Quote:
Originally Posted by MetroMPG
Do airline pilots hypermile?
Or would saving fuel cost too much money overall through lower passenger throughput (due to going slower)?
I would think that an obvious opportunity to save fuel (aside from flying slower) is in the approach to land.
I don't fly often, but have wondered:does a pilot typically make the most of the opportunity to literally glide in toward landing, or do they do the equivalent of what most drivers do: hard on the gas, late on the brakes?
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For the airline industry, fuel conservation is a planning factor for every flight. Flight planning is done by a "dispatcher" which is a FAA licensed occupation. All commercial carriers (above 31 pax seats) in the US are mandated by the FAA to use licensed dispatchers to plan all flights.
Flight planning includes:
• current/forecast weather (including clear air turbulence, thunderstorms, wind shear, icing, snow) for takeoff, enroute, landing and alternate airports.
• condition/status of airports & navigational aids
• over water requirements
• arrival & alternate airport weather minimums, runway in use, types of approaches available & minimums
• fuel load (in pounds), max. weight allowed for takeoff (based on length of to runway, obstacles off of end of RW, fuel burn enroute, max allowable landing wt., fuel to alternate airport, etc.
• planning includes spot cost of fuel, planned length of flight, temperatures, winds, expected ATC delays, etc.
Once the dispatcher finishes planning the specific flight, he will then make up a "flight release" on a computer. The "release" includes but is not limited to max allowable takeoff weight, fuel burn to destination, alternate airport, tail number of airplane, maintenance status of airplane, call-sign for the flight, departure, arrival & alternate airport, dispatcher's name. The release is sent to the Captain who reviews the "release". If the Captain concurs with the release, he signs the release. The release then becomes a part of the required documents to be kept on file for that specific flight.
Climb, enroute & descent speeds are determined by a number of factors including route length, fuel costs, winds aloft, temperatures, etc. Pilots have an onboard computer that has many of the variables plugged into it and will determine the climb, enroute & descent speed to the knot or 1/1000 of a mach number.
• airlines estimate their cost to passengers by a "cost per seat mile". It is usually around $0.08-0.15 per seat mile.
• indirect costs include cost of aircraft amortized over its estimated life time in hours, plus all the other costs associated with the airline, (headquarters, gate & ground equip. leases, maintenance, scheduling, IT, advertising, personal, etc.)
Ideally all flights would be a max power climb, economy cruise, & idle descent all the way to a 3 mile final at which time you would configure the aircraft for landing. Ideal doesn't happen very often. Arriving at large to medium size airports can be very complicated.
Example: aircraft arriving from the SW USA destination JFK in NY, start queueing-up over Atlanta, GA, and heading to JFK just off the eastern seaboard.
Boeing 747-400
Max To weight: 875,000 lb
Max Fuel Capacity: 57,285 US gal.
Max range: 7,260 nautical miles
Max seating: 524 seats
Max cargo: 6,025 cu. ft.
Boeing: Commercial Airplanes -- 747 -- 747-400 Technical Characteristics