MD Helicopters MD900 with PW206E, Flight Manual

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CSP–900RFM206E–1
ROTORCRAFT FLIGHT MANUAL
MD900 With PW 206E
Systems Description
Original
7–28
7–9. ENGINE AIR INTAKE AND INLET PARTICLE SEPARATOR (IPS)
The air intake system provides a path for ambient air to enter each engine compressor
case inlet. The air intake system consists of an inlet screen or optional inlet particle
separator for each engine that prevents debris from entering the engine ducts.
Inlet screen:
The standard inlet screens are 1/4 inch steel wire mesh screens located on the
upper intake cowlings (Ref. Figure 7−16). Each engine inlet screen prevents large
foreign objects from entering the inlet plenum. A bypass opening is located at
the aft end of each inlet screen. The aft facing bypass opening assures airflow
if the screen becomes clogged.
IPS (if installed):
The inlet particle separator is an inertial type particle separator that removes
debris from the ambient air before it enters the engine. The particle separator
is located on the upper intake cowling (Ref. Figure 7−16). Ambient air enters
the particle separator and the air velocity is increased as the air passes over
swirl guides. The swirl guides create a vortex that separates heavy particles
from the air. The particles drop to the bottom of the particle separator panel.
A solenoid valve and bleed air lines route engine compressor bleed air to the
particle separator ejector to eject the particles overboard. The ejector is controlled
by the pilot through the IPS switch located on the Utility panel. In the event
that the particle separator becomes clogged with debris, solenoid operated bypass
doors automatically open for both engines inlets.
NACA inlet:
The NACA engine inlets provide ‘‘ram air’’ for enhanced engine operation/perfor
mance during cruise flight. If the aircraft is equipped with an IPS, the NACA
inlets incorporate doors that open/close automatically when the airspeed is great
er/less than 47 KIAS.
On aircraft with the standard engine inlet screen, the NACA inlet does not include
doors, but has a screen covering the inlet.
If the aircraft is equipped with an IPS, a NACA inlet switch is provided on the
options switch panel that allows the pilot to override the automatic door opening
feature and leave the NACA inlet doors in the closed position. NACA door position
indicator lights are located on the instrument panel below the VSCS indicators.
Additional information for operations with the NACA inlet may be found in Sec
tions III, and IV.