NPRM, Airworthiness Directive (AD) for Boeing 737-100 through 737-500 airplanes

Wed, Nov 28, 2007 — David Evans

Regulatory & Other Items

17 October 2007
FR Doc E7-20466 – Docket No.  FAA-2007-0046

Proposed AD requires inspection of cockpit windows after two were damaged in flight, causing one plane to lose cabin pressure. The proposed AD follows similar AD action in July on all B747 jetliners after a cockpit window fell out, causing a loss of cabin pressure and an emergency landing.

The NPRM describes the unsafe condition thusly:

“This AD results from reports of in-flight departure and separation of flight deck windows. We are issuing this AD to detect and correct cracking in the vinyl interlayer or damage to the structural inner glass panels of the flight deck No. 2, No. 4 and No. 5 windows, which could result in loss of a window and rapid loss of cabin pressure. Loss of cabin pressure could cause crew communication difficulties or crew incapacitation.”

Inspections are required “before further flight.” A Boeing Alert Service Bulletin, issued in May 2007, describes detailed inspection and repair criteria.

Action affects 2,685 B737s worldwide, of which 799 are in U.S. registry.

Comments are due on the proposed AD by 3 December 2007. Given the nature of the hazard, one would have thought the FAA would mandate immediate action rather than a proposed AD (although operators are already in receipt of Boeing’s alert service bulletin).

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