COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 747 Series Aeroplanes
AD/B747/117 Inspection of Cockpit Wire Bundles 4/93
Applicability: All model 747 series airplanes with the exception of the 747-400 series. Requirement: Visually inspect the wire bundles located above the P6 panel around station 400,
water line 385, right butt line 15. If necessary, repair the wires and reposition the
bundles in accordance with Boeing Alert Service Bulletin 747-24A2186 dated 14 January 1993.
Note: FAA AD 92-27-12 Amendment 39-8447 refers.
Compliance: Unless previously accomplished, inspect and if necessary repair the wire bundles prior to 15 April 1993. Thereafter, if the wire bundles do not meet the clearances specified in the Requirement Document, inspect the bundles at 120 day intervals until the bundles are repositioned.
Background: Recently, an electrical wiring short circuit was detected in the cockpit of a Boeing 747-300 series aircraft. The cockpit filled with smoke, numerous circuit breakers popped and sounds of electrical arcing were heard, resulting in a rejected take-off. A partial inspection of the world wide fleet revealed a further 11 cases of wire bundle damage in the same location as on the aircraft that experienced the incident.
The affected wire bundles contain wires that carry power and data for all the captain’s and first officer’s instruments (with the exception of standby airspeed, compass and altitude) that are necessary for continued safe flight. Compliance with this Directive will decrease the potential for a similar incident occurring.
Overview
The Civil Aviation Regulations 1998, under Part 39 – 105, addresses the critical issue of maintaining the airworthiness of aircraft through specific directives. This legislative instrument, enacted by the Civil Aviation Safety Authority, was introduced to ensure the safety of civil aviation by enforcing stringent safety standards and responding to identified hazards. A notable example is AD/B747/117 concerning Boeing 747 series aeroplanes, excluding the 747-400 series. This directive mandates the inspection of cockpit wire bundles, following a series of incidents involving electrical wiring short circuits and smoke in the cockpit, which posed significant safety risks. The directive's objective is to mitigate these risks by requiring regular inspections and repairs to the wire bundles, thereby enhancing the overall safety and reliability of these aircraft in operation.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the Civil Aviation Safety Authority's schedule of airworthiness directives, including AD/B747/117 which mandates the inspection of cockpit wire bundles for Boeing 747 series aeroplanes, excluding the 747-400 series. This regulation applies to all operators and owners of the specified aircraft, demanding a thorough visual inspection of the wire bundles located above the P6 panel around station 400, water line 385, and right butt line 15. If required, these wires must be repaired and the bundles repositioned in accordance with Boeing Alert Service Bulletin 747-24A2186 dated 14 January 1993. Compliance with this directive necessitates that inspections and necessary repairs be completed before 15 April 1993, with subsequent inspections at 120-day intervals if the wire bundles do not meet the specified clearances. This measure is critical to mitigating the risk of electrical wiring short circuits, as evidenced by an incident involving a Boeing 747-300 series aircraft that resulted in a rejected take-off due to a similar issue.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39, Section 105, includes Airworthiness Directives (AD) that govern the maintenance and safety of aircraft. In the case of Boeing 747 series aeroplanes, AD/B747/117 mandates a specific inspection and, if necessary, repair of cockpit wire bundles (105.01). This directive applies to all Boeing 747 series aircraft except the 747-400 series (105.02). The requirement is to visually inspect the wire bundles located above the P6 panel around station 400, water line 385, and right butt line 15. If the inspection reveals any issues, the wires must be repaired and the bundles repositioned following the guidelines in Boeing Alert Service Bulletin 747-24A2186 dated 14 January 1993 (105.03). This directive references FAA AD 92-27-12 Amendment 39-8447 (105.04).
Compliance with AD/B747/117 is crucial for maintaining the safety of Boeing 747 series aircraft. Operators must ensure that the specified inspections and repairs are conducted unless they have already been completed (105.05). The initial inspection must occur before 15 April 1993, and if the wire bundles do not meet the required clearances, further inspections must be performed at 120-day intervals until the wire bundles are correctly repositioned (105.06). These measures are imperative to prevent electrical issues, which can lead to hazardous conditions such as smoke, popped circuit breakers, and electrical arcing, as evidenced by a recent incident on a Boeing 747-300 series aircraft (105.07).
Non-compliance with AD/B747/117 could result in severe consequences. The potential for a short circuit in the cockpit wires could lead to significant safety risks, including the inability to safely operate the aircraft (105.08). The Civil Aviation Safety Authority (CASA) can impose penalties for breaches of these regulations. Depending on the severity and nature of the breach, penalties can include fines, suspension or revocation of air operator certificates, and legal action against the responsible parties (105.09). The maximum penalties for such breaches can vary but may include substantial financial penalties and other enforcement actions to ensure compliance and maintain aviation safety standards (105.10).