Eurocopter 350/550 airframe problems!!!
 

We just had a major inspection at our company of our fleet of 20 aircraft. On just over 1/3 of the fleet we found major cracks and debonding of fiberglass/kevlar and aluminum all over the forward portions of the fuselage, mainly upper door runners and door posts, one aircraft had one door post top completely severed in half due to a major cracks attaching to the roof. The oldest aircraft has just over 1000 hours, while some of the others have just over 100 hours. Does anyone have any prior knowledge or experience with this? This was addressed to Eurocopter a year ago with no feedback from them.

If this is as bad as you say(and I have no reason to doubt that it is) has it been reported to your local FAA field office for AD evaluation?

Mods, to Engineers and Technicians please?

And to Rotorheads to please. Don't know who has been notified, but EC is just not responsive!

1000 hrs? Our fleet has over 7000hrs per airframe, and not seen those faults (and these are training aircraft that do a lot of 'firm' and running landings as well as hundreds of EOLs.

Reply to Eurocopter 350/550 airframe problems!!!
 

Weird Info, I have been flying 350 and 355 for 25 years, in many remote places doing hard jobs and I never heard about such big problemon those, even few machines can be damaged sometimes with few cracks on cabin nose.
The machines you talk about were built in Grand Prairie or Marignane?
I am not Eurocopter enginer but what kind of flight do you do with those machines?
Do you fly often with open or removed doors? Wich speeds or powers do you fly?
Do your maintenance or even your pilots, respect the vibrations limitations??
Check the speed for open/removed doors use.
Also, it is defenitely not usefull to fly at full continous power (pmc)on cruse all the time, because you get into little vibrations with only 2/3 knots gain.Those vibrations may not be that uncomfortable for former Bell pilots for exemple, but you better down the pitch a little bit to have a smoother flight. The 350 is the smoothest machine I know, and when it is vibrating, it means that balance (maintenance) or simply inflight pilot use is not suitable.
Peace
Philippe

Without getting into detail of what we use them for, we do fly often without doors. We have a nose mounted FLIR that weighs about 100lbs. offset to the left of the nose centerline. Looking today, the high time airframe is 1097 hours, still a youngster. Some with the debonding and crack issues have less than 130 hours. The aircraft that came apart has less than 780 hours. All aircraft were manufactured in the Marignane plant. We routinely fly at 5000-5200 lbs. We have the Arriel 2B engine (550 C3). We do touchdown autos when training.

Without knowing full details of this case I note that EC recently issued warnings about STC's that had been incorporated without factory input and without adequate investigation. EC are highlighting the potential for problems with these installations.

This sounds exactly like what the Australian Navy had with their fleet of AS350's in the mid to late 80's, with cracking and debonding in the canopy. They decided it was due to the twisting stress as a result of having the aircraft tied down to the ship's deck while the ship pitched and rolled. Not saying this is what caused your problems but just pointing out that it has happened before. It took months of repair work before the problems were sorted out. Eurocopter should have plenty of knowledge of this problem.

what is a STC?

Supplementary Type Certificate. Issued by FAA it is the authority to install optional equipment on a type certified aircraft. Typically they are granted to non OEM's . The package will normally include Installation instructions , maintenance manual suplement ( if applicable ) , Instructions for continued airworthiness and in some cases a flight manual suplement.

Supplemental Type Certificates

Transport Canada - NICO (NAPA Issued Certificates Online)

It’s been a few years since I worked on AS350’s, but cracking in the door posts, upper arches, canopy and ceiling arches was so common that it is on our daily inspection. When I was trained on AS350’s it was stressed to me to look closely at this area every day. I’ve seen aircraft with as little as a few hundred hours develop cracks. The material in this area is thin and is not robust. Also, we do not fly with doors off and have no STC equipment installed in this area.

All of our "extra" equipment was installed by EC either at the factory or on site. We have no STC equipment (doesn't apply to us) anywhere around where we are having problems. Scary stuff.

I have quite a few years on survey and ems 350's. Yes, the cracks is something you always look out for especially on the door posts near the pilot door hinge attachment. However, there are pretty straight forward repair procedures if you catch it soon enough. If not, debonding of the composite will occur due to moisture absorbtion. I have only had one cracking along the canopy on the outside just above the upper pilot door hinge. We caught it before it took the turns which would have caused it to run right around and since had no problems again although we watch it closely after the repair.

I do agree with the doors off scenario's.

What do you do when the debonding takes over? Seems like a major scenario?

Eurocrapter, unfortunately the repair schemes are mostly for the initial stages of a crack found-often even before it is the composite but just a paint crack showing something is going to happen. Once the debonding started, it means moisture has entered in between the various layers of the composite fibre bondings and resin(same for your blades). Dependant on which area of the canopy you are talking about will influence whether repairable by drilling and refilling with the specified bonding agent or not. Again, if caught early enough on your MR blades, you have a similiar repair possible. In other areas they might require a step repair and in others a canopy replacement.

Update - our high time airframe has over 9000hrs - apart from minor repairs around the lower corner of the canopy near the door hinge they're fine.

just a thought, but while upsetting to see a crack at the top of the door post or at the top of the door rail am I not right in thinking that this isn't part of the primary structure?

Also a seem to remember that there was a lot of fuss about cracking at the bottom of the windscreen outboard pillers and it turned out to be cracking in filler that had been used to cover the little grove that is where the piller and nose meet.

Either way it's in the repair manual to fix these faults, unless they are far more serious than you imply.

It would be worth looking at your flight profiles if this is affecting your whole fleet as I've only seen this a couple of times and grew up of squirrels that were used for everything from filming to training.

good luck with finding a fix

Forgive an old beginner, maybe I will sound stupid.
Most or replies talk about fixing the cracks or regulations, but 1/3 of the fleet would make me think about the cause. Sea salt or pollution, extreme temperatures for an environment cause, or the habit of a human hand of an engineer or passenger/crew.
One reply asked about the kind of flight. I would ask where the fleet is based.

Eurocrapter,

I am aware of some preliminary STC work to resolve this problem. You are welcomed to PM me if you wish...

Pilot DAR

FAA Malfunction or Defect Report
 

Eurocrapter-

Too often large problems like this are found and not reported to the FAA as Matkat suggests. Sounds like this is significant enough to warrant submitting a Malfunction or Defect Report to the FAA. Here is the link:
SDR Submission Form