Just when you thought something

had been sorted years ago....

  It's as if Swissair 111 had taught nobody anything about the importance of being able to quickly isolate power to tentacular systems such as an Inflight Entertainment System.
 

AD 2008-23-15]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 767-200, -300, and -400ER Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain Boeing Model 767-

200, -300, and -400ER series airplanes. This AD requires installing new relay(s), circuit breakers as

applicable, and wiring to allow the flightcrew to turn off electrical power to the in-flight

entertainment (IFE) systems and certain circuit breakers through a utility bus switch, and doing other

specified actions. This AD results from an IFE systems review. We are issuing this AD to ensure that

the flightcrew is able to turn off electrical power to IFE systems and other non-essential electrical

systems through a switch in the flight compartment. The flightcrew'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 the inability to control smoke or fumes in the airplane flight deck or cabin.

DATES: This AD is effective December 26, 2008.

Request To Clarify Analysis and Background of the IFE System Review

JAL states that the technical analysis and engineering background of the IFE system should be

clearly explained in the NPRM. JAL also states that the NPRM does not clearly address Transistor

Transistor Logic (TTL) power consumption, location or quantity of the units, operation during flight,

or system shutdown in the event of smoke. For example, JAL points out that the ''Discussion'' section

of the NPRM states that the IFE review did not consider systems that provide only audio signals to

each passenger seat or the passenger flight information system, and in-seat power supply (ISPS)

systems that provide power to less than 20 percent of the total passenger seats. JAL states that the

NPRM provides no engineering analysis as to why 40 seats with an ISPS system are a concern on a

150-seat airplane, while 60 seats with an ISPS system on a 350-seat airplane is not a concern. JAL

also states that this kind of definition leads to confusion (including IFE development and

configuration in the future). JAL also states that the technical definition and background on safety

must be clear and properly understood by everyone.

We infer that JAL requests that we clarify the analysis and background of the IFE system review,

and we agree to provide clarification. The ''Discussion'' section of the NPRM provides the

background information that led to FAA regulatory actions requiring the removal of power from

complex IFE system installations in the event of smoke or fire, without affecting other systems

essential for safe flight and landing and without the use of circuit breakers for power removal. JAL's

concerns related to TTL power consumption, etc., are immaterial to correcting the unsafe condition,

which is the inability to disconnect power from the IFE system in the event of smoke or fire. The

FAA study focused on IFE installations that are complex in terms of electrical circuitry and power

demands. This study excluded non-essential systems that are simple in design and demand low power

for operation. Due to the large number of ISPS installations, we reviewed only those ISPS

installations that provided power to more than 20 percent of the total passenger seats. However, the

requirements of this AD apply to all airplanes that have any seats equipped with power supplies. The

applicability of this AD is not limited only airplanes having more than 20 percent of the passenger

seats equipped with power supplies. No change to the AD is necessary in this regard.