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Engine start: no APU bleed, no fuel, but N2 keeps speed?

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Windmilling on ground? You probably shouldn't fly in tornado.

 

But well it's a bug.

Absolute NO. I speak as a experienced ground engineer.

Regards

The engine isn't started, it's cranking over with no ignition and no air source. It could happen in real life if the APU failed during engine start before light off but in that case the engine N2 would run down to zero and the start valve would close.

 

The start valve needs air pressure to open. If air pressure is lost it should close.

The r/h engine is in the "GND" position and is not only for cranking. Thats the way you start the 737 engine. At 18-20% N2 you open the fuel cntrl valve. Read your engine strart procedure!

Regards Jovabras

  • Commercial Member

Absolute NO. I speak as a experienced ground engineer.

Regards

The r/h engine is in the "GND" position and is not only for cranking. Thats the way you start the 737 engine. At 18-20% N2 you open the fuel cntrl valve. Read your engine strart procedure!

Regards Jovabras

 

All due respect, I think you should take your own advice.  I'm not sure what "ground engineer" means, but over here, we use that term to fancy up the term "rampie."  That being said, a rampie is telling off a 73 mechanic (I think) and a sim guy (almost called you a sim tech again Kevin...haha), and not even getting the right procedure.

 

Boeing specifies 25% N2 or max motoring, if 25% isn't reached (defined as a lack of change in % N2 for at least a second, I believe).

 

Believe me - I've been in your position more than I'd like to admit.  While a lot of us appreciate enthusiasm, be careful where you use it, and how you use it.  I speak from very unfortunate experience.

Kyle Rodgers

Absolute NO. I speak as a experienced ground engineer.

Regards

 

The r/h engine is in the "GND" position and is not only for cranking. Thats the way you start the 737 engine. At 18-20% N2 you open the fuel cntrl valve. Read your engine strart procedure!

Regards Jovabras

If the APU bleed air failed as the engine lit you'd have a very expensive engine repair bill unless you rapidly cut the fuel again. Whether you turn the fuel on at 18% or 23% the engine still needs assistance from the starter motor to avoid a hung start. As an experienced ground engineer you ought to know that.

 

In the situation the OP described fuel is off, therefore no ignition and no light off. Therefore the engine is cranking. Please read the post I originally replied to get the context in which I replied. My knowledge of start procedures is at least as good as yours.

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