servo, and it should have. Also of concern is mandatory operational system checks by the pilots weren't done by the book and that might have been another missed opportunity to detect the faulty servo.

@212man is correct. Servo had nothing to do with either Nigeria accident (the crash, and the hero pilot ditching), or the Indonesia accident.

[Copterline 103]

It's a shame to spoil your day, but FDR data reveals that Stick Jump test was completed during the start up in the morning on August 10, 2005. There was no other engine start-ups before accident.

The crew flew in the morning on 10th of August, 2005 eleven 18 minutes flight sequences with one start.This will kill your theory completely.

Instead, now focus on Servo Actuator's design and how it meets the Type Certification conditions as well as what TC Holder has known since the late 70's? Why all the relevant data has been concealed? Is it the affect to the airworthiness of a helicopter type?

You have good information about Nigeria, but so I have first-hand information, for example contamination of hydraulic fluids etc. All the parties (stakeholders, family members, relatives etc.) related Nigeria S-76 accidents I'm ready to share my knowledge and all related documents to these "whom don't know" that the cause of the Nigerian accidents were not servo actuator or improper overhaul related.

[gulliBell]

It's a shame to spoil your day, but FDR data reveals that Stick Jump test was completed during the start up in the morning on August 10, 2005...

That's great, but what about the 11 times it wasn't done in the previous 13 starts? Your photos do nothing to dim my comments on this. I'd like to see the FDR data that was captured on those hydraulic checks...half the crews I've seen in the sim don't do the check properly. If that is typical across the wider S76 pilot cadre then there is an issue with training, and with CRM. One pilot can't be watching the other do the check incorrectly and say nothing. Or not do a mandatory check at all and the other says nothing. They might as well not be there. Might as well not do the check either if you're not going to do it properly, because doing incorrectly does not reveal the malfunction your checking for.

[Copterline 103]

That's great, but what about the 11 times it wasn't done in the previous 13 starts?

Let's go back to the right tree! The case is the possible lack of airworthiness of the S-76 helicopter type. The case is that there might be still hundreds of Servo Actuator Piston's which has been reworked with improper overhaul procedures. In addition the identification of the maintenance history of the reworked piston has been lost. This will make most like impossible to track defected and unairworthy pistons because nobody doesn't know which pistons have been installed to the specific Servo Actuator. The tracking capability has been lost during the improper overhaul process where the original piston's serial number has been over sprayed by new plasma coating. Due to this is unknown which S-76 helicopters have these improperly overhauled pistons and whichone not.

The type certification of S-76 (transport class helicopter) don't allow any kind of risks "low likelihood" in the critical flight components or critical systems.

This is the a tree that should bark.

[HeliComparator]

That's great, but what about the 11 times it wasn't done in the previous 13 starts? Your photos do nothing to dim my comments on this. I'd like to see the FDR data that was captured on those hydraulic checks...half the crews I've seen in the sim don't do the check properly. If that is typical across the wider S76 pilot cadre then there is an issue with training, and with CRM. One pilot can't be watching the other do the check incorrectly and say nothing. Or not do a mandatory check at all and the other says nothing. They might as well not be there. Might as well not do the check either if you're not going to do it properly, because doing incorrectly does not reveal the malfunction your checking for.




It could of course be argued that if so many crews do the check so badly, there is either a problem with the description of the check, or the check is too difficult for the average crew to do satisfactorily, meaning the design is not airworthy. Of course a manufacturer will always want to blame the crews and the training when things go wrong, but sometimes the manufacturer needs to look closer to home.

[Copterline 103]

meaning the design is not airworthy.

This is the right question; is the Servo Actuator design airworthy?

I hope that the attached attachments will also be useful for finding the possible root causes of the Bristow's Nigerian accidents.

Please note that the very sophisticated MSC.Software EASY5/Adams "NTSB Sikorsky S-76 Investigation, S-76 Flight Controls study and modelling has been made using the FDR Data from Copterline 103 accident despite as descript on the page 95, the first row "Loads were always set to the reduced Sikorsky-provided condition for 80 % VNE (124 kts.). Copterline 103 accident speed was 93,5 % VNE (145 kts.).

It is very easy to understand the aerodynamical and load differences between the actual Copterline 103 speed and this Sikorsky-provided speed assumption for the NTSB simulation results?

The other NTSB EASY5/Adams test report with the 93,5 % VNE will extend the collective max up position about one second and the Sikorsky-provided 80 % VNE will extend the collective max up position within 3,5 second.

The FDR Data between Copterline 103 and Bristow 12th August, 2015 its well matching. Maybe the real root cause of the Copterline 103 accident was a separated Control tube from the Rod End?

[Copterline 103]

I assure you!

Could you explain how you can assure me and the others? Why the accident reports are still pending? Do you know what were the root causes of Bristow's accidents 12th August, 2015 and 4th February, 2016? You should know it if you can deny all Servo Actuator defects away?

Also you may have information about Indonesia? What was the story there?

[212man]

Could you explain how you can assure me and the others? Why the accident reports are still pending? Do you know what were the root causes of Bristow's accidents 12th August, 2015 and 4th February, 2016? You should know it if you can deny all Servo Actuator defects away?

Also you may have information about Indonesia? What was the story there?
I am not going to give any details but can say with certainty that the two BHNL accidents are unrelated (other than concerns about what happened on the 12th August may have impaired decisions/analysis on the 4th Feb), whereas the first BHNL accident and the Indonesia one are almost certainly similar, and none of them are related to servo actuators.

Maybe the real root cause of the Copterline 103 accident was a separated Control tube from the Rod End?
No idea, but continue that thought.....

[Copterline 103]

Since the final accident report of Bristow 12th August 2015 crash is heavily overdue, one can both wonder the reason for such a delay and also make some assumptions based on the data released in the preliminary accident report.

a) The accident was violent and totally surprised the crew; no MAYDAY call was made.
b) At accident onset, aircraft pitched up and entered left roll.
c) Pushrod separation from rod end was a pre-impact condition, not pre-onset

For helicopter to pitch up, forward servo actuator must have been operated either with or without pilot control. If, for argument's sake, we assume that forward servo was operated without pilot input due to similar servo piston flaking as in COPTERLINE 103 case, following chain of events can occur.

1) Forward servo extends to the max.
2) Cyclic travels to full aft position
3) Collective raises to full up position (due to mechanical connection to the Servo Actuator scissor coupling)
4) Left pedal is floored by mixing unit (mechanical compensation link)
5) Controls are stuck.
6) Perplexed pilots are tossed around in the cockpit in heavy g-loads from violent rotation.
7) Fueled by sheer adrenaline, pilots begin fighting back to regain the control of the aircraft.
8) Both pilots exert in excess of 600kg of combined force on both left pedal and cyclic.
9) Since the cyclic control travel is normally on the order of 30cm and resulting control rod movement 3.5cm, the links, mixing unit and everything between pilots and servo actuator control valve act as a reduction gear of 10:1.
10) Pilots fighting for their and passengers' life are stressing the control rod by 6000 kg of force.
11) Aluminum threads give way. Control pushrod is detached from control rod end.
12) All means to control the aircraft have been lost.

In normal case, when system works as planned, the friction load in links and mixing unit is roughly 5 lbf (2-3 kg). In the normal operation the Control Tubes, Rods, Rod Ends, links or the Mixing Unit never face more stress or force that the systems itself mechanically creates through friction. The Flight Controls (Collective, Cyclic Stick, Pedals) have mechanical limiters which are stopping the travel of the Flight Controls. Since the Flight Control system has never been designed for a situation, where both pilots are pulling the pushrod with thousands of kilos, the system components will most likely fail. It must be remembered, that pushing the cyclic forward in a fully extended forward servo actuator situation will initiate a positive tension (pull) in each of the control line member, including the reported and failed pushrod. That, in turn, can create a situation where aluminum threads, which are designed for 2-3 kg loads, fail at stress of thousands of kilos.

When contemplating other routes of reported failure, one must take into account:
1) none of the control line member are able to rotate, so threads must have given way by de-threading and sliding
2) Pushrod is "secured" by witness wire only, ie. manufacturer knows, that threaded joint is not prone to fail. Witness wire serves as a means to verify "a correct lenght installation".
3) The mass of pushrod is about 100 g. Vibration induced damage in a system, where both ends of the connected pushrod and rod end are fixed to the same vibrating frame, is unlikely.

If pushrod would have been detached from the rod end pre-onset, controls would have been free and pilots would have been able to affect the spiral through mixing unit (not necessarily recover though). Nothing of a sort was heard from survivors. Therefore, an assumption of stuck controls is plausible.

This and everything else speculative related to this "mysterious" crash would be unnecessary if the final report was released. Interestingly, identical behavior was reported in Indonesia and the final accident report is overdue there as well.

Factually, the Indonesia 21st March, 2015 accident and the Nigeria 12th August, 2015 accident have been initiated by a sudden nose pitch-up within a second from the zero-time line. Similarly, it is also an undeniable fact that the nose-up needs to have FWD Servo Actuator extension commanded by a pilot input (cyclic) or uncommand Servo Actuator run away. If this FWD Servo Actuator extension doesn’t take place, the helicopter will maintain the level flight. If the case has been that the helicopter nose has dive down the pilots or electrical line actuator commands has been push “the Control Tube forward” to steer FWD Servo Actuator down or lower position. This action should has push the FWD Servo Actuator Input Control Pushrod and Rod end apart from each other, SEPARATING the Rod End from Input Control Pushrod. But this was not the case, the helicopter pitched up!

The recovered FDR DATA will reveal all of this. It will be easy to see the cyclic position at the time when the helicopter nose pitched up and later how the pilots tried to stabilized the helicopter which had suddenly and without any cautions or warnings become unflyable.

If it turns out that these accidents happened as depicted above, my worries are increasing how this S-76 helicopter could hold it Type Certificate. Also, if the manufacturer does not know or does not want to reveal why the S-76 helicopters are losing the controllability from time to time resulting in fatal accidents, the airplane is not safe and the fleet needs to be grounded for further analysis, until the helicopter type is safe and airworthy to operate.

The root cause and the consequence must be kept separate from each other.

[212man]

Interestingly, the detailed preliminary report appears to have gone now!

Pushrod separation from rod end was a pre-impact condition, not pre-onset

You have added the last bit yourself based on what? I know the EAD says "pre-impact" but that is simply stating a fact evident from its condition and does not attempt to act as the actual investigation conclusion about whether it was pre-onset or occurred after the upset onset.

You omit to note that the Indonesia one was survived by the crew, so their testimony on how the controls were behaving and what forces they experienced would have been passed on.

[Copterline 103]

I know the EAD says "pre-impact" but that is simply stating a fact evident from its condition and does not attempt to act as the actual investigation conclusion about whether it was pre-onset or occurred after the upset onset.


As many have already commented earlier, the weight of the pushrod would have commanded FWD servo DOWN, not UP if decoupling would have been pre-onset. The only way of producing described aerodynamical behavior (nose up, left roll) is to extend FWD servo.

Additionally, de-threading by pushing the rod end into pushrod is not possible due to jamnut. Therefore, if threaded joint has been destroyed by pilot action, it has been subjected to positive tension of the Pushrod - Rod End (pulling the rod, not push). In that scenario pilots are trying to pull extended FWD servo down by pushing the Cyclic stick forward by brute force.

FDR data will stop all speculations and the truth will be revealed.

[Copterline 103]

This picture tells more than a thousand words. Everyone is able to imagine what power is needed to break this collective head and what circumstances can it happen?

I hope that gulliBell and 212man will make comments about the facts what I have revealed. My benefit has been the fact that I was able to see behind the curtain and to know what is the ultimate truth of the matter. Sometimes the truth can hurt somebody.

[212man]

I couldn't find the Heavylift accident thread but it does not matter because it has direct relevance to this one - as has been mentioned earlier. The final report oft the Heavylift accident is out: http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2015%20-%20008%20-%20PK-FUP%20FINAL%20Report.pdf

It confirms, what several of us already knew through other sources, that the circumstances are identical to this accident and neither are related to the Copterline 103 accident and there is specific discussion about and the resulting Sikorsky actions.

[megan]

Everyone is able to imagine what power is needed to break this collective head and what circumstances can it happen Force would be substantial and far more than anyone could apply with their thumb. Have no idea what you're implying.

[gulliBell]

That bit of broken plastic on the collective head certainly has nothing to do with anything a hydraulic servo might have done. If that was the implication. The HL crash had nothing to do with the hydraulic system, which we said right from the outset. Neither did the Bristow Lagos crash. But the Copterline accident did.