Paul;
About a year ago on a flight from South Fla., I was about an hour away from my
home base at Leesburg, in normal cruise, at 5300 RPM and 33" MP. The red over
boost light came on. I looked at the MP which was normal, RPM was normal. I then
turned off the "switch" for about 5 seconds then turned it back on. The TCU
recycled itself, the red boost light went out., and I continued the flight home
with no further problems.
In the maintenance manual for the 914 there is a section on troubleshooting the
servo and the red and yellow lights. The switch is part of the system and it
needs to be installed.
Paul McAllister wrote:
>
> Gilles,
>
> Thank you for sharing your thoughts. I am still curious about the need to
> be able to disable the waste gate servo. My thoughts are about the
> delectability of a failure and what remedial actions can be taken in flight.
> Assuming I don't have a Flydat, how could I tell if the waste gate has been
> commanded by the TCU to an incorrect position. Secondly, lets assume that
> the TCU drove the waste gate to fully open or fully closed and I was able to
> determine that this was incorrect, how could I move it from that position in
> flight. Disabling the servo in this situation doesn't really buy me much.
> I suspect that if the TCU failed in a manner that keep driving the servo
> hard against the stops that it would cause enough over current to trip the
> circuit breaker.
>
> Paul
>
> > According to the Rotax documents the purpose of this switch is to
> > disconnect the waste gate actuator in case of turbo surge or calculator
> > troubles.
> > Virtually every Rotax 914 owner I know of have installed it. Some had
> > to use it.
> >
>
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