EMERGENCY PROCEDURES
RSUK0287_POH_Cavalon Revision 2, Issue Date 24.06.2015 3-5
3.8.4 Trim runaway
Failure of a trim selector switch or pneumatic valve may result in trim runaway (where the
trim system runs to one extreme and pushes the control stick accordingly). Although the
average pilot is able to resist the out-of-trim stick force and continue to fly the aircraft it may
be possible to reduce the stick load by intervention:
(i) High forward stick load required to prevent aircraft nose rising (this will be
coincident with a high air-pressure reading) – briefly turn the Flight/Brake selector
to “Brake” to deplete system air pressure. If the air compressor is heard to start
and the pressure rises again then pull the circuit-breaker marked “Comp” to stop
the compressor. Repeat the brief selection of “Brake” to deplete system air
pressure as required.
(ii) High aft stick load required to prevent aircraft diving (this will be coincident with
low or zero air pressure) – check “Comp” circuit breaker, if activated push to reset
then try to trim aircraft nose-up. If unsuccessful then continue to expedited
landing. Note: reset the circuit-breaker once only.
(iii) High roll-left or roll-right stick load required to maintain balanced flight (coincident
with high air-pressure reading). Pull the “Comp” circuit breaker to prevent further
increase in air pressure and attempt to re-trim. If unsuccessful then continue to
expedited landing. Do not select “Brake” in an attempt to reduce air pressure as
this will disturb the pitch trim (in which the out-of-trim forces are significantly
higher)
3.9 Pitch oscillation recovery
There are generally two types of pitch oscillation: that caused by pilot over control (‘PIO,
Pilot Induced Oscillation’) and that caused by aerodynamic oscillation.
PIO is not generally found on two seat gyroplanes due their inherent stability. It is initiated
by the pilot over-controlling the stick. If a situation develops where a divergent aircraft
pitching oscillation is occurring in sympathy with fore-aft control stick inputs, firstly stop the
control input – do NOT try to control PIO with the stick.
For both situations, smoothly closing the throttle whilst maintaining a level flight attitude will
return the aircraft to a stable, slow speed condition very quickly, from which the pilot can
recover to normal flight.
Recovery from PIO or aerodynamic oscillation can result in height loss.
3.10 Vibration
A gyroplane is subject to a number of out of balance forces which will generate different
levels of vibration depending on the engine and rotor rpms, and on loading conditions.
Rotors are normally balanced two seated, so a reduction in occupant loading will naturally
change the rotor response.
1. Engine and propeller. Vibration in this area will change with engine rpm, and can
therefore be affected and isolated by the pilot. The propeller is normally balanced to less
than 0.1ips, meaning low vibration. Vibration will increase as the propeller gets dirty, and will
also increase if damaged. A sudden change in flight will indicate a fault has developed,
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