Airworthiness Directive · Amendment 39-11282 · Boeing Model 747-400, 757-200, 767-200, and 767-300 Series Airplanes
Boeing Model 747-400, 757-200, 767-200, and 767-300 Series Airplanes
Superseded. A later AD replaced this one: AD 2001-11-08. Comply with the one in force.
Model 747-400 series airplanes, line numbers 1121 through 1177 inclusive; Model 757-200 series airplanes, line numbers 761 through 828 inclusive; and Model 767-200 and 767-3300 series airplanes, line numbers 668 through 723 inclusive; equipped with either a modular avionics warning electronic assembly (MAWEA) or a warning electronics unit (WEU) power supply, part number 285T0035- 201; certificated in any category.
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400, 757-200, 767-200, and 767-300 series airplanes. This action requires repetitive checks to detect certain failures in the warning electronic unit (WEU) or modular avionic warning electronic assembly (MAWEA); repetitive tests to detect any failure of tactile, visual, or aural alert generated by the WEU or MAWEA; and corrective action, if necessary. This AD also provides for an optional terminating action for the repetitive checks and tests. This amendment is prompted by a report of a MAWEA power supply failure due to inadequate over-voltage protection. The actions specified in this AD are intended to detect and correct such a failure, which could result in loss of visual, aural, and tactile alerts to the flightcrew. Absence of such alerts could result in the flightcrew being unaware that an immediate or appropriate action should be taken in the event of an unsafe condition.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
