Yet another AW139 tail incident at Gulf helis
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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.
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.
Tail Gear Box
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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.
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 ?
"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 ?
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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
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
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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
Kevlar is also used in Super Puma Mk2, (prob EC225 as well) Main ant Tail rotor heads as reinforcement bands
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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.
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 guys, I fly this machine.....
You can all fcuk off with your speculation...
The FMS sucks but the airframe rocks
If the tail rotor falls off I'll let you know..
You can all fcuk off with your speculation...
The FMS sucks but the airframe rocks
If the tail rotor falls off I'll let you know..
Chief Bottle Washer
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Mmmmm ...
Griffo .... your really way too subtle for this forum .....
(BTW ... have now left 'you know where' for a real future (?) back home).
Griffo .... your really way too subtle for this forum .....
(BTW ... have now left 'you know where' for a real future (?) back home).
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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.
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.
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
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
Last edited by griffothefog; 13th May 2011 at 04:15.
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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.
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,
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!!!
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!!!
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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...
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...
