Yet another AW139 tail incident at Gulf helis

[thehighlander959]

^^

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???

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]

Safe To Fly

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]

Another AW product

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

[blakmax]

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/pa...ve%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]

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!

Blackmax you have got an email...

Regards
Aser

[Chi Sin Gei Si]

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]

sad for HK

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]

and the solution is.............

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

[9Aplus]

no, no Bell uses that one on TT straps only

[TRC]

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]

blakmax,

Can't you find a shed for your wheelbarrow?

[CopterDokter]

Reply to Aser

Aser, I just sent a PM to you --

[helihub]

"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]

as always, for educational purposes:





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



Regards
Aser

[TRC]

We aw139 drivers really need answers...

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

[500e]

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]

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

[Aser]

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/...es/139-251.pdf


Regards
Aser

[blakmax]

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]

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.