Engine start switch not move to off?

[fjsharry 0]

I plane to flight from finland,and during start engine notice engine start switch not move to OFF position,before this flight always turn to off after engine start with stable.Is possible OAT got too cold -22C? or other reason?

[Guest]

Maybe you are using another livery with different default options?

[davierosoft 13]

The starter switch must return to OFF (spring loaded to the OFF position with a detent solenoid for the starting) above 55% of N2.Make sure N2 is at or above this value, if not, the starter switch must be moved manually.Also, make sure there are no failures active, I don't know if it is simulated, but, the starter switches suffer sometimes of increased friction due to dirt accumulation. In that case the starter switch could not return or will return after some seconds to the OFF position. To prevent damages to the starter, move it manually.In the NGX, have you updated recently to a service pack? Are you using old saved flight?Have you tried to reboot and try again?

[PerWel 23]

I have also seen this. Up in Alaska when it was -25C outside, had to turn it off manual. Engine did still run so it worked, I think it is because the N2 does not reach 56 or what ever it is when it releases automatic.Same happend to the other engine so had to manualy switch it off. Engines worked OK and could make the flight.

[davierosoft 13]

Yes, you're right, I just tried at -40°C and N2 has not reached the starter cutout speed, giving thrust was of no help.Maybe something wrong...I will check.

[Spin737 102]

I have also seen this. Up in Alaska when it was -25C outside, had to turn it off manual. Engine did still run so it worked, I think it is because the N2 does not reach 56 or what ever it is when it releases automatic.Same happend to the other engine so had to manualy switch it off. Engines worked OK and could make the flight.

The started doesn't shut off until 56% and idle should be around 60%, so that really shouldn't happen. I flew a -900 out of Fairbanks last week at -30C and it was no problem. RW.

[davierosoft 13]

I was checking manuals about N2 speed in relation with OAT at ground idle, but your answer clears me most of the dubts. Maybe is another of the little issues.

[Spin737 102]

I was checking manuals about N2 speed in relation with OAT at ground idle, but your answer clears me most of the dubts. Maybe is another of the little issues.

I don't have any hard facts other than that's what N2 normally is. I've only had starter-cut out issues in the sim. It's never been an issue RW due to cold weather ops. I've never seen a stabilized N2 below 56%.

[davierosoft 13]

Under +52°C of TAT probe temperature the idle control will mantain at least 58% of N2 for IDG operation. Above 52°C the idle is controlled above 66%, so it is an issue...the idle control will never let the N2 go under 58%:

These are the ground idle speed requirements:N2 speed more than 58 percent (8500 RPM) if TAT is less than 125F (52C) to keep N2 speed high enough for IDG operationN2 speed more than 66 percent (9500 RPM) if TAT is more than 125F (52C) to provide improved engine component coolingMaintain fuel flow at or more than 300 lb/hr (136 kg/h).

Edited February 5, 2012 by davierosoft

[davierosoft 13]

Anyone want to open a ticket about it? I opened maybe 4 or 5 tickets till today and still waiting an answer from Ryan because he asked to Vangelis about it, I don't want to open another one If someone will do it, could include also the Fuel flow issue when in reverse thrust?

[fjsharry 0]

@Per wel Seem you situation just like me,engine was run stably,but start switch not turn to off.@Jeroen I always use same livery,and i was flight in yesterday and not happen this.@Andrea I was update SP1C,and using saved flight after sp1c.And i was check not any falture in fmc.In fcom was mention,At 56% N2, verify that the ENGINE START switch moves to OFF. If not, move the ENGINE START switch to OFF.Then i notice N2 only reach about 55% to both engine...and i tried twice.

Edited February 5, 2012 by fjsharry

[Spin737 102]

Sounds like the starter logic is there, but the EEC isn't.This time the idle is too low! ;)

[fjsharry 0]

I thinking i found reason,is temp problem,i try start engine with TAT is 15C,and start switch was move to off after N2 reach 56%,and N2 still run to 60%.So if TAT was too low like -22C N2 will not reach to 56,i not sure is happen in real NG.

[davierosoft 13]

If you read above, we have already said that it is an issue as the idle will never go under 58% of N2

[fjsharry 0]

Ha,ok it's small bug. :)