Another disadvantage is that it blows loose items around the ramp.

The idea of powered gear has been tossed around, but there are two points against it: it's heavier, and it's one more thing to go wrong.

Anything that adds weight to the jet is going to increase fuel burn. Not only do you have the motors themselves, but you've also got heavy wiring and control circuits for the massive amount of power it will take to drive the jet.

The complexity argument is simple. You're adding more potential failure modes to the gear -- wheels that won't turn, turn too fast, or turn at different speeds. The drive system has be compatible with the high heat from braking and wide environmental conditions encountered.

So far, tugs are the cheapest option.

BTW, driven gear also comes up with respect to the big puff of smoke when the wheels touch down. It's cheaper to change tires slightly more often than to spin up the wheels.

I've been in planes that did that a couple of times recently.

I've wondered about this. Yes, motors would be heavy and expensive. How about a few blades instead? The wheels are exposed to the airstream for some minutes before touchdown, it wouldn't take much force to spin them up. How about a few little plastic vanes to use the energy of the airstream to spin them?

With tail mounted wings going bye bye we will see it a lot less.

Where else will they mount the wings? ;)

I used to watch the MD-80s do this at ORD from the AA terminal. Always was a good view from the bar.. (but maybe it was to many scoops of beer that made them look like they were going backwards) :eek:

I know the DC-9 and derivatives can do this, but given the cost of fuel wouldn't it now be cheaper to use the tug? I guess you have to analyze everything including the cost of labor, time, etc.

Not just jets .....
 

If you take Scot Airways (Dornier 328 turboprop) from Edinburgh to London City they will usually reverse back from the terminal at Edinburgh under their own power. It's so unusual to then change instantly from reverse to taxying forward.

Powerback with jets seems to be pretty much a US phenomenon, never seen it elsewhere in the world. If a tug is unavailable the aircraft is just swung round in front of the terminal and external steps or airstairs are used. The US however seems to just dislike boarding jets other than by a jetway, so they are always nose-in to the terminal.

It was SOP for American Airlines on Super-80s at DFW until a few years ago. Not sure why they stopped doing it.

This was done during Skylink construction. I don't know what the correlation was, but once Skylink was finished, it was back to the tugs.

I actually enjoy watching the smug little man at LHR guiding the plane backwards like it's a dog on a lead (I guess for the same reason that many people envy, just a little bit, people who get to demolish buildings or get to test destructive military systems for a living).

The smug little man's job is a Wing Walker. At a Heathrow stand there's one at each wingtip, in addition to the usual tractor driver.

Heathrow's stands are extremely tight (notice as you walk down the pier how close the wingtips of 747s or 340s are to each other). Following just one too many ground collisions there, wing walkers were made a requirement at the tightest spots.

Ground collisions are taken extremely seriously, not only because they end up costing £m for even quite minor damage, but the likelihood, particularly at night, of the crew not noticing it happen and going to take off with the damage done.

Now you've given me a job title to envy (and no, my eye sight will never be enough to make the grade) :D.

Thanks!

Not this sort of wingwalking !

NW at DTW
 

As mentioned, the MD/DC9 types at DTW NW A gates power back. I like waiting in that area and watching the last of the cowboy pilots back up. :D

It takes fuel, but it saves the cost and labor of a tug and driver. I think its done for time. The A gate NW flights are the short haul connector flights. They try to do a quick 20 min turnaround, just unload, load, and go. No waiting for a tug driver, no hookup/unhooking, just light the fires and back up. Better be seated in the gate area if you have one of those flights. A half full DC9 takes almost no time to load, they load them and GO. Stragglers in the WC get left.

I'll have to check my book, but IIR that short forward roll of a plane, even with a tug attached, is something to do with releasing the parking brake or resetting the parking brake sensors or something on some models. They always need a short forward roll before backing up.