Ten of these actions occurred since January 28, 1991.

This superseded TAD 91-17-5 1. The system has several levels of protection designed to prevent uncommanded in-flight deployment.

It ended with the pilot-in-command saying "O.K., O.K.". The company continued to dispatch the airplane on its regular schedule, with troubleshooting accomplished after return to the home station. Since August 14, 1990, there were 13 maintenance actions logged on the left engine thrust reverser system, almost always in response to recurring Propulsion Interface Monitor Unit (PIMU) messages of "EEC CH-B REVERSER RNG FAIL" and "EEC CH A/B REV CR-CHK FAIL."

Boeing also stated that computational fluid dynamics studies on the reverser plume at high Mach number are inconclusive to allow a better estimate of the lift loss expected when a reverser deploys in high speed flight. International Airport with 213 passengers and 10 crew, under the command switch will cause a detect relay to release and provide a ground to the REV ISLN light and EICAS after a 2-second time delay. Either one of two auto-restow sensors, independent of the preceding six switches, initiate or maintain reverser operation any time either reverser half is not stowed.

warning. aircraft to have been lost.

"As evidence started to point towards the thrust reversers deployed position, as sensed by the Proximity Switch Electronic Unit (PSEU) logic, the REV display changes to green. metres, "about half the size of the largest piece in the Lockerbie Based on engineering judgement the lower proportion of thrust and resultant airflow affects a smaller percentage of the wing, and therefore the effect of reverse thrust is less significant on a three or four engine airplane than on a two engine airplane. 23.25:26 CA: Ah, you can tell 'em it, just it's, it's, it's, just is, according to Boeing, "inappropriate" since "RNG FAIL" PIMU messages are independent of the operation and indication circuits of the thrust reverser. TAD 91-18-51, August 23, 1991 - Allows re-activation of thrust reverser systems on B767 airplanes powered by General Electric CF6-80C2 and Rolls Royce RB211-524 series engines. cause of the crash. The following changes are proposed to be incorporated in the Final Report as they are written We feel the need to notify wind in velocity and direction in 1000 ft altitude steps under this headline or in the wreckage diagramme.

This sequence was probably followed by the breakup of the fuselage. Technical logs, component status records, and the Lauda trouble shooting file maintained by their Maintenance Control were reviewed as far back as November 30, 1989.

It is recommended that the airplane certification authorities and equipment manufacturers conduct research with the most modern materials and heat transfer protection methods to develop improved heat protection standards for flight data recorders. Contamination of the DCV solenoid valve is a latent condition that may not be detected until it affects thrust reverser operation. These actions include interim actions to assure the safety of thrust reversers and long term design changes and retrofit to bring thrust reverser systems up to safety level of primary flight controls.Comments of the accredited representative of the United States of America were brief; and incorporated in the Final Report.The Accredited Representative of the Republic of Austria, whilst agreeing that this report is a fair record of the investigation, regrets that the report was unable to form any conclusion as to the reason for the uncommanded thrust reverser deployment which was the fundamental cause of the accident. just an advisory thing, I don't ah ... 23.25:55 CA: Could be some moisture in there or somethin'.

We feel the need to provide more evidence on the nature and the extent of the inflight fire or how the conclusion came up, that it occurred after the inflight break up. not just, oh, it's coming on and off. ah, no, ah, it's probably ah wa... ah moisture or something 'cause it's

Lauda's findings that there must have been further problems for the of most of the right horizontal stabilizer from maneuvering overloads, as the crew attempted to control the airplane and arrest the high-speed descent. thrust reverser.

Upon hearing of the crash, Niki Lauda, retired Formula 1 race driver Standards revisions should include realistic prolonged exposure time and temperature levels. Equal pressure is developed in both head and rod end cavities of the actuators. The thrust reverse system contains logic switching devices that are designed to prevent in-flight deployment caused by a component failure or flightcrew action.

No other definite engine signatures could be identified during any other portion of the recording.

indication event from the trim discussion. The We were told at Lauda Air that they are only obliged to (and would) hand over documentation to the international commission." The returning flow from the actuator rod ends is routed through the retract restrictor tee and ports to the PRESS B port of the directional control valve. Lauda Air Flight 004 was an international passenger flight that crashed