Combat Vehicle Schedule
Combat vehicle design tradeoffs include requirements and performance parameters. However, there are two other parameters that affect the Army’s ability to procure a combat vehicle that derive from requirements: cost and schedule. System schedule, the time it takes a vehicle to go from concept to production, is a function of system complexity and process requirements.
A highly capable, complex system, which requires components that are more advanced, requires more design and integration time than a simpler system with fewer capabilities. New designs usually require more design time than modified designs, but only to a point. An extensively modified off-the-shelf vehicle can require more design time than new, as the modifications must be adapted to an existing vehicle’s limitations. More capabilities translate to increased testing requirements, as each capability is tested and evaluated against system requirements.
New designs usually require more design time than modified designs, but only to a point. An extensively modified off-the-shelf vehicle can require more design time than new, as the modifications must be adapted to an existing vehicle’s limitations. More capabilities translate to increased testing requirements, as each capability is tested and evaluated against system requirements.
Testing time is the largest single schedule driver for a combat vehicle, driven primarily by the need to accumulate sufficient operating time to assess the vehicle’s durability and reliability with an appropriate degree of statistical certainty to predict how it will perform when fielded. Reducing test requirements or producing more prototypes to allow parallel testing (with an increase in cost) can shorten test time. Test scheduling is a careful balancing act between time available, costs associated with available prototypes, and the value of information gained during testing that leads to earlier improvements in capability.
Process requirements also drive the schedule. Requirements can include everything from decision gates and reviews, which require multiple levels of stakeholder review and decision before the program can move forward, to the volume of documentation generated, reviewed, and approved to meet statutory and regulatory requirements. Process requirements drive specific test events and engineering activities that affect scheduling significantly. For example, validating both prototype performance and production article performance drives two complete rounds of testing for combat vehicles, which can equate to four years of program schedule.
While many process requirements take place in parallel with other vehicle program activities, they do contribute to the overall length of the schedule. A Program Executive Office GCS analysis of statutory and regulatory requirements, called the “Null Program,” concluded that an Acquisition Category I program that met all statutory and regulatory requirements but required just one day of development and one day of production still had five years of process-generated schedule and related costs.
Changes that affect vehicle design, whether at the operating concept, requirements, or design tradeoffs level, will increase the cost, schedule, or performance risk of a vehicle program, and the later those changes occur in the program the greater the risk. Stability in requirements, unless the source of instability is a lessening or elimination of requirements, is key to keeping cost, schedule, and performance factors predictable and under control.
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