Always check your rear-view mirror before backing up

Airliner wheels aren't powered; they move on engine power only. Some aircraft can power back from the gate using the thrust reversers if they have tail-mounted engines, but 737s are not among those.

The issue is that using the reversers on underwing engines to back up creates a lot of air movement, which can easily lift debris off the ramp and into the engine intake...which would make for a really, REALLY bad day.

where they deploy the thrust reversers and use engine power to go backwards. (Some prop planes have reversible-pitch propellers.) However, there are concerns about foreign object damage to the engines and the aircraft, as well as blast damage to the terminal building and the ground. So in order to do a power back:

• It has to be under circumstances allowed by FAA regulations.
• The aircraft manufacturer has to have designated the maneuver as permitted under non-emergency circumstances in the aircraft in question.
• The airport operator has to allow it at the gate in question, under the weather conditions prevailing at the time of departure.
• The carrier's operating procedures have to allow it. (Often, they don't.)
• It has to be advantageous to do a powerback as opposed to getting a tug to push the aircraft back. (The powerback is sometimes faster, but it uses fuel.)
• A powerback runs the risk of tipping the aircraft back on its tail in the event the pilot brakes sharply.

With all those exceptions, it's no wonder that powerbacks are somewhat rare.

As an example of what can happen, Air Florida Flight 90 was a 737 that crashed shortly after takeoff from Washington National Airport in 1982. Because the tractor was having difficulty getting traction on the accumulated ice in the gate area to push the aircraft back, the crew attempted a powerback, despite Boeing's warnings against powering back in those weather conditions. Snow and ice were aspirated into the intake. The eventual NTSB report on the crash cited the improper use of powerback contrary to Boeing's recommendations as a contributing factor to the accident.

Airplane! with the Zucker Brothers' cameo as ground workers guiding the 747 into the gate:

Hey Larry! Where's the fork lift?

Fork lift? Oh yeah, it's over there by the baggage loader

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