WheelTug®

Basic Variables
Select an aircraft model and modify the below figures to match your airline's specific application.

Aircraft

This regional jet has been enjoying growing popularity in recent years.

Although discontinued, there are quite a few 727s in service - primarily with cargo airlines.

This is the baseline aircraft for the analysis. It is a 300/700 hybrid because many figures are developed from Southwest Airlines reports. SWA is a particularly good source of data because they operate an almost perfectly uniform fleet.

Long the world's largest passenger airliner, WheelTug™ can deliver significant savings for this aircraft.

Although discontinued, the 757 is still quite popular. American Airlines, for example, flies 143 of them.

The 767 is a larger capable of carrying around 200 passengers.

The 777 is Boeing's second largest offering, capable of carrying just over 300 passengers.

The future of Boeing, this extremely long-range and highly efficient aircraft may revolutionize point-to-point air traffic.

The MD80 is a popular aircraft that is no longer being produced.

The most popular Airbus aircraft, the A320 is a competitor to the somewhat smaller 737.

When it enters commercial service, the A380 will be the world's largest aircraft. On a per flight basis, WheelTug can offer this aircraft unparalleled savings.

Photo © Bruno David

Photo © Michael Carter

Photo © Bruno David

Photo © Jorge Meneses

Photo © Bruno David

Photo © Steve Brimley

Ground Taxi Time

Minutes

Includes time from gate to runway and back. The industry average is 25 minutes. This calculator will factor in the 5 minutes that the engines will need to be running prior to takeoff.

CO₂ Credit Value

/Metric Tonne

This is only relevant to airlines in Kyoto signatory countries. $33.50/metric tonne was the value as of Febuary 3rd, 2006.

Fuel Price

/Gallon

$1.649 was the average price paid from Jan-Nov 2005.

Turnaround Savings

Minutes

This is the number of minutes that would be saved by using WheelTug. Savings would be realized by not having to wait for a tug push-back from the gate.

Turnaround Savings Calc Method

Less Time/Flight	The average aircraft in a fleet would have less flying time for the same number of flights.
More Seat Miles/Day	The average aircraft in a fleet would enjoy more flying minutes without additional operational time.


See sources and assumptions for more information.

Cycles/Day

The industry average is 3.55. Southwest does 6.7.

Sources and Assumptions
Fuel and Maintenance:	http://www.southwest.com/investor_relations/fs_quarterly_earnings.html Fourth quarter of 2005 numbers were used to help calculate calculating fuel use for 737s. Fuel use for the other aircraft was based on weight proportions of the various aircraft. A direct relationship was assumed. All fuel and maintenance calculations assume that the APU will be running with WheelTug (and not running with turbine propulsion) and that the jets will need to warm up during the final 5 minutes prior to takeoff. http://www.passur.com/pst/report_app_c.htm This graph shows costs of around $1,750/hr for ground costs. This includes labor, fuel, gate costs etc. For our baseline 737, we assumed fuel use of 20 lbs/minute (from the operations manual) and we assumed that maintenance costs/minute would be equivalent both in the air and on the ground. Built into the maintenance savings are costs associated with tug accidents, dirt and other small debris getting into the engines and cycling of engines speeds through the taxiing exercise. As our cost/minute for fuel and maintenance works out to $540/hour our numbers are conservative. Considering that their ground costs would not include indirect costs like ticketing or gate management, the major costs under consideration are labor, fuel and maintenance. Our fuel and maintenance numbers only use about 31% of this total. Assigning 70% to labor and other captured expenses seems very conservative. This is particularly so because labor is only 50% of all operational costs for an airline like AMR. http://www.airlines.org/econ/d.aspx?nid=5806 Jet fuel prices http://www.bts.gov/programs/airline_information/airline_ontime_statistics/ To determine turnaround times.

Emissions and Kyoto:	http://www.eia.doe.gov/oiaf/1605/factors.html Emissions per gallon of aviation fuel http://www.epa.gov/otaq/regs/nonroad/aviation/r99013.pdf EDMA v. 4.11 FAA, 2003 Kyoto credit prices supplied by Point Carbon (www.pointcarbon.com).

Turnaround Savings:	http://www.bts.gov/press_releases/2004/bts016_04/html/bts016_04.html Used to determine industry revenues per available seat mile (10.75) and costs per available seat mile (11.26). http://www.aa.com/content/images/amrcorp/amrcorp2004ar.pdf page 31 Showed that about 50% of all costs are removable with 'free' additional flights. This is because extra labor, for example, is not required when more flights are squeezed into less time. This works out to a new cost/seat mile of 5.63 and revenues of 10.75 for a profit per new seat mile is 5.12. If you are reducing the operational time for the same number of flights, the calculation is somewhat more complex. You have to determine the cost of labor/minute from the cost of labor/Available Seat Mile (which is 3.9 cents). You can then calculate the number of saved minutes and determine overall savings.

Yearly Calculations:	Flights/yr come from the Air Transport Association of America, 2004 Annual Report

NPV:	http://www.aa.com/content/images/amrcorp/amrcorp2004ar.pdf Shows the expected life of aircraft as 30 years. Used for NPV calculation. As of last check: AMR Bonds are yielding 11%, Southwest are yielding 5%

Other:	Data about individual aircraft came from Aviation Week & Space Technology's Aviation Source Book 2006. Tug savings were not factored in due to the difficulty estimating tugs/flight. It is estimated that the yearly savings for 767-sized plane are about $50,000. But it is very hard to pin down on a flight by flight basis without knowing more operational data about an airline. Collecting this data on the form to do the calculation was not reasonable considering the relatively small values involved. We were conservative on APU use. We assumed no APU usage if WheelTug was not being used. We used only public information for this tool. Privately gathered information on fuel use, for example, is not disclosed here. This does not capture the importance of WheelTug to Boeing's Automated Airport Initiative. By enabling planes to move without ground vehicle support, the automated airport and its savings becomes realizable.

Financial Benefits Calculator