I'm conducting some test flights and I have noticed that on the PW variant the TOGA is exceeding the engine EPR (1.54) it goes to (1.55) and goes red(while rotating). I followed the takeoff procedures.(move throttle to 50% engage TOGA then move throttle forward once thrust ref is displayed on the pfd). However if I derate power on the thrust lim page it does not happen 1.46 EPR. My throttle is calibrated and are not moving while all this is happening. Also I have not noticed this the GE or RR engines.

Neil Vince

I met the same problem.

Gents,

 

There are umpteen protections against this. One would have to lean on F4 with his elbow to red line. Can you please open a ticket with support and state temperature and altitude that you have seen this ? Also are we talking -ERF and 4062 engines or -400/-F regular and 4056 engines ?

 

Thank you

Gents,

 

There are umpteen protections against this. One would have to lean on F4 with his elbow to red line. Can you please open a ticket with support and state temperature and altitude that you have seen this ? Also are we talking -ERF and 4062 engines or -400/-F regular and 4056 engines ?

 

Thank you

It's happening on the 400 and 400F PW models. Haven't really tested the ERF.

Hi,
It seems I have the same issue. I have just took off with United 747-400 PW4056 engines, this is my first flight with PW engines.

I took off as usual, throttle to ~50% then press TOGA, push my throttle to 100%, EPR went above and got red boxes. After take off I press CANC to get rid of the red box but this is the first time happen to me with the new Queen. I did everything the same as I have done since I bought the aircraft.
I will do another take off later after I finish this flight.
Hoang Le

Also I have not noticed this the GE or RR engines.

You wouldn't notice it with the General Electric engines because General Electric does not use EPR, so it would be impossible to have a red EPR indication for a gauge that doesn't exist.

Hi,

 

Same here with B747-400F RR, the only one I'm using.

 

Best

I have had this happen with R.R.(EPR)and G.E.(N1) engines on pushing TOGA at approx 50% EPR or N1 and advancing throttles once THR REF appears.If I carefully advance the throttles the EPR or N1 just goes above the red line and the THR REF annunciation changes to SPD. Once in the air the annunciation returns to THR REF. If I advance the throttles quickly I get the red box appearing. I have presumed that this is due to spiking from my four lever throttle quadrant. I have another throttle quadrant that I successfully use with the 737 NGX and the 777. Am going to use this

quadrant next time I fly the 747 and assign one lever to operate all four throttles. Hopefully this will solve the problem. I will post the outcome in this thread.

This happened to me 2 hours ago out of Quito on my current flight, advanced throttles gently, pressed TOGA, flap 20 takeoff no de-rate. real weather. 747BCF pw engines. first time I used no de-rate and my EPR still has the red boxes in cruise. - David Lee

Hi,

For all of these who have the problem, how did you set the A/t override option in the CDU? Mine is set to IN HOLD MODE ONLY and I don't recall having had this issue (though I may have missed it, I seldom use full TO thrust).

30 minutes ago, Budbud said:

Hi,

For all of these who have the problem, how did you set the A/t override option in the CDU? Mine is set to IN HOLD MODE ONLY and I don't recall having had this issue (though I may have missed it, I seldom use full TO thrust).

set to never and I have not had an issue in the 777 or 747 before, first time non de-rated takeoff and I got the redline - David Lee

Won't this be related to the more times highlighted bug of the actual N1 constantly increasing by itself during HOLD mode at takeoff (when it should not change, unless the pilot moves the throttles), so exceeding the takeoff reference N1, with the danger of an engine exceedance?

53 minutes ago, jgoggi said:

Won't this be related to the more times highlighted BUG of the actual N1 constantly increasing by itself during HOLD mode at takeoff (when it should not change, unless the pilot moves the throttles), so exceeding the takeoff reference N1, with the danger of an engine exceedance?

I don't think so. From what I've noticed, the N1 might increase slightly, but the EPR doesn't change when this happens.

Just had a derated T/O from VTCC  go rogue in the red. 25% gas in the tanks and few PAX. I assume this is now something the great folks @ PMDG are looking at? 

I think it would be useful if a video could be posted...