(2024) Service Advisory 23100 Rev B: Flight Level Change (FLT) Transition

REVISION B:

Updated Resolution

PRODUCTS AFFECTED:

Garmin G3000 systems installed in the following airframes are affected:

NOTE
GIA software versions can be viewed on the System Status Page be selecting the LRU Info tab. Refer to the appropriate pilot’s guide for more details.

• Daher TBM 940 with GIA Software Versions 2.00, 2.01, and 2.02
  
• Daher TBM 960 with GIA Software Version 2.01
  
• Piper M600 with GIA Software Versions 2.04, 2.05, 2.14, 2.18, and 2.1B

ISSUE:

When autothrottle (AT) is engaged and a Flight Level Change (FLC) climb or descent is initiated, the autothrottle tracks airspeed while the autopilot (AP) follows an internal vertical speed reference. Once the AT becomes limited by power lever angle, engine torque, ITT, or Ng, the AT switches to maintaining its respective limit, and the AP switches to tracking airspeed.

When an FLC climb is initiated while the AT is engaged and already actively maintaining the ITT or Ng configured limit, the transition of speed tracking from the AT to the AP may not always occur. This may result in the AP pitching up to achieve an internal vertical speed target while airspeed decays away from the reference until reaching the minimum autopilot speed.

ACTION:

If the AT is engaged and actively maintaining the ITT or Ng configured limit, avoid using the FLC flight director mode to begin a climb. Refer to airframe specific AFMS documents for engine limits.

RESOLUTION:

This has been fixed in GIA Software Versions 2.23, 2.1D, and 2.40. Contact the TC/STC holder for applicability.