B777 immediate return single engine at high weights

[Cropduster]

Any thoughts greatly appreciated.

A recent sim scenario was an uncontrollable engine fire at liftoff at max TO weight in visual conditions. Obviously the goal is to maneuver the aircraft back to the runway as quickly as safely able. No time for fuel dumping.

The issue is at that high weights, Flap 30 is unavailable for landing due to the high approach speed exceeding the 180 knot flap extension speed. The single engine checklist will direct you to use Flap 20 if not using Flap 30. But why not Flap 25 -Vfe 200 knots? We don't need to autoland and both the single engine and gear down rate of climbs for Flap 25 are provided in the QRH. The approach speeds with Flap 25 are significantly slower than Flap 20 (about 13 knots) and the go around performance (not that you would want to in this scenario) are catered to at most altitudes and temperatures.
Are Flap 25 landings in this scenario permitted? If so, why does the checklist lead you to only Flap 20?
If they are not permitted, why not, and why is there data for them in the QRH?

Thanks Cropduster.

[awair]

Our (GE) checklist states the option:
“Land using Flap 30 (if performance allows)“

For the Engine Inoperative case you are only choosing between F20/F30. My understanding is that if runway length/brake temps permits, F20 is the preference (for possible Go Around). If you don't like F20, select the F30 option on the Engine Fail checklist, then re-direct to the Over-Weight Landing checklist which will direct F25 on account of the Vref.

Hope this helps.

[ejet3]

doesn't the fctm say you can bug below ur Fspeed or into the yellow if ur heavy or in a emergency? it has been a while tho

[extricate]

Our (GE) checklist states the option:
“Land using Flap 30 (if performance allows)“

For the Engine Inoperative case you are only choosing between F20/F30. My understanding is that if runway length/brake temps permits, F20 is the preference (for possible Go Around). If you don't like F20, select the F30 option on the Engine Fail checklist, then re-direct to the Over-Weight Landing checklist which will direct F25 on account of the Vref.

Hope this helps.


Hi there,

Yes as mentioned by the user above, if we were to treat it as an overweight landing at MTOW with one engine inop, it will be a flaps 20 landing for greater climb capability in case of a go-around. Why not flaps 25 landing? I guess it's a balance between stopping distance and climb capability in case of a go-around. Boeing must have weighed them already.

Good question though

With Regards,
extricate
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