MD Helicopters MD900 with PW206E, Flight Manual

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CSP–900RFM206E–1
ROTORCRAFT FLIGHT MANUAL
MD900 With PW 206E
Systems Description
Original
7–30
Train Mode:
Placing an engine control switch in the TRAIN position will simulate a one engine
inoperative condition by resetting the selected engine’s governed speed to 92
percent N
P
, thereby putting the engine on standby while allowing single engine
training on the opposite engine. In the event of an engine failure on the opposite
engine, the engine in TRAIN will automatically revert to 100% N
P
.
Emergency Manual Control:
The controls for manual operation of the engine power consist of two twist grips
on the collective pitch stick and a push button located on the collective control
module at the end of the collective stick.
The EEC is designed to ‘‘fail−fixed" (EEC’s stepper motor is fixed at its last con
trolled power setting) so there is no sudden change in the level of power if an
EEC becomes inoperative. The only noticeable happening is illumination of the
yellow EEC/red FAIL
warning on the Integrated Instrument Display System
(IIDS). No matter at what power level the EEC becomes inoperative, there is
sufficient travel in the twist grip to control the engine manually from full power
to idle and engine shutdown.
After the EEC becomes inoperative, the pilot uses the appropriate twist grip
on the collective stick to modulate the power.
7–11. FUEL SYSTEM
The single crash−resistant elastomeric fuel cell is capable of holding 161.3 U.S.
gallons of jet fuel and is located in the lower fuselage under the main cabin floor.
It is contained between crash−resistant keelbeams and bulkheads, with a support
panel underneath.
The powerplant separation feature includes a partial−height baffle that runs fore
and aft along the bottom center of the cell to trap enough fuel on either side to
prevent simultaneous dual engine flameout if one side were punctured and the
cell lost all its fuel down to that retained on the undamaged side of the baffle. This
is a pressurized fuel system with a separate fuel pump located in the sump in each
side of the cell.
The cell is designed with a seven percent expansion space, and has two anti−slosh
baffles across it. Pilot−operated shutoff valves are positioned at the engine firewalls.
Selfclosing breakaway fittings are installed where fuel lines penetrate the cell walls
and where they penetrate the engine deck. Overboard fuel cell vent lines incorporate
rollover valves and flame arrestors located in the vent system stand pipes.
The gravity−type fuel filler port is located on the right side of the fuselage just
aft of the pilot’s cockpit door.
Two sump overboard drains for removing sediment and water (one for each side
of the cell) are operated by knobs located under the right side cabin step.