From: Keith Steele <firstname.lastname@example.org> Organization: Delphi (email@example.com email, 800-695-4005 voice) Date: 12 Jan 95 01:56:04 References: 1 2
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The bottom indication on the EGT indicator in the 727 is 100 deg C. On the ground it would take a few minutes for the EGT indicator to reach the bottom of the scale. In flight with temperatures well below 0 and a 600 mph breeze the EGT will peg low very quickly. The problem however is not that the indications for a seperated engine are different from a failed engine. It is the difference between an engine that sustained severe structural damage during the failure and one that has seperated. If the engine sustains severe damage during the failure many of the indicator wires or the sensors themselves will be damaged. How do you tell if the wires broke because of the shaking and ratteling or because the engine departed the aircraft. Engine failures due to severe or because of severe damage are less common than your garden variety flameout but they do occurr. The most common reasons for severe engine damage are foreign object injestion -birds - ice from some part of the airframe, and turbine disk or turbine blade failure. As I recall in the American incident the failure was due to the engine injesting a hunk of ice caused by a leaking toilet servicing fitting.