Boeing 737 startup - without the autostart

[expat]

Thanks for the pat on the back Nexus
You are correct about trim air. It is on the 700, 800 and 900.
I work mainly on 800's. We have a few 400's, and then I have to really scratch my head. As for the APU, with the 800, only one switch has function over the buses. The second switch, it can be left or right, depending which one was switched first only turns the remaining bus light out. Effectively it "tidies" up the panel, nothing more. However, I will look in the books tonight and check again. I am only human after all :-/

Matt

[Midnight_LS1]

Allright allright...hold on here midnight.

"On most boeings, you can start the APU from the nose gear"

Huh? The APU is located far aft, you start it on the overhead panel. I'm guessing you're talking about the ground power connector, which is located close to the nose gear.

Wrong, on the 757 you can start the APU from the nose gear.  There are dual controls, one in the flight deck and one in the nose.
You lift up this cover and the controls are there.
Bad part is that you can't hear the APU well at a busy time at the airport while starting because if it does catch on fire, I'd have to continue attempting to start it to blow it out otherwise I'd have to shut it down and deploy the apu fire ext system.
The 767 may have the same setup but I'd have to check it next time.

"Pull the start switch, monitor N1 speed to 3.2% or higher but not to high to grenade the air starter but not to low or it will do a hot start and EGT limits will exceed which will call for a engine inspection."

Always monitor the N2 speed when starting the engines. It's the N2 shaft that gets spooled up by the APU bleed air. It's also the N2 % that determines weither or not you have sufficient gas flow through the turbine

I'm talking about the N1 speeds in FS9 panel, in the default 767/777 panel the N2 speeds are on the 2nd EICAS page while N1 and EGT are on the first.
I rather monitor N1 and EGT instead of constantly switching back to page 2 to see a update of the N2 speed.

Actual N2 speeds are specific to engine types since there's so many types, I'd have to look it up if I need to know if I'm going to do a taxi or engine run.
Like the 757 and the EMB 145 has different N2 speeds for starting and the engine size is a big difference in these two.
But I use N1 as a reference for the start.  
And I don't do it often, just once in a while.

The air start is almost like a turbocharger with a shaft connecting to it.  The shaft connects to a bevel gear which then goes up 90* vertically into the center of the engine to where N2 spool is, that will be the direct connection there and it will be the first to turn at the start of rotation.  
And the air starter has a ratachting merchanism and you may hear it during shutdown when the fan blades are not clanking at each other (some are louder than others), the 777 fan blades do not hit each other.

But if the engine is spinning faster than the air starter, it's automatically disconnected.  If not, the air start is engaged when it rotates faster than the shaft that's connected (when starting while the engine is windmilling that is)

The intake of the air starter is designed to "choke" the air if too much is going into it causing the starter to overspeed, but it does not always bulletproof it, it still can grenade apart.
Then there's the shear pin which would shear should the starting system sieze up while the engine is running.

For the 737:
Should the bleed air start valve be InOp, an manual start can be performed by removing the cover, put an socket extenstion in it and with communication set up to the pilots, you turn it and it will manually open the valve but have to shut it off when the pilots say they have sufficient speed otherwise you would not want to be standing next to a generade that will have a high chance of exploding.

I would not do it for my safety.  I'm not standing next to a low hung engine on the 737 and right next to the air starter during a manual start.

There's also a N3 spools on RB211 on the 747

[expat]

For the 737:
Should the bleed air start valve be InOp, an manual start can be performed by removing the cover, put an socket extenstion in it and with communication set up to the pilots, you turn it and it will manually open the valve but have to shut it off when the pilots say they have sufficient speed otherwise you would not want to be standing next to a generade that will have a high chance of exploding.

I would not do it for my safety.  I'm not standing next to a low hung engine on the 737 and right next to the air starter during a manual start.

We need to be a little more specific here. Sweeping statements about aircraft operations only confuses.
Manual start on the 737, model 400 to 900, you require a 3/4 drive socket and extension. Insert extension in the whole marked Manual Starter. There are no covers to be removed or doors to open.

Also I am a little confused myself as to your grenading starter motors. You have no input as to the volume of air that enters the starter. It is a function of the APU. If the APU is producing to much air, enough to grenade the starter, then we have far greater problems, they being that the entire pneumatic system is about to go into orbit, or indeed the APU its self. The APU would auto shut down.  APU speed is a direct reflection of how much air is being produced and a direct reflection of that is fuel consumption. If the APU was to over speed, to produce too much air, the ECU will shut it down. What aircraft and models are we talking about, pre-digital?

However I am open to new information. What is you experience of starters grenading? What was the circumstance, hours on the starter(s)? Had anyone pulled the chip detector and missed any early warning signs. Had the starter shown any signs of leaking oil, internally or at the gearbox pad? Had the pilots reported any starting speed or spoolup time fluctuations during previouse starts? Please share, it may save a trip to the Doc.

Matt

[Midnight_LS1]

We need to be a little more specific here. Sweeping statements about aircraft operations only confuses.
Manual start on the 737, model 400 to 900, you require a 3/4 drive socket and extension. Insert extension in the whole marked Manual Starter. There are no covers to be removed or doors to open.

I thought there was 2 screws holding a small cover over the manual start provisions?  I must be getting confused with the RB211 from a L-1011 which does have one but it's only used for the manual deployment of the thrust reversers for line maintenance but it doesn't use a 3/4 drive socket, it just uses a 1/4 extenstion to crank it open or close.

[quote]
Also I am a little confused myself as to your grenading starter motors. You have no input as to the volume of air that enters the starter. It is a function of the APU. If the APU is producing to much air, enough to grenade the starter, then we have far greater problems, they being that the entire pneumatic system is about to go into orbit, or indeed the APU its self. The APU would auto shut down.

[expat]

We live and learn...........maybe some sort of lower body/groin protection is required for a manual start. I would hate to go home with less than I arrived with

Complancency............The mother of all screw ups.

Matt

[Hai Perso Coyone?]

PMDG products rule....I know because I own all of them