Originally Posted by Rudderrat
Especially since they had failed to turn on the engine anti-icing. The FO tried to tell the Capt. that something was not right with the engine power settings (N1 was way too low). EPR is only one parameter to be checked - it's not the sole indicator.
Unfortunately, EPR is the
main parameter used (by both ATS and crew). That's why they speared in! The FO thought something was wrong but couldn't convince the captain; had he been able to say "we need 92% but only have 88%", the accident would never had happened. The EPR was correct; the N1 and therefore thrust wasn't, but couldn't be readily accepted by the captain because he probably didn't have any "normal" N1 numbers in his head.
Do
you know what you N1 should be on any given takeoff, or do you trust the EPR?
The only real measure of thrust is the speed of the big fan on the front of the donk!
Er no - that will only tell you how fast the big fan is rotating.
The actual thrust will also depend on forward airspeed and air density.
Of course it does, as does EPR. You missed my point. N1 is a physical number not reliant on any blocked pressure probes, anti ice or whatever; if the N1 is spinning at the required speed, then you
will have the thrust required, much more so than EPR, even considering "forward speed and air density".
In my books, N1 is a far more reliable thrust indicator than EPR. Now what is it supposed to be?!
