8. FCOM procedures require not less than a defined time before shutting down the other engine(s) after landing. On engines with a high bypass ratio, the cool-down time after reverse operation, prior to shut down has a significant effect on engine  life.

9.  If an operator decides to use one or two engine out taxi, then FCOM       recommendations about which engine(s) to use should be followed.

 
As engine-out taxi requires more thrust per engine to taxi and maneuver, caution must be exercised to avoid excessive jet blast and FOD. More thrust is necessary for breakaways and 180 degrees turns.
On twin-engine aircraft slow and/or tight taxi turns in the direction of the operating engine may not be possible at high gross weight.
Single engine taxi may also be considered at low weights to avoid  excessive use of the brakes to control the acceleration tendency with all engines. This brake use would be detrimental to carbon brake life.
The following table gives an indication of the advantages of engine out taxi for 8 of the 12 minutes total taxi time, leaving 4 minutes warm up time.
 
  Fuel savings with Engine out taxi  
Aircraft types
 12 minutes taxi    (all engines) 
 12 minutes taxi    (8 with engine out)
 Engine Out taxi savings 
 
A300-600
 300kg
 200kg
 100kg
 
A310
 240kg
 160kg
 80kg
 
A318
 120kg
 80kg
 40kg
 
A319
 120kg
 80kg
 40kg
 
A320
 138kg
 92kg
 46kg
 
A321
 162kg
 108kg
 54kg
 
A330
 300kg
 200kg
 100kg
 
A340-200/300
 300kg
 250kg
  50kg
 
A340-500/600
 420kg
 350kg
  70kg
 

 
 For engine out or all engines taxi, the use of a slow taxi speed costs fuel and time. A burst of power should be used to get the aircraft to taxi speed, then the power should be reduced to idle. However 30kt should not be exceeded.
 
 
 
 
 
4.5 FUEL FOR TRANSPORTATION

 
The normal message regarding fuel burn is that it is more economical to carry the minimum amount required for the sector. However there are occasions when it is economic to carry more fuel. This is when the price of fuel at the destination airfield is significantly higher than the price at the departure airfield. 
However, since the extra fuel on board leads to an increase in fuel consumption the breakeven point must be carefully determined. 
　
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