AD/B737/72 - Side of Body Floor Panel Inserts

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, introduced the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives to ensure that commercial aircraft meet safety standards. This legislative instrument addresses potential safety risks associated with aircraft components. One such directive, AD/B737/72, pertains to Boeing 737 Series Aeroplanes, focusing on the side-of-body floor panels for the 737-400 and 737-500 series. The directive was enacted to address issues of panel disbonding that could lead to structural failure during flight, as reported by the Federal Aviation Administration (FAA). The policy objective is to mandate inspections and repairs or replacements of floor panels manufactured by Hexcel before 7 January 1991 to mitigate the risk of catastrophic failure during a 9g forward load event. Compliance with this directive was required before 8 September 1994.

Scope and Application

The Civil Aviation Regulations 1998, under PART 39 - 105, mandate the application of the Civil Aviation Safety Authority's Schedule of Airworthiness Directives concerning specific Boeing 737 Series Aeroplanes. This particular directive, AD/B737/72, applies to Boeing 737-400 and 737-500 series aircraft as listed in Boeing ASB 737-53A1152, Revision 1. The directive requires an inspection of the side-of-body floor panels forward of Body Station 887 to ascertain whether these panels were manufactured by Hexcel and to determine their manufacturing date. The directive provides specific instructions on what action to take based on the findings: if the floor panels were not manufactured by Hexcel or were manufactured by Hexcel on or after 7 January 1991, no further action is required; however, if the floor panels were manufactured by Hexcel before 7 January 1991, they must either be replaced or repaired according to Boeing ASB 737-53A1152 Revision 1 before further flight. Compliance with these directives must be achieved prior to 8 September 1994, with the directive referencing FAA AD 92-16-01 Amdt 39-8310 to address issues of disbonded one-piece inserts in certain floor panels, aiming to prevent floor panels from detaching from the floor structure during a 9g forward load event.

Key Provisions

The Civil Aviation Regulations 1998, Part 39 - 105 (Section 39.105) includes an airworthiness directive for Boeing 737 series aeroplanes, specifically AD/B737/72, which mandates inspections of the side-of-body floor panels on the 737-400 and 737-500 models. These inspections (Section 39.105(1)) are to determine if the panels were manufactured by Hexcel and the date of their manufacture, following the instructions provided in Boeing ASB 737-53A1152 Revision 1. If the panels were not manufactured by Hexcel, or were manufactured by Hexcel on or after 7 January 1991, no further action is required (Section 39.105(2)(a)). However, if the panels were manufactured by Hexcel before 7 January 1991, they must either be replaced or repaired before further flight, as per the specified Boeing Accomplishment Instructions (Section 39.105(2)(b)). The directive references FAA AD 92-16-01 Amdt 39-8310 and aims to prevent floor panels from breaking away during a 9g forward load event, following reports of disbonded inserts. Operators of Boeing 737-400 and 737-500 aeroplanes must comply with this directive by ensuring that the required inspections are carried out and that any necessary repairs or replacements are completed before further flights. The inspections must be performed in accordance with the instructions set out in Boeing ASB 737-53A1152 Revision 1, and any findings must be acted upon as per the directive's stipulations. This includes verifying the manufacturer of the floor panels and their production date, and implementing the specified corrective actions if the panels were manufactured by Hexcel before 7 January 1991. Compliance with this directive is mandatory and must be achieved before 8 September 1994 (Section 39.105(3)). Failure to comply with the provisions of this airworthiness directive may result in serious safety risks, including the potential for floor panels to break away during flight, which could lead to significant structural damage and compromise the safety of the aircraft and its occupants. The regulations do not specify civil or criminal penalties for non-compliance, but non-compliance could result in enforcement actions by the Civil Aviation Safety Authority, including potential grounding of the aircraft until the required actions are taken. The directive is supported by FAA AD 92-16-01 Amdt 39-8310, which provides additional context and background information on the issue of disbonded one-piece inserts in the side-of-body floor panels. The aim of this directive is to ensure that the identified safety issue is addressed promptly and effectively, thereby maintaining the airworthiness of the affected aircraft. Operators are expected to follow the detailed instructions and timelines provided to ensure compliance and maintain the highest standards of aviation safety.