The US Federal Aviation Administration (FAA) has released another proposed airworthiness directive for Boeing 777-200 series aircraft prompted by reports of smoke or flames on other aircraft types in relation to the wiring for inflight entertainment, seats and lighting.
The FAA is requiring 777 operators to install new switches to allow the flight crew to turn off the power to inflight entertainment (IFE) systems and other "non-essential" electrical systems in the case of smoke or a fire. Failure to do this could result in uncontrollable smoke or flames in the flight deck or cabin and subsequent loss of control of the aircraft, says the FAA.
The new notice of proposed rulemaking (NPRM) requires operators to inspect the electrical power control panel on some 777-200 models for a certain part number. On other aircraft, operators would have to install a new electrical power control panel and also change wiring and electrical load management system (ELMS) panels.
The reports of smoke and fire in the cabin originated on Boeing MD-11 and DC-9 aircraft as well as the Lockheed Martin L-1011 aircraft, and were connected with the wiring, says the FAA. This prompted the FAA to do a review of IFE systems on several aircraft types.
Another proposed airworthiness directive for the 777 was issued on 10 May in relation to the IFE review to install wiring and change panels on the 777-200 and -300 ELMS. Boeing told Flightglobal in May that the NPRM was related to a series of recommended actions that the manufacturer communicated to operators between April 2001 and August 2010.
The 777 directives come after several previous rules to change or modify electrical components and wiring on other Boeing aircraft types. Boeing 757-200 and -300 operators were issued an amendment to a 2007 airworthiness directive that requires new wiring as well as new circuit breakers, relays and relay connectors.
An amendment to a 2009 airworthiness directive required operators to install new circuit breakers, relays and wiring on Boeing 767-200 -300 and -400ER models to accommodate the switch to turn off the IFE and non-essential systems. Another change to a previous AD was enacted for 747-400 and -400D models requiring relays on those aircraft that allowed the cabin crew to power down the IFE and electrical systems.
An additional amendment mandated that classic and next-generation Boeing 737s also receive new circuit breakers, relays and wiring to turn off the IFE and systems.
The FAA estimates that 49 aircraft registered in the USA would be affected by the most recent proposed airworthiness directive, which could cost US operators up to $207 million.
The NPRM is scheduled for publication in the federal register on 17 July and will go into effect 45 days later.