. IAS = 120 kt
Descent
For descent with the
AT engaged, it is recommended to use the
FLC or VS FD
vertical mode.
When FLC is active, AT engagement activates the DESC AT mode that sets
engine power from around
18% TRQ at high altitude to 0% at the end of the
descent. Then, the target airspeed is tracked via FD pitch orders. In MAN mode,
the target airspeed is the manually selected airspeed. In FMS mode, the target
airspeed is retrieved from the FMS descent schedule.
When
VS is active, AT engagement activates the SPD XXXkt AT mode that
controls engine power within
operational limits to reach and maintain the target
airspeed. In MAN mode, the target airspeed is the manually selected airspeed. In
FMS mode, the target airspeed is retrieved from the FMS descent schedule. Then,
the target vertical speed is tracked via FD pitch orders.
NOTE
If the inertial separator deploys, the FADEC changes engine ratings and
reduces power. At the same time, the maximum available TRQ is reduced (the
size of the green arc on the SEI reduces).
If the AT was active with a speed target requiring TRQ below the maximum
available TRQ, the AT will try to maintain the speed at the selected target and
then may move the THROTTLE forward.
Approach
For approaches (i.e. from
the Initial Approach Fix), the SPD source switch must be
in MAN mode or the autothrottle must be disengaged – refer to
Paragraph
Autothrottle (AT) Limits in Subsection 2.6. .
This is because use
of AT in FMS mode until final approach may result in an
unstabilized approach, because the predefined FMS descent schedule is not
appropriate for approach. A go-around maneuver may be necessary, due to all of
the following:
- Airspeed may be too high at GS/GP capture,
- Airspeed may be too high to timely configure the airplane before landing,
- AT automatically disengages at GS/GP capture and cannot be re-engaged, if
in FMS mode.
As a result, only MAN mode is permitted for approach, to ensure an appropriate
airspeed management until touchdown.
Section 7
Description
Pilot's Information Manual
PIM TBM 960 - Edition 0
Rev. 01
Page 7.7.8
PIM - DO NOT USE FOR FLIGHT OPERATIONS
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