EGT jump on start

[uhntissbaby111 58]

I just experienced, it may have been happening the whole time but I just noticed now, the 1 engine EGT jump approx 60 degrees on start. The engine will spool up and EGT will rise until it stope for some seconds, then jump up to normal. I searched and saw others experienced this but no official comment. Any word on this issue?

 

 

Adam

[flightwatch 68]

I've noticed it too.  I have absolutely 0 experience with rw 777's, so I have no idea.  I imagine that's how it is irl as PMDG worked to bypass the fsx egt limitation for the NGX.

[ckeddf 4]

I have seen this jump but not consistently during every flight. My guess: it is related to panel state problems and falls under that category in the issues tracking thread.

[pedwards 20]

I think it is related to the OAT, and happens because of the software not the actual aircraft. I notice this happens with the NGX as well (I think the lower the OAT the bigger the jump?).

 

Regards

[scandinavian13 5,192]

So...not sure if anyone's had a look at the inside of a combustion chamber, but, there's fire in there.

 

This isn't some little fire in your back yard that gets larger over time.  The fire appears pretty suddenly.

 

Thus, there's a jump in temp.

 

Skip the first 15 seconds:

[ckeddf 4]

Interesting video, that certainly could put a twist on those boring fireplace DVDs.

 

In my case this jump occurs some time after the engines have stabilized, about 30 seconds or so. After a peak of 550 °C EGT settles on a value around 390 °C, then (30 sec later) jumps to something like 445 °C, no values in between. It was in one of Froogles beta-videos, too - he commented on it ("look, it jumped").

[kevinh 409]

It is possible it's the packs coming back on line after the engine start, adding an air bleed to the engine. That would suddenly increase EGT in this way. You could watch the EICAS Air page during engine start to see if the EGT jump coincides with pack operation. It might also be a surge bleed valve opening, after the start is stable.

 

Alternatively, there might be some custom EGT modelling PMDG added to get the start overshoot right which is being switched out after the engine stabilises and the steady state EGT value doesn't quite match.

[pedwards 20]

 

So...not sure if anyone's had a look at the inside of a combustion chamber, but, there's fire in there.

 

This isn't some little fire in your back yard that gets larger over time. The fire appears pretty suddenly.

 

Thus, there's a jump in temp.

 

Mmmm. The jump in egt that I am referring to happens after the engine reaches idle, settles then jumps to a new value.

 

Regards

[johndrago 4]

I just experienced, it may have been happening the whole time but I just noticed now, the 1 engine EGT jump approx 60 degrees on start. The engine will spool up and EGT will rise until it stope for some seconds, then jump up to normal. I searched and saw others experienced this but no official comment. Any word on this issue?

 

 

Adam

 

I've seen this too many times.  Not sure if it's realistic, or an issue.

 

John

[scandinavian13 5,192]

 

 

Mmmm. The jump in egt that I am referring to happens after the engine reaches idle, settles then jumps to a new value.

 

How was I supposed to know that if nobody stated it in the above posts?

 

Either way, see Kevin's post, for the case you mention:

 

 

 

It is possible it's the packs coming back on line after the engine start, adding an air bleed to the engine. That would suddenly increase EGT in this way. You could watch the EICAS Air page during engine start to see if the EGT jump coincides with pack operation. It might also be a surge bleed valve opening, after the start is stable.

[kevinh 409]

I checked the start again and the EGT jump does not coincide with any bleeds switching on. It happens before the packs restart. If you start with a warm engine the step increase is less because the initial stable EGT is higher. The EGT it jumps to is the same. So I think there is a mismatch between the starting EGT model and the steady state EGT model which needs smoothing out so temperature doesn't simple jump suddenly like that.

[EGLL77W 1,508]

Doesn't this happen in the NGX too? I've never seen the engines stabilise smoothly in the NGX/777. There's always a jump in N1 by at least 1% and around 60 degrees sometimes for EGT. I'd assume this is something in FSX... The real aircraft don't do it after the amount of starts I've seen on the real EICAS.

[CaptKornDog 286]

Doesn't this happen in the NGX too? I've never seen the engines stabilise smoothly in the NGX/777. There's always a jump in N1 by at least 1% and around 60 degrees sometimes for EGT. I'd assume this is something in FSX... The real aircraft don't do it after the amount of starts I've seen on the real EICAS.

 

It happened for me on the NGX until SP 1c.

[willywonka 36]

I've seen this EGT jump in the 777, but not NGX.

[Peter Clark 21]

Is it when the generators kick in?