Re: Loss of an engine

From:         Keith Steele <keithsteele@delphi.com>
Organization: Delphi (info@delphi.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.