1. Situation

a. The Army recently investigated a design deficiency in the head assembly of a fielded armored vehicle engine. Users in the field reported that the head assembly had failed to cause fuel leakage and serious fire damage to the vehicle engine and engine compartment. There were several instances where the fire spread outside the engine compartment and completely destroyed the vehicle. In each instance, the crews had ample time to evacuate the vehicle.

b. U.S. Army Tank Automotive Command (TACOM) found two possible solutions to reduce or eliminate the fuel leakage problem. The first is a new engine with a modified block and head assembly that eliminates the fuel leakage problem. A second solution is a field modification to the existing head assemblies accomplished at DS maintenance units.

2. Results of Initial Investigation

a. Impact of continuing to use the vehicles in their present condition. Data collection indicates that the probability of fuel leakage and fire is 0.2. Experience also indicates that when there is a fire, 90% of the time the damage is confined to the engine compartment and the repair cost is $200,000. The remainder of the time a fire occurs, a catastrophic fire destroys the entire vehicle. The replacement cost is about $1,300,000.

b. Impact of replacing the complete engine with the new engine which has a modified block and head assembly. Direct Support Maintenance Units could replace the existing engines at a cost of $100,000 each. The new engines should not manifest this particular problem.

c. Impact of making the minor modification to the existing head assemblies. Engineers estimate that this modification would cut the probability of fuel leakage and fire in half. If the modified assembly fails, the results are the same as with the old assembly. This modification would also take place at Direct Support Maintenance at a cost of $30,000 per assembly replacement.

3. Requirements

1. Determine which course of action the Army should take using a Decision Tree with the minimum expected unit cost as the decision criterion

2. Perform a sensitivity analysis as directed by the instructor