barit1, (quoting bsieker):
(bsieker): So the FDR readout will most likely reflect actual thrust lever setting, although I'm certain the investigation will look into the possibility of an undetected fault here, too.
barit1 in response:
I suspect (but have no specific knowledge of the A320) that the FDR will show both sensors on each TL, along with the resulting FADEC response.
It depends upon the dataframe in use. While there is far greater standardization among DFDRs than QARs (typical of FDA/FOQA installations), some recorders are programmed or otherwise limited to as few as 600 parameters, near the legal minimum, whereas others may provide upwards of 2000 parameters. I am told that the C17 provides upwards of 30,000 parameters, just for comparison.
Also, there may be different sample rates, varying from once per second to eight times per second. It depends upon the installation...ie, storage capacity, programming and the country's regulator requirements.
In such circumstances, the one-second recording rate for some critical parameters can be exceedingly limiting although experience can help. In the same way a strobe light illuminates disco-dancers in an-otherwise completely dark room, it is always a risky venture to merely "interpolate" what happened in the intervening darkness (time) period between flashes.... An ideal recording rate might be approximated by either video or film rates of around 26 to 32 fps's but then processor, memory and storage issues arise even with wireless or satellite download solutions.
Among the many parameters we'll see (all likely one-second sample rates), are the left and right TLA (thrust lever angle) parameters as well as the standard engine parameters (essentially, engine responses to FADEC commands), but we may not see very many parameters from the FADEC itself.
Again, apologize for thread-creep...