pushback tug stuff

[Chock 17,769]

In case anyone was wondering how the pushback driver knows where exactly to push the airliner out to, here's the little manual in the tug which tells us that. Unless ATC says otherwise with instructions for a 'non-standard push' to somewhere different, this is the guide we follow. As you can see, most prop aeroplane pushbacks are straight back, this is to avoid stressing the nose gear too much. You would think this would make prop aeroplane pushbacks 'easy' and a good one to start learning on when new to doing pushbacks, but in fact they are some of the harder ones to do because the view is not great with the aeroplane being so close to the ground, and smaller aeroplanes are a bit harder to control on a pushback because they react very quickly to small steering inputs. Big aeroplanes react a lot slower to steering inputs, giving you more time to correct things, and the view underneath them is very much better:

Because there may be a requirement to not follow a standard pushback procedure, usually to make room for something else on the taxiways (especially on this bit of the airport, which we refer to as the 'cul-de-sac'), we monitor the ground frequency on a radio and can if we wish, clarify things by speaking to ATC. If we are towing stuff, we definitely have to speak to ATC because all aircraft movements, have an ATC movement 'strip' in the tower (including tows), so we get given a specific route and have to do readbacks etc, just like you do when taxying an aeroplane under its own power. Each tug on the airport has its own callsign, just like an aeroplane has, so the radio procedure is the same as with aeroplanes, where you say your ID, do readbacks and so on. You need an additional licence beyond the typical airside driving permit to drive one of these things, because that allows you to drive on the taxiways, the course for this permit trains you on radio procedures, identifying runway and taxiway signs and all that sort of thing. The tug driving/pushback licence is known as the 'M' permit.

When towing, we connect the towbar to the rear of the tug, for pushbacks we connect it to the front. This picture shows the lower centre console on a tug; from the bottom on this pic you can see a perspex-enclosed card reader, this is for the telematics on the tug, it makes an annoying bleep tone until you touch it with your airside driver ID licence card (so there is a record of who was driving the tug), the large knob above it is the parking brake lever, and above that is the mike for the radio which is tuned to the ATC ground frequency:

Below you can see the main centre console of the tug: You can see the radio is tuned to channel 1, which is ATC ground, the stuff on the panel is for lights, different steering modes and that sort of thing (most tugs can do two wheel conventional steering, four wheel steering, and crab mode, but we normally just use four wheel steering), the big joystick knob is the gear lever, the button on top of it switches between automatic and manual transmission, up selects forward gears, down selects reverse gears, it has four forward gears and two reverse gears. We typically push back aeroplanes in manual forward second gear, because first gear is a bit snatchy which would be uncomfortable for passengers on the aeroplane, you can see we are in neutral on this pic from the N showing on the LCD display:

Below you can see how much aeroplane such as this ATR-72 restrict your view of the taxiway line, so much so in fact that you typically have to put a bit of a turn on the aeroplane in order to see where you are going. In this case I am waiting to push back off stand 16 at EGCC, which requires us to push pretty much straight back, although in fact we have to turn right a bit to go down taxiway Echo to end up on the centreline with the nose wheel stopping in line with the turnoff centreline for stand 5. Engine two is already running in Hotel Mode on the aeroplane (that's with the propeller brake engaged so the prop does not turn), but not all the GSE has been removed from the aeroplane yet, so the headset person has clipped the headset to the aeroplane, but has not plugged it in yet which is why you can see the jack plug dangling out. The access door where this will be plugged in, is also the access door for the ground power plug (or at least it is one of them, the aeroplane has two so it can use different connectors if necessary), but since the engine is now running, the power has been removed. This is pretty unusual actually, normally we get all the GSE clear of the aeroplane, then someone goes on the headset and supervises an engine start up in hotel mode, but the crew started the engine up without us doing that on this occasion, so we just went with it although it did mean that passengers were still boarding with an engine running, which isn't ideal:

 

 

Edited July 12, 2022 by Chock

[Lord Farringdon 495]

Interesting stuff Chock. Tell me, why does the tug pushback to taxiway centreline, then drive forward, sometimes quite a way before stopping and detaching from the aircraft? I was told it was to do with relieving stress on the NLG but presumably there is stress on the gear whether it is it is being pushed or pulled? The NLG is expected to take backward pressure on landing and is strutted for that but not for being pulled from the front which is more likely to result in a NLG collapse (notwithstanding the gear pin is inserted during any towing operations). So why the pull forward?