Originally Posted by
drakkar
There is an other possibility to perform an EPC when the reading seems to be not accurate. FLM authorises to perform it engine by engine in training mode. The training OEI Hi is equivalent to the real AEO take off power, it will not damage the engines if you respect the limitation. Stabilisation 3 minutes, EPC 50 seconds, computation 20 seconds. Total time below 5 minutes.
Cheers
This is called a reference check. In the old days (pre 2A1) it used to give better results than the AEO check. However this was simply because of the way the graphs were drawn up. The AEO graphs were of course trying to extrapolate what was happening at cruise power, to what might happen when the engine was flat out at OEI power.
However with the 2A1 the graphs are better or even slightly the other way so it is rare to get better results by doing a reference check, although I'll agree it is the more accurate way of doing it. That said, the way the engines are tuned now for greater Tq margin and less TOT margin it is really easy to exceed the 5 minute (AEO takeoff rating) TOT limit. You need to "pre-heat" the engine at highish power before going right up to training OEI Hi since for some reason, the TOT tends to reduce a bit over a minute or so at training OEI HI rating. If you go straight to it there is a fair chance of an AEO TOT exceedance and the limit is not clearly marked on the gauge in training OEI mode.