C560XLS experienced autopilot disconnect and pitch up when flaps are selected on approach; 300 ft al...

Attributes
ACN	824663
Time
Date	200902
Local Time Of Day	1801-2400
Place
Locale Reference	FRG.Airport
State Reference	NY
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Citation Excel (C560XL)
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Flight Plan	VFR
Component
Aircraft Component	Elevator Trim System
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Loss Of Aircraft Control

Narrative:

We were on the GPS approach to runway 1 circle-to-land runway 32 at frg. We were at 2;000 ft about 15 miles from the airport on the final approach with the autopilot engaged in navigation and altitude hold modes. We were at about 190 KIAS and selected 15 degrees (approach) flaps. Without warning; the autopilot disengaged the altitude hold and pitched up and we climbed 300 ft. At the same time; I disengaged the autopilot and had to place very heavy nose down force on the yoke to return to our assigned altitude. We returned to 2;000 ft and continued the approach which was uneventful. Upon landing; exterior inspection revealed the elevator trim tab was deflected down while in the neutral position which created a heavy pitch-up force. Maintenance was contacted and the problem was written up. I don't see any way this problem can be avoided given it is a maintenance problem driven event.

Original NASA ASRS Text

Title: C560XLS experienced autopilot disconnect and pitch up when flaps are selected on approach; 300 FT altitude deviation resulted.

Narrative: We were on the GPS approach to Runway 1 circle-to-land Runway 32 at FRG. We were at 2;000 FT about 15 miles from the airport on the final approach with the autopilot engaged in Navigation and Altitude Hold modes. We were at about 190 KIAS and selected 15 degrees (approach) flaps. Without warning; the autopilot disengaged the Altitude Hold and pitched up and we climbed 300 FT. At the same time; I disengaged the autopilot and had to place very heavy nose down force on the yoke to return to our assigned altitude. We returned to 2;000 FT and continued the approach which was uneventful. Upon landing; exterior inspection revealed the elevator trim tab was deflected down while in the neutral position which created a heavy pitch-up force. Maintenance was contacted and the problem was written up. I don't see any way this problem can be avoided given it is a Maintenance problem driven event.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

C560XLS experienced autopilot disconnect and pitch up when flaps are selected on approach; 300 ft altitude deviation resulted.