YES now were back on track again!!
Is their an answer for this question
If the C+ has the equipment should we not follow / belive what it tells us!
Does the flight manual or maintenance manual state that if a discrepency occurs then resort to the flight manual charts or are the charts there for aircraft without the onboard system? IMHO, If not and you read the charts and decide to dispatch by using the charts then you have taken all the responsibility as it is all based on your perceptions. If something happens and you are dispatching after repeated power assurance failures of the onboard system you will be deemed at fault.
The proper thing to do is to determine why a difference occurs between the onboard system and the manual. What if the gages are off just enough to show you to pass but the onboard system says it fails? It is still failing power assurance.
At another company I worked for years ago, we would fail power assurance by Ng speed so they would swap indicators side to side or get another indicator that would read good enough to pass the check. All they were doing was getting a gage that read lower than the others. Years later when I starting working with onboard systems and measuring the actual tach frequency to those gages on that aircraft model, I found out that they are quite often in error and the onboard system would indicate one reading and the gage another. First response by everyone was that the onboard sytem was in error, but in fact it was getting the same signal input as the gage and then when using a third source to read the signal it proved the onboard system to read correctly and the gage was in fact in error.
C-Y-A