When i want to start, APU or engines while all fuel pomps off position, thats OK! No any problem. APU or engines are starting very well. I just wondered that, is this normal?And on the other hand, two engines are starting at the same time. Is this normal situation according to the Boeing 737 start up procedures?Best regards...Serhan Onur

Its normal that you would be able to run at least the engines with no fuel pump on, as the engines are gravity fed (engines are below the fuel tanks.) As for the APU, im not so sure about that, I thought the APU was located in the tail of the plane, well above the fuel tanks. I didnt think the APU was powerful enough to start two engines at the same time either.

The APU has its (its'(?)) own DC fuel pump. The only reason you switch on an AC pump is to save wear and tear on the APU pump.If I remember correctly, the same reason goes for starting one engine at a time, to save wear and tear on the APU. In most cases, you have plenty of time to start the engines one by one, and monitoring the parameters for one engine starting up is way more manageable than two.

A post maintenance check on the Boeing 717 (and I would imagine all commercial jets), is to confirm the engines operate normally with all fuel pumps off.

The APU has its (its'(?)) own DC fuel pump

its = belonging to itit's = it isits' - there's no such word

Thanks Michael ;-) I usually have quite a good feeling for languages, but for some reason, the apostrophes always confuse me.

Is the real NG's APU really powerful enough to start both engines at the same time?Let's assume a normal day (ISA, density altitude at say 500 ft AGL)Mark

Is the real NG's APU really powerful enough to start both engines at the same time?Let's assume a normal day (ISA, density altitude at say 500 ft AGL)Mark

I don't know 100%, but I know it 99,99999999999999999999999% sure: no.

:( What's a fuel pomp?

Thank you very much, for all answers and sory for word not "pomp" of course i mean "pump"Regards.Serhan onur

so, the APU having its own fuel pump..is this turned on automatically at buss connection or when APU start is initialised?bestjake

Thank you very much, for all answers and sory for word not "pomp" of course i mean "pump"Regards.Serhan onur

only joking mate! :(

so, the APU having its own fuel pump..is this turned on automatically at buss connection or when APU start is initialised?bestjake

Have a look at this:

Thanks, Lukas..I wasn't even aware that AOA had released more vids..I haven't checked in weeks! Off I go...bestjake

Fuel pumps: not bug.But the NGX shouldn't be able to start 2 engines at the same time. This is might be bug?