AD/F100/85 Amdt 1 Flight Controls Elevator Booster Control Unit (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/F100/85 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.
Fokker F100 (F28 Mk 100) Series Aeroplanes
| AD/F100/85 Amdt 1 | Flight Controls - Elevator Booster Control Unit | 5/2009 |
Applicability: | F28 Mark 0070 and Mark 0100 aircraft, all serial numbers. |
Requirement: | 1. For aircraft equipped with Elevator Booster Control Unit (BCU) part number (P/N) 23400-3B or P/N 23400-7: Perform a one-time inspection of the Elevator BCU as defined in Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088 dated 2. For aircraft equipped with BCU P/N 23400-3 or P/N 23400-5: Perform a one-time inspection of the Elevator BCU as defined in Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088. 3. Replace the Elevator BCU with a P/N 23400-3B or P/N 23400-7 unit that has been modified in accordance with Goodrich CSB 23400-27-27. 4. Replace all remaining unmodified Elevator BCU P/N 23400-3B and P/N 23400-7 with units modified in accordance with Goodrich CSB 23400-27-27 and Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088. 5. Replace all remaining unmodified Elevator BCU P/N 23400-3 and P/N 23400-5 with, respectively, P/N 23400-3B and P/N 23400-7 units modified in accordance with Goodrich CSB 23400-27-27 and Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-088. 6. Do not install a spare Goodrich P/N 23400-3B or P/N 23400-7 Elevator BCU on any aircraft, unless it has been modified in accordance with Goodrich CSB 23400-27-27. 7. Do not install Goodrich P/N 23400-3 or P/N 23400-5 Elevator BCU on any aircraft. The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD. |
| Note: EASA AD 2009-0032 dated 17 February 2009 refers. This AD supersedes EASA AD 2007-0228. | |
Compliance: | For Requirement 1 - Remains unchanged as detailed in the original issue of this AD as prior to 25 October 2008. For Requirement 2 - Within 12 months from the effective date of this AD. For Requirement 3 - Depending on the result of the inspection conducted in Requirement 1 or 2 of this AD, as applicable, within the time interval as indicated in Table 2 on page 8 of the referenced Fokker SB. For Requirement 4 - Within 5 years after the 25 October 2007. For Requirement 5 - Within 5 years after the effective date of this AD. For Requirement 6 - From 29 August 2012. For Requirement 7 - From 3 March 2014. |
| This Amendment becomes effective on 7 May 2009. | |
Background: | Excessive wear and tear of the backlash remover mechanism has been found several times. The wear and tear may result in a (partly) blocked operation of the elevator system in the normal (hydraulic) mode. Together with the manufacturer of this equipment (Goodrich) it has been decided to modify the Elevator Booster Control Unit in accordance with Goodrich Component Service Bulletin (CSB) 23400-27-27. In order to detect and correct an excessively worn backlash remover mechanism, this AD required a one-time inspection and eventual replacement of the affected Elevator Booster Control Units. Amendment 1 includes inspections for addition BCUs and eventual replacement of all affected units. The original issue of this AD became effective on 25 October 2007. |
James Coyne
Delegate of the Civil Aviation Safety Authority
26 March 2009
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