APU Usage

[gutshotdraw]

Dang 'Gut" didn't know we could turn em off. I thought we just left them running and did a hot hand-off...

Wish that was every trip amigo! What really sucks is getting to level off and realizing you forgot to shut the bloody thing down (not that I've ever done that).

See you this week maybe....been working harder on vacation the past three weeks than I do on the job

 

[CA1900]

On the X, some guys go by the "Climb Checklist" that lets you turn it off then, at 18,000 feet. I think that is a little late.

I would rather turn it off during the "After Start Checklist"...

You must have a better ACM than the Excel! :laugh: On a hot day, we need the extra air to keep the thing to cool on the ground. Our normal checklists have us kill it at 10,000; if it's not a hot day, I'll often shut it down on the taxi out to cut down the noise on takeoff.

 

[DO-82 driver]

Thanks Flex and Sparse.

 

[bailey3083]

At Flex, APU start is generally 30-45 minutes before scheduled departure. It might be up to an hour if it's really hot or cold. We leave it run if the turn is less than an hour or so. If the last leg is empty, normally the PNF will clean the cabin during the flight so we can shut down without powering the APU up and head straight to the hotel. The quiet is nice!

That is the rule but I have seen plenty of people rub the APU for hours.

 

[CA1900]

That is the rule but I have seen plenty of people rub the APU for hours.

Uhhhhhh.... huh huh huh....

 

[NETFLIER]

My number of $14 million is the hard accurate number.

the summation of apu hours added off the hobbs meter on each fleet times the average hour of fuel.

thats simple math, if you think its 10% of the number above you are dead wrong. on your next tour give it a shot.

most guys for some reason burn it a full hour. thats roughly 29 gallons of fuel an hour(200#'s), times avg price of fuel at $5.5, lets keep it simple round down and it equals $150.

multiply 150 times 3(average legs a day with 1 hour turns) equals $450 a day in apu fuel.

your 1.4 million would be burned up in 3,111 hours, across 300 some airplanes with apu. now you know better than that.

my number of $14 million was straight from the ponies mouth at reccurent and is most believeable.

 

[gutshotdraw]

I agree with you NET. My rough math came out around $4 million just for the Gulfstream fleet and I think I'm low by at least 50%. Last night, we had to burn the APU for almost FIVE hours to do two legs totaling 1.3 hours (three hour slide, gotta love 'em).

 

[dime line]

I agree with you NET. My rough math came out around $4 million just for the Gulfstream fleet and I think I'm low by at least 50%. Last night, we had to burn the APU for almost FIVE hours to do two legs totaling 1.3 hours (three hour slide, gotta love 'em).

I don't fly an APU plane. But I have started up the planes motors and then shut them down because of operational requirements. How hard is it to shut down an apu on the plane?

 

[gutshotdraw]

Harder than you think on a 450/550. A good 20 minutes from pushing the first button to taxi. The Laseref's alone take 12-15 minutes to align. When you have a slide and don't know when they're coming, Mr. Moneybags doesn't want to wait 20 seconds, let alone 20 minutes.

This is one of the major reasons why we can't STAND this stooopid new Customs rule of SHUTTING THE AIRPLANE DOWN TO BLACK on international inbounds so they can run their little geiger counter through the airplane. The term "quick turn" on a Customs stop is now a distant memory.

 

[blueridge71]

It isn't hard at all. I normally shut it down during taxi if it isn't needed for operational reasons. I normally start it about 30 minutes prior to pax arrival so the cabin can be cooling/heating while I get the clearance and set up the FMS.

 

[gutshotdraw]

The 450/550 is a computer and a finicky one at that. You have to wait three-four minutes after turning on the batteries before you can even start the APU because of the Built-In-Test (BIT) feature. Then the graphics modules have to boot up, and the Inertials have to spool up, and then the FMS load and performance init....blah, blah. Believe me, you need a Snickers bar.

 

[Coool Hand Luke]

Maybe I missed something here but you cannot always control your APU usage to just the 30 minutes prior to your departure:

- APU start 30 mins. prior to sked. departure

- 30 mins. later and still no sign of Mr. Jet Card

- 30 mins. after scheduled departure and still no sign of Mr. Jet Card

- 45 mins. after departure and Mr. Jet finally shows up with all his bags and entourage.

- 1 hour late and you are just now starting your engines

1 1/2 APU run and nothing you can do about it

 

[dime line]

understood, like i said i don't have an apu

 

[bailey3083]

I don't fly an APU plane. But I have started up the planes motors and then shut them down because of operational requirements. How hard is it to shut down an apu on the plane?

Easy just push the fire button. LOL

 

[Diesel]

Yeah I don't really understand all this questioning on apu usage. The other night we sat with the apu running for 5 hours waiting and waiting. To do an hour flight. Could we have shut down? Nope.

Owner get saying another 30 minutes another 30 minutes. At the end of it all he decided not to go. Good it was 3am and I was tired anyway.

This isn't like the airlines where you know you have x amount of time at each gate. This customs thing is such a pain in the ass its unreal. Shut it down, then refire the thing, even in the "classic" it sometimes doesn't fire up right.

Sure you're going to have a few knuckleheads that don't have a good policy on apu ussage. They will be balanced out by those that are extremely thrifty.

It all balances out in the end.

Also a quiet shutdown is only good when the FA is done.