Originally Posted by PJ2
In response to your questions, EPR, like hundreds of other parameters are indeed recorded on DFDRs as would N1, N2, (N3), fuel flow, EGT, N1/N2/(N3) vibration levels etc. It would be part of a legal (certified/required) parameter set.
That's what I would have thought.
Interestingly enough, Airbus stated in the appendix of the Taipei-Sungshan-Overrun, that N1 was not recorded on that particular model. This surprised me, since IAE-equipped A320s have three "quasi-analog" circular gauges for engine parameters, EPR, EGT, N1 (and a smaller one for N2). If N1 is deemed important enough to show on the primary engine display, even if the "main" power parameter is EPR, why not record it?
Originally Posted by Appendix to GE536-Overrun-Report
3/ Thrust in relation with EPR
We cannot provide this information as in order to accurately compute this we would require the N1 for the Engine 1 in reverse, and this is not recorded, and also there would be some time spent in unusual transitory phases between REV MAX and REV IDLE. For the Engine 2 at 1.08 EPR the thrust would be of the order of 3000 DaN. (Please see NOTE to previous reply).
Bernd