A helicopter that's vibrating? OH MY GOD!!
There are a couple of "dirty little secrets" in aviation. One of them is that ag aircraft are not maintained like Microsoft's S-76. At some operators, maintenance is...err, "dodgy." You do what you've got to do to get the job done. Fussy, nervous, "white shirt" pilots who write up torn seat cushions and ground the aircraft for any little reason need not apply. Operators such as these attract employees who understand that ag is, well, ag.
[/editorial mode.]
The accident aircraft is reported to be a Falcon ("civilianized") OH-58A. That would indicate to me that it had in it a 250-C18 engine which, let's face it, is not a viable powerplant anymore despite what the legion of C-18 operators out there will tell you to the contrary.
Jim63 makes a first-hand report that this very aircraft had of the snap rings on one of the transfer tubes had come undone, allowing an air leak. And yes, that will result in a VERY hot running engine. ...An engine, mind you, that doesn't have a whole lot of TOT to spare in the first place.
In the accident on 2Feb, it appears that the pilot did report the generator failure shortly before crashing. A newspaper picture I saw of that accident showed the main rotor blades fairly intact, indicating low rpm upon arrival at the crash site. This might point toward some sort of prior power interruption to the rotor.
Look, all helicopters vibrate. Mine does. What's "horrible and grounding" to one pilot is "acceptable for flight" to another. It's fairly subjective until you can get the vibration gear on it. But some pilots do put up with a lot before they get to the point of demanding something be done. One would hope that a pilot didn't put up with so much vibration that it actually caused a structural failure of some sort.
Back to the editorial mode. I don't like ag work. Every ag operator I've ever seen has been shady. The equipment is rough. It might look like a helicopter, but it ain't. The aircraft become industrial farm implements. As long as they start and get off the ground, they're good-to-go. During the working season, any "maintenance" that is performed is usually hasty and crude. Or deferred until...later.
In the U.S., the FAA usually doesn't go after ag operators with much aggresiveness. The danger to the public is small. When a crash occurs it's usually out in a field. No one gets hurt except the pilot, who has accepted the risks that go along with that type of flying. Which is why I don't do it.
So back to the subject of this thread: An ag helicopter with reportedly dodgy maintenance crashed. Is anyone surprised? Nope. The pilot lived to fly another day, and another aircraft will be procured for him to do it in.
