Federal Register of Legislation - Australian Government

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AD/750XL/9 Airworthiness Directives/Pt 105 — Aircraft as made
S-Tec X 55 Autopilot System – Disconnect
Administered by: Infrastructure, Transport, Regional Development and Communications
Exempt from sunsetting by the Legislation (Exemptions and Other Matters) Regulation 2015 s12 item 15
Registered 02 Apr 2007
Tabling HistoryDate
Tabled HR08-May-2007
Tabled Senate09-May-2007



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/750XL/9 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.

Pacific Aerospace 750XL Series Aeroplanes

AD/750XL/9 Amdt 1

S-Tec X 55 Autopilot System – Disconnect

5/2007 TX



Model PAC 750XL aircraft, serial numbers 125, 126 and 127.


1.    If not previously accomplished in accordance with the original issue of this Directive, disconnect the autopilot by pulling and collaring the autopilot circuit breaker to prevent re-engagement (this may be accomplished by using a cable tie), and install a placard, in clear view of the pilot on or adjacent to the autopilot controller, with the following wording:


Pacific Aerospace Limited (PAC) 750XL Alert Service Bulletin (SB) PACASB/XL/001 dated 16 February 2007 refers.


Note 1:  Requirement 1 of this Directive is a temporary measure until Requirement 2 is accomplished.


2.    Inspect the pitch servo identification plate to confirm that the pitch servo part number (P/N) is 108-15-P1.  If the P/N is not 108-15-P1, replace the pitch servo with a P/N 108-15-P1 servo, per instruction 2.C. in PAC 750XL Mandatory SB PACSB/XL/025, dated 5 March 2007.


Note 2:  A replacement pitch servo P/N 108-15-P1 can be sourced from an authorized S-Tec dealer.


3.    Reconnect the autopilot by removing the cable tie on the autopilot circuit breaker and resetting the circuit breaker.  Accomplish a functional check of the autopilot system and remove the “DO NOT USE” placard.


4.    Modify the autopilot system in accordance with paragraph 2.B. of SB PACSB/XL/025 and PAC Drawing 11-81639 Issue C.


Note 3:  CAA(NZ) AD DAC/750XL/12A refers.


For Requirement 1 - Before further flight after 4 April 2007.


For Requirement 2 and 3 - Before returning the autopilot system to service.



For Requirement 4 - Within the next 150 hours time in service after the effective date of this Amendment.


This Amendment becomes effective on 2 April 2007.


The original issue of this Directive was issued to prevent failure of the Autopilot System Computer resulting in the possibility of an out of trim condition, which may lead to loss of aircraft control.


This Amendment introduces actions which allow the autopilot to be returned to service.  The amendment also clarifies how to disconnect the autopilot and where to install the placard.


The original issue of this Directive became effective on 12 March 2007.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

30 March 2007