Flight Safety
10th Apr 2001, 02:29
I noticed this last night and thought I'd post it to get other opinions.
I was comparing fuel usage/passenger figures last night (I was working up some operating cost data) for the A380, 747-400, and A340-600 and I was surprised at what I found. I'll start with the following info (from a table) from an Aviation Week article published late last year following the A380 launch.
A380 COMPARISON CHART
Airbus A380-100 Boeing 747-400 Boeing 747X Stretch
Passengers (3-class) 555* 416** 522**
Engines (fourturbofans) @ 68,000-75,000 lbf. @ 59,500-63,300 lbf. @ 68,000 lbf.
Wingspan 261.8 ft. 211.4 ft. 228.9 ft.
Wing area 9,100 sq. ft. 5,600 sq. ft. 6,820 sq. ft.
Aspect ratio 7.53 7.98 7.68
Wing sweep (1/4-chord) 33.5 deg. outboard 37.5 deg. outboard 37.5 deg. outboard
Length 239.5 ft. 231.8 ft. 264.3 ft.
Height 79.1 ft. 63.7 ft. 65.2 ft.
Maximum takeoff weight 1,235,000 lb. 875,000 lb. 1,043,000 lb.
Maximum landing weight 844,000 lb. 652,000 lb. N/A
Maximum zero fuel weight 789,000 lb. 555,000 lb. N/A
Operating weight empty 606,000 lb. 399,300 lb. 495,000 lb.
Fuel capacity 85,900 U.S. gal. 57,285 U.S. gal. 72,573 U.S. gal.
Wing loading @ MTOW 136 psf. 156 psf. 153 psf.
Thrust-to-weight @ MTOW 0.24 0.29 0.26
OWE/passenger 1,092 lb./pax 960 lb./pax 948 lb./pax
Normalized OWE/pax 114% 100% (reference) 99%
Range with full 8,150 naut. mi. 7,330 naut. mi. 7,785 naut. mi.
Passenger payload @ 116,550 lb. @ 87,360 lb. @ 109,620 lb.
Long range cruise speed Mach 0.85 Mach 0.85 Mach 0.86
Initial cruise altitude capability 35,000 ft. N/A 34,000 ft.
Takeoff field length (MTOW, sea level, 86F) <11,000 ft. N/A 11,000 ft.
Approach speed @ MLW <145 kt. N/A N/A
Notes:
*A380 cabin configuration is 22 first class at six abreast, 68-in. seat pitch; 96 business class at six-abreast, 44-in. pitch; and 437 economy at 8-10-abreast, 32-33-in. pitch.
**747-400 cabin configuration is 23 first class at 61-in. seat pitch; 78 business class at 39-in. pitch; and 315 economy at 10-abreast, 32-in. pitch. The 747X Stretch has the same seating dimensions.
N/A--data not available due to Christmas holiday closure.
Several things stand out here, but I'll just focus on the fuel usage/passenger data.
I had to normalize the fuel usage figures to the range of the 747-400, since it has the shortest range of the 3 aircraft listed in the table. I also used the "typical 3 class" passenger load so as to compare "apples to apples" as much as possible. I'm also assuming that appropriate fuel reserves are calculated into the maximum ranges of each aircraft.
Normalized fuel usage for the A380 at 7330nm would be (7330/8150)*85,900 = 77257.3 gallons. Take this figure and divide it by 555 passengers (77257.3/555 = 139.2 gals) yields 139.2 gallons/passenger at a full passenger load for a trip 7330nm long.
For the 747-400, take the total fuel load divided by the total passenger load (57,285/416 = 137.7 gals), yields 137.7 gallons/passenger for a trip 7330nm long.
The A340-600 can carry 380 passengers in a "typical 3 class" arrangement, has 7500nm range, and can carry 51,480 USgal of fuel. Its MTOW is 804,000 lbs. Normalizing the fuel used at 7330nm (7330/7500)*51480 = 50313 gallons of fuel. Take this figure and divide by total passenger load (50313/380 = 132.4 gals), yields 132.4 gallons/passenger at full load for a 7330nm trip.
All of this assumes that the 747-400 can actually fly 7330nm with a full load of passengers, which it can if each passenger with luggage weighs an average of 210 lbs. The passenger payload weight in the chart above assumes an average of 210 lbs. per passenger, which I think is a little low.
So now this leads me to conclude that the A340-600 is the most efficient of these 3 airliners on a long haul trip, followed by the 747-400, then the A380.
Now to the marketing of the A380, which says that the A380 can "break even" at a passenger load of only 58 percent compared to 70 percent for the "competition", which can be determined to be a 747-400 based on the passenger load being compared. I noticed from the chart above that the OWE (operating empty weight) of the A380 is slightly more than 50 percent higher than the 747-400. That thing is 206,700 lbs heavier than a 747-400 at OWE. I also noticed that the A380 is 132 lbs heavier per passenger in the OWE/passenger figure in the chart above.
How will it be possible for the A380 to have a "break even" passenger load point that is 12 percent lower (70%-58%) than the 747-400 based on these figures?
Any other comments would be welcome, and you can check my figures.
------------------
Safe flying to you...
[This message has been edited by Flight Safety (edited 09 April 2001).]
I was comparing fuel usage/passenger figures last night (I was working up some operating cost data) for the A380, 747-400, and A340-600 and I was surprised at what I found. I'll start with the following info (from a table) from an Aviation Week article published late last year following the A380 launch.
A380 COMPARISON CHART
Airbus A380-100 Boeing 747-400 Boeing 747X Stretch
Passengers (3-class) 555* 416** 522**
Engines (fourturbofans) @ 68,000-75,000 lbf. @ 59,500-63,300 lbf. @ 68,000 lbf.
Wingspan 261.8 ft. 211.4 ft. 228.9 ft.
Wing area 9,100 sq. ft. 5,600 sq. ft. 6,820 sq. ft.
Aspect ratio 7.53 7.98 7.68
Wing sweep (1/4-chord) 33.5 deg. outboard 37.5 deg. outboard 37.5 deg. outboard
Length 239.5 ft. 231.8 ft. 264.3 ft.
Height 79.1 ft. 63.7 ft. 65.2 ft.
Maximum takeoff weight 1,235,000 lb. 875,000 lb. 1,043,000 lb.
Maximum landing weight 844,000 lb. 652,000 lb. N/A
Maximum zero fuel weight 789,000 lb. 555,000 lb. N/A
Operating weight empty 606,000 lb. 399,300 lb. 495,000 lb.
Fuel capacity 85,900 U.S. gal. 57,285 U.S. gal. 72,573 U.S. gal.
Wing loading @ MTOW 136 psf. 156 psf. 153 psf.
Thrust-to-weight @ MTOW 0.24 0.29 0.26
OWE/passenger 1,092 lb./pax 960 lb./pax 948 lb./pax
Normalized OWE/pax 114% 100% (reference) 99%
Range with full 8,150 naut. mi. 7,330 naut. mi. 7,785 naut. mi.
Passenger payload @ 116,550 lb. @ 87,360 lb. @ 109,620 lb.
Long range cruise speed Mach 0.85 Mach 0.85 Mach 0.86
Initial cruise altitude capability 35,000 ft. N/A 34,000 ft.
Takeoff field length (MTOW, sea level, 86F) <11,000 ft. N/A 11,000 ft.
Approach speed @ MLW <145 kt. N/A N/A
Notes:
*A380 cabin configuration is 22 first class at six abreast, 68-in. seat pitch; 96 business class at six-abreast, 44-in. pitch; and 437 economy at 8-10-abreast, 32-33-in. pitch.
**747-400 cabin configuration is 23 first class at 61-in. seat pitch; 78 business class at 39-in. pitch; and 315 economy at 10-abreast, 32-in. pitch. The 747X Stretch has the same seating dimensions.
N/A--data not available due to Christmas holiday closure.
Several things stand out here, but I'll just focus on the fuel usage/passenger data.
I had to normalize the fuel usage figures to the range of the 747-400, since it has the shortest range of the 3 aircraft listed in the table. I also used the "typical 3 class" passenger load so as to compare "apples to apples" as much as possible. I'm also assuming that appropriate fuel reserves are calculated into the maximum ranges of each aircraft.
Normalized fuel usage for the A380 at 7330nm would be (7330/8150)*85,900 = 77257.3 gallons. Take this figure and divide it by 555 passengers (77257.3/555 = 139.2 gals) yields 139.2 gallons/passenger at a full passenger load for a trip 7330nm long.
For the 747-400, take the total fuel load divided by the total passenger load (57,285/416 = 137.7 gals), yields 137.7 gallons/passenger for a trip 7330nm long.
The A340-600 can carry 380 passengers in a "typical 3 class" arrangement, has 7500nm range, and can carry 51,480 USgal of fuel. Its MTOW is 804,000 lbs. Normalizing the fuel used at 7330nm (7330/7500)*51480 = 50313 gallons of fuel. Take this figure and divide by total passenger load (50313/380 = 132.4 gals), yields 132.4 gallons/passenger at full load for a 7330nm trip.
All of this assumes that the 747-400 can actually fly 7330nm with a full load of passengers, which it can if each passenger with luggage weighs an average of 210 lbs. The passenger payload weight in the chart above assumes an average of 210 lbs. per passenger, which I think is a little low.
So now this leads me to conclude that the A340-600 is the most efficient of these 3 airliners on a long haul trip, followed by the 747-400, then the A380.
Now to the marketing of the A380, which says that the A380 can "break even" at a passenger load of only 58 percent compared to 70 percent for the "competition", which can be determined to be a 747-400 based on the passenger load being compared. I noticed from the chart above that the OWE (operating empty weight) of the A380 is slightly more than 50 percent higher than the 747-400. That thing is 206,700 lbs heavier than a 747-400 at OWE. I also noticed that the A380 is 132 lbs heavier per passenger in the OWE/passenger figure in the chart above.
How will it be possible for the A380 to have a "break even" passenger load point that is 12 percent lower (70%-58%) than the 747-400 based on these figures?
Any other comments would be welcome, and you can check my figures.
------------------
Safe flying to you...
[This message has been edited by Flight Safety (edited 09 April 2001).]