R22 overspeed on start due to throttle being fully open
Join Date: Nov 2007
Location: Massachusetts
Age: 67
Posts: 172
Likes: 0
Received 0 Likes
on
0 Posts
1) Has anyone else ever had this happen or am I just a complete idiot?
2) What damage likely occurred
3) How many dollars worth of damage did I just do?
2) What damage likely occurred
3) How many dollars worth of damage did I just do?
Dynamic Roller said:
My own starting rule is "thumb down, feel the spring". There is no spring on the other side.
Arm out the window said:
The unobtrusive fingers of the examiner's left hand resting lightly on the throttle would have let him or her monitor the candidate and prevent an expensive stuff up too - it surprises me that wasn't done. It's not interfering with the test, just sensible.
Cylinder Head said:
Another gotcha to watch for is the habit of some pilots ticking the throttle open slightly to help the start.
Bell ringer mentioned that this is the reason to check that the white line on the fan is aligned - if you find it misaligned I wouldn't fly the machine. It's an indication that someone had a startup overspeed (or, possibly, overspeed/acceleration during a power recovery autorotation). If the school claims they don't bother to paint the white line when they've had the fan off, you should encourage them to do so and do what Bell ringer suggested: take a picture of the fan with your phone so that if there's any question about who spun the fan you can prove it was already spun when you flew it. But I personally would (and have!) refuse to fly a ship that doesn't have he line marked.
Jelico:
This is pretty common in both R44 and R22. Have seen it (from the hangar) once in an R44. Damage was fairly minimal, an inspection and I believe a mag overhaul.
One problem is that lots of schools don't have the cash lying around to do this, so either they encourage the pilot to say it was a smaller overspeed than it really was, or they perform the 5-10% inspection regardless of how high the RPM might have gone. The problem of course is that you're asking for engine problems in the future, possibly while some student pilot is flying alone.
Given that people feel guilty about overspeeds, and that they are worried they might be charged a fee for doing it, it's not that hard for a school to pressure the student/pilot into saying it was a small overspeed. This is why I always recommend you "fly rich people's helicopters" - especially if they fly in them - they're less likely to pressure the maintenance staff to not do the required inspection. As our chief of maintenance told me once "I'm not going to jail just to save <owner's name> some money". Therefore they do it by the book and are reluctant to even trust a student to say what the peak RPM was (because really, the student probably didn't actually see what the RPM reached).
vaqueroaero said:
Seen it done in an R22 before. Sounded like a chainsaw starting up.