Pushback (airplane)
Pushback ( English for "push back" ) is an Anglicism for backing up an aircraft that is standing with the aircraft nose at an airport building ( gate ) (so-called "nose-in-position"). Pushing back is necessary because most jet aircraft have no ability to roll backwards on their own or are not allowed to roll backwards.
Pushback process
The pushback is carried out by specially developed vehicles, the aircraft tugs. There are two possibilities: either a push rod (tow bar, english towbar ) used (similar to a tow bar) - the pushback goes here at walking pace vonstatten. Or a lifting tug is used, which can grip the nose wheel of the machine - so the aircraft can be pushed much faster.
The aircraft is pushed onto the runway by the pushback , in order to then continue on its way to the runway on its own.
During the pushback, the aircraft's own control of the nose landing gear is deactivated, which is done by means of a steering pin that the apron staff insert into the landing gear leg . This actuates a corresponding switch or a hydraulic valve and thereby decouples the steering actuation.
The nose landing gear, which can now be freely pivoted to the left and right , is steered in the pushback phase by the push rod that is rigidly coupled to the aircraft - similar to a drawbar on a multi-axle trailer. On the other hand, on the aircraft tractor, the push rod is pivotable on all sides in order to be able to push the aircraft around curves through the interaction of the steering movements of the tractor, towbar and nose landing gear.
After the pushback and unhooking of the push rod, it must be ensured that the steering pin is removed again, otherwise the cockpit crew cannot use the nose wheel controls.
Startup
Before or during the pushback is started at a sufficient safety distance from buildings, objects and people, the engines start ( english startup ), soon to release the taxiways as possible for the following aircraft. This also results in a shorter ground time. Approval is required for this at controlled airfields.
Ramp agent
During the pushback, the cockpit is in voice contact with the ramp agent , an employee of the ground staff who either runs alongside the nose wheel of the aircraft or rides on the tug. The voice connection ( interphone ) is established by means of a cable. It informs the pilot when the distance to buildings, objects and people is large enough to be able to start the engines safely (“Engine Area Clear”). This ensures that no persons, vehicles or other objects are located behind the aircraft during the engine start and could be damaged. The pilots can also provide information about any problems. The agent on the headset is the last to “leave” the aircraft and uses a tape on the steering pin with the label “Remove before flight” to indicate that all handling equipment has been removed and the aircraft is ready to taxi.
Series of images for pushback
Aircraft tractor pushes the aircraft backwards from the parking position.
Aircraft tractor has parked the aircraft on the taxiway.
Aircraft tractor drives away; Push-back ended.
Airplane asks for permission to taxi.
Airplane turns on headlights and rolls to the runway.
Powerback
At some airports it is allowed to do a powerback . Here the aircraft is using reverse thrust to reverse.
Nose-out position
Parking positions for aircraft are divided into nose-in positions and nose-out positions. As a rule, nose-out positions are located some distance from the pier on the apron of an airfield. As a rule, the pilots are told by the apron control in which direction their aircraft should be parked. In these upstream positions, no pushback processes are necessary for nose-out positions, as the prescribed safety area behind the running engines (up to 125 m) can be kept free. The aircraft is then allowed to roll away from its parking position on its own.
No aircraft tugs are required for these nose-out positions. Low-cost airlines, in particular, tend to forego costly, fee-based positions because the passengers themselves can go to the nose-out aircraft, usually uncovered, and the pilot does not have to move the aircraft. Not having to reposition the aircraft is a significant cost and time advantage.
Push-in positions, where the aircraft has to be pushed in after arrival, but can then roll out on its own for the next flight, are very rare.
Web link
Individual evidence
- ↑ a b c Explanation of the Push-Back ( Memento from March 31, 2005 in the Internet Archive )
- ↑ Task of the ramp agent
- ↑ EFM: We move planes ( Memento of the original from January 1, 2011 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ The miniature wonderland about the aircraft tugs at the model airport Knuffingen Airport, plus a brief explanation of the aircraft tug
- ↑ Pushback at luftfahrt.net ( Memento of the original from December 19, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
