EC225 crash near Bergen, Norway April 2016
What kind of Container does CHC use for Shipping the Gearbox to/from the Overhaul Facility?
Ref this ..does the requirement to remove the oil filter everyday raise any red flags with you guys..thats a lot of removals and reinstalls IMO
This came from AH this afternoon
15/06/2016
[EC 225]
"E"ASB 05A049 TIME LIMITS - MAINTENANCE CHECKS – Main rotor drive - Check of the Main Gearbox (MGB) oil filter and chip detectors, limitation of the epicyclic modules. - Rev0
Through this ALERT SERVICE BULLETIN, Airbus Helicopters introduces the following precautionary measures for helicopters which are not subject to EASA Airworthiness Directive No. 2016-0104-E: - inspection of the MGB oil filter and chip detectors after the last flight of the day, - identification of the epicyclic modules which have been involved in an unusual event since new or Complete Overhaul, for a return for Complete Overhaul.
Download EASB / TA document
15/06/2016
[EC 225]
"E"ASB 05A049 TIME LIMITS - MAINTENANCE CHECKS – Main rotor drive - Check of the Main Gearbox (MGB) oil filter and chip detectors, limitation of the epicyclic modules. - Rev0
Through this ALERT SERVICE BULLETIN, Airbus Helicopters introduces the following precautionary measures for helicopters which are not subject to EASA Airworthiness Directive No. 2016-0104-E: - inspection of the MGB oil filter and chip detectors after the last flight of the day, - identification of the epicyclic modules which have been involved in an unusual event since new or Complete Overhaul, for a return for Complete Overhaul.
Download EASB / TA document
Good question considering the history of another member of the class. Anyone able to post illustrations of the filter and fixings and tell us the materials used?
Shucking Rotorheads and Oil Filter issues.....uh oh!
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Sasless,
Don't believe they are suggesting filter issues. Chip detectors are obviously not doing the job well enough so requiring a physical inspection now. Luckily, the filter on the puma is much more maintenance friendly then others. The ground run/leak check is more of a pain then the actual inspection.
Shucking Rotorheads and Oil Filter issues.....uh oh!
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Inner bearing races and outer bearing races are made from hard brittle material and can easily be cracked with a moderate blow from a hammer or dropping it or whatever. I have seen mechanics remove (industrial) bearings faster than anyone using the best pullers , he would place a rag over the bearing (to prevent flying fragments) , carefully position a dull punch or chisel on the race , then deliver a careful moderate blow with a hammer and the bearing would crack.
That is why I was surprised to see the outer race incorporated into the gear on the EC225 , I always thought gear teeth should be less brittle and the bearing should have its own outer race pressed in. Reading the fine print it sounds like they use different hardening for the inside of the gear (race) so obviously they have figured out a way to make it work and are obviously much more knowledgeable than I am
Mostly I wanted to point out that impact damage or shipping damage has some merit in this discussion. Actually I think it would most likely happen pre-installation , the gear was dropped or impacted in some way to start a microscopic crack
I repeat my surprise while watching a (careful) mechanic disintegrate a bearing race with a light hammer blow , it breaks like glass , pieces fly all over the place.
That is why I was surprised to see the outer race incorporated into the gear on the EC225 , I always thought gear teeth should be less brittle and the bearing should have its own outer race pressed in. Reading the fine print it sounds like they use different hardening for the inside of the gear (race) so obviously they have figured out a way to make it work and are obviously much more knowledgeable than I am
Mostly I wanted to point out that impact damage or shipping damage has some merit in this discussion. Actually I think it would most likely happen pre-installation , the gear was dropped or impacted in some way to start a microscopic crack
I repeat my surprise while watching a (careful) mechanic disintegrate a bearing race with a light hammer blow , it breaks like glass , pieces fly all over the place.
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Arnie,
Am surprised to hear your experience of seeing a bearing shatter with a light hammer blow, was that bearing from a helicopter MGB?
re the transit damage to MGB - was it in the correct transit container? MGB are usually pretty well mounted inside them. Would be interested to see the damage to container and gearbox, anybody have pictures?
BS
Am surprised to hear your experience of seeing a bearing shatter with a light hammer blow, was that bearing from a helicopter MGB?
re the transit damage to MGB - was it in the correct transit container? MGB are usually pretty well mounted inside them. Would be interested to see the damage to container and gearbox, anybody have pictures?
BS
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Am surprised to hear your experience of seeing a bearing shatter with a light hammer blow, was that bearing from a helicopter MGB?
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I have an epicyclic gear complete with bearings on my desk, and given the ongoing discussion and it's in-visual line to my computer screen I have just decided to satisfy my curiosity to see if it it will break when hit with a hammer.
I don't know what alloy it's made of or what they do to harden it but it didn't break and I don't recommend anyone doing it either.
It does however satisfy my curiosity about this ongoing discussion and a personal theory that if it was going to break easily it would have done so years ago from the abuse it regularly receives by 'accidentally' falling on the floor due to enthusiastic dusting.
I don't know what alloy it's made of or what they do to harden it but it didn't break and I don't recommend anyone doing it either.
It does however satisfy my curiosity about this ongoing discussion and a personal theory that if it was going to break easily it would have done so years ago from the abuse it regularly receives by 'accidentally' falling on the floor due to enthusiastic dusting.
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The OP specified a dull punch or chisel was placed against the bearing to provide a point load and that this was then hit with a moderate blow. Just hitting the bearing with a hammer is unlikely to shatter it as the blow is distributed over too wide an area.
Similar principle to hammering a nail into wood. Hit the wood with a moderate blow with a hammer and little or no damage. Concentrate the energy into the point of a nail and it penetrates the wood easily.
Similar principle to hammering a nail into wood. Hit the wood with a moderate blow with a hammer and little or no damage. Concentrate the energy into the point of a nail and it penetrates the wood easily.
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DCVC asks about RTA - cannot resist to tell the tale!
Probably off-thread sorry but was fowl at the time: RTA lowloader carrying S76 (all less blades) colliding with swerving articulated trailer filled with live chickens; re-named KFC ........
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Radial roller bearings outer races are heated up and pressed oval in a die when mounting the balls.
They would not crack with a hammer hit. The standard bearing material is 100Cr6 and has a surface hardness of around 60 HRC.
here are two interesting reports that gives a bit more insight in the materials used
https://www.google.de/url?sa=t&rct=j...,d.ZGg&cad=rja
https://www.google.de/url?sa=t&rct=j...,d.ZGg&cad=rja
And here it refers the material of the 332L2 planet gear outer race material:
Fractured Gear | Flight Safety Foundation
Subsequent testing determined that the particle was not silver or cadmium but 16NCD13 steel, planet gear outer race/gear material.
They would not crack with a hammer hit. The standard bearing material is 100Cr6 and has a surface hardness of around 60 HRC.
here are two interesting reports that gives a bit more insight in the materials used
https://www.google.de/url?sa=t&rct=j...,d.ZGg&cad=rja
https://www.google.de/url?sa=t&rct=j...,d.ZGg&cad=rja
And here it refers the material of the 332L2 planet gear outer race material:
Fractured Gear | Flight Safety Foundation
Subsequent testing determined that the particle was not silver or cadmium but 16NCD13 steel, planet gear outer race/gear material.