engine start sequence

[alexban]

I'm sure this was asked before,but I didn't find it. Why we normally start with engine 2 first (on 737 and 320, at least) ?
Any ideea?

[BOAC]

Look down, Sir. Bottom of page!

[FLX/MCT]

The yellow hydraulic system, driven by ENG 2, on the A320 serves the brake accumulator, the alternate braking system including parking brake and nosewheel steering. So it makes sense for an single engine taxi - you can start ENG 2 during pushback and after the truck is disconected you can brake with your own system while starting ENG 1....
Just my thoghts...

[wasteofcargospace]

On the BAe 146/RJ, the start sequence is 4,3,2,1.
The park brake is off the yellow system driven by engine 2, so the last but 1 to be started. However engine starts are normally done with a fully charged brake accumulator and nose chocks in so it doesn't matter. Not sure I fully understand the question.

[airfoilmod]

Ramp Thing?

Valuables and profit Port side, expendables starboard (Galley rig). Jetway and SLF Port. Critical engine Starboard. Otherwise if #1 started first, FOD shed by Jetway, or worse, FPD (Foreign Person Damage). It's very historical.

[Centaurus]

Depends on aircraft type but it goes back many years. Tradition, maybe? DC3, Convair 440, Friendship et al start No 2 engine first. Maybe because the captain usually starts the engine and with certain piston engines one became super-tuned to the progress of the start by the engine noise. Certainly in the R2800 engine of the Convair one listened carefully for a small drop in rpm that signified a mixture control/primer relationship. In other words you kept priming and ran on primer while opening the mixture control slowly and when the engine cut you released the primer switch and the engine than ran smoothly on mixture. Sounds complicated and it was, too. Then you closed the first officer's window to keep the noise of No 2 out and played the game again with No 1 engine. With some of the wartime four engine types the starting order was 3,4,2,1.

Useless info I know but a bit of history of interest to a few.

[OutOfRunWay]

Turboprop

I know that on many older small turboprops the battery was on the right side (presumably to offset the weight of a single pilot) and the wiring to the right engine was shorter. Since the turboprops have electric starters, the right engine was started first to reduce the chance of electrical cables or the battery overheating.

I doubt its really relevant nowadays.

OORW

[VRSCSE2]

For single engine taxi on the A320 you start eng # 1 for pressurization of green system and normal braking. You then turn on yellow electric pump for NWS and to limit the operation of the PTU.
For both engine start....start eng #2 first for alt/parking brake on the yellow system.
VRSC