Paddy attacks C-130 with hatchet at Shannon Airport in Ireland
Timeline
Post
Remote status
Context
3
HIT THE PROP
HIT THE PROP
A prop strike is a prop strike, the protocol is the same no matter what actually happened - it's usually a gearbox teardown and the prop has to go out to a prop shop to be re-certified.
HIT THE PROP
A prop strike is a prop strike, the protocol is the same no matter what actually happened - it's usually a gearbox teardown and the prop has to go out to a prop shop to be re-certified.
Any dynamic event like that means at a minimum that the prop blade gets changed out, but in this case, it would be the entire prop, since all 4 blades are installed as a matched set. If the powertrain was running, that's the prop & gearbox assembly and an airframe conditional inspection. The high speed driveshaft will likely need to get changed too.
Okay so they do make a distinction based on whether it's running.
What I'd heard was relative to piston/GA, that if you damage a prop, you are required to split the engine.
What I'd heard was relative to piston/GA, that if you damage a prop, you are required to split the engine.
Replies
2
A blade strike with engine running on a direct-drive piston (like a Lycoming, Continental or Titan) is an automatic tear down. I've done a bunch of them. Time consuming and rediculously expensive.
The Rotax 9 series is not direct drive- they use a prop speed reduction unit (PSRU) with an elastomeric connection from the crank to the gearbox (to help absorb torsional vibrations) and a slipper clutch immediately upstream in the PSRU to absorb a strike. Rotaxes typically use low-inertia props, ie, composite or wood, so a prop strike is not traumatic on the main power unit at all. In many cases, it is a borescope inspect of the power unit, changeout of the PSRU and elastomer, then oil samples at 10, 25, 50 and 100 hours after to ensure all is good. Much easier. Quicker and cheaper to do.
Rotax engines are my jam; I was factory-trained in Austria.
The Rotax 9 series is not direct drive- they use a prop speed reduction unit (PSRU) with an elastomeric connection from the crank to the gearbox (to help absorb torsional vibrations) and a slipper clutch immediately upstream in the PSRU to absorb a strike. Rotaxes typically use low-inertia props, ie, composite or wood, so a prop strike is not traumatic on the main power unit at all. In many cases, it is a borescope inspect of the power unit, changeout of the PSRU and elastomer, then oil samples at 10, 25, 50 and 100 hours after to ensure all is good. Much easier. Quicker and cheaper to do.
Rotax engines are my jam; I was factory-trained in Austria.
Okay so then what I had heard is wrong entirely. I knew tagging you would lead to good info...