Aircraft : PMDG-737  

 Goal : After landing  to shut down engines and restart them again.

 Procedure to restart :

  a) Start APU
  b) The two APU Bus on ( second and third counting from left )
  c) Shut down engines
  d) All fuel pumps on,Pneumatic Panel : Recirc Fans : Off   APU Bleed : off ( switch down )
  e) Ignition : Both
  f) Ignition : Ground ( for engine 1 )
  g) N2 increases

  What is strange is that I cannot start engine 2 using the above method and I wonder what
  am I doing wrong or if this could be a computer bug ?

  I also tried to the above procedure for engine 2 only but it failed as there wa no increase in N2.

  I appreciate your help

  Hubert Werni

 

 
 

You say you set APU Bleed Off. Surely you mean On? You need that on to be able to start unless using external air. I guess that's a typo.

 

As you can't start engine 2 make sure the pneumatic Isolation Valve is open otherwise no APU air pressure can get to it.

You say you set APU Bleed Off. Surely you mean On? You need that on to be able to start unless using external air. I guess that's a typo.

 

As you can't start engine 2 make sure the pneumatic Isolation Valve is open otherwise no APU air pressure can get to it.

 

Yes,that was a typo,APU Bleed is on.

What I do not understand :  engine 1 starts without any problem.

But I cannot make engine 2 work for whatever reason.I tried your suggestion,opened the Pneumatic Isolation valve

and started by ignition to GND .

Result: N2 increased to 18.1 and remained there.( Two messages on the EICAS,"Start Valve Open " amd "Low Oil Pressure "

 

Any suggestion of what is wrong ? If it is not asking to much and you have a PMDG-737 could you check and see what

happens ?

 

Thanks

 

Hubert Werni

What are your packs and bleeds configuration (BLEED 1 and 2, L and R PACK)?

What is the outside air temperature?

 

You don't need to turn off recirc fans as they are only electrically operated.

It sounds like your packs are not turned off.

 

Please confirm you Air condition panel looks like this prior to engine start.

 

 

Please also note that you should get a Duct pressure of about 7-8 PSI on both left and right channel!

When starting an engine this should rise to almost 40 PSI on both channels.

Increase thrust to start the other engine.

 

 

engine 1 starts without any problem.
But I cannot make engine 2 work for whatever reason

 

Usually means your isolation valve is not OPEN.  It needs to be OPEN - not AUTO - but OPEN.

 

Disregard the above comment in the last post (Post #6) unless you're doing a crossbleed start, which you are not.

It sounds like your packs are not turned off.

 

Please confirm you Air condition panel looks like this prior to engine start.

 

 

Please also note that you should get a Duct pressure of about 7-8 PSI on both left and right channel!

When starting an engine this should rise to almost 40 PSI on both channels.

 

 I did this and bingo.Problem soved.Thank you

Yes,that was a typo,APU Bleed is on.

What I do not understand :  engine 1 starts without any problem.

But I cannot make engine 2 work for whatever reason.I tried your suggestion,opened the Pneumatic Isolation valve

and started by ignition to GND .

Result: N2 increased to 18.1 and remained there.( Two messages on the EICAS,"Start Valve Open " amd "Low Oil Pressure "

 

Any suggestion of what is wrong ? If it is not asking to much and you have a PMDG-737 could you check and see what

happens ?

 

Thanks

 

Hubert Werni

I can match your result for engine 2 start exactly under the following conditions:

 

1. Pack 2 in AUTO, both engine bleed switches ON (down), isolation valve OPEN.

2. Engine 1 running at idle.

3. APU bleed OFF

4. Crossbleed start of engine 2 from engine 1 at idle. (N2 only reaches 18.1%).

 

However, even with a Pack valve in AUTO I can start both engines normally from APU bleed air.

 

To restart the engines after a previous flight make sure the both packs are off, both engine bleed air switches are off and apu bleed switch is on. Then you should have no problems starting both engines.

Usually means your isolation valve is not OPEN. It needs to be OPEN - not AUTO - but OPEN.

 

Disregard the above comment in the last post (Post #6) unless you're doing a crossbleed start, which you are not.

Yep, I thought that he was trying to do a cross bleed start.. That happens if you only read the first post.