Page 1 of 1

Engine Start Question

Posted: Fri Jun 25, 2004 1:58 am
by masseybrown
A recent AW&ST article on the 777-300ER makes a point of the fact that only one engine can be started at a time apparently because of start-air volume limits. Is it possible to start BOTH engines simultaneously on other twins? Is it ever done?

RE: Engine Start Question

Posted: Fri Jun 25, 2004 2:06 am
by A/c train
Not that I know of, you dont get the mass flow air required for 2 at a time, never heard of it done.

RE: Engine Start Question

Posted: Fri Jun 25, 2004 3:53 am
by Georg
Sure it may be possible when good pressure appears. Though they usually start two engines together with 4 engine jets, like A340 or 747, because their engines are smaller and a bit easier to run into RPM too.

RE: Engine Start Question

Posted: Fri Jun 25, 2004 4:55 am
by ba299
talking about the 777 we can start both engine at the same time only on the aircraft with the RR engine it's impossible with the GE due to the big amout of air that they need...

RE: Engine Start Question

Posted: Fri Jun 25, 2004 7:24 am
by cdfmxtech
We operate the B777-200 with GE90s, and simulataneous engine start is available. I think the biggest factor is the APU. The APU on the B777 is capable of putting out a bunch of air, where-as on other airplanes - the APU bleed air cannot put out the pressure needed for "good" engine starts.

RE: Engine Start Question

Posted: Fri Jun 25, 2004 3:18 pm
by Jetfixer75
The 737NG supposedly can start both engines at once with their APU. Unlike the 737 Classic, the APU duct pressure rises during engine start.

RE: Engine Start Question

Posted: Fri Jun 25, 2004 7:39 pm
by NZ1
Though they usually start two engines together with 4 engine jets, like A340 or 747, because their engines are smaller and a bit easier to run into RPM too.

What bollocks. The engines on a 747 are the same size as a 767/757 in a lot of cases. I realise you may have been meaning the 777, but you cannot dual-start a 767 or 757 either.

When we carry out ground runs on our 744's, we often start 3 engines at once. Plenty of duct pressure makes this a breeze.

Regards
NZ1





RE: Engine Start Question

Posted: Mon Jun 28, 2004 5:51 pm
by wing
Neither the 737 training books nor the company SOP manuals we have, does not indicate that 737NG has a procedure to start both engines at once.We do start from the no 2 unless we have GPU hooked to the right side.Regards.WING

RE: Engine Start Question

Posted: Tue Jun 29, 2004 12:05 am
by HAWK21M
The 737NG supposedly can start both engines at once with their APU. Unlike the 737 Classic, the APU duct pressure rises during engine start.
Where did you get this Data from.
regds
HAWK