The private aviation glossary

12 terms buyers and operators use, each defined in plain words.

Empty leg

A flight an aircraft has to make without passengers, usually to return to base or reach its next pickup. Operators often sell these seats at a reduced rate, with the catch that the timing and route are set by the original booking.

Positioning flight

A flight that moves an aircraft to where a charter begins, or back to base after it ends. The cost is normally built into the charter quote.

AOC

Air Operator Certificate: the approval a national aviation authority issues to a company allowing it to carry passengers or cargo for hire. The company holding the AOC is the operator responsible for the flight.

Part 135

The section of US Federal Aviation Administration rules that covers on-demand and commuter commercial flights. A US charter operator needs a Part 135 certificate to fly paying passengers.

Wet lease

An arrangement where one operator provides an aircraft together with its crew to another, usually with maintenance and insurance included. The aircraft flies under the provider's operating certificate.

Block hours

The time from when an aircraft first moves off its stand for departure until it comes to a stop at its destination. Charter and management costs are often calculated on block hours rather than time in the air.

Light, midsize and heavy jet

The common size categories for private jets. Light jets suit short trips for small groups, midsize jets add cabin space and range, and heavy jets offer large cabins and the range for long and intercontinental flights.

ACMI

Aircraft, Crew, Maintenance and Insurance: a form of wet lease where the provider supplies those four elements. The customer usually pays for fuel, landing, handling and other operating costs.

Slot

Permission to land or take off at a particular airport at a particular time. Busy or coordinated airports require a slot for each movement, which can limit when a private flight can operate.

FBO

Fixed-base operator: the business at an airport that serves private aircraft and their passengers, with services such as a private terminal, handling, fuel and hangar space.

Crew duty time

The maximum time a flight crew may be on duty, and the rest they must have afterwards, as set by the regulator. It decides how long a day trip can run and when a second crew is needed.

Charter broker

An intermediary who finds and books aircraft from operators on a client's behalf. The broker arranges the trip but does not fly it; the operator holding the AOC does.