AD/B737/111 Amdt 1 - Seat Track Alignment

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, aims to ensure the safety of civil aviation within Australia. Specifically, Part 39 - 105 of the Civil Aviation Regulations 1998, which includes the Schedule of Airworthiness Directives, focuses on addressing safety concerns and issuing directives to maintain the airworthiness of aircraft. This legislative instrument addresses issues such as the misalignment of seat tracks in Boeing 737 series aeroplanes, which was identified as a safety concern that could lead to uncommanded movement of the pilots’ seats during critical phases of flight. The policy objective behind this regulation is to mandate safety measures that ensure aircraft remain airworthy and safe for operation, thus protecting passengers, crew, and the public. The compliance requirements outlined in the legislation ensure that specific maintenance actions are taken to address identified safety issues promptly.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to the Boeing 737 series aeroplanes equipped with non-powered IPECO pilot’s seats and having line position numbers 1 through 2836. This regulation is applicable on a national level across Australia, under the purview of the Civil Aviation Safety Authority (CASA). The primary requirement of this directive is to ensure the safety of the aircraft by performing a one-time operational test of the pilot's seats and seat locks to confirm that the lock pin of the seat track fully engages in all lock positions of the seat track. This is in line with Boeing Service Bulletin 737-25-1334, or Revision 1, dated 15 January 1998. If the lock pin does not fully engage, the seat tracks must be realigned as per the specified Boeing Service Bulletin. Compliance with this directive is mandatory and must be completed before 21 August 1998. The directive became effective on 21 May 1998, in response to reports from the FAA indicating potential issues with seat misalignment leading to uncommanded movement of the pilots' seats during critical phases of flight, such as acceleration and take-off, which could compromise aircraft controllability.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, include provisions pertinent to Boeing 737 series aeroplanes. One such provision is AD/B737/111 Amendment 1, concerning seat track alignment. This directive applies to all Boeing 737 series aircraft equipped with non-powered IPECO pilot’s seats and having line position numbers from 1 through 2836. The primary requirement outlined in this directive (section 105) is to conduct a one-time operational test on the pilot’s seats and their locks. The test must ascertain whether the lock pin of the seat track fully engages in all lock positions of the seat track, in accordance with Boeing Service Bulletin 737-25-1334, or Revision 1, dated 15 January 1998. To comply with this regulation, operators must ensure that the specified operational test is conducted unless it has already been performed. If the test reveals that the seat lock pin fully engages in all positions of the seat track, no further action is required. However, if the lock pin does not fully engage in all positions, the seat tracks must be re-aligned as per the same Boeing Service Bulletin (section 105). This directive references FAA AD 98-03-10 Amendment 39-10302. The directive became effective on 21 May 1998, and compliance is mandated before 21 August 1998, unless already accomplished. The obligations imposed by this directive are clear: operators of Boeing 737 series aircraft must perform the required operational test and any necessary realignment of seat tracks to ensure compliance with safety standards. The directive aims to prevent the misalignment of seat tracks, which could lead to uncommanded movement of the pilots’ crew seats and subsequently reduce the aircraft's controllability during critical phases of flight such as take-off. This requirement is part of a broader effort to mitigate safety risks associated with seat misalignment, which was identified by the Federal Aviation Administration (FAA) following reports of seat movement during critical flight operations. Failure to comply with the Airworthiness Directive AD/B737/111 Amendment 1 can result in significant civil or criminal consequences. While specific penalties are not detailed within the text, non-compliance with Civil Aviation Regulations can lead to enforcement actions, fines, and potential grounding of the aircraft. Such actions are taken to ensure that the safety standards set forth by the Civil Aviation Safety Authority are upheld, thereby protecting the public and maintaining the integrity of the aviation industry.