Engine Overspeed; Engine Underspeed - Bell BHT-206L3-FM-1 LongRanger-III Flight Manual

BHT-206L3-FM-1
DOTAPPROVED
. .
IF START IS NOT INITIATED
BEFORE GAS PRODUCER
DECREASES BELOW 30% RPM
(APPROXIMATELY 10 SECONDS
AFTER ENGINE FAILURE),
THROTTLE SHALL BE
MODULATED DURING START TO
PREVENT EXCEEDING TURB OUT
TEMP LIMIT.
7. Throttle - Idle.
NOTE
If TOT gage has a red triangle at
826°C, refer to BHT-206L3-FMS-17
for alternate TURB OUT TEMP.
8. TURB OUT TEMP - Monitor
range 716 to 768°C.
9. Throttle - Advance smoothly to
fully open position.
If a restart is unsuccessful, abort start
and secure engine as follows:
10. Throttle - Closed.
11. FUEL VALVE switch - OFF.
12. Accomplish autorotative descent
and landing.
3-10. ENGINE OVERSPEED
An engine overspeed may be due to one of
the following: fuel control failure, power
turbine governor failure, or mechanical
drive failure to the power turbine or gas
producer accessory sections.
If the GAS PRODUCER RPM can be
controlled with throttle, then a power
turbine governor failure or power turbine
accessory drive failure is indicated.
If the GAS PRODUCER RPM and POWER
TURBINE RPM are unstable and cannot be
3-8 Rev. 3
controlled with throttle, then the fuel
control has malfunctioned or the gas
producer accessory drive has failed. A gas
producer accessory drive failure-is
indicated by a rapid loss of ENG OIL
pressure.
*INDICATIONS:
1. Increase in ROTOR RPM.
2. Increase in POWER TURBINE
RPM.
3. Increase in GAS PRODUCER
RPM.
4. Increase in TORQUE.
*PROCEDURE:
1. Throttle - Retard.
2. GAS PRODUCER RPM or POWER
TURBINE RPM - Stabilized with
throttle control.
3. TURB OUT TEMP - Monitor for
normal operation.
4. Collective - Adjust as required
to maintain 90 TO 107% ROTOR
RPM.
5. Cyclic - Adjust as required to
maintain desired AIRSPEED.
6. Prepare for power-off landing.
.
.
IF RPM AND TURB OUT TEMP
CANNOT BE MAINTAINED, THE
ENGINE MUST BE SHUT DOWN.
3-11. ENGINE UNDERSPEED
*INDICATIONS:
1. Abrupt decrease in GAS
PRODUCER RPM.