OT: Ground Resonance

[cessna170bdriver]

Bruce,

How often does something like this happen?

[Bruce Fenstermacher]

It doesn't happen often but obviously it can happen. The A-Star, which this is, may be a bit more prone to it because of the type of head it has and may be why that helicopter has anti ground resonance springs that look like leaf springs that hang of the back of the skids to give positive pressure to the landing gear. This has a higher chance of happening on uneven terrain if the springs don't make contact and the skids aren't planted firmly but resting precariously on a rock or some other protrusion from the ground.

Can't tell from the video exactly what phase of landing the pilot was in. If this starts are with the rotor at flight speed the procedure is to lift of the ground and it stops instantly. Can't recall the low rotor procedure. Probably hold on. Looks to me like the rotor is not at flight speed. The key is did the pilot realize he had a problem and rolled the throttle off when he could have just lifted off otherwise and stopped the problem.

I've got about 2200 in A-Stars of all landing gear configurations and probably 6000 landings in the airframe, maybe more. Never had ground resonance.

[blueldr]

Truth be told, I believe it is just Earth rejecting anything as complex and improbable as a helicopter. Of course, it's very possible that all of it's parts time life expired at the same time.

[busav8or]

Probably burning Mogas!