MD Helicopters 369-500, Maintenance Instructions Manual

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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Revision 7
95-30-00
The information disclosed herein is proprietary to MD Helicopters, Inc.
Neither this document nor any part hereof may be reproduced or transferred to
other documents or used or disclosed to others for manufacturing or any other
purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright
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1999 − 2016 by MD Helicopters, Inc.
Hz) will cause an alarm condition and
would activate the voice warning
system. The LRU, upon receiving this
signal, provides the voice warning
”ENGINE OUT” into the audio outputs.
In addition, the LRU will provide a
di28 Vdc (2.5 Amps max.)
output to drive the caution warning
light and fire the igniters. In the event
the monitored frequency rose above the
55% level, the light and voice warning
circuitry will reset.
B. Fire
The signal is +28 Vdc from the fire detection
unit and is only present when the system is in
alarm condition. The LRU, upon receiving this
signal, provides the voice warning ”FIRE” into
the audio outputs.
C. Low Rotor
The N
R
signal, coming from one coil of the
rotor speed sensor, is monitored in the LRU.
After power up and the RPM has exceeded
95% (1325.3 Hz), any deviation below 95% N
R
and down to 75% N
R
(1046.3 Hz) will cause an
alarm condition. The LRU, upon receiving the
signal, will provide the voice warning ”LOW
ROTOR” into the audio outputs. In the event
the monitored frequency rose above the 95%
level, the warning circuitry will reset.
D. ECU Manual
The manual mode signal is derived from the
output to the caution warning light. When
activated in an alarm condition, the relay
provides a ground that activates the light. The
LRU, upon receiving this signal, provides the
voice warning ”ECU MANUAL” into the audio
outputs.
E. Power
The signal for power activation is any voltage
above 2.98 Vdc. The signal is derived from the
torque pressure transducer signal to the
engine torque indicator. The LRU, upon
receiving this signal, provides the voice
warning ”POWER” into the audio outputs.
F. Fuel Flow Fixed
The fuel flow fixed signal is derived from the
output to the ECU fail caution warning light.
When activated in an alarm condition, the
relay provides a ground that activates the
caution warning light. Upon receiving this
signal, the LRU provides the voice warning
”FUEL FLOW FIXED” into the audio outputs.
NOTE:
In the event that the ECU MANUAL
and FUEL FLOW FIXED condition is acti­
vated simultaneously, the ECU MANUAL
voice warning will cancel out the FUEL
FLOW FIXED message.