COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Fokker F28 Series Aeroplanes

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 39.1 (1) of CAR 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.

AD/F28/85 Liftdumper Microswitches  9/2000 DM

Applicability: All Model F.28 Mk 1000, 2000, 3000, 4000 series aeroplanes.

Requirement: 1. If not previously accomplished, visually inspect and functionally check the liftdumper microswitches installed in the pedestal in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin (SB) F28/27-186 dated 8 May 2000.

2. If, as a result of the Requirement 1 inspection, the position of the centreline of the microswitch activating roller is found to be 2mm ±0.5mm before the end of the cam, the aircraft may be returned to service. However, if the position of the centreline of the microswitch activating roller is found to be less than 1.5mm before the end of the cam, re-rig the cam in accordance with Part 2.A(5) of the Accomplishment Instructions of Fokker SB F28/27-186.

Note: RLD AD 2000-073 (A) refers.

Compliance: For Requirement 1 - Before 19 September 2000.

For Requirement 2 - Before further flight.

This Airworthiness Directive becomes effective on 19 July 2000.

Background:  The Netherlands Rijksluchtvaartdienst has received two reports of inadvertent liftdumper deployment in F28 series aeroplanes during the take-off roll. Investigation revealed that with the throttle leavers in full forward position and the liftdumper system armed, the rollers of both 75% liftdumper microswitches ran off the end of the cam.

This condition, if not corrected, could result in occurrences of inadvertent liftdumper deployment during take-off. This Directive requires a once only inspection of the liftdumper microswitches and, if necessary, re-rigging of the microswitches.

Eugene Paul Holzapfel

Delegate of the Civil Aviation Safety Authority 13 July 2000

The above AD is notified in the Commonwealth of Australia Gazette on 19 July 2000.