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5. IN FLIGHT PROCEDURES
When an aircraft arrives at the end of the runway for take-off, it is the flying techniques (speed, altitude, configuration, etc) that have the biggest influence on fuel economy. Disciplined flight crews adhering to a flight plan based on the operator’s priorities can save much fuel and/or costs.
This part intends to give recommendations to flight crews on the means to save fuel during the flight. It reviews the different phases of the flight, that is to say:
. Take-off and Initial Climb
. Climb
. Cruise
. Descent
. Holding
. Approach
5.1 TAKE-OFF AND INITIAL CLIMB
5.1.1 INTRODUCTION
There are many variations in take-off technique that can directly affect the fuel burn. In general the effects are very dependent on the airframe/engine combination as well as aircraft weight, airfield altitude and temperature. The following fuel effects are representative values.
5.1.2 BLEEDS
For take-off, full bleeds can be used or one can consider selecting packs off or APU bleed on to improve take-off performance. Selecting packs off without APU will also improve fuel burn. The normal procedure would then be to select pack 1 on after climb thrust is selected and pack 2 on after flap retraction. This has the effect of reducing fuel burn by 2-3 kg on an A320 increasing to 5-10 kg on an A340-500/600.
With APU bleed the engine fuel burn will be decreased by the same amount. However with APU used from pushback with 12minutes taxi, the additional APU fuel burn is 30kg for an A320 and 60-70kg for an A340.
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