getting to grips with fuel economy(36)

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In order to allow an assessment of the sensitivity of each aircraft type to different hold techniques, the following table shows the extra fuel required to hold for 15 minutes at 10000ft in the first flap configuration at ‘S’ speed, compared to Conf clean at green dot speed. 
 
 
 
 
 
1
Effect of Holding in First flap Setting at ‘S’ speed compared with Clean at Green Dot speed
Aircraft types
 Fuel Increase (kg)
Low Holding Weight
 Fuel Increase (kg)
High Holding Weight
 
A300B4-605R
 70
 110
 
A300B4-622R
 110
 190
 
A310-324
 70
 135
 
A318
 5
 10
 
A319 
 10
 30
 
A320 
 10
 30
 
A321
 30
 50
 
A330-203 
 135
 175
 
A330-223
 175
 205
 
A330-343
 145
 175
 
A340-212
 170
 230
 
A340-313
 125
 175
 
A340-642
 130
 150
 

 
The table shows that the green dot speed/clean configuration combination enables significant savings to be made.
However, green dot speed increases with weight and can become higher than the maximum recommended speeds, which are listed below:
 
Levels
 ICAO
 PAN-OPS
 FAA
 France
 
Up to 6,000 ft inclusive
 230 KT
 210 KT
 200 KT
 220 KT
 
Above 6,000 ft to 14,000 ft inclusive
 230 KT
 230 KT
 230 KT
 220 KT
 
Above 14,000 ft to 20,000 ft inclusive
 240 KT
 240 KT
 265 KT
 240 KT
 
Above 20,000 ft to 24,000 ft inclusive
 265 KT
 240 KT
 265 KT
 240 KT
 
Above 24,000 ft to 34,000 ft inclusive
　
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