Yet another AW139 tail incident at Gulf helis [Archive]

Bespoke

3rd May 2011, 03:07

Apparently one TR Blade detached and flew across the apron and came to a stop 50m later in front of the main departure terminal. Good fortune not to hit anything or anyone, although I'm told may have clipped a couple of main rotor blades.

Also believed to be just out of maintenance.

Additionally Im told P2 shut it down as it came apart.:D

Now that the one picture is now available, come on guys give us more. Apparently every man and his dog were snapping away !

Spoke.

Swinging Spanner

3rd May 2011, 03:31

I believe that not "all" AW139's in country are grounded. I think you will find it has to do with local aviation authority policy and company procedure to ground the affected company's remaining fleet of AW139's only, until such time both the manufacturer and aviation authority deem to be safe to resume operations. ;)

aegir

3rd May 2011, 08:36

This Incident is similar to the Hong Kong one, or it seems...

helihub

3rd May 2011, 09:42

The AB139 is a major leap forward in safety and has yet to be involved in a fatal accident (at least with a pilot at the controls)

ShellManagement. Can you tell us how a pilot was not "at the controls" on these fatal accidents

21-Jan-10 SAR aircraft off Almeria, Spain - 3 Fatal (http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=es&tl=en&u=http%3A%2F%2Fwww.cope.es%2Fsociedad%2F24-01-10--localizados-cuerpos-tres-tripulantes-helicoptero-que-cayo-al-mar-almeria-128990-1)
23-Feb-11 Korean Coast Guard - 5 Fatal (http://english.yonhapnews.co.kr/national/2011/02/24/77/0302000000AEN20110224002900315F.HTML)

helihub

3rd May 2011, 09:52

Just found another photo of the Hong Kong one

http://www.helihub.com/wordpress/wp-content/uploads/100703-bmhj.jpg

eivissa

3rd May 2011, 11:00

@helihub: although I dont think it was appropriate, SM probably meant that in the Almeria accident one is led to believe both pilots lost situational awareness, then made wrong corrections on the flight controls and let it fly its-self into the water.

http://www.fomento.es/NR/rdonlyres/70DD0C48-1459-407A-9D9F-99D00819505A/97971/2010_002_A_Interim_statement.pdf

thehighlander959

3rd May 2011, 11:59

I am in Qatar at present offshore. There have been no AW139 Operation in our field out here today.Not sure about anywhere else.
Flights in our field are being done by the Bell 214 which are the in-field helicopters running back and forward to Doha.

blakmax

3rd May 2011, 12:30

Hard to tell from the photos, but what is the structure like? Is there any composite/adhesive bonded structure as in the tail boom?

Regards

blakmax

aegir

3rd May 2011, 13:02

and what about the korean AW139? no pilot at the controls?
these are the accident/incident involving AW139 helicopters (thank to Aviation Safety Network)

22-APR-2002 (http://aviation-safety.net/wikibase/wiki.php?id=75607) I-ACOI / 01 Bell/Agusta Aerospace fat. 2 near Monteleone, Cesena
21-JAN-2010 (http://aviation-safety.net/wikibase/wiki.php?id=71765) EC-KYR Salvamento Marítimo (Helisureste) fat. 3 Mediterranean Sea, off Almeria
03-JUL-2010 (http://aviation-safety.net/wikibase/wiki.php?id=75389) B-MHJ Sky Shuttle Helicopters, opf. East Asia Airlines fat.0 Victoria Harbour
23-FEB-2011 (http://aviation-safety.net/wikibase/wiki.php?id=90478) South Korean Coast Guard fat. 5 West of the resort island of Jeju

It's missing theaccident of June in Abu Dhabi involving Sheikh Nasser Bin Zayed Al Nahyan. all the passengers died.

In addition we have the 2 accident to Gulf helicopter, the one of 2009 and the seconf of yesterday.

So we have some fatal accident with pilot at the controls and the AW139 isn't safe as SM says.
But no helicopter are totally safer, for sure!

IntheTin

3rd May 2011, 13:17

22-APR-2002 I-ACOI / 01 Bell/Agusta Aerospace fat. 2 near Monteleone, Cesena
21-JAN-2010 EC-KYR Salvamento Marítimo (Helisureste) fat. 3 Mediterranean Sea, off Almeria
03-JUL-2010 B-MHJ Sky Shuttle Helicopters, opf. East Asia Airlines fat.0 Victoria Harbour
23-FEB-2011 South Korean Coast Guard fat. 5 West of the resort island of Jeju

It's missing theaccident of June in Abu Dhabi involving Sheikh Nasser Bin Zayed Al Nahyan. all the passengers died.

In addition we have the 2 accident to Gulf helicopter, the one of 2009 and the seconf of yesterday.

The AB crash was being test flown.
The Almeria was flown into the sea. Nothing mechanical as far as I was aware. CFIT.
The Hong Kong accident is still under investigation. Amazing how well the aircraft flew if it had no MGB.
The South Korean crash is also still under investigation isn't it?
Abu-Dhabi crash was flown into the sea. Not too sure who was flying at the time.
Gulf's two aircraft had no fatalities thankfully.

eivissa

3rd May 2011, 13:52

You are right. We dont know yet what happened to the Korean AW139 or at least I haven't seen any new information and I forgot to address that. Also I forgot to mention the crash in Abu Dhabi, but that was probably what SM was on about.

Some people like to think it was Sheikh Nasser Bin Zayed Al Nahyan at the controls at the time of the crash. We will probably never find out.

If all the AW139 crash rumours were true we have a machine with considerable weaknesses in the aft section as well as pilots loosing situational awareness in best flying conditions.

Outwest

3rd May 2011, 13:56

Does anyone have the airframe and/or component times (TR) of the HK and Doha a/c? Are the numbers close?

Gordy

3rd May 2011, 14:00

Another photo:

http://sjdrimages.com/Mb/UserUploads/s85Ar11QPl6n56.JPG

aegir

3rd May 2011, 16:30

I completly agree with you, this weakness of the AW139 it's very dangerous and seems that Agusta hasn't found a solution up to now!

Thankfully these two accidents happened when the helicopter was on ground!

stickysunrise

3rd May 2011, 17:27

what about the collective control snapping in two mid-flight on the 412 at gulf helis last year?

seems things have gone very quiet about that incident- any news?

Now another major component breaking in their fleet? :sad: who's looking after the ponies in gulf heli's stables?

griffothefog

3rd May 2011, 17:40

Yes, GHC are very consistent...:eek:

Perhaps the old chestnut of "you pay peanuts.." refers to their Engineering history of recent years.. :{

When I was there early 2000, they had a great team of Aussie engineers and pilots and things ran pretty smoothly.. :ok:

I'll say this only once... White middle UN-TRAINED management.......

9Aplus

3rd May 2011, 18:26

this weakness of the AW139 it's very dangerous and seems that Agusta hasn't found a solution up to now!
:ugh: Like to know what was source of that "tail fire" than
jump in to big words cloclusions....

Aser

3rd May 2011, 19:16

Hydraulic fire? :rolleyes:

Aser

3rd May 2011, 22:21

For educational purposes...
http://i66.photobucket.com/albums/h263/aser_martinez/IMG_2999Small.jpg

http://i66.photobucket.com/albums/h263/aser_martinez/IMG_3015Small.jpg

Regards
Aser

SK76

3rd May 2011, 23:03

Let see to whom to be blame this time ... Manufacturer or engineering .
This is too much now

SASless

4th May 2011, 00:01

Bleeding nice of 'em to shuck their bits while on the ground now iddnit!:ok:

Bespoke

4th May 2011, 01:39

It would seem very similar to the HK aircraft.

Similar style of "Vertical Fin" break with one wayward Tail Rotor Blade.

6. In the evening of 3 July 2010, the helicopter was lifted out of water. The top section
of the vertical fin, the tail rotor, the tail gearbox and the associated drive shaft, control
rods and cover fairings of the helicopter were found missing. After extensive
underwater search, the tail rotor and the tail gearbox were salvaged from the harbour on 14 July 2010 but one of the four blades of the tail rotor was still missing. Search of the remaining missing parts is on-going.Spoke

thehighlander959

4th May 2011, 03:32

I am at present working offshore in Qatar. I fly on these aircraft on a very regular basis.
Someone somwhere needs to get to the bottom of this issue and very quickly. The people at GH are more concerned about covering up the name of their prestigious company and registration of the helicopter concerned than really trying to resolve the problems and issues within the company.

Confidence here in the carrier has taken quite a knock,its either a manufacturers or engineering and maintenance issue.Someone has to put their hands up and say its our problem!!!

Somehow I fear that will never be the case.

spinwing

4th May 2011, 03:44

Mmm ...

Well at least now Agusta have a nice bunch of parts which hopefully will allow them to determine how this thing failed !!

:uhoh:

NOW FIX IT PLEASE !!!! :*

Swinging Spanner

4th May 2011, 09:33

thehighlander959
Again, I believe that GH had covered up the registration/logo as part of company procedure-which is standard for the aviation industry including airlines.

You are right in commenting on the hope to get to the bottom of the issue whether its manufacturer/engineering/maintenance...I couldn't agree more.

Regardless, what doesn't help the situation is a slow decline in level of technical competance of maintenance staff. For sure there are very skilled/capable technicians from the countries where GH are currently hiring from but generally speaking-people from these countries are "culturally" non-confrontational and passive in nature.
In any work environment there needs to be a balance between this passive culture and people that will stand up and say something if it isn't right. Finally to have management who are encouraged to embrace this dynamic to then find a happy medium.
I think GH has continued to lean one way for quite a while, and this can only be done with the direction from the very top. Hopefully this event may influence the current culture with the end result being the supply of a good product.

Best of luck.:)

noooby

4th May 2011, 10:30

Spinwing,

You are assuming the problem is with the aircraft.

You've never worked at Gulf Helis have you. I have. Was good for a while, then the MD was replaced, then the Chief Eng (has been replaced once or twice since I left too), then things started to go rapidly downhill. We (the expat AME's) basically all left within a few months of each other so that we wouldn't be there when the accidents started happening.

Guess what, they are now happening. Surprise sur-freakin-prise.

How about Qatar CAA allowing other operators to come in and operate there so that at least the people going offshore have a choice, instead of being forced to use the only company allowed to fly in Qatar.

Now lets wait and see if Agusta come out with an Alert for us, and if not, lets see what the interim or final report has to say.

I can't think of any helicopter that will keep a TGB in place with one tailrotor blade missing, so the strength of the fin is not an issue. The issue is why did the blade depart. Lets try to focus on that shall we???

thehighlander959

4th May 2011, 10:34

Swinging Spanner...

We have some of the same issues offshore, the passive nature of some of employees working as contractors for our company.

I have stood and looked at a serious engineering issue and asked them if they are seeing the same problems I am seeing? Either they are to frightened to answer to a white face or theIr level of engineering skill and expertees is nowhere near what it says on their CV.

This problem at GH is not just a manufacturer,engineering or maintainence issue. It goes beyond that its a safety culture issue where people are afraid to give honest answers and put their point of view forward when something is seriously wrong.

Hope the aircraft involved is not A7-GHC as this aircraft has already been down that road.

SASless

4th May 2011, 11:16

Gulf Heli's management (or the Offshore Helicopter Industry in general)....some folks have cash variable Consciences as I recall. Seems they run in direct reverse of one another....the higher the cash....the lower the level of Conscience.

stickysunrise

4th May 2011, 11:26

How about Qatar CAA allowing other operators to come in and operate there so that at least the people going offshore have a choice, instead of being forced to use the only company allowed to fly in Qatar.

if only this would happen! But won't as long as Qatar CAA and GHC in bed together!

...united by their common Cash variable consciences :ok: and shared attitude of DILLIGAF

no wonder these incidents!

thehighlander959, build yourself a boat, mate. :sad:

SASless

4th May 2011, 11:53

http://i66.photobucket.com/albums/h263/aser_martinez/IMG_3015Small.jpg

Any one care to explain to me how the TRAILING edge got eaten up....and not the Leading edge?

While you are at it....please explain how the blade incurred the damage we see on the root end?

Is this evidence of a fabrication failure.....or a maintenance failure?

OvertHawk

4th May 2011, 12:41

SAS - Looks like the leading edge has sustained a bit of damage, but has stood up to it better being of stronger construction than the training edge which has more apparent damage. Also - i suppose it depends on what orientation it was in when it landed and what it landed on.

Concerning indeed! :eek:

OH

gittijan

4th May 2011, 13:11

The interesting items to me are the lead lag damper for the missing blade showing the attaching lug still in apparently good condition and what appears to be a bolt or part of one, laying on the ground nearby. Are they part of the same assembly? If so, could explain a lot.

blakmax

4th May 2011, 14:11

SASLess,

I can't explain the damage on the trailing edge, but the root end I can. The left side shows fibres which are furry, indicating a high energy tension failure, while the right side shows a more confined failure, indicating a compression failure. The item was snapped in the direction of rotation of the blade, but I guess that would be obvious even without a knowledge of composite failure forensics.

I'd love to see close-up pictures to see if the micro-voiding apparent in the tail boom disbonds is present here too.

Regards

Blakmax

Hedge36

4th May 2011, 16:04

Apparently one TR Blade detached and flew across the apron and came to a stop 50m later in front of the main departure terminal. Good fortune not to hit anything or anyone, although I'm told may have clipped a couple of main rotor blades.

Perhaps the tail rotor blade was liberated in the general direction of the MR. That would certainly explain the trailing edge damage.

prehar

4th May 2011, 18:19

I believe there is a picture on heliops forum of the 139 registration A7GHA that was supposed to do a flight for Qatar Petroleum . After start and a Power Assurance check on ground the pilots noticed very heavy vibration so they shutdown and asked the pax to exit . The tail gear box fell of and a fire in the tail area ....( probably of hydraulic fluid origin ) was quickly put off by the ground crew . Some initial details suggest that one tail rotor blade probably came off first , which put the tail rotor out of balance which caused the TGB to shear off from the fin area and the fire that followed .This might have been what happened to the Hong Kong 139 too .
Any more info from the GHC guys or gals ??!!

SASless

4th May 2011, 18:34

The item was snapped in the direction of rotation of the blade, but I guess that would be obvious even without a knowledge of composite failure forensics.

Blakmax,

Am I correct to assume most Tail Rotor Blades would fail "opposite" to the direction of rotation?

If one were to have a typical tail rotor strike....blade smacking something....the leading edge gets damaged the most...and the blade fails backwards (towards the trailing edge).

Am I understanding you to say the photograph shows just the opposite....a failure from rear to front in the direction of rotation? As if the rear leg of the blade failed first....and the forward leg of the blade followed in turn?

blakmax

4th May 2011, 20:38

SASLess

I am assuming that the LE is on the left of the picture, as is the root arm with the furry edge. That would be consistent with the LE striking something and the blade bending away from the object, putting the LE arm in tension and the TE arm in compression.

I still can't explain the obvious TE damage.

Regards

Blakmax

Wiggins61

4th May 2011, 21:28

I am not that familiar with the 139 but when most helicopters loose a T/R blade the TRGB attachment studs let go or pull through. This looks like a structural failure and as the TRGB and upper part of the pylon rolled off to one side the blades struck the fin causing one to depart the scene. From a witness stand point it would look like one blade departing before the poo hit the fan. I hope they find the cause soon before someone gets hurt.

Bespoke

5th May 2011, 02:35

GHC News

A briefing was held yesterday for the benefit of the Pilots with AW representatives in attendance.
This was to assure the crews of the safety to continue flight operations on the 139.

It was confirmed that the assessment is of a Tail rotor blade having failed with the out of balance effect causing the failure of the Tail Rotor Gearbox support structure. Similarities with the Hong Kong Aircraft were also confirmed.

I understand many of those in attendance were not entirely convinced.

More as it filters through the region.

Spoke

spinwing

5th May 2011, 03:41

Mmmmm ....

So .... then the question becomes .... Why (or what caused) the blade to fail when we have been told it had been designed NOT to fail in that manner!

:eek:

thehighlander959

5th May 2011, 05:06

^^

I am not sure I would be to convinced by that explanation either. If there are similarities with the incident in Hong Kong, then there needs to be a much deeper investigation to prevent any re-occurrence.And find out what the real problem is AW are just covering their ass.
Can you get specialist helicopter passenger insurance???:O

Information to the contractors from GH is very sketchy at least and non existent for personnel offshore.

I think if I had a choice I will stick with the in-field helicopters, the Bell Choppers are not getting to much bad press.

Sanus

5th May 2011, 06:15

So AW support GH with the statement the aircraft is safe to fly since the TGB will only let go if a TRB lets go first. That's alright then!

And this is similar to the HK event so unlikely to be maintenance induced.

Is there a special inspection now called out to inspect all 139 TRB's for cracks, delamination etc?

onevan

5th May 2011, 09:29

How does this failure compare with the TRB / TRGB failure on the Royal Navy merlin in 2004? :suspect:

blakmax

5th May 2011, 14:04

Sanus said the aircraft is safe to fly since the TGB will only let go if a TRB lets go first

My son Darius first promulgated the Darius Asterisk Proposition. His representation of your statement would be

" the aircraft is safe to fly* since the TGB will only let go if a TRB lets go first"

Note the asterisk, which implies "under certain, controled, modified and restricted circumstances and in no other cases whatsoever"...

You get the idea. It is a bit like the big M healthy* burger. I never eat the big M. Who would eat a product sold by a clown? It might taste funny!

This response tastes funny. Your cheque is in the mail, I'll still love you in the morning????

I still ask if there are close photos of the edge of the failures of the blade root. I'll bet that there is evidence of the same micro-voiding as seen in other examples of disbonds for that adhesive in the tail boom. (I can explain why the "undiscovered damage*" theory promulgated by the AW report is * if anyone wants to PM me).

If there is micro-voiding in the bondlines, this is is a systemic problem with their bonding facilities.

I have made approaches to AW through a number of contacts suggested by member of PPRune and even EASA, to no evail. I have even provided the information for FREE at http://www.adhesionassociates.com/papers/Managing%20Micro-Voiding%20of%20Adhesive%20Bonds.pdf

I guess that the old addage applies: You can lead a horse to water, but you can't make him think it is wine. Or even a Big Mac.

Regards

Blakmax

Aser

5th May 2011, 16:40

I've been told the following, from a good source:

they forgot a special tool for the free play check at the 25hrs inspection, connected connected to the blade....that's why they had so much vibrations right from the start- up.

they find the tool (which is a bracket) 140 m away on the ramp....that's what they told me yesterday. If you ask your technicians they will be able to show you the tool (it's a support for the compass of a dial gauge) and you see the dimensions!

:ugh::confused:

Blackmax you have got an email...

Regards
Aser

Chi Sin Gei Si

5th May 2011, 18:33

It must have gone through everyone's mind to make a link between GH and SS (HK). Indeed, a blade departing SSH due to some defective part, would be a tidy explanation. At least better than the bird strike theory.

Let's hope the investigators look carefully into that link, to see if there is a trend to watch for in the components.

At the same time, let's hope that the investigators resist the urge to get sidetracked by such 'obvious' links, which might cause them to miss something else more crucial. This is a danger when two incidents with similar symptoms happen. Until they find evidence of the link then, its only speculative. It could be that both incidents were totally unrelated.

At least with GH, they have all the parts, possibly video replay or eyewitnesses. Unlike HK when they really didn't have much to go on, and the critical part (a blade) is presumably lost forever. (Though it would make a lovely sampan paddle should a fisherman should trawl it up and stick it on the end of a bamboo pole. We should keep an eye out; it may turn up yet.)

I think if I had a choice I will stick with the in-field helicopters, the Bell Choppers are not getting to much bad press.

The lion always gets the lion's share of bad press.
CSGS

stickysunrise

5th May 2011, 19:06

thehighlander959: I think if I had a choice I will stick with the in-field helicopters, the Bell Choppers are not getting to much bad press.

CSGS: The lion always gets the lion's share of bad press.

Yuh huh, you guys! Funny when the Bell 412 incident happened at GHC last year and the collective snapped in two mid-flight to make an emergency landing at DOH carrying 9 pax + 2 that didn't get much bad press... in helicopter world. It made a front page of a newspaper in the UK though... yet nothing on Google. And still no positive conclusion to my knowledge (anyone else...?) Is it again a kind of "these things happen"? Really? So often? To the same company?

I again feel sorry for you thehighlander959, it's either a AW139, a Bell 412, swim or bateau for you off o'there. still, all are flying again now I believe?

These things are very easily swept under the carpet. A solution must be found. No more incidents at GHC!

Flyting

5th May 2011, 20:30

http://i1045.photobucket.com/albums/b451/Flyting/IMG00096-20110505-1742-1.jpg

if you're flying a 139, get out to your local store and buy a tube. It's a quick 5min fix....

:E :E :E :E :E

9Aplus

5th May 2011, 20:41

:= no, no Bell uses that one on TT straps only :}

TRC

5th May 2011, 20:44

Hang on - unless I'm missing something, isn't there a rumour from Aser's source that suggests that a rigging tool was left attached. Not suggesting 'that's OK then' - but it would be a maintenance error rather than anything else.

Any more info to confirm or deny that?

I accept that the similarity with the GHC incident and the HK ditching have more than some things in common.

RVDT

6th May 2011, 03:40

blakmax,

Can't you find a shed for your wheelbarrow? :rolleyes:

CopterDokter

6th May 2011, 08:58

Aser, I just sent a PM to you -- :ok:

helihub

6th May 2011, 12:28

"The aircraft, which was located in the parking area and was preparing to carry out the operation of a flight taxiing to take off-shore, with two crew and nine passengers, suffered the separation along the entire tail rotor.The initial findings have identified a tail rotor blade at approximately 75 m from the aircraft. "

(Electronic translation of Italian authorities statement)

Aser

6th May 2011, 19:11

as always, for educational purposes:

http://i66.photobucket.com/albums/h263/aser_martinez/IMG_2968Small.jpg

http://i66.photobucket.com/albums/h263/aser_martinez/IMG_2985Small.jpg

We aw139 drivers really need answers... I'm waiting some kind of statement from Agusta apart the letter saying they are sending the investigation team

:confused:

Regards
Aser

TRC

6th May 2011, 19:45

We aw139 drivers really need answers...

What happened to the rigging-tool-left-in-place rumour?

500e

6th May 2011, 22:18

Surely the rigging tool rumour is just that? a rumour.
How did the AP miss it? (no shadow board for tools? or other tool verification method) also the PIC on walk round pre flight, especially if just out of maintenance.

Turco

7th May 2011, 00:15

Gents has anyone taken a look at BT 139-251 as a response from AW?

Aser

7th May 2011, 08:55

TRC and 500e , it's just a rumor, a good one from a good source but of course I wasn't there...

Thanks for the head up Turco.

http://www.agustawestland.com/sites/default/files/139-251.pdf

Regards
Aser

blakmax

7th May 2011, 11:19

RVDT

I am really concerned about this issue, not just because of the AW139. I am aware of another European helicopter type where multiple voids in a fibre composite tail boom were repaired by injection repairs and these voids are almost certainly also caused by moisture absorption by the resin system during the production process, which is the same mechanism as I suggest applies to the tail boom problems. The voids were so extensive that the customer insisted on separate repairs on a significant number of shipsets to restore the strength lost by the number of injection holes.

Now, I have a really BIG wheel barrow for injection repairs for voids. I absolutely defy any manufacturer to show me any evidence that injection repairs for adhesive bond or composite laminate production voids restore strength. They fill the disbond and NDI can't find it, but absence of evidence is not evidence of absence. I want to see hard, reliable and irrefutable test data. The surface of a void is fully reacted out during the cure process. It is glazed and slick. Adhesives require a chemically active surface for a bond to form. You do not get that from a slick or glazed surface.

These are both interrelated problems caused by a lack of humidity control in the composites shop.

Now I have no evidence that this current failure is even remotely related, simply because I do not have close-up photos. I would be happy to back off if I could be satisfied that there were no micro-voids in this current case.

I do have close-up photos for the tail boom disbonds and I am prepared to place the family jewels on micro-voiding of the adhesive being the cause. The offical "undiscovered" damage theory for the Doha incident does not explain the other 168 cases of boom disbonds (their figures). Did they all have tail strikes?

So I can't put the wheel barrow away now because the family jewels are in it, and my garden shed is not big enough.

Regards

Blakmax

OK, the big enough comment is a bit of an exageration.

tcvennen

7th May 2011, 19:19

SASless,The failure occurs on the blade root (where the bearing sits). Under the bearing, cracks are developing, causing failure. The failed blade root causes the blade to fly off, causing terrific imbalance in the TRGB, which then causes separation of the entire gearbox. The damage to the trailing edge comes from flying thru the main rotor and impacting ground. Inspections are now being conducted at the blade root, under the elastrometric bearing. Actually the bearing has to be removed. Anyone old enough to have flown the Bell 206 when it first came out can certainly remember the main rotors (TT straps), or the SK 76 hand greenade engines, they have turned into outstanding, safe aircraft, as this one will, it's a "A" model, it will have growning pains.

The Sultan

7th May 2011, 22:03

tcv

You left out the UH-60 and the S-76 shucking main rotor blades due to spindle failure. There was also the Govt of Kentucky S-76 that shucked a tail rotor blade. The report was that the tail rotor blade was used in ultimate load tests and instead of being scrapped as is practiced was repainted and delivered.

The Sultan

SASless

7th May 2011, 22:56

500......if one considers how many times S-61's have been flown with the Tail Rotor gust lock installed....a rigging tool should be no mystery!

cayuse365

8th May 2011, 01:45

The Kentucky accident was due to a unsecured engine cowling which resulted in the loss of one TR blade, but the gearbox did not separate from the airframe, it also contacted the MR and the TR driveshaft. NTSB report NYC92GA147.

[email protected]

8th May 2011, 10:15

Well they must have found a faulty blade at Lee on Solent yesterday - their 139 was off state for a 'tail rotor crack' and the Portland one stood in overnight.

TCV - the big difference here is that with conventional engineering, more sensitive NDT procedures can be used to identify cracks before they become visible. With the composite blade roots you can only use the 'technologically advanced' tap test which may or may not identify voids (which really shouldn't exist at all in such important structures) and rely on visual inspection to see any surface cracks.

I agree the 139 will become an outstanding and safe aircraft but only if AW address their composite material manufacturing process and quality assurance testing as per Blackmax's suggestions.

Senior Pilot

8th May 2011, 10:20

I agree the 139 will become an outstanding and safe aircraft but only if AW address their composite material manufacturing process and quality assurance testing as per Blackmax's suggestions.

After 8 years in customer service, I would have expected this sort of issue to be one of the past: not something to be treating as for a 'new' aircraft :=

Or has there been a recent change in quality control at AW that has resulted in what seems to be a rash of composite bond problems?

RVDT

8th May 2011, 10:38

BT 139-251 area of interest.

http://i1135.photobucket.com/albums/m630/RVDT/139TR.jpg

Dan Reno

8th May 2011, 11:12

After all the S92 negative traffic, it looks like this helo has joined the POS brigade also.

IntheTin

8th May 2011, 11:55

After all the S92 negative traffic, it looks like this helo has joined the POS brigade also.

I'm assuming judging by your profile you don't fly this aircraft Dan. It's far from a POS. It certainly has some issues but POS it's not! :=

Turkeyslapper

8th May 2011, 12:15

My operator here in the ME has grounded aircraft pending tail rotor inspections of the area of interest....one u/s blade with crack so far and waiting.

Dan Reno

8th May 2011, 14:55

Perhaps its just a little scary to ride in then. Your call.

thehighlander959

8th May 2011, 16:10

^

I work offshore in Qatar and fly on Gulf Helicopters aircraft offshore on a regular basis. I have never had a bad flight on the AW139 out here. Comfort wise its a good tool for operations offshore.

My concern is that these TR AND TRB issues need to be resolved. Whether it is a manufacturing AW issue, a Fleet issue GH, or a poor maintenace issue GH, someone needs to put their hands up and say its our problem.

Looking at the bulletin that has come out from AW it seems that there are issues concerning manufacturing and warnings for increased inspections and service intervals. If this is AW holding their hands up and saying this is our problem its a very poor way of admitting their production process is not up to the standard required.

There needs to be a better way of testing a rotor blade than tapping it with a special hammer.
I am not convinced by AW in this at all.:eek:

9Aplus

8th May 2011, 17:53

Out there on field it is sad true, no standard certified NDT procedure
other than "modern" tap test :{

So it is time to use ultrasound, like this one:
(I am not related with producer :})

http://www.olympus-ims.com/en/.downloads/download/?file=285212998&lang=en_US

http://www.olympus-ims.com/en/.downloads/download/?file=285212996&lang=en_US

Who is going to make "certification"? :cool:

Or visit your doctor and take some ultrasound souvenirs from there :p

zlocko2002

8th May 2011, 19:07

or take some old fashion helicopter and fly without worries :}

500e

8th May 2011, 20:03

9A
Interesting tools could\should show the tail section disbonds, when they have reached a level that is measurable.
How quick is the de lamination\ failure once it starts ?
So far the tails have been on ground, & the HK is suspected blade failure, it would appear that there are numerous others reported here (that cannot be all not every user is a PPRUNER)

If as BM is saying these could be due to micro bubbles, the way I read the literature, it does not go down to the level that is starting these problems.
It would appear that manufacturers are using either flawed calculations, poor \ incorrect procedures, or the material is not stable enough for the job.

blakmax

8th May 2011, 22:58

500e

If as BM is saying these could be due to micro bubbles, the way I read the literature, it does not go down to the level that is starting these problems.

The size of these bubbles is small, and individually they are much smaller than the tolerable defect size determined during certification testing. However, collectively the sum total of the voids can well and truly exceed the TDS. In the case of extensive micro-voiding the adhesive surrounding any disbond may have a shear strength of only 50% of the prisitine adhesive bond. Further, the reduced strength may result in fatigue of the small segments of adhesive between the bubbles, leading to disbonding. A further complication is that when an OEM undertakes certification tests they use a teflon insert in an otherwise pristine bond, where the inserted "dsibond" is surrounded by good adhesive. The same approach is used for damage tolerance analysis using computer modelling, where the properties of the adjacent adhesive are unaltered for the purposes of modelling. Most of the literature considers only on this type of large voids (macro-voids).

Hence the certification basis for the original damage tolerance analysis and the computer modelling are compromised if the adhesive has extensive micro-voids.

I am preparing a paper for a conference in Brisbane in July on this and other risks to safety as a result of the application of damage tolerance analysis to adhesive bonds. I'll post it on my web site after the conference.

Regards

blakmax

meade

9th May 2011, 08:46

Blakmax,
Could you provide a link to the conference in Brisbane in July. Thanks Alan.

blakmax

9th May 2011, 09:32

Alan

Hopefully this link works Aircraft Airworthiness and Sustainment Conferences (http://www.ageingaircraft.com.au/aasc)

I believe that my paper is scheduled for Wednesday. I can only attend the conference for that day, so make yourself known to me if you wish.

Regards

Max

Aser

9th May 2011, 10:53

Well they must have found a faulty blade at Lee on Solent yesterday - their 139 was off state for a 'tail rotor crack' and the Portland one stood in overnight.

Turkeyslapper
My operator here in the ME has grounded aircraft pending tail rotor inspections of the area of interest....one u/s blade with crack so far and waiting.

Can any of you confirm if the cracks are in the area to be inspected by the bulletin? or forward from it, just before where the trailing edge starts.

Thanks
Aser

outhouse

9th May 2011, 12:21

Just drifting back a while, I seem to recall a tail rotor blade *inspection called by Augusta regarding the same area as this one re cracking.
I also remember a number of tail rotor blades that showed cracking in the paint covering. Removing the paint layer showed progression through the first layer or two of the carbon fibre Multy layers. These blades returned for repair.*
Question was the blade in question one of these? Is this latest failure a progression of the original problem? how many hours on the subject blade? What was learned by Augusta from the results of the original problem that generated the original inspection.:sad:

cayuse365

9th May 2011, 13:16

Outhouse,

The area of interest is made of fibreglass not carbon fibre acccording to the maintenance manual.

outhouse

9th May 2011, 14:05

Thanks for the info, when I viewed the area after the paint had been removed and looking at the make up it resembled CF however my comment still is valid in my view.*
The layers were very thin and the top layer was compromised. thanks for your info and look forward to further comments on the on going situation.:ok:

meade

9th May 2011, 20:53

Blakmax,
Thanks for info, plan on attending. Alan

Aser

10th May 2011, 09:05

EASA Airworthiness Directives Publishing Tool (http://ad.easa.europa.eu/ad/2011-0081)

EASA AD for the agusta bulletin.

Regards
Aser

nick121

10th May 2011, 11:54

TheTail Gearbox did not come off, the tail fin sheared, mainly because a Blade came off. Now! why did the blade come off????:ok:

cayuse365

10th May 2011, 13:29

Who knows, maybe the tail fin let go first. There is not a whole lot of structure holding things together back there. Let's hope the investigators do a good job, but I have some reservations.

500e

10th May 2011, 15:36

cayuse365
"The area of interest is made of fibreglass not carbon fibre according to the maintenance manual."

Would have thought some kevlar or carbon would be incorporated ?

blakmax

11th May 2011, 11:47

500e

Despite common misconceptions, fibre-glass is quite strong, probably close to the strength of some forms of carbon composites. What it lacks is stiffness. It stretches further for the same stress. The colour of the fibres in the fracture is clearly white, so it is glass.

I am hearing rumours (it is a rumour network, right?) that on other aircraft the surface of the composite at the end of the blade appears white, while away from the blade end it is a yellowish colour. Anyone else observe that? It could be significant. If the resin is a yellowish colour and in some regions the laminate apears to be white, it could be that the white areas are resin starved, with a high fibre-to-resin content.

There is an optimum resin content; too low and you loose strength because there are not enough fibres to carry the load, too high and you loose strength because there is not enough resin to transfer the load between the fibres. The resin content is controlled by the resin bleeding process during production. Bleed too much resin off and the laminate is dry and the strength is reduced.

Regards

Blakmax

ironchefflay

11th May 2011, 20:00

im no expert on flack vests, but im pretty sure they have never been made from Carbon fibre. Usually Kevlar, which is a yellowish colour when made up in vests. like really old cloth. thats what they make Stab vests, Helmets, etc out of.

Kevlar is also used in Super Puma Mk2, (prob EC225 as well) Main ant Tail rotor heads as reinforcement bands

outhouse

12th May 2011, 12:10

Ok typo:ugh:

outhouse

12th May 2011, 16:14

Just to come back for the last time. Sorry about the typo, should have said Kevlar and thanks for the correction, however though an old *soldier and maybe infirm I get the impression that my main point was completely ignored.
I have deleted my post. I felt that it may have been of interest regarding the history, visual impression and the view of the area after the paint covering had been removed. With the present discussions and the lack of information available maybe my observations may have been informative.*
However over the last 45 odd-years and the mechanical failures that have cost many lives and the times that I have attended funerals of old friends, Has technology and the improved computerised systems to assess structural integrity made you any more confidant than the old farts regarding the product you fly. Or are you still looking at the same progression of failures possible loss of life, fix the problem and see the progression through the ongoing A, B, C versions until it becomes a reliable, respected and safe working machine.*

I wish you all safe flying and blue skies, this old timer is hanging his head set up and accepting that after a life that has given me an opportunity to participate in a exiting and challenging job it must*
come to an end.
Outhouse signing off.:ok:

griffothefog

12th May 2011, 17:33

OK guys, I fly this machine.....:uhoh:

You can all fcuk off with your speculation... :ugh:

The FMS sucks but the airframe rocks :ok:

If the tail rotor falls off I'll let you know..:ok:

9Aplus

12th May 2011, 17:53

:D
:ok: you make my day to end with :)

Senior Pilot

12th May 2011, 22:43

OK guys, I fly this machine.....:uhoh:

You can all fcuk off with your speculation... :ugh:

The FMS sucks but the airframe rocks :ok:

If the tail rotor falls off I'll let you know..:ok:

:=

http://img.photobucket.com/albums/v493/jimmorr/NoSwearing.png

spinwing

12th May 2011, 22:49

Mmmmm ...

Griffo .... your really way too subtle for this forum ..... :E

(BTW ... have now left 'you know where' for a real future (?) back home). :D

thehighlander959

13th May 2011, 03:30

I am still offshore in Qatar, I still have not seen any AW 139 in the field since the incident on shore on 2nd of May.

I am presuming that TR and TRB safety checks are being carried out by Gulf Helicoters as I type this.

As for the poster who said that if the TR or TRB falls off he will let us as he flys these things. May I suggest that he finds another occupation as air safety does not seem to be part of his mandate.

Griffo:

I suggest taxi driving as its a little bit safer and there is less chance of flying the taxi into the ground at 130knots.
By the way your Safety attitude is crap.:(

griffothefog

13th May 2011, 03:53

highlander and any other sensitive types....

Having suffered a genuine t/r failure in the past and survived and having to now fly the 139 for a living with all the speculation, let me assure you all I take my flight safety very seriously.

I don't know whats wrong with the aircraft.... But like you H, I am forced to continue operating in this type to pay my mortgage and keep the wolves at bay... Do you really think I'm happy??

I am waiting for a full and comprehensive assessment from AW....

The type of sling work and SAR we often do in the curve up to 10,000ft puts the airframe
right in the groove, but I'm happy with it and it has not let me down yet... I hope that continues... I will continue with very careful pre-flights as I actually do care about the safety of me and my crew (and pax H).

fcuk taxi driving...I'd rather work in a bar.

Safe flying to all and lets hope AW can get this sorted....

Senior pilot.... no comment :E

thehighlander959

13th May 2011, 06:28

Not to sensitive here:) however I do have issues as I fly on these aircraft on a very regular basis out here in the sand-pit.

Like most offshore workers I do have concerns, I have lost friends in helicopter accidents in the North Sea in the past, and have no wish to see any family relieved of a husband/wife due to a helicopter crash due to poor design (AW) or bad maintenance (GH) or any other reason.

AW along with AW139 Operators are the only people who can solve this problem. My main concern is that they solve it sooner than later before we get another similar problem to Hong Kong, only this time the passengers and crew might not be so lucky.

Aser

17th May 2011, 15:10

Ok, we don't need to worry, as far as we don't forget the tools on the blade and keep an eye on the craks... :}

See below:
http://i66.photobucket.com/albums/h263/aser_martinez/statement162.jpg
http://i66.photobucket.com/albums/h263/aser_martinez/statement163.jpg
http://i66.photobucket.com/albums/h263/aser_martinez/statement164.jpg
:suspect:

Regards
Aser

noooby

17th May 2011, 16:31

Aser,

This is basically a rehash of an old Agusta letter. These "cracks" have been on the blades for more than 4 years. Agusta put out a letter a long time ago detailing the construction used on the blades. On the fork end, there is a sacrificial layer of composite matting that protects the load carrying fibers underneath from impact damage. This layer is not in one piece, but is made up of 2 or 3 separate pieces. There is a joint between 2 of these pieces at, you guessed it, the very inboard end of the fork end near the word Blade Root on your diagram from Agusta. Agusta have always said that if you find cracking in this area you should investigate to make sure it is only in the sacrificial layer, which is NOT cause for blade rejection. You would hope that maintenance staff are actually looking at things like this on their daily inspection, after all, that is what a daily inspection is for!

I know of one 139 operator that has so far inspected over 60 tail rotor blades and have found a few with the cracking in the superficial layer, and 1 or 2 that they are sending back to Agusta for confirmation that they are Ok.

Personally, I'm still more than happy to fly in 139's from my company, just like I'm happy to fly in machines from other operators if I know their maintenance and operations are above board. There are some operators that I wouldn't fly with just now as I don't believe they're doing a very good job of maintaining their aircraft in a safe state, just like some fixed wing operators out there.

With regard to the weak tail structure, the structure is a hell of a lot stronger than any 212/412 or S76 (even with all the scab patches and CSN's applied). 2 Spars to carry the load and an enclosed box structure to handle torsion loads. It is quite a robust unit, and on the AW149 has been tested up to a max takeoff of 8000kg or more.

I'm hoping Agusta can pinpoint why this blade came apart quickly. Maintenance error/involvement, or manufacturing process errors?

I heard that Agusta had a main rotor blade fail on an early 109 (in the USA??) that killed people, which was traced back to one working not cleaning the blades surfaces properly during the bonding process (or so I was told).

Lets hope that the manufacturing process is not to blame again, otherwise we'll be looking at a major recall of tail rotor blades!!!

TukTuk BoomBoom

17th May 2011, 19:36

The A109 accident was tragic.
An employee in the blade manufacture section was slicing off excess adhesive that had squeezed out during the spar to skin assembly process. Unfortunately he was using a sharp knife and scoring the spar. This led to a stress crack and a main rotor blade separating inflight with the loss of the crew and the passengers, "Trump" executives.
Human Factors...

noooby

18th May 2011, 19:59

TukTuk BoomBoom, thanks for the clarification. It is the seemingly inconsequential things that lead to catastrophic failures.
Like the Colgate BK117 fin failure, which brought to light the improper and potentially disastrous substitution of solid rivets with blind rivets by some AME's during repairs and modifications, and the FU-24 fin failure in New Zealand due to the abrasion boot being trimmed with a knife after installation, which scored the skin, eventually leading to the departure of the complete fin assy in flight.

Sorry for the thread drift.

zudhir

31st May 2011, 14:54

Any idea what the acceptable TR radial and axial vibration levels are?

noooby

31st May 2011, 15:31

0.1 IPS Radial, 0.2 IPS Axial according to the manual I have (using Chadwick).
Easily achieved although I am used to using HUMS which is an excellent piece of kit.
If doing Tail rotor adjustments, do the weights first and then go do another run. You'll more often than not find that just doing weight adjustments will bring the axial vibe in to limits as well. Adjusting the Pitch Links is a bit of a pain and they are VERY sensitive

RotorDompteur

1st Jun 2011, 07:42

Since this being a rumour network I feel that I can air what I heard;
That a tool mounted on the root of one of the tail rotor blades had not been removed after maintenance/prior to start up. And that the tool was found on the apron a long way from the helicopter.
The suspicion being that the major imbalance caused the blade to separate soon followed by the collapse of the tail fin.

RD

Runway101

2nd Jun 2011, 18:47

This was already posted by Aser in post #64 (http://www.pprune.org/6431356-post65.html) a few weeks back.

spinwing

2nd Jun 2011, 22:48

Mmmmm ...

Perhaps Stacey S would enlighten us all ??? :oh:

Aser

18th Jun 2011, 11:42

New report from AW:

16-June-2011-Follow-Up on AW139 Tail Rotor Dynamic Unbalance Event in Qatar and BT139-251 Application (http://es.scribd.com/doc/58148752/16-June-2011-Follow-Up-on-AW139-Tail-Rotor-Dynamic-Unbalance-Event-in-Qatar-and-BT139-251-Application)

Regards
Aser

500e

18th Jun 2011, 12:08

So aprox 30% are suspect at least, not a happy state

noooby

18th Jun 2011, 12:46

Actually doesn't mean a lot 500e. People are pulling their blades for the slightest imperfection that they don't want to say is Ok, even if it is. They would rather hand that responsibility over to someone else (Agusta).

outhouse

18th Jun 2011, 12:50

Hi, maybe another view is, 70% have passed the inspection, 30% have been removed as being suspect and not passing the inspection. Generally they may seem to be repairable.*
I guess they will be inspected and form part of the ongoing investigation and not release after any repair.
I also guess that those in the know are familiar with the history of the blade in question. So will look forward to the final report to emerge in the fullness of time.

Sandy Toad

18th Jun 2011, 16:26

I think the key parts are on Page 2
Sub para 1 "Cracks found on the fork area are superficial and do not involve components on the main load path"
Sub para 2 "affect only the filler material which is not structural"

Any item from any manufacturer subjected to minute scrutiny will be flag up imperfections. That is what has happened here and as Nooby said blades are being returned to the Manufacturer for second opinions. Not heard of any blades being scrapped - anybody else?

Awaiting the final report with interest!

thehighlander959

12th Jul 2011, 15:07

I am still in the sand pit here in Qatar. Have just received an email from our company that AW139 flights will continue from the 10th July 2011. Heli briefing is being carried out at GH, telling all personnel waiting to fly how safe the AW 139 is.
HUMS is now fitted to the aircraft we are flying in and we have been told safe flying operations are assured????
Yeah right.......:rolleyes:

IntheTin

12th Jul 2011, 15:29

GHC aircraft have HUMS fitted to all the 139's.

If the company wasn't happy with the fleet then they would just continue to fly the 412's, which as you probably know is no fun for either crew or pax in the 40 degree plus heat of summer.

The 139's have daily inspections and crews are happy to be flying them with the AC rather than the 412's that do not.

Most crew have families. Do you really think that if they were concerned with their safety then they would be flying them! :hmm:

blakmax

16th Jul 2011, 01:11

Alan I have sent you a PM re conference.

Blakmax

thehighlander959

17th Jul 2011, 04:11

^^
So explain to me why with all AW139 aircraft fitted with HUMS and the system in operation,that two aircraft had failures in their tail sections and this was not foreseen by HUMS?

1. Tail Boom Failure
2. Tail rotor blade failure

IntheTin

17th Jul 2011, 06:19

So explain to me why with all AW139 aircraft fitted with HUMS and the system in operation,that two aircraft had failures in their tail sections and this was not foreseen by HUMS?

1. Tail Boom Failure
2. Tail rotor blade failure

Not sure you actually understand HUMS re your post but it's used to monitor vibrations to key components, drive trains, gear boxes, engines etc. It is also integrated with the FDR.

It's 'on-demand info' using accelerometers around the aircraft so whilst the aircraft is running then HUMS can see if the rotors are out of track or balance or there is anything unusual happening in one of these critical components. The pilot can access this data. If there are any issues of concern then the pilot will inform MX.
On the ground the MX guys can then take the data card and analyse that!
Helicopters vibrate as you well know. They are all different too.

The tail boom failed due to a previous incident, along with possible de-bonding in that area.
The blade departed (yet to be proved) at the fork area of the blade.

As I said earlier, HUMS is on demand. There is a cockpit based unit that can be accessed anytime in flight or on the ground.
The crew wouldn't have had any indication that these issues were about to take place, or are you suggesting that the MX had gathered this data but decided to say nothing and have a cuppa instead!:cool:

unstable load

17th Jul 2011, 06:47

HUMS also need to "learn" it's limits of operation. Across a fleet or type, data is gathered and compared across the monitored parameters and as the flying hours build, a set of maximum acceptable limits starts to emerge and these become the "baseline" that is used to decide if a particular component is in or out of limits.

If as stated earlier, the tail fracture was a consequence of a previous incident and/or delamination, it is possible the HUMS would not have registered at all.

stacey_s

17th Jul 2011, 09:43

Just a Quickie, all GHC aircraft now HUMS installed, at the time of both incidents, both aircraft did not have HUMS installed, so no HUMS data, easy eh!

thehighlander959

18th Jul 2011, 07:07

My question concerning HUMS was that I was not sure if the AW139 aircraft belonging to GH had HUMS fitted, and would/should it have detected any of the pre-flight abnormalities that happened on both aircraft?

I suppose it is better late than never to have HUMS fitted after the events, however this is a only one small step in air safety, there are many more to be taken to ensure safe flying operations here in the sand.
We are told here that maintenance is the number one concern at GH for all customers and passengers.

Why was HUMS not ordered as part of the aircraft delivery specification if the customers and passengers are so important to their core business?