View Full Version : Apu use on ground
I-WEBA
2nd May 2016, 22:59
Hi, I have just a simple question for all pilots as a spectator.
On ground, in the airports where there's no particular restrictions I see the APU start (even with GPU and normal temperature) follows no rule. Somebody starts before boarding, others 20 mins or later.
When do you usually start? Do you look at the time and eobt or just start when see pax boarding?
I read fuel for APU is included in the flight plan, how much fuel for apu use is included in the OFP?
Cheers
Airline and airport policy dictate.
If there is no preconditioned air available then the cabin will get uncomfortably warm pretty quickly once boarding starts. Some look after the pax some don't give a Damn as long as it saves fuel and wear and tear on the APU.
Usually when the crew want hot water for a brew :}
172_driver
3rd May 2016, 23:07
Also nice to consider ground staff in your decision. It's damn noisy for them if you run the APU while they're packing your aircraft.
Normally only used for air conditioning for us on the Dash-8, but we try and wait until the fuel truck is gone before starting as the jet efflux is damn near right where they park the truck...plus, as someone else mentioned, its very loud.
As for fuel burn, our APUs are planned at 150 pounds per hour - not sure about the bigger iron, but I can't imagine it would be that much more.
MarkerInbound
4th May 2016, 03:00
We plan 300 kg an hour so it's more.
de facto
4th May 2016, 14:43
:everything is simply bigger in Texas:E
300 kg an hour
Damn near as much as a PT6...makes sense I guess considering how big those APUs get for heavy metal.
Di_Vosh
5th May 2016, 00:40
We use it on the ground (for the Dash) mainly to keep airflow in the cabin, which can get very stuffy even on a cold day if you've got 70 odd passengers on board.
Also, we have pushback starts at our main ports, so require APU on for engine start on pushback.
IMHO, noise on the ramp should never be a consideration for NOT using the APU if you require it. Ramp staff should be wearing PPE.
IMHO, noise on the ramp should never be a consideration for NOT using the APU if you require it. Ramp staff should be wearing PPE.
I could be wrong here, but I believe in CPH the loaders won't even touch your aircraft till the APU is off?
172_driver
5th May 2016, 21:58
They're really fussy in CPH! And they let you know in typical Danish style.. :E
Di_Vosh
8th May 2016, 04:35
I've only ever operated in Australia (maybe should have said that earlier).
Having said that (and have never been to CPH so I don't know what other traffic there is) what do the loaders do when an A330 taxis past?
DIVOSH!
Wageslave
8th May 2016, 11:30
CPH loaders have long been rather bolshie on this, the precious little flowers. It wouldn't be so bad if they were as quick to plug in the conditioning air as they are to get snotty about an APU running, and if your company don't or won't pay for it the "quiet" policy quickly produces a sweatbath or worse, in winter with doors open an icebath on board. Perhaps pilots should reciprocate the bolshiness? As with so much scandawegian idealism it may be a nice idea but it has major flaws in practice.
Having said that CPH is an eerily quiet place because of it.
172_driver
9th May 2016, 07:39
And in the UK I must turn on the APU as ground crew won't approach the aircraft with anti-collision on. Somehow, in all other places it can be done safely? Different places, different cultures. The Danes have their flaws, but at least they're standing upright and tell you what they think.
I wasn't saying ground crew should be the only ones in consideration.
Max Angle
9th May 2016, 10:22
Damn near as much as a PT6...makes sense I guess considering how big those APUs get for heavy metal.
Most widebody APUs share their basic cores with other turboprop and small biz jet engines so the fuel burn is going to be much the same.
ground crew won't approach the aircraft with anti-collision on
You'll find the same attitude here in Canada. Anti-collision on is the standard "I'm about to start my engines." An old company of mine who operated almost exclusively in the arctic found that out the hard way while running the APU in Edmonton one day. No one approached us until us rednecks went to go ask where the southern hospitality was. Turned the light off and we were surrounded.
Di_Vosh
11th May 2016, 05:34
172_driver
I wasn't saying ground crew should be the only ones in consideration.
In my airline we only board using the front door of the dash, so the APU noise is pretty insignificant for any passengers. There is nobody else on the ramp who wouldn't have PPE.
I can only write from the perspective of an Australian pilot who flies the Dash, so please don't take this as me arguing with you.
DIVOSH!
I-WEBA
10th Sep 2016, 22:57
I see in many airports there are restrictions such as 5mins before ETD. If I arrive on block, from the previous inbound flight, 5 mins late, I have to update my ETD and also the APU start in case?
For instance scheduled in block time 19.00 , scheduled departure time 19.35
On time I could start the APU at 19.30... Today I'm 5mins late, so actual in block time 19.05, will my EOBT be 19.40 and so the APU should be started not before 19.35?
lasernigel
22nd Sep 2016, 23:19
SFO has a ban on APU's until departure, supposedly to do with being environmentally friendly. However with V8 gas guzzlers going up and down 101 next to the airport, I think it a bit stupid.
aterpster
24th Sep 2016, 13:59
lasernigel:
SFO has a ban on APU's until departure, supposedly to do with being environmentally friendly. However with V8 gas guzzlers going up and down 101 next to the airport, I think it a bit stupid.
I thought everyone in San Francisco drives either a Prius or a Tesla. In that way they transfer the pollution to out-of-area power plants.