What i'm saying is i have as many attempts untill 2 mins but i need to wait 10 sec between each

I think I know what you're asking; can you switch from OFF to GND as many times as you like, as quickly or slowly as you like, for the period of two minutes as long as there is 10 seconds between each attempt. Is that what you are asking?

What i'm saying is i have as many attempts untill 2 mins but i need to wait 10 sec between each

 

The inclusion of "second and subsequent" points to it being unrestricted to the number of attempts, but I think a good bit of pilot judgment gets added here. If it didn't start the first few times, it's probably one of those signs that you shouldn't press your luck. Call ops, get the plane swap gears moving, and call maint to come out and have a look at it.

What i'm saying is i have as many attempts untill 2 mins but i need to wait 10 sec between each

No, it clearly states that after the second and subsequent attempts you must wait 3 minutes. The 10 second wait time only applies after the first attempt.

I think I know what you're asking; can you switch from OFF to GND as many times as you like, as quickly or slowly as you like, for the period of two minutes as long as there is 10 seconds between each attempt. Is that what you are asking?

 

Yes

Well there must be some wisdom in boeing saying that you need to put the start lever to idle at 25% or they would have mentioned to wait till the N2 reached max motoring

 

The faster you spin the engine (ensures proper air flow through the engine), the lower the chance of running into a condition where you're going to get a hot/hung start. While there are more factors to hot/hung starts, this one is the most controllable. Instead of reading it as it's written, it might be better to look at it like this:

"Use the 25% core speed that has proven to be reliable in avoiding hot/hung starts. If this cannot be achieved, use the closest speed possible to that value (max motoring)."

Also, not sure where this 10 seconds is coming from, but based on the original post's SOP:

 

First attempt:

2 min. ON

20 sec. OFF

[After 20 seconds, additional attempts are possible]

 

Subsequent attempts:

2 min. ON

3 min. OFF

[After 3 minutes, additional attempts are possible - repeat process beginning at "subsequent attempts"]

 

 

 

 

E.g.:

 

Starter on. Tried to light. Isn't working. Two minutes is up. Wait 30 seconds.

Starter on. Tried to light. Isn't working. Two minutes is up. Wait 3 minutes.

[Repeat last line.]

Maybe the 10 seconds has come about through errors, we're speaking so many numbers here I'm getting confused myself.

 

So I think the summer is, turn starter to GND and you can leave it there for a maximum of two minutes. Which nullifies Vernon's question of going from OFF to GND to OFF multiple times in two minutes. You wouldn't, you'd go to GND until it cut-out's itself, i.e engine started. Or two minutes are up and you need to force it backto OFF. Where you wait for 20 seconds.

 

I think that's right

 

 

Also, not sure where this 10 seconds is coming from, but based on the original post's SOP:

 

If you get a wet start (no light off) you are supposed to abort the start after 10 seconds.  That may be where he is getting that from.

Maybe the 10 seconds has come about through errors, we're speaking so many numbers here I'm getting confused myself.

 

Yeh same lol

 

I'll need to read kyles post soon just busy at the moment

Starter on. Tried to light. Isn't working. Two minutes is up. Wait 30 seconds.

Starter on. Tried to light. Isn't working. Two minutes is up. Wait 3 minutes.

[Repeat last line.]

 

But can you release the start swich GRD within 2 mins and place it back to GRD when N2 drops below 20% N2 and after 10 sec

If you get a wet start (no light off) you are supposed to abort the start after 10 seconds.  That may be where he is getting that from.

 

Would that be no positive EGT

No, it clearly states that after the second and subsequent attempts you must wait 3 minutes. The 10 second wait time only applies after the first attempt.

 

Thanks

 

 

But can you release the start swich GRD within 2 mins and place it back to GRD when N2 drops below 20% N2 and after 10 sec

 

Per your original post. 20 sec after the first attempt and 3 min after subsequent attempts.

I'm reading all different kinds of figures

I'm reading all different kinds of figures

 

Use Boeing's as the basic measure. Airlines add in their own interpretations.

Will do kyle but then it got more confusing reading the standard FCOM -

 

Extended engine motorings: • Starter usage is limited to 15 minutes for the first two extended engine motorings. A minimum of 2 minutes is needed between each attempt. • For the third and subsequent extended engine motorings, starter usage is limited to 5 minutes. A minimum of 10 minutes is needed between each attempt.

while this is slightly irrelevant in a sim from a maintenance point of view running starters for extended periods are a sure fire way to damage the starter in the real world..

 

What i'm saying is i have as many attempts untill 2 mins but i need to wait 10 sec between each

 Again from a maintenance point,No.you should give the starter a chance to get up  to speed eg 20-25% N2 or N3 if this is not achieved, then you turn the starter off and wait the 2 minitutes before trying again.the engine should also be allowed to stop rotating. you then try starting  again, You should again wait until you get it up to speed, if you can't get max rotation you should have already called the engineers.continued attempts is a big no as you will just break the starter.I've changed hundreds of starters over the years because of this.

some engines actually specify that a cooldown of 30 mins is required after 2 failed starts Cant remember which ones although the JT8 and the RB211  ring a bell.

 

finally the engine may not  achieve 25% due to several reasons.

 

Wind blowing up the jet pipe 

An APU air supply about to die 

A starter on its way out 

 

Starters are checked  on a regular basis for internal damage and oil quantity due to the heavy forces on a start and the heat generated  which is why these time limits are imposed.

 

rgds

Good stuff there pete! So basically, on your first attempt you only try once and wait 2 minutes.