Boeing "Landing Gear Disagree" QRH Question

[extricate]

Hi,

In Boeing's QRH for Landing Gear Disagree, it says

At Pattern Altitude,

1) Open all outflow valves

2) Switch off all Fuel Pumps

I understand that if landing with gear not down, by switching off fuel pumps will prevent fuel leak and worst case, fire. But what if you need to go-around and need the fuel pumps to be supplying fuel?

[I-2021]

Hi,

In Boeing's QRH

Hi,

which Boeing ? There are a few different out there.

[extricate]

Specifically for the B777

[clear to land]

The EDFP's are more than capable of supplying fuel flow for a G/A with the assistance of suction feed. Cavitation only becomes a problem (on the 777) if you are above 38000'. The threat of the pumps continuing to provide fuel thus fire risk in the event of a structural failure after landing with Gear Disagree is considered to be much bigger than the engines possibly not getting fuel.

[extricate]

Thanks for this.

Is there any place that talk more about this? Cant seem to find any references. QRH may never be wrong but just want to understand further rather than just blindly following the steps when encountered.

[overstress]

Your FCOM? Boeing FTM for your type?

[tdracer]

Cavitation only becomes a problem (on the 777) if you are above 38000'.
38k is pretty optimistic for suction feed on any aircraft unless you have well weathered fuel (i.e. significant time at altitude to allow any dissolved gases in the fuel to boil out). But the engine driven pumps can easily deal with lack of boost pumps below about 20k regardless of the fuel. But what clear to land posted is otherwise correct - no reason to actively pump fuel into a potentially ruptured fuel line after a gear up landing.