Page 14 - May 25

The AFCS circuit breaker location on a modified circuit breaker
panel is noted with a red box in this photo.
When the G1000 NXi is installed, the red button on
the yoke is modified. It is now a one-position switch.
When depressed, the AP and YD are disconnected and
the electric trim is interrupted. Once released, the
AP and YD remain disconnected though the electric
trim will reengage. Therefore, the AFMS emergency
procedure will have you push and hold the red button
until the automatic flight control system (AFCS) circuit
breaker is pulled. If you had used the original AFM
procedure – pushing and releasing the red button – the
pitch trim would just reengage resulting in a possible
loss of aircraft control.
The voice in your head just said, “I would just pull
the pitch trim circuit breaker if it continues to run
away.” Unfortunately, with the Garmin modification
the original pitch trim circuit breaker is no longer on
the circuit breaker panel. The AFCS circuit breaker is
the breaker that needs to be pulled now. This step is
also included in the supplement. If you did not know
this, you would have trouble finding the proper circuit
breaker to pull after you released the red button and it
continued to run away.
Reading and knowing the new procedures listed in
the AFMS can be critical.
You may even have trouble in the heat of the moment
finding the AFMS emergency checklist. Who can look
through the extremely cumbersome AFM and find the
one AFMS that is needed for this emergency? Once found,
locating the emergency section of that supplement and
the specific emergency checklist is not optimum to say
the least. Back to our originally named unscheduled
elevator trim checklist, it has now been superseded by
the Garmin AFMS emergency checklist named autopilot
or ESP (if installed) malfunction/pitch trim runaway.
12 •
­ KING AIR MAGAZINE It could make your life slightly easier if you make a
copy of the emergency and abnormal sections of the
supplement and keep them in an easily accessible spot in
the cockpit, for example in your iPad Foreflight document
section or in an old-school, three-ring binder with tabs
for abnormals and emergencies.
Besides the emergency section of the AFM, other
sections can be supplemented or superseded. The
performance section is a good example. When a
modification is made, such as upgrading engines, you
would think a whole new performance section would
be included in the AFMS. However, this doesn’t always
happen.
The FAA requires that for any modification that may
adversely affect the time/distance/fuel used to climb
performance in the AFM, the manufacturer must either:
1. Publish new cruise, range, endurance and/or fuel
used performance data, or
2. Include both a limitation (in the limitations section)
prohibiting the use of the fuel consumption data in
the basic AFM and a statement in the performance
section stating that the data is not approved for
use.
Examples of the types of modifications that this
pertains to include but are not limited to modifications
that significantly increase the total drag on the aircraft
or engine changes that affect the fuel consumption.
This policy only applies to the cruise, range, endurance
or fuel used data and should not be applied to the
performance data required to be published by the FARs
(e.g. takeoff/land distance, climb performance). This
data must still be published or a statement made that it
is equal to or better than that shown in the basic AFM.
It is not unusual to see this statement in an AFMS:
“Performance will be as good or better than originally
published.” That can leave you wondering, “What is my
true performance data?” All you can do in this instance
is use the original data in the AFM.
The AFM supplements section contains information
necessary to operate the aircraft when equipped with
optional systems and equipment (not provided with
the standard aircraft). The appropriate information is
inserted into the flight manual at the time the equipment
is installed. These supplements are easy to miss, but as
you can see, they can contain information critical to
operating your King Air safely and efficiently.
Don’t forget to take your supplements! KA
Pete Marx has more than 30 years of experience in the aviation
industry, from flying as a captain and first officer on Beech 1900s,
Jetstream 42s and Dash 8s for commuter airlines to flying cargo as
a flight engineer and check airman in the Airbus 300 and DC-8 for
DHL. He has been instructing in King Airs for the past 13 years and is
currently an instructor at King Air Academy in Phoenix, Arizona.
MAY 2025