Definition

A pre-departure service check (PDSC), often discussed in terms of extended-range operations, verifies the aircraft's status and the condition of its systems for long-range flights, typically over water. 

Description

U.S. Federal Aviation Administration (FAA) regulations state that at a minimum, a PDSC for extended-range operations (ETOPS) must:

• Verify the condition of all ETOPS-significant systems
• Verify the overall status of the airplane by reviewing applicable maintenance records
• Include an interior and exterior inspection to include a determination of engine and auxiliary power unit (APU) oil levels and consumption rates

FAA Advisory Circular 135-42, "Extended Operations (ETOPS) in the North Polar Area," states: "Specifically, the PDSC is a maintenance task that should include an applicable maintenance records review and an interior and exterior inspection. The PDSC is sometimes referred to as an expanded transit check inspection."