Large-Scale Production of the M1 Tank Should Be Delayed Until Its Power Train Is Made More Durable

MASAD-82-7: Published: Dec 15, 1981. Publicly Released: Dec 15, 1981.

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GAO reviewed the M1 tank acquisition program after it had reached the purchasing stage. The M1 system represents the Army's most costly new weapons system; the course the Army follows in acquiring the M1 will have a significant effect on its budget. The M1 has recorded numerous difficulties during its planning and testing phases resulting in production delays; generally, problems were related to the engine and the transmission. A panel of experts convened by the Department of Defense, just prior to the purchasing phase, believes the M1 will show substantial improvement provided certain modifications to the functional operations of the tank are incorporated.

GAO believes that, regardless of the nature of these modifications, serious questions still remain concerning the reliability of the M1 tank. The latest series of tests has again confirmed that the M1 has met nearly all of its major combat requirements: firepower, armor protection, and mobility. Despite this fine showing, a problem of great concern was disclosed in the testing. The M1 power train failed to meet the Army's durability goal. The Army reported that the power train had demonstrated a 37-percent probability of meeting the requirement to achieve 4,000 miles without a need to replace a major component compared to the 50-percent probability required. Because of congressional concerns over the turbine engine's durability, the Army began developing a backup diesel engine. This engine is currently scheduled for completion in December 1982. To take full advantage of the M1 tank's excellent inherent capability, an improvement in the tank's power train durability is necessary. Until the durability requirement is met, it appears unwise to produce large numbers of tanks. To do so before an improvement is effected will create a large inventory of tanks hampered by engines requiring frequent replacement and expensive maintenance. The Army plans to continue improving the turbine engine and is also testing the alternative diesel engine. Thus, the Army has the opportunity to compare the performance of both engines so that ultimately the more cost-effective of the two engines will be selected. Prudence dictates that this opportunity should not be overlooked.

Matter for Congressional Consideration

  1. Status: Closed - Not Implemented

    Comments: Congress supports large-scale production of the tank to meet defense needs as quickly as possible.

    Matter: Congress should consider conditioning future appropriations for large production of the M1 on the power train meeting the Army's durability requirement.

Recommendations for Executive Action

  1. Status: Closed - Not Implemented

    Comments: The Army has no serious interest in a diesel engine for the M1 tank and Congress has shown no further interest in pressing the Army to pursue it as an alternative for the turbine engine.

    Recommendation: The Secretary of Defense should direct the Army, if the requirement has not been met, to compare the performance and durability of the turbine and diesel engines as demonstrated in testing and to prepare an analysis of the two engines.

    Agency Affected: Department of Defense

  2. Status: Closed - Not Implemented

    Comments: Neither the Secretary of Defense nor Congress are interested in changing from the turbine engine.

    Recommendation: The Secretary of Defense should evaluate the Army's analysis and select one of the two engines for incorporation in the balance of the production run.

    Agency Affected: Department of Defense

  3. Status: Closed - Not Implemented

    Comments: The Army is using available funds to make the assessment and does not plan additional funding requests for this purpose.

    Recommendation: The Secretary of Defense should provide the key congressional committees with an assessment of the power train's capability and with an estimate of funds that may still be needed for improvement to elicit, from whichever engine is selected, the type of performance that would enable the power train to meet the durability requirement.

    Agency Affected: Department of Defense

  4. Status: Closed - Not Implemented

    Comments: Tests were suspended after a short period because the engines being tested developed serious cracks and the tanks could not run. The Army attributes the cracking to a quality control problem. There is no evidence that the Army plans to halt production of the engine in spite of its problems nor has any recent interest been evinced by Congress in halting tank production.

    Recommendation: The Secretary of Defense should evaluate the results of the turbine engine's testing in production model tanks, scheduled for 1982, to determine whether the engine has improved sufficiently to raise the power train's durability to a level that meets or exceeds the Army's requirement.

    Agency Affected: Department of Defense


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