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Aeros Grounds ALL Topless Combat HG's 2011-2013 for potential Cross-Bar Failure
Categories: Trike Talk, Equipment, Safety, Hang Gliders, Soaring, Maintenance
From the Oz Report Volume 17, Number 161 Wednesday, Aug 14 2013:
Aeros has released a safety directive grounding all Combats produced between 2011 and 2013 (see below).
Detailed instructions for the crossbar check are being created and will be published at Aeros website and e-mailed to dealers within the next few days.
Grounding Aeros Combat Hang Gliders Produced in 2011, 2012 and 2013 Safety Directive-016 August 12, 2013
Status: Mandatory
Background: During the last week we had information of two in-flight crossbeam accidents on our latest Combat gliders. Fortunately, both pilots were unharmed. The first accident happened on August 2nd, and while the investigation was still on the way, we received news about the similar accident that happened on August 8th. Both accidents happened during level flight at moderate speed and the weather more or less calm (normal flight load). Both crossbeams broke in the same place and in a very similar pattern. Both gliders were not new and had between 40 and 60 flights, some of the flights in far worse conditions. Both crossbeams that failed had passed the factory load test. After a thorough investigation made by the representatives of Aeros together with the representatives of the crossbeam manufacturer, based on both accident reports and a personal check of one of the gliders, the reason of this structural failure has been discovered. In both cases it was caused by an infrequent manufacturing defect that went undetected by our quality control system.
Scope This Safety Directive covers all Combat hang gliders with a carbon crossbeam manufactured in 2011, 2012 and 2013.
Compliance: To avoid any further incidents, we strongly recommend to STOP FLYING all Aeros Combat hang gliders manufactured between 2011 and 2013 until their crossbeams are inspected by our authorized dealers.
Please, contact an Aeros dealer nearest to you for the carbon crossbeam inspection on your Combat hang glider. All Aeros hang glider dealers will receive detailed instructions for the crossbeam inspection and testing. These procedures will allow us to find any further similar defects in the crossbeams and fully exclude similar failures on the re-tested pieces. The same additional test procedures will immediately be implemented in our production process as well. In case of any questions do not hesitate to contact Aeros at <<aerosint>>
COMPLIANCE IS MANDATORY AND HAS TO BE ACHIEVED BEFORE THE NEXT FLIGHT! Fly safe!
From: Oz Report
Volume 17, Number 159
Monday, Aug 12 2013
Aeros glider cross bar failure
Fri, Aug 9 2013, 8:11:48 am CST
Pilots looking for answers (Roldanillo)
Daniel Vélez Bravo <<danielvelezbravo>> writes:
Today during a free flight day on our Colombian Nationals (some ugly clouds called the day but about 10 pilots took off to a soft and peaceful flight) one of the Aeros pilots had an emergency when his left carbon crossbar broke on mid air for no apparent reason.
Weather was not an issue, with smooth 8 km winds, some localized rain a few kilometers away, but that did not represent any danger. Smooth air and slow and consistent climbs of 1.5 - 2.5 m/s.
The pilot was flying with 75% vg at 65km/h on a straight line, when glider made a hard sound, then started to spin left. Pilot was at 600 meters above the ground. He tried to straighten the flight with no luck, even when glider looked ok. He threw the chute successfully and went down in 75 seconds according to tracklog. After fighting with the glider pointing down, he let the glider tumble and fell slowly on his back, keel first on the ground.
Damage included a broken keel near the cables and bent downtube. Sail, battens, leading edges were ok. Only one broken crossbar was visible as the cause of the problem.
We have some local pilots (engineers) doing some analysis and some writing.
At the moment it looks like the crossbar had a lot of porosity showing perhaps a lack of resin. Also there's some delaminating at the fracture, like if there where two different layers that were working separately without cohesion in between, lowering the total strength.
Pilot is ok. Fortunately he is also a skydiver with a lot of experience so he didn't feel that bad.
Glider was almost new (June 2012) with less than 40 flights, only one downtube bent on all it's lifespan. No whacks nor extremely hard landings.
[Picture of what appears to be a delaminated carbon fiber cross bar posted on OzReport.com]
The local Columbian pilots are trying to determine what would have caused this problem and are looking for any assistance that Oz Reports can provide.
Comments
Additional Updates-- Safety Directive-016dd has been EXPANDED:
Aeros's web page : http://www.aeros.com.ua/news.php?lang=english&id=350
Based on the in-depth study of the problem we have decided to extend the scope of the Safety Directive-016 dd. August 12, 2013 and to arrange immediate re-testing of all the carbon crossbeams on Combat gliders produced since January 2010 to date. Combat gliders produced between January 2007 and January 2010 are not within the scope of the Safety Directive-016. However, Aeros recommends to check the crossbeam in the same manner at the next detailed glider check-up according to the glider maintenance schedule.
The infrequent manufacturing defect referred to in the Safety Directive-016 is displacement of a carbon fabric layer while the crossbeam preform is compressed in the course of production process. This can result in a weak line forming along the crossbeam wall. And this is exactly what happened on both crossbeams that failed.
After the numerous factory tests Aeros has developed the method of revealing such defects. Please, contact an Aeros dealer nearest to you to have the crossbeam checked.
Just a couple days prior to that, as posted on the Oz report:
"My local Aeros dealer received this explanation from Aeros (and they later confirmed that it should be shared in this thread):
"All carbon crossbeams used by Aeros are tested by our crossbeam supplier. At some stage both bending and torsional tests were performed. Since some time only bending tests were made, as bending is the load most critical for the crossbeam. Normally torsion is not as important in this application. However, it was made critical by the manufacturing mistake. The infrequent manufacturing defect to which we were referring in the Safety Directive-016 is displacement of a carbon fabric layer while the crossbeam preform is compressed in the course of production process. This can result in a weak line forming along the crossbeam wall. And this is what happened on both crossbeams that failed. The incidents made us renew factory torsional tests of the crossbeams. Of course we are now re-testing carbon crossbeams on all Combat gliders that were waiting for delivery at the factory. And as we already know about the possible problem, from now on every carbon crossbeam will definitely undergo both bending and torsion test as a part of production control."