Joined: 11 Dec 2005
|Posted: Sat Aug 09, 2008 5:14 pm Post subject: Cruise Fuel Penalties of B737
|Below is an analysis of fuel penalties associated with the cruise segment of a flight. Cruise fuel penalties include:
- ISA +10 C = 1% increase in trip fuel.
- 2000 feet above/below optimum altitude = 1% to 2% increase in trip fuel.
- 4000 feet below optimum altitude = 3% to 5% increase in trip fuel.
- 8000 feet below optimum altitude = 8% to 14% increase in trip fuel.
- Cruise speed 0.01M above LRC = 1% to 2% increase in trip fuel.
The planned fuel burn can increase due to:
- Temperature above planned.
- A lower cruise altitude than planned.
- Cruise altitude more than 2000 feet above optimum altitude.
- Speed faster than planned or appreciably slower than LRC.
- Stronger headwind component.
- Fuel imbalance.
- Improperly trimmed airplane.
- Excessive thrust lever adjustments.