2/10/16 AC 91-37B
4.4 Lease. For the purpose of part 91, § 91.23, a lease means any agreement by a person to
furnish an aircraft to another person for compensation or hire, with or without flightcrew
members, that is not a contract of conditional sale. The person furnishing the aircraft is
referred to as the lessor and the person to whom it is furnished is referred to as the lessee.
4.5 Operate. As defined in § 1.1, operate “with respect to aircraft, means use, cause to use or
authorize to use aircraft, for the purpose (except as provided in § 91.13 of this chapter) of
air navigation including the piloting of aircraft, with or without the right of legal control
(as owner, lessee, or otherwise).”
4.6 Operational Control. As defined in § 1.1, operational control “with respect to a flight;
means the exercise of authority over initiating, conducting or terminating a flight.”
Operational control involves three basic areas: Aircrew, Aircraft, and Flight
Management. These areas, summarized below, are intended to give a general
understanding of operational control. When chartering an aircraft, the charter air carrier
has operational control and is responsible for regulatory compliance and the safety of the
flight. When an aircraft lessee operates an aircraft under general operating rules, the
lessee accepts operational control responsibilities. Operational control is an important
regulatory concept for lessees to understand and it is explained in more detail in
FAA Order 8900.1, Flight Standards Information Management System (FSIMS),
Volume 6, Chapter 2, Section 22, Safety Assurance System: Operational Control
Inspections, available at http://fsims.faa.gov.
4.6.1 Aircrew. Ensures that crewmembers are trained and qualified in accordance with the
applicable regulations and remain in compliance with all applicable flight, duty, and rest
requirements including designating a pilot in command (PIC) for each flight.
4.6.2 Aircraft. Ensures that an aircraft is Airworthy and is in compliance with applicable
4.6.3 Flight Management. Specifies the conditions under which a flight may be operated, such
as determining weather minimums, proper aircraft loading, center of gravity (CG)
limitations, icing conditions, and fuel requirements. Handles the monetary and logistical
issues associated with the aircrew and aircraft.
5 TYPES OF LEASES. A lease involving aircraft is sometimes referred to as a wet lease
or a dry lease. Title 14 CFR part 110, § 110.2 defines a wet lease as “any leasing
arrangement whereby a person agrees to provide an entire aircraft and at least one
crewmember. A wet lease does not include a code-sharing arrangement.” Leasing of an
aircraft without the crew is considered to be a dry lease.
5.1 Normally, in the case of a dry lease, the lessee exercises operational control of the
aircraft. Conversely, in a wet lease the lessor normally exercises operational control.
The determination in each situation as to whether the lessor or lessee exercises
operational control requires consideration of all relevant factors present in each situation.
The terms of the lease itself are important but since they may not reflect the true