A320 engine start procedure change
 

Anyone know why the start procedure changed to start number 1 first? I’ve heard rumours that it is to minimise air bubbles in the fuel lines or to pressurise green system hydraulics first . Standardisation across the fleet?

Mainly green operating procedures. As of now the single engine taxi out/in is considered normal SOP and actions done by memory.

To align with single engine taxi out procedures. That itself has been simplified to allow taxiing pilot to focus on taxi and the PM do do the engine start bits without needing PF input.

PTU will power Green system. Air bubbles in the fuel line??? And how would either engine start prevent those bubbles for the other side? Like the others said: single engine taxi. And for some nothing changed, my last company has been starting #1 first since 2010.

We've always started #1 first, I've been on the -320 just over 11 years now.

According to the official FCOM/FCTM advance copies by Airbus, the reason for the change is to incorporate single-engine taxi out into the SOPs and it would be done by memory, just like single-engine in.

No. 2 used to be started first as it ensured yellow hydraulics were available for the park brake after the push. The single engine taxi procedure requires the yellow accumulator pressure to be checked prior to push as if only no.1 is started the accumulator is the only source of brake pressure until the yellow elec pump is selected on.

I guess airbus have decided having a single source of yellow hyd pressure during the push is acceptable.

LD

You still have normal brakes from the Green system, so you have two ways to stop the aircraft.