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Old 6th September 2010 | 13:04
  #6 (permalink)  
HazelNuts39
 
Joined: Jul 2009
Posts: 1,682
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From: France - mostly
TAS is not immediately affected by a sudden increase of static temperature. However CAS decreases, therefore AoA must increase to restore Lift=Weight to maintain altitude. With N1 held constant N1/root(T1) is reduced, and hence thrust decreases.

Due to the thrust deficit the aircraft decelerates at constant altitude, hence TAS decreases.
SFC has a minimum somewhere between idle and max. thrust. For low power settings sfc increases with decreasing thrust, for high power settings SFC decreases with decreasing thrust.

In most practical cases (airspeed higher than max. range speed) TAS and sfc both decrease, so none of the answers is correct.

regards,
HN39

Last edited by HazelNuts39; 7th September 2010 at 21:58. Reason: AoA
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