Summary: While the M1 tank is impressive in meeting its three major combat requirements of firepower, mobility, and armor protection, these advantages are offset to a considerable degree by shortcomings in reliability, availability, durability, maintainability, and by the tank's rising cost. The tests conducted by the Army were not as stressful as operational tests, and the tanks received maintenance which could not be expected in a combat environment. Engine failures have been more frequent, and the maintenance burden is substantially above the Army's desired levels. Efforts to improve the durability of the power train have not made much progress during the past year. The M60 tank is superior to the M1 in all test results except for system reliability. However, durability was not scored on the tests of the M60 tank. The Department of Defense (DOD) is to decide in September whether to permit the Army to increase its rate of M1 procurement above the present limitation. GAO would urge DOD to also consider continuing with the development and testing of a back-up diesel engine in view of the Army's failure to improve the turbine to a more acceptable level of durability than a year ago. The cost of the M1 has increased significantly since its development began due to program changes, inflation, and an increase in quantities ordered. GAO foresees further significant changes in cost estimates in the future. Future funding constraints could force changes in the production schedule which would increase production costs. M1 production has not kept pace with planned deliveries.
