APU Generator bug.

[BlueRidgeDx]

Hassata,

 

No, you can't start (or even attempt to start) the second engine until the first engine's start cycle is completed. It's been mentioned elsewhere that there is an electrical inhibit that prevents both ATS valves from opening simultaneously.

 

The autostart system doesn't take any action until three things have occurred:

 

1) Throttle in the IDLE detent

2) Electrical power available

3) Air source available

 

Without an air source (and without engine rotation), the autostart system will not attempt to provide fuel or ignition. Therefore, it's not possible to get a hung start in the manner you describe.

[Snoopy]

Hassata,

 

No, you can't start (or even attempt to start) the second engine until the first engine's start cycle is completed. It's been mentioned elsewhere that there is an electrical inhibit that prevents both ATS valves from opening simultaneously.

 

The autostart system doesn't take any action until three things have occurred:

 

1) Throttle in the IDLE detent

2) Electrical power available

3) Air source available

 

Without an air source (and without engine rotation), the autostart system will not attempt to provide fuel or ignition. Therefore, it's not possible to get a hung start in the manner you describe.

 

I posted the details here:

 

http://forums.eagle.ru/showpost.php?p=1231004&postcount=15

[Depth]

Has anyone been able to force-flood the turbines?

 

1. APU running

2. Inverter switch, ground power and APU generator OFF

3. Fuel pumps ON

4. Throttle to IDLE

5. Engine Fuel Flow Switches to OVERRIDE

6a. Alternate throttle between MAX and IDLE for 5 minutes

6b. Leave throttle on IDLE for 5 minutes

 

Why does it still start normally after doing this?

[BlueRidgeDx]

I'm not sure, but what on Earth are you trying to accomplish with that procedure?

 

The Boost Pumps don't work without AC power, the Fuel Flow switches play no role in engine starting, and moving the throttle any higher than firmly against the IDLE stop will cause the ATS valve to close and abort the start.

 

If DCS is going wrong somehwere, it's probably the electrical system, because all the other aspects have tested correctly in the past.

[Depth]

Both DCS and the plane is working perfectly, which annoys me. I wanted to force out user-related faults after starting on the emergency procedures part of the manual but it's just too damn foolproof. :P

 

Fuel pumps on AC power, god I should have thought of that...

[hassata]

After a failed attempt to start No.2 due to doing so while the Eng-Cyc light was on, what would be the procedure to re-start correctly? I always end up getting stuck around 10-20 rpm.

[Snoopy]

After a failed attempt to start No.2 due to doing so while the Eng-Cyc light was on, what would be the procedure to re-start correctly? I always end up getting stuck around 10-20 rpm.

 

I don't have access to my text orders but you need to put the throttle back to off, wait a few minutes, motor the engine first to purge residual fuel and ensure the temp is correct take the throttle over the hump and motor to normal.

[Depth]

Set the affected engine throttle to off and set the engines operate switch to motor and keep it like that for at least 30 seconds. The engine operate switches are directly over the APU switch on the Throttle quadrant

 

Edit: Ah, beaten to it :)

[Frostiken]

Complain to the crew chief, shut down, and step to a spare.

 

 

:D