See, that's just what they want you to think. It's a trick. ;) With the START SWITCHes in OFF, you'll still get a relight if the EEC sees a rapid decrease in N2. Just another Boeingism.

Ok, well like I said before in other posts, I learn something new everyday. :)So is this a fact, that even with the IGN to OFF, the real NG will still trigger a relight? Or are you just pulling my leg?I would expect it in FLT, but wouldn't you think it might be a bit haphazard, if the crew doesn't have a way to overide the IGN system? Sounds like Airbus Logic to me... :) I guess I need to break out the FCOM. ;)JB

I guess I need to break out the FCOM. ;)

I don't even bother putting it away any more. :(

I don't even bother putting it away any more. :(

What about my question? Are you just pulling my leg about the autorelight in OFF, or do you know for a fact that it works that way?JB

What about my question? Are you just pulling my leg about the autorelight in OFF, or do you know for a fact that it works that way?JB

The NG's EEC does have logic to catch a decrease in N2. It will begin relight. I thought this was only with ignition switches in the "ON" position, though. (Flight)ie You're only protected if the Switches are in Flight.

Edited January 11, 201214 yr by ZachLW

What about my question? Are you just pulling my leg about the autorelight in OFF, or do you know for a fact that it works that way?JB

Well, I've never tested it in flight, but that's what the books say. There's a fairly non-confusing section on it in the engines section in the FCOM.The positions should probably called START, RESTART, UH-OH, and OMG!

The NG's EEC does have logic to catch a decrease in N2. It will begin relight. I thought this was only with ignition switches in the "ON" position, though. (Flight)

I would expect it in FLT as well.But I wouldn't expect it in OFF. That would mean that the crew could not disable ignition if they had to for an abnormality.JB

Well, I've never tested it in flight, but that's what the books say. There's a fairly non-confusing section on it in the engines section in the FCOM.The positions should probably called START, RESTART, UH-OH, and OMG!

Don't doubt you at all, I swear.. LOLCurious, what section of the FCOM is that in?JB

Edited January 11, 201214 yr by Buzz313th

737 NG Auto Relight

• An auto-relight capability is provided for flameout protection. Whenever the EEC detects an engineflameout with the ENGINE START switches in OFF, both ignitors are activated. A flameout isdetected when an uncommanded rapid decrease in N2 occurs or N2 is between 57% and 50%.

From Smartcockpit. So from Boeing manuals.I was wrong. Protection is provided also in the "OFF" position.

Edited January 11, 201214 yr by ZachLW

I was wrong. Protection is provided also in the "OFF" position.

Except from the FAA, who would roast you for not using the "correct" mode. All falls on the PIC with pilot error, right?"We're not happy 'til you're not happy!"

Edited January 11, 201214 yr by scandinavian13

737 NG Auto Relight

• An auto-relight capability is provided for flameout protection. Whenever the EEC detects an engineflameout with the ENGINE START switches in OFF, both ignitors are activated. A flameout isdetected when an uncommanded rapid decrease in N2 occurs or N2 is between 57% and 50%.

From Smartcockpit. So from Boeing manuals.I was wrong. Protection is provided also in the "OFF" position.

Interesting, thanks...Just learned something. Good job PMDG!So I guess the only way to kill the IGN system for a given engine would be to pull the Ohh Shiite handles (Fire handles)So whats the logic difference between FLT and OFF?Thanks again.JB

Edited January 11, 201214 yr by Buzz313th

Interesting, thanks...Just learned something. Good job PMDG!So I guess the only way to kill the IGN system for a given engine would be to pull the Ohh Shiite handles (Fire handles)So whats the logic difference between FLT and OFF?Thanks again.JB

OOOhhh... LOLJust thought of something. What about trying the same test as above with the EEC's off?That might give manual overide to the OFF state in the IGN switch, right?JB

Edited January 11, 201214 yr by Buzz313th

The relight protection is only given if the fuel cutoff levers are in idle and EEC detects the rapid N2 decrease, if you manually shut down there is no relight.Just to test I've done an inflight aircraft powerup from cold and dark, including engine start without APU.I used the slew mode of FSX to take the aircraft to a reasonable altitude, then battery and stby power, switches to FLT and started engines, than all the other things and the IRS on ATT (just to have attitude info).I often use this way to test systems that needs the aircraft in air.I used also for bleed trip off problem.This way let me try also the windmilling function.Nice to see that PMDG reproduced also the IDG functionality related to the N2 speed. Is so possible to turn on the engine generators with them in windmilling, provided you have enough speed to mantain N2 at the right speed.

Just thought of something. What about trying the same test as above with the EEC's off?That might give manual overide to the OFF state in the IGN switch, right?JB

Good idea!

Just to test I've done an inflight aircraft powerup from cold and dark, including engine start without APU.

Nice. Thanks for posting.

The relight protection is only given if the fuel cutoff levers are in idle and EEC detects the rapid N2 decrease, if you manually shut down there is no relight

Maybe there is a relight attempt, but there is no fuel.JB

Edited January 11, 201214 yr by Buzz313th

Before someone tell me that I'm crazy (Maybe it can be right :) ), by not following always the boring checklist on the game/simulator I can go more in depth inside the simulation and as same as for the issues I found, I sometimes find nice features, like, here for the IDG simulation.

Just to test I've done an inflight aircraft powerup from cold and dark, including engine start without APU.I used the slew mode of FSX to take the aircraft to a reasonable altitude, then battery and stby power, switches to FLT and started engines, than all the other things and the IRS on ATT (just to have attitude info).I often use this way to test systems that needs the aircraft in air.

Yeah, nice test.Would be fun to see at whats the lowest altitude you could do the test from. ;)JB

Before someone tell me that I'm crazy (Maybe it can be right :) ), by not following always the boring checklist on the game/simulator I can go more in depth inside the simulation and as same as for the issues I found, I sometimes find nice features, like, here for the IDG simulation.

To be honest, I had more fun playing with the NGX before I ever opened the FCOM. Still, I haven't read the whole thing, more like only breezed over 20% of it.JB