AD/F100/32 - Thrust Reverser Electrical Control Modification

Overview

The Civil Aviation Regulations 1998, amended by PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES, specifically address the thrust reverser electrical control modifications for Fokker F100 (F28 Mk 100) Series aeroplanes. This legislation was enacted to rectify issues identified with the thrust reverser system, particularly the risk of accidental deployment during take-off. The Civil Aviation Safety Authority, operating under the authority of the Commonwealth of Australia, introduced this directive to enhance safety by ensuring compliance with specified modifications and operational checks. The policy objective is to mitigate risks associated with the thrust reverser system to maintain the highest standards of aviation safety. The directive mandates specific modifications to the Flight Warning Computer and Thrust Reverser systems, operational checks, and updates to the Aircraft Flight Manual, all aimed at preventing accidental deployment and ensuring reliable operation of the thrust reverser system.

Scope and Application

The Civil Aviation Safety Authority's Airworthiness Directive AD/F100/32, issued under the Civil Aviation Regulations 1998, applies specifically to all Fokker F100 (F28 Mk 100) series aeroplanes, namely those identified as Mk.0070 and Mk.0100. The directive mandates a series of modifications and checks to ensure the safe operation of the thrust reverser system in these aircraft. The requirements include modifications to the Flight Warning Computer and the Thrust Reverser Stow Limit relay wiring, operational checks of the Thrust Reverser Secondary Lock Actuator and Primary Lock Switch, functional checks for internal leakage of the Thrust Reverser Selector Valve, updates to the Aircraft Flight Manual, further modifications to the wiring of the Thrust Reverser Electrical Control System, and specific changes to certain Aft Engine Cowling parts. The directive applies to aircraft within the Commonwealth of Australia and is intended to prevent accidental deployment of the thrust reverser during take-off. Compliance with these requirements is mandatory and must be completed by specified deadlines, with ongoing checks required at regular intervals.

Key Provisions

The Civil Aviation Regulations 1998, specifically PART 39 - 105, establish the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives for Fokker F100 (F28 Mk 100) series aeroplanes, including modifications related to the Thrust Reverser Electrical Control System. The directive AD/F100/32, effective from 20 May 1999, mandates several critical modifications to ensure the safety and airworthiness of the aircraft. These modifications include the alteration of the Flight Warning Computer (FWC) and the Thrust Reverser Stow Limit relay wiring, in line with Fokker Service Bulletin (SB) F100-78-012 dated 22 November 1996 (section 1). It also requires operational checks for the Thrust Reverser Secondary Lock Actuator, Primary Lock Switch, and the Indicating and Alerting System, as per Fokker SB F100-78-013 dated 22 November 1996 (section 2). For aircraft modified post SB F100-78-004, a functional check for internal leakage of the Thrust Reverser Selector Valve must be conducted (section 3). The Aircraft Flight Manual (AFM) must be updated to incorporate Flight Manual information specified in RLD AD BLA nr: 1996- 140/2 (section 4). Further modifications to the wiring of the Thrust Reverser Electrical Control System and Indication and Warning System, as per Fokker SB F100-78-014 dated 15 August 1998, are also required (section 5). Additionally, modifications to the Aft Engine Cowling part number 1159P41440, as per Fokker Component SB P41440-78-05 dated 15 August 1998, must be performed (section 6), and a Voltage Spike Protection Diode must be installed over the coil of the Thrust Reverser Secondary Lock Solenoid on all Aft Engine Cowling part number 1159P41440 (section 7). Entities governed by this Act, such as aircraft owners, operators, and maintenance providers, must ensure compliance with the specified modifications and checks. This involves adhering to timelines and intervals outlined in the directive. For instance, modifications to the FWC and Thrust Reverser Stow Limit relay wiring must be completed before 22 June 1999 (section 1), and operational checks must be conducted within 500 flight cycles after the initial modification and at intervals not exceeding 500 flight cycles thereafter (section 2). Functional checks for internal leakage of the Thrust Reverser Selector Valve must occur within specific timeframes post modification (section 3). The Aircraft Flight Manual must be updated by 22 July 1999 (section 4), and further modifications and installations must be completed before fitting to an aircraft or by 22 September 2000 (sections 5, 6, and 7). Failure to comply with these directives can result in significant safety risks and legal repercussions. Failure to adhere to the requirements outlined in this Airworthiness Directive may lead to severe consequences. Non-compliance with the specified modifications and checks can result in the aircraft being deemed unairworthy, which could lead to grounding and potentially severe financial and operational impacts for the entities involved. Furthermore, the directive does not explicitly state penalties for non-compliance, but it can be inferred that violations may lead to enforcement actions by CASA, which could include fines, suspension of airworthiness certificates, or other regulatory sanctions. The specific penalties would depend on the nature and extent of the non-compliance, but they are intended to ensure that all aircraft meet the highest safety standards.