Shutdown procedure

[tomigp 0]

Good day

I have a question.

After landing is it compulsory to start the APU and later on to connect to ground plugs or the APU can be skipped and the airplane is able to connect to ground directly?

 

Thanks for your answer!

[ph-cxz 28]

I think it depends on how quick ground crew can hook up the gpu. But if engines are running ground crew isn’t allowed to start with the turnaround. Also most airports require you to shutdown your engines as fast as possible for safety reasons and noise. Apu usage is also limited per airport.

[vc10man 732]

You can connect the GPU directly sans APU after applying handbrake, OH switch, then switching off engines once power established, which I normally do without the APU.

Edited November 26, 2018 by vc10man

[tomigp 0]

Sometimes, when I conect to ground without turning on the APU and then switch-off both engines, the airplane seems to have a instant blackout while some others the airplane switch smoothly to the ground plugs without any issues 

[ph-cxz 28]

you need to turn on the GPU on the overhead. simply hooking up the GPU doesn't do anything . the B777 requires a lot of electrical power that is also why there are two GPU plugs on the overhead. a primary and a secondary.

also please put your first and last name in every post as it is pmdg forum rules.

[Chock 17,769]

Normally what happens (in real life) is that the airliner taxies onto the stand with its anti-collision beacons going, and these are switched off only when the engine(s) fans have slowed down to a speed where it would be safe to approach the aircraft.

It's at this point that the ramp personnel will then chock the aircraft and connect the ground power. The flight deck crew don't have to request this, this is standard procedure at pretty much every airport in the world unless otherwise stated. So this tells you that generally speaking, ground power is not normally connected to an airliner until after the engines have stopped turning, since the ramp personnel have to approach the aircraft in order to connect ground power obviously, so they wait until it is safe to do so, as being sucked into an engine will ruin your day lol.

Thus if you were not using the APU and had no ground power, the aircraft would be reliant solely upon batteries for all electrical services when the engines were shut off and before the ground power was connected, which is not a good idea since if the batteries aren't in good shape, it would cut the power to the aircraft when it had passengers on board. so, there is a special procedure for this, it is called 'an APU shutdown arrival'.

Normally, you have the APU on as you taxy in and only switch it off when you had confirmed that ground power was available via the light indicator on your overhead panel. But since APUs can break sometimes (more often than you'd think); if this has occurred, the crew will use either ACARS text, or the radio, to let their ramp crew know in advance that they will have no APU running when they taxy in. As noted, this is referred to as 'an APU shutdown' arrival' and is why the ground crew need to be aware of this. When this happens, the aircraft will drive onto the stand as normal, with its anti-collision lights on, but it will leave the engine(s) (at least one) running so that running engine can deliver electrical power and the crew will of course leave the anti-collision lights on because of this to warn people on the ground not to go near the engine. The ground crew will approach the aircraft, taking care to stay away from the running engine, they will chock the nosewheel and then connect the ground power. After this is done, they will signal the crew that they have ground power available, so the crew will know they can shut down the engine(s) and still have the aircraft powered electrically even without a functional APU.

This procedure is one of the few exceptions to the general rule that ground crews don't approach an aircraft until the engines have spooled down and the anti-collision lights have been turned off. It is why as the pilot, you monitor the engine rotation speed when you shut down your engines and check that they have dropped to a low RPM percentage before flipping the anti-collision lights off, thus you don't endanger the ground personnel.

Edited November 26, 2018 by Chock

[scandinavian13 5,192]

3 hours ago, Chock said:

It's at this point that the ramp personnel will then chock the aircraft and connect the ground power. The flight deck crew don't have to request this, this is standard procedure at pretty much every airport in the world unless otherwise stated. So this tells you that generally speaking, ground power is not normally connected to an airliner until after the engines have stopped turning, since the ramp personnel have to approach the aircraft in order to connect ground power obviously, so they wait until it is safe to do so, as being sucked into an engine will ruin your day lol.

For what it's worth, as a former rampie, I was entirely indifferent to the engines once I could tell they were shut down (it's pretty audible) when it came to the nose chocks and GPU. Even with the SAABs, where the props were still a hazard for a decent amount of time after the shutdown, there was a safe access angle down the centerline of the plane that you could follow right after setting the nose chocks. With fans, I was aware of them in the sense that I didn't want any thing to get pulled off of me (hats, loose articles, etc.) until they'd spun down, but 

Granted, I'm sure some of it would've received (and borderline merited) discussion with the safety officer had they seen some of what I did, but I didn't find any of what I did actually dangerous, beyond the scope of the natural danger of the job (some of us would occasionally 'manually' load bags if we were down a belt loader by boosting someone up into the bin and handing bags in and out - that was more risky, injury-wise, than what normally did regarding engine spin down, in my opinion).

...you're absolutely right though: it was taught to us that the plane, upon arrival, (relatively) immediately, and without request, received chocks, GPU, and (usually) pre-conditioned air.

3 hours ago, Chock said:

This procedure is one of the few exceptions to the general rule that ground crews don't approach an aircraft until the engines have spooled down and the anti-collision lights have been turned off. It is why as the pilot, you monitor the engine rotation speed when you shut down your engines and check that they have dropped to a low RPM percentage before flipping the anti-collision lights off, thus you don't endanger the ground personnel.

I know this is taught in ground classes, and have seen both real world and sim pilots apply this. I also know that we were taught as rampies not to approach the aircraft until the beacon was turned off, but most of us did anyway. We wanted planes chocked and on GPUs ASAP, and the access points for either of those didn't put us in much more danger than the marshal for any of the planes, except the SAAB (GPU panel on the wing box - thanks Swedes). Once the beacon was off, we'd go place chocks on the mains (per the ops book / agreement), and approach with other equipment (stairs, loaders, etc).

 

 

----

To the OP's question, and to supplement Alan's answer, we occasionally did no-APU arrivals. One of the United Express operators had routine issues with APUs in their RJs, so they'd call ahead to let us know (our computer display would show it, too), park, shut down engine 1, we'd put the GPU plug in and turn it on, and then once they transferred over to the GPU, they'd cut engine 2.

If I recall correctly, we tried this in spring/fall back at Independence Air, too. They wouldn't spin the APU to avoid burning extra fuel, park on 2, get the wall-mount GPU, and then kill 1. In the winter it was too cold, and in the summer it was too hot, and we didn't have pre-conditioned at the gate (low cost carrier life) - APU was necessary to keep the cabin reasonable as boarding/deboarding took place.