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bbildik

PMDG 777 Go Around Altitude Overshoot

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Sorry for the second reply. But my problem hasn't solved yet. I put a youtube link for you to observe what's happening.

My problem is, as the altitude captures during the go-around, the speed starts to increase, as N1 goes up and down on the max levels. Than the aircraft overshoots the altitude due to high speed. Looks like the speed stays on the go-around thrust and doesn't cone back for a level flight. I've tried disconencting my joystick just in case it might be interfering. No joy..

Please help..

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yeah.....been reported before.

The Go Around function in general and the level off especially need work.

Just report it to PMDG via ticket.

 

What happens is that as ALT captures the MCP speed is automatically increased.

This is correct, the real 777 does that as well.

 

But the PMDG then adds FULL thrust to reach the higher speed.....and since the airplane is still pitched up quite high, this additional thrust just causes a level off overshoot :-(

I think the real 777 would just keep the thrust it had when ALT captures, level off nicely and then accelerate with that same thrust.

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Howdy All

 

It's probably not helpful, but the auto throttle behavior in this instance is correct in respect of the actual aircraft.

 

With a single push of the TOGA switches to commence a go-around, the auto throttle THR command aims to provide enough thrust for a 2000 fpm rate of climb (usually somewhat more than that ...) - Hence THR / TOGA / TOGA and less than full GA thrust shown on the N1's.

 

A second push gives you full Go-Around thrust hence the transition to THR REF / TOGA / TOGA. But usually the single push gives you more than most can handle, particularly if you have a early level off and any kind of complication/distraction during the missed approach - the Airline Industry is focusing on two engine go-arounds at the moment as something of a problem, see here for a quite comprehensive analysis into go-around errors. Unfortunately the traditional regulatory focus has been on single engine go-arounds, to the point where we get lots of them, but very few 2 engine go-around in training.

 

But when the AFDS captures altitude and transitions into SPD / ??? / ALT, the auto throttle is no longer encumbered by the 2000 fpm "limit" on thrust. The auto throttles are now commanding for speed and if the aircraft is a little slow, speed will increase. This is most noticeable during manual flight when the airspeed is a little below target - but you see it during autoflight as well, particularly with early altitude captures.

 

I recently wrote about a procedural issue we were seeing in relation to missed approaches and I think I'll add this issue as a sidebar ...

 

Returning to the issue at hand however - I have seen some poorly handled level offs in the FSB PMDG 777, nothing quite this bad when other factors weren't involved (auto flight, not an early level off, no speed change during the capture maneuver, etc). I haven't had much time with the P3D version yet, but hopefully it's better in this area.

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Sorry for the second reply. But my problem hasn't solved yet. I put a youtube link for you to observe what's happening.

My problem is, as the altitude captures during the go-around, the speed starts to increase, as N1 goes up and down on the max levels. Than the aircraft overshoots the altitude due to high speed. Looks like the speed stays on the go-around thrust and doesn't cone back for a level flight. I've tried disconencting my joystick just in case it might be interfering. No joy..

Please help..

As you've been told repeatedly in the past, you MUST sign your posts with your full name otherwise your posts WILL be deleted.

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