AD/B737/306 Horizontal Stabilizer Trim Capability (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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.

Boeing 737 Series Aeroplanes

AD/B737/306 Horizontal Stabilizer Trim Capability 9/2007

Applicability:

All Boeing 737-100 and -200 series aeroplanes certificated at takeoff weights in excess of 97,800 pounds and containing the horizontal stabilizer trim actuator P/N
10-61326-4 or P/N 10-61326-5.

Note 1:  The 737 aeroplanes from line number 482 and on were delivered with horizontal stabilizer trim actuator P/N 10-61326-6.  This AD will apply to those 737 aeroplanes line number 482 and on if P/N 10-61326-4 or -5 have been exchanged for P/N 10-61326-6.

Requirement:

Accomplish either A or B below:

A.   For horizontal stabilizer trim actuators having the P/N 10-61326-4 or P/N
10-61326-5, test the actuator stall torque in accordance with Boeing Service Bulletin No. 737-27-1101, dated 1 February 1980 or later NAA approved revision.  The actuators found to have less than 350 inch pounds of torque must be replaced with a serviceable actuator P/N 10-61326-4, -5, or -6.  Thereafter, for the actuators P/N 10-61326-4 and -5, conduct repetitive torque test per the "Actual Stall Torque/Maximum Test Interval" chart, Figure 2, of that service bulletin at intervals not to exceed the maximum test intervals (hours) indicated by the curve on the chart.

B.    Replace the horizontal stabilizer trim actuator, Boeing P/N 10-61326-4 or -5 with stabilizer trim actuator, Boeing P/N 10-63126-6 in accordance with Boeing Service Bulletin No. 737-27-1101, dated February 1, 1980.  Replacing the stabilizer trim actuator, Boeing P/N 10- 61326-4 or -5, with Boeing P/N
10-61326-6 is the terminating requirement for this AD.

Note 2:  FAA AD 80-09-05 Amdt 39-3760 dated 6 May 1980 refers.

Compliance:

Within the next six months after the effective date of this AD, unless already accomplished.

This Airworthiness Directive becomes effective on 30 August 2007.

Background: The aim of this AD is to assure sufficient horizontal stabilizer trim capability

David Punshon
Delegate of the Civil Aviation Safety Authority

20 July 2007