Glossary
Hobbs Time
Definition
Elapsed real-time counter that runs whenever the engine is operating. Usually activated by oil pressure, though some installations use the master switch. One Hobbs hour always equals one clock hour.
Why It Matters
Hobbs time is the standard billing reference at most flight schools. Students pay for Hobbs time because it's a straightforward measure of how long they had the aircraft. Maintenance tracking, however, typically uses tach time.