I A P 2 0 2 3 . 0 0 1 - A F M / I R I S T E X A N I I P A G E | 175
FOR SIMULATION USE ONLY – NOT A TRAINING AID
ENGINE START
CAUTION
Do not connect external power if battery voltage is below 22.0 volts.
Connecting external power could cause damage to the aircraft battery.
NOTE
The primary method for engine start is battery power.
External power may be used to perform a normal engine start. External
power shall be used to perform a normal engine start if battery voltage is
less than 23.5 volts. Also, consider using external power when motoring the
engine.
HIGH IOAT AT START >80 °C.
The aircraft IOAT indication is generated by a sensor located in the engine inlet
plenum. It is possible, during periods on the ground after engine shutdown, that
radiant heat from the engine may heat soak the IOAT sensor, raising IOAT beyond
ambient temperatures.
When this occurs and IOAT is greater than 96 °C but less than 121 °C, the PMU will
default to 121 °C for all PMU functions (including IOAT display).
If IOAT does not exceed 96 °C, the PMU will use the indicated value. If the PMU is
activated with IOAT above 96 °C, IOAT and ITT data will be invalid (red Xs in counter
display and missing ITT pointer) and EDM FAIL will be displayed in the bottom of the
EICAS display.
IOAT and ITT will remain invalid until the PMU is reset (PMU switch cycled from
NORM to OFF and back to NORM). Once the PMU is reset, IOAT and ITT displays
should return to normal and the EDM FAIL message should be removed.
NOTE
The EDM FAIL message indicates that the engine indicating system has
accommodated a fault. Parameters with the EDM FAIL message which do not
display red X’s and/or missing pointers are functional and may be used
normally.
If IOAT exceeds 121 °C, the PMU will flag the IOAT signal, lose the ability to calculate
ITT, and go offline. This condition is indicated by red Xs in the IOAT and ITT counters,
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