by tikibar » Mon Feb 16, 2015 11:26 pm
Hi Francis,
You need 3 things in order to get the engines started: AC power, fuel pressure, and bleed air pressure.
- AC power comes from the external power, the APU generators, or the generator in a running engine.
- Fuel pressure comes from the fuel pumps, which require AC power to run.
- Bleed air comes from the APU or from a running engine. The APU provides enough pressure to start 2 engines at one time. There's also air from a ground source available in the "Boeing 747-8" menu under "Control Panel." The ground air is only sufficient to start one engine at a time.
Here's a typical engine start up procedure:
1. Battery on
2. APU on, wait ~1 minute for it to spool up (it will say "APU RUNNING" on the EICAS)
3. APU generators on
4. APU bleed on (should go on automatically when APU is running)
5. Fuel pumps on
6. Packs Off, #1 Hydraulic demand pump off, #4 Hydraulic demand pump off or AUX
7. Pull #3 and #4 starters
8. When N1 > 30, pull #1 and #2 starters
The starters reset automatically when the engine is running.
Cheers,
John