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Hillblom86

Fuel INOP, lower Max LDW?

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Hello guys and girls.Sorry if I post in the wrong place but i figured that there are some phenomenal expertise on the 737NG on this forum so I give it a shot.I work at a regional airport in Sweden as an ATC and today when one of SAS B737NG came it descended way to early down to FL100 for a continious descend in ATCC airspace (border to uncontrolled FL95 outside our TMA). ATCC called us up telling us they didn't know why he requested descend so early. But no problem for us anyhow.Later when he had landed and taxied to apron we asked him why he was crusing at FL100 for aprox. 40-45 nm. The reason was according to him a malfunctioning fuel pump that caused them the need to burn more fuel so they wouldn't land overweight.I find it a bit strange so I checked the manuals I bought from PMDG (truly awesome documents btw) but couldn't find anything saying that a fuel pump causes a lower max landing weight.The aircraft was a B736. Flight time around fifty minutes. Rwy 2,500 meters with 20 kts headwind.So I'm a bit confused but maybee some of you can enlighten me. rolleyes.gifedit: Sorry missed the topic, it should say 'Fuel pump INOP, lower max LDW'

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Were they landing at the scheduled airport or an alternate for emergency? If so, a lower altitude even at airspeed used would be less efficient overall and more fuel would burn off with the remaining amount less on landing. The pilot might have introduced drag elements as well to further reduce efficiency.http://www.b737.org.uk/fuel.htm#Pumpsmight be of interest. It depends on which pump was inop.

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Yepp, scheduled flight to our airport I'll check that link, thank you!

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A single pump should still be able to supply the fuel demanded by the engine, so that doesn't add up...I know pilots who did things because it was advantageous later when entering busy airspace... :( e.g. low cruise altitudes when they know they're going to hold, putting them lower in the stack thus making it sooner to landing. Best regards,Robin.

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To call our airspace busy is exaggerating, allot. He was the only one in our airspace at the time. biggrin.gifI'm starting to think the pilot didn't tell the complete truth or something as it, as you say, makes no sense to fly low just for one malfunctioning pump.Maybe the pilot ordered to much fuel when departing so they would be to heavy to do a quick turnaround and told a white lie. tongue.gif

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