Exercise $4$: $25$ points

As a low$-$fare airline, Southwest Airlines constantly focuses on ways to improve the efficiency of its operations and maintain a cost structure below that of its competition. In spring $2002,$ Scott Topping, the director of corporate, was approached by Aviation Partners Boeing $($APB$)$ regarding an innovative way to save on fuel costs$$the installation of a new technology known as the blended winglet. The winglets, made of carbon graphite, were designed for the Boeing $737-700$ aircraft. Southwest currently had $142$ planes of this model in its fleet.

The blended winglet system was developed by APB, a joint venture between Aviation Partners Inc. and The Boeing Company. The main purpose of the winglet is to reduce turbulence, leading to higher flying efficiency. As a result, the winglets provided three important benefits that allowed the airplane to extend its range, carry a greater payload, and save on fuel consumption. The winglets accomplished this by increasing the spread of the wings$$ trailing edge and creating more lift at thewingtips.

To complete his financial analysis, Scott had to verify potential costs and benefits as well as get the approval of the Maintenance Engineering Department, the Flight Operations Department, and the Facilities Department. However, Scott was well aware that regardless of the potential financial benefits, safety was the first priority. This process took several months due to the complexity of the project. After discussing the project with the requisite departments, Scott made the following estimates of the costs and benefits of the winglet system to Southwest:

$$ The winglets, which cost $$700,000$ a pair, could be installed at an additional cost of $$56,000$ per aircraft. Installation could be scheduled at each maintenance facility to coincide with regular maintenance. As a result, each aircraft was expected to experience downtime for only one extra day, at a cost of $$5,000.$

$$ After considering the short$-$ and long$-$term effects of the winglets, the Maintenance Engineering Department estimated that repair costs would average $$2,100$ yearly per aircraft due primarily to incidental damage.

$$ The increased wingspan was expected to allow each of Southwest$$s aircraft to fly up to $115$ nautical miles further and to decrease fuel usage by $4\%$ to $6\%.$ This meant that Southwest could expect to save $178,500$ gallons of jet fuel per airplane per year.

$$ Flight Operations$22$ estimated that the additional lift capability provided by the winglets would reduce Southwest$$s costs of using restricted runways, with an estimated$ savings of $$500$ per aircraft per year.

$$ The Facilities Department assessed the effect of the added wingspan on each of the fifty$-$nine airports Southwest utilized in its current route structure. The department estimated that the necessary facilities modifications could be achieved at a onetime cost of about $$1,200$ per aircraft.

$$ The blended winglet project qualified for accelerated tax write$-$off benefits under the Job Creation and Worker Assistance Act of $2002.$ With a marginal tax rate of $39\%$ and using a seven$-$year depreciation schedule $($see Exhibit P$3-13\mathrm{.}1$ below$),$ Southwest would be allowed to depreciate an additional $50\%$ of the project in the first year.