When the U.S.
Federal Aviation Administration (FAA) asked Boeing to test activating the thrust reverser in flight,
[26] the FAA had allowed Boeing to devise the tests. Boeing had insisted that a deployment was not possible in flight. In 1982, Boeing conducted a test in which the aircraft was flown at 10,000 feet (3,000 m) and then slowed to 250 knots (460 km/h; 290 mph; 130 m/s), and the test pilots then deployed the thrust reverser. The control of the aircraft was not jeopardized, and the FAA accepted the results of the test.
[27]
The Lauda aircraft was travelling at a high speed (400 knots (740 km/h; 460 mph; 210 m/s)) and at almost 30,000 feet (9,100 m) when the left thrust reverser deployed, causing the pilots to lose control of the aircraft. James R. Chiles, author of
Inviting Disaster, said: "[T]he point here is not that a thorough test would have told the pilots Thomas J. Welch and Josef Thurner what to do. A thrust reverser deploying in flight might not have been survivable, anyway. But a thorough test would have informed the FAA and Boeing that thrust reversers deploying in midair was such a dangerous occurrence that Boeing needed to install a positive lock that would prevent such an event."
[28]
