ARCHIVES - Unharried Harrier Upgrades


Unharried Harrier Upgrades

The Harrier jet, with its ability to takeoff and land vertically, provides an operational versatility unmatched by any other fighter jet in the western world. The flexibility and rapid response capability have made it one of the Marine's primary ground attack aircraft. A key factor in scheduling upgrades to their fleet is making sure they have a high number of Harriers operational at all times. The Center for Naval Analysis (CNA) has found What'sBest! can be an extremely useful tool in pursuing this goal.

The upgrade schedules need to take into consideration funding constraints, production constraints and requirements, opportunities for economies of common installation setups, and, perhaps most important, fleet readiness due to scheduled downtime. The CNA has developed a What'sBest! model to make the Harrier upgrade scheduling and subsequent rescheduling more manageable and, at the same time, produce better quality schedules in terms of operational fleet downtime.

The upgrade schedules are extremely dynamic and difficult to manage. This is due to the large number of aircraft to be upgraded through the coordination of a number of different organizations at several different locations around the globe. The upgrade kit installations are subject to frequent delays due to supply chain shortages, high defect rates, and failed inspections. Delays are often also compounded by unpredictable changing operational conditions and from engineering changes and contract modifications.

Traditionally, the master schedule has been developed by trial-and-error, but this has proven to be labor intensive and error prone. The schedule is also difficult to evaluate and update given the inevitable need for frequent changes. As an alternative to trial-and-error, the CNA formulated the upgrade schedule as an integer programming model in Excel to be solved using What'sBest!.

"I found What'sBest! very easy to use. To solve an integer programming problem, simply enter it into an Excel spreadsheet and the rest is straightforward, all menu-driven and very intuitive." says David Kelly, Researcher for the CNA. "I chose What'sBest! for two reasons - mainly because it is spreadsheet software and also because it explicitly displays all the constraints and objective function of my customers' problems the same way they have seen them elsewhere in their project reports. Sponsors and users alike seem to feel comfortable with the spreadsheet format. And they become much more receptive to analyses. By using Excel, they can understand and can question the model, looking for similarities and differences with their own thinking. What's Best! lets them easily do that."

The resulting schedule allows the Marines to maintain maximum fleet readiness. And, through efficiently scheduling and rescheduling, they can better avoid missed milestones, late identification and resolution of conflicts, unnecessary contract extensions, and costly contract modifications.

For more details, see "Master Scheduling and Tracking Aircraft Upgrades" in Military Operations Research, V4 N2 1999.

For more information on What'sBest!, please see the product pages. You can also download a demo version from our download page or order a full blown version directly from our order page.