November 16, 2007 – PRESSURE is building on suppliers, airlines and aircraft manufacturers to modify IFE cables and other components in response to continuing reports of smoke and flames in Boeing cabins as a result of failures in IFE, lighting and seat power systems.

The latest development is a proposed FAA airworthiness directive that would require US-based Boeing 737 operators to install new circuit-breakers, relays, wiring and switches in the cabin to give pilots the ability to cut off power to an IFE system believed to be creating a hazard.

The proposal was prompted by an FAA review of 180 IFE systems on various aircraft, itself originating in the September 1998 crash of a Swissair MD-11 off the east coast of Canada. The subsequent investigation found that a fire resulting from arcing between IFE cables had fatally compromised the ability of the flight crew to control the aircraft.

The FAA review covered all IFE systems with in-seat or overhead (not bulkhead)
screens, and in-seat power systems that supply power to more than 20 per cent of the passenger capacity.

“The review indicated that unsafe conditions exist on some IFE systems installed on various transport-category aircraft,” the FAA says. The agency points specifically to certain systems that cannot be powered down without also removing power from systems needed for flight and landing, and those that require the crew to pull circuit-breakers. It adds that failures to properly revise crew procedures after the installation of an IFE system also contribute to the hazard.

The agency says that a number of aircraft from among the population of 737-300s, 400s, 500s, 600s, 700s, 800s and 900s must be modified with a new circuit-breaker, relays and wiring to allow the pilots to turn off power to the IFE and other non-essential electrical systems through a switch on the flight deck. “The flight crew’s inability to turn off power to IFE systems and other non-essential electrical systems during a non-normal or emergency situation could result in an inability to control smoke or fumes on the flight deck or in the cabin,” says the FAA.

Comments on the proposed directive are due in to the FAA by December 24, suggesting that it could enter into force as soon as the middle of next year. The agency says 1,176 aircraft on the US registry could be affected by the rule, with the proposed upgrades costing a total of about $15 million.

Similar requirements for certain Boeing 747-400s and 767s could soon come into force following a comparable process that began in August, with a comment deadline early last month. “Any flight crew should have the ability to turn off any piece of equipment in the aircraft and they should be able to do it with a relative minimum of effort. That is what these ADs are designed to do,” an FAA representative said. The agency estimates that compliance will cost operators up to $21,776 per aircraft.

In the meantime, at least one company has moved to accommodate the likely new requirements. Montreal-based IFE installations and support specialist Inflight Canada has responded to an earlier FAA policy guidance letter by developing a switch assembly that meets and exceeds the proposed requirements.

“We have taken the guidance a few steps further and made the switch assembly applicable not only to the IFE system but also to any other similar system,” says company president George Smallhorn. “It can also control other electrical systems in the cabin, including those that power electrically controlled seats, and it allows the pilots to quickly shed non-essential systems in the event of an engine or generator failure so that they can focus on flying the aircraft.” Finally, the switch assembly can be used on the ground by line maintenance personnel to isolate the source of problems.