Page 13 - May 25

(AFM). Is this a problem? Maybe, maybe not. It all
depends on what the aircraft flight manual supplement
(AFMS) states for that specific modification.
The AFMS is approved as an addendum to the aircraft’s
basic FAA-approved AFM. The AFMS is an essential part
of the aircraft’s inventory and is required by the FAA
to be on board the aircraft. You will find it buried in
the AFM’s supplements section. If you have not looked
through the supplemental section of the AFM, you are
probably not alone.
The AFMS augments or supersedes the limitations,
procedures and/or performance information in the
original FAA-approved AFM for that specific tail number.
The AFMS contains crucial information. It is important
to compare the supplements to the original AFM to see
what changes were made.
Any section of the AFM not changed by the AFMS
remains the governing body. Depending on the
modification, there may be many changes, a few changes
or no changes at all. As the pilot in command, you are
required to know the AFM and the AFMS, and you must
be able to combine the two.
Factory Pitch Trim Disc Switch vs. Two-position switch
First detent: AP and YD off
Second detent: electric trim disconnected
To reconnect: the electric trim switch on the
pedestal needs to be reset
MAY 2025 Let’s look at an example: the emergency procedure
sections in a factory King Air B200 AFM compared to
the Garmin G1000 NXi B200 AFMS – specifically, the
unscheduled electric elevator trim checklist. There is a
subtle difference between the two. This difference could
greatly affect the outcome.
Before King Airs were produced with Collins’ Pro Line
21 and Pro Line Fusion systems, they had an autopilot
(AP) yaw damper (YD) electric trim disconnect red
button on the yoke that was a two-position switch.
Pushing down to the first detent results in the AP and
YD disconnecting; continuing to fully push to the TRIM
DISC position results in the electric trim disconnecting.
The electric trim could only be reset using the electric
pitch trim switch on the pedestal. The unscheduled
elevator trim checklist in the original AFM called for
the red button to be pushed. There is no call to hold
the button fully depressed because the electric trim is
disconnected even after the red button is released. If
the pitch trim continues to run away, some King Air
checklists include a last step to pull the pitch trim
circuit breaker.
G1000 NXi Pitch Trim Disc Switch
One-position switch
Push button fully depressed: autopilot
and yaw damper off, electric trim
interrupted
Push button released: AP and YD
remain off, the electric trim returns
to operation
KING AIR MAGAZINE •
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