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Push and Hold

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Article Information
Category: Ground Operations Ground Operations
Content source: SKYbrary About SKYbrary
Content control: EUROCONTROL EUROCONTROL

Description

This is a procedure adopted by some aircraft operators when ATC have advised of an expected significant delay for take off so as to allow their flights to record an on-time departure and / or to clear a gate for re-use. If the airport operator directly controls gate occupation, then the procedure may also be used by them for gate-release purposes. It involves an aircraft ground-positioning, usually under its own power, to what are often specially designated remote parking stands. Here, the engines are shut down and aircraft services are maintained by the use of the APU until engine re-start is authorised by ATC.

Operational Safety Implications

The principal issue raised is the absence of ground supervision of the engine restart at the remote parking position. This absence also implies a lack of aircraft fire cover during engine start which is contrary to the case for normal pre-flight engine starts which take place either on the turn round parking gate or during / immediately after the pushback with the ground crew in attendance and in communication and ground fire extinguishers in proximity to the aircraft.

Naturally, in weather conditions where airframe icing is a consideration, it may be necessary to carry out de-icing/anti-icing prior to the eventual departure of the aircraft.

Solutions

Proactive risk management should be based upon Flight crew and ATC awareness of potential safety issues and any procedural mitigations of them. In particular, Operations Manual Procedures should clarify the actual and the potential effect of starting engines without the presence of ground fire cover from a start crew. In certain circumstances, where particular remote positions are designated for prolonged holding of departing aircraft with engines shut down, there may, exceptionally, be a system for partial supervision of engine starting.

Consideration should be given to using supernumerary/cabin crew, on intercom, to monitor the engines visually from inside the aircraft during the start sequence and report anything unusual.

In addition, there should be an ATC and / or Company procedure which provides for early notification of an intention to issue and / or accept a push and hold gate departure clearance, so that any appropriate loading of additional fuel for the running of the APU when holding remotely is facilitated.

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