Block Time
Block time is the elapsed time from when an aircraft pushes back from its parking spot at origin to when it's parked at destination — engine start to engine shutdown. Private jet charter (including empty legs) is billed on block time, not on flight time in the air.
Also known as: block hours, block-to-block, block hour billing, block time billing
Block time is the operational accounting standard in commercial aviation and private charter for measuring aircraft use. It starts when the aircraft moves under its own power at the origin (typically pushback or taxi) and ends when it comes to a final stop at the destination. Taxi time on the ground at both ends is included; the en-route flight time ("wheels up to wheels down") is a subset of block time.
Operators bill charter on block time because their costs scale with block time — crew duty time, engine hours, fuel burn including taxi, all accrue across the full block period. A trip with a long taxi-out on a congested ramp (KTEB on a Friday afternoon, for example) bills slightly more than the same trip with a fast departure.
Most charter quotes show an estimated block time computed from the OD pair, aircraft type, expected winds, and historical ramp delays at the airports involved. Actual block time on the invoice can vary 10–20 minutes from the quote in either direction; reputable operators don't game the variance.
Frequently asked questions
- How is private jet charter billed — flight time or block time?
- Block time. The clock starts when the aircraft pushes back at origin and stops when it parks at destination. Taxi time on the ground at both ends is included in the billable hours.
Related terms
- Empty Leg Flight
An empty leg flight is a one-way private jet flight sold at a discount because the aircraft has to fly without passengers to its next paid booking. Empty legs are typically priced 25–80% below retail charter, with the discount widening as the departure window narrows.
- Part 135 Operator
A Part 135 operator is an FAA-certificated company authorized to fly paying passengers on private (non-scheduled) charter aircraft under 14 CFR Part 135. Every legitimate private jet charter flown in the United States — including every empty leg — is operated under a Part 135 certificate; operators based elsewhere fly under the equivalent authority in their own jurisdiction.
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