Engine Failure Containment Certification

[LegacyDriver]

I understand what the regs say about engine failures and containment (or at least think I do) but the actual TESTING and IMPLEMENTATION of these rules is not something I know much (if anything about).

It is my impression that containment shrouds/rings are built to withstand a theoretical uncontained engine failure. However, what I want to know is, how is the actual ring/shroud size, shape, thickness, etc. arrived at? Do they just do a measure on the energy of a rotating part coming off the engine and build it to withstand that? It seems to me that blowing up a multi-million dollar engine on purpose would be prohibitively expensive.

The first parts-shedding engine failure on a production airplane would seem to be the first true test of the effectiveness of a containment ring/shroud. Am I wrong?

 

[fly4free]

saw a slow mo video of a BMW BR-710 (GV engine)

blow a blade off at TO power...pretty cool to watch the titanium diaper do its work!!

but otherwise I have no frickin clue how they design the shrouds.

 

[bocefus]

[QUO
The first parts-shedding engine failure on a production airplane would seem to be the first true test of the effectiveness of a containment ring/shroud. Am I wrong?[/QUOTE]


No, testing to failure is a requirement of FAR 33 certification. Simulation and modeling get you to the test rig, the test rig validates the data.

 

[erj-145mech]

I have no frickin clue how they design the shrouds.

BWAG, Best Wild A$$ Guess.

 

[LegacyDriver]

No, testing to failure is a requirement of FAR 33 certification. Simulation and modeling get you to the test rig, the test rig validates the data.

So when we have an uncontained failure (i.e. parts poking through the shroud) they engineers dropped the ball or what?

Seems expensive as heck to blow stuff up on purpose. I was under the impression it was all based on calculations and computer models. Interesting for sure.

 

[bocefus]

Basically, yes. Make sure you understand the FAA definition of "uncontained failure". It is acceptable to have parts eject from the intake or exhaust areas and still meet the certification criteria. Yes, certification requires testing to failure and verification of the containment barrier.