AD/EMB-120/29 Amdt 4 - Elevator Trim System (Cth)

AIRWORTHINESS DIRECTIVE On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/EMB-120/29 Amdt 3 and issues the following AD under subregulation 39.001(1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Embraer EMB-120 (Brasilia) Series Aeroplanes AD/EMB-120/29 Amdt 4 Elevator Trim System 10/2007

Applicability: All Model EMB-120 aircraft. Requirement: Action in accordance with the instructions contained in Brazil ANAC AD 2001-06-01 R4 Amdt 39-1193.

The flight manual amendment required by this Directive is incorporated into the Aircraft Flight Manual at Revision 67, dated 5 June 2001. Once the Flight Manual has been amended to include this revision, the copy of the AD, which ANAC AD 2001-06-01 R4 requires to be inserted into the Flight Manual, may be removed.

Note: Embraer Service Bulletins 120-25-0262, 120-27-0095, and 120-27-0096, all original issues, or later ANAC approved revisions, refer. Compliance: As specified in the Requirement document. This Amendment becomes effective on 27 September 2007. Background: The occurrence of pitch trim upsets, caused by spring back effect of the elevator trim system control cables, was found to be due to sudden autopilot disengagement during flight descent phase. The problem results from jammed or frozen trim actuators associated with the autopilot trim servo action stretching the cables up to the servo torque limit and consequent release.