Re: Engine start sequence

Date:         10 Jul 99 02:33:25 
From:         rdd@netcom.nospam.com (Robert Dorsett)
Organization: NETCOM / MindSpring Enterprises, Inc.
References:   1 2 3
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In article <airliners.1999.722@ohare.Chicago.COM>,
JF Mezei  <jfmezei.spamnot@videotron.ca> wrote:
>If engine #2 is almost always the first one to be started in commercial
>operations , how come it was called "#2" and not "#1" ?

There have been some lovely rationalizations in this thread, but in
reality, for most modern jet airplanes, it really doesn't make any
difference what order the engines are started in.

Boeing operations manuals (Boeing originals) typically specify 1-2-3-4.
Company manuals may very well deviate.

The argument about pneumatic duct path is weak (we're talking about
turbines with enough air pressure to run an air conditioning system and
keep 400 hot passengers cool--it can handle turning an outer engine).

The bit about not wanting to start the left engines first near the gate
is weak, too-- engines are usually started after the push-back is
complete, not before.

The number of airplanes that push back with reverse thrust is typically
limited to those with rear-mounted engines, and, to my knowledge, the
DC-9/MD-8x series is the only ones that really do this.  So that blows
the "risk to ground personnel" argument out of the water.

Reality is that the start order is usually dictated by the prejudices
and experiences of the chief pilot of the airline.  If he started
3-4-1-2 on a DC-8 or Electra or whatever, likely that *tradition* will
survive.  It's the same thing that lends to four INS's in a 747, or 8
HSI's, or whatever.  Tradition, which becomes fact and company policy.

Now, no doubt there are exceptions to this, in which there are valid
non- sequential start sequences, but they are the exception.

Just my $0.02 worth.

Cheers,

R.
--
Robert Dorsett                         Moderator, sci.aeronautics.simulation
rdd@netcom.com                         aero-simulation@cactus.org

           "Bother," said Pooh when his engine quit on take-off.