Production Acceptance Test (PAT)

PAT is the test sequence each individual production unit must pass before it ships, distinct from qualification testing (done once on a representative unit). For an avionics LRU, PAT might be 4 to 8 hours of power-on sequencing, built-in test, functional tests across temperature, and environmental stress screening. Unit failure rate on PAT is a closely watched KPI: 5 percent is acceptable, 10-plus triggers a containment investigation. The first 100 units off a new line typically PAT-fail at 30 to 50 percent. Getting to under 5 percent by unit 500 is the standard ramp expectation. Roles where this matters: Manufacturing, Quality, Test Engineering.