Hello, just a short question.

 

I noticed in the Tutorial 1, in the Cold and Dark addendum the APU is started just after the battery is switched on.

 

My question: Is the activation of the APU sometimes delayed until shortly before pushback, like in the 737 or is the APU usually running this early on the checklist?

 

APU is turned on when you need it & within the guidelines of the airport you are operating in. A tutorial is just a guide.

Ok thanks. The 777 has a 4 minutes self-check. Is this tied to the power on of the APU, or will ground power do? How much of the flight preparation can be done before the aircraft runs the those checks?

You wouldn't normally receive the aircraft cold & dark when line flying. Regarding the self check, it doesn't matter if you power up using the APU or GPU, you should be on the battery anyway.

 

Not sure about your last question, plenty to do while the aircraft self tests.

 

 

How much of the flight preparation can be done before the aircraft runs the those checks?

 

You can do all of it during them if you're quick.  The self-checks run in the background, and I can't think of a way you could interfere with them in normal procedures.

 

As Rob mentioned, though, you're really never going to come across a cold and dark aircraft.  In order to get some questions answered while the PMDG version was being tested, pilots would occasionally ask the maintenance crew, because they're normally the only ones who see the plane in that state (unless you fly freight, where you may occasionally see it).

 

 

My question: Is the activation of the APU sometimes delayed until shortly before pushback, like in the 737 or is the APU usually running this early on the checklist?

 

AA and just now Qatar run their APU for the entire turn but Qatar used to shut it down and then they turn it on approximately half hour before boarding to bring cabin the cabin atmosphere to comfortable temperatures, so I guess it really depends on the operator and airport rules. Cold and dark is very rare for passenger ops (and since aircraft mechanics have to run ETOPS checks for overseas flights a pilot will never find a cockpit cold when he arrives for a longer flight). When I worked in the regionals it was fairly common if the GPU is inop so they shut EVERYTHING down to avoid burning fuel with the APU if the turn is long.

Thanks for the answers. I will use "777 LONG" for Startup State now.

 

Slightly off topic but how much fuel does the APU use anyway? May an air conditioning unit replace the job of adjusting the cabin temperature? I guess the APU/onboard systems will always do a better job.

In hot climates the APU does a much better job, so as mentioned above you will often see it left running during turns, especially out here in the Middle East during the summer.

 

According to the MEL, the APU uses 240 KG/HR on the ground and 90 KG/HR in the air plus an additional 2.5% onto the trip fuel to account for the open APU air inlet door.

 

The QRH details this increment from 140 KG/HR at 43,000' and 140 Tons Gross weight to 270 KG/HR at 5,000' and 300 Tons Gross weight. The heavier the aircraft, and the lower the altitude, the higher the burn. The QRH values include the APU fuel flow and the effect of the increased drag from the APU door.

 

Btw, I still haven't got round to purchasing the 777, is the MEL. Included in the docs?

Honestly I don't know. There seem to be a bug so only the "Introduction" and "Tutorial #1" was installed to my Start -> PMDG Simulations -> PMDG 777 Start Menu...

Honestly I don't know. There seem to be a bug so only the "Introduction" and "Tutorial #1" was installed to my Start -> PMDG Simulations -> PMDG 777 Start Menu...

 

That is all I got too in the Start Menu. Introduction and Tutorial 1. However, all the FCOMs, FTM, etc are in FSX/PMDG/777/DOCS.

 

Michael Cubine

Great! Well, there seems to be no separate "MEL" manual there, but maybe the info is covered wuthin the included manuals, they are as extensive as in the NGX!

 

Great! Well, there seems to be no separate "MEL" manual there, but maybe the info is covered wuthin the included manuals, they are as extensive as in the NGX!

 

No, the MEL (Minimum Equipment List) isn't included. I believe the MEL is an airline specific document, but don't hold me to that.

That is all I got too in the Start Menu. Introduction and Tutorial 1. However, all the FCOMs, FTM, etc are in FSX/PMDG/777/DOCS.

Honestly I don't know. There seem to be a bug so only the "Introduction" and "Tutorial #1" was installed to my Start -> PMDG Simulations -> PMDG 777 Start Menu...

Not a bug.  You can get to the other manuals via the Ops Center, but knowing the Ops Center exists and how to get to it required reading the intro manual (for those who didn't ask here, anyway), so the intro manual had to be more accessible than the others.

what can be the airport restrictions for APU usage?

what can be the airport restrictions for APU usage?

 

Many airports in the EU restrict APU usage for noise and environmental concerns to so many minutes after landing or prior to departure.  It varies airport by airport.