SkyOps Registry

FAA Part 135 Intelligence

Glossary

Part 135 charter vocabulary decoded

Definitions for the regulatory acronyms, safety programs, and commercial terms that appear in FAA filings and charter proposals. Use this glossary to brief stakeholders or align internal teams on Part 135 requirements.

A

Air Taxi

operations

Commercial aviation service operating under Part 135 providing on-demand flights with small aircraft, typically carrying 9 or fewer passengers. Air taxi operations offer flexible scheduling and routes not served by scheduled airlines.

AOC (Air Operator Certificate)

certification

Certificate issued by the FAA authorizing an operator to conduct commercial air transportation. For Part 135 operations, the AOC specifies the types of operations authorized, aircraft approved, and operational limitations.

ATP (Airline Transport Pilot)

training

Highest level of aircraft pilot certification, required for Part 135 PICs in most operations. ATP certification requires extensive flight experience, training, and successful completion of written and practical examinations.

C

Charter Certificate

certification

FAA-issued operating certificate under Part 135 that authorizes an operator to conduct on-demand charter flights. The certificate specifies approved aircraft types, operational areas, and authorized flight operations.

Commuter Operations

operations

Part 135 scheduled operations serving smaller communities with aircraft having 30 or fewer seats. Commuter operations provide essential air service to areas not economically viable for major airlines.

Crew Rest

safety

Mandatory rest periods required for Part 135 flight crews between duty periods. Crew rest requirements ensure pilots are adequately rested for safe flight operations.

CVR (Cockpit Voice Recorder)

equipment

Recording device that captures audio in aircraft cockpits, including crew communications, radio transmissions, and ambient sounds. CVRs are required on certain Part 135 aircraft for accident investigation purposes.

D

Deadhead

operations

Positioning flight to move aircraft or crew to another location without revenue passengers. Deadhead flights are operational necessities that charter companies must account for in their scheduling and pricing.

Dispatch

operations

Process of flight planning, monitoring, and operational control of Part 135 flights. Larger Part 135 operators must employ qualified dispatchers to ensure safe and efficient flight operations.

Dry Lease

business

Aircraft leasing arrangement where only the aircraft is provided, with the lessee responsible for crew, maintenance, and operations. Dry leases require the lessee to have appropriate Part 135 authority.

Duty Time

safety

Period during which a Part 135 crew member is required to be available for work, including flight time, ground duties, and other work-related activities. Duty time limits prevent crew fatigue.

E

Empty Leg

operations

Charter flight segment where an aircraft flies without passengers to position for another flight. Empty legs are often sold at discounted rates, providing cost-effective charter options for flexible travelers.

ETOPS (Extended Operations)

operations

Certification allowing twin-engine aircraft to fly routes more than 60 minutes from the nearest suitable airport. ETOPS requires special aircraft certification, crew training, and maintenance procedures for enhanced safety.

F

FBO (Fixed Base Operator)

services

Commercial business operating at an airport providing services to general aviation aircraft, including fuel, maintenance, hangar space, ground handling, and passenger amenities. FBOs serve as the primary service point for charter flights.

FDR (Flight Data Recorder)

equipment

Recording device that captures aircraft flight parameters including altitude, airspeed, heading, and control inputs. FDRs provide crucial information for accident investigation and flight safety analysis.

Flight Time

safety

Time from aircraft first movement for takeoff until final stop at destination. Part 135 regulations limit pilot flight time to ensure safety and prevent fatigue-related incidents.

FOQA (Flight Operational Quality Assurance)

safety

Safety program using digital flight data to identify and address safety risks before they result in incidents. FOQA helps operators monitor flight operations and improve safety through data analysis.

FSDO (Flight Standards District Office)

oversight

Local FAA office responsible for oversight of aviation operations in a specific geographic area. FSDOs conduct inspections, issue certificates, and ensure compliance with federal aviation regulations for Part 135 operators.

I

IFR (Instrument Flight Rules)

operations

Flight rules requiring pilots to navigate using aircraft instruments rather than visual references. IFR operations allow flights in weather conditions with reduced visibility and are essential for professional charter operations.

K

Known Crewmember

security

TSA program allowing qualified flight crew members to use expedited security screening. Part 135 crew members can participate in KCM to streamline security processes at participating airports.

M

Maintenance Control

maintenance

System for tracking and scheduling aircraft maintenance required under Part 135. Maintenance control ensures aircraft meet all regulatory requirements and remain airworthy for charter operations.

MEL (Minimum Equipment List)

operations

Document specifying equipment that may be inoperative while still allowing safe flight operations. The MEL allows Part 135 operators to continue operations with certain non-critical equipment out of service under specific conditions.

N

NOTAM (Notice to Airmen)

information

Notice providing time-critical information about changes to airports, airspace, or flight procedures. Charter operators must review NOTAMs before each flight to ensure safe operations.

O

On-Demand Operations

operations

Charter flight services provided when requested by customers, as opposed to scheduled operations. On-demand flights operate on flexible schedules and routes based on customer needs rather than published timetables.

OpSpecs (Operations Specifications)

operations

FAA document detailing the specific operations a Part 135 carrier is authorized to conduct. OpSpecs include approved aircraft, operational areas, crew requirements, and maintenance procedures specific to each operator.

P

Part 121

regulation

Federal Aviation Regulation governing scheduled airline operations with large aircraft. Part 121 covers major airlines operating aircraft with more than 30 passenger seats or maximum payload capacity exceeding 7,500 pounds on scheduled routes.

Part 135

regulation

Federal Aviation Regulation governing on-demand air carrier operations and commuter airlines. Part 135 operators provide charter flights, air taxi services, and scheduled commuter operations with aircraft having 30 or fewer passenger seats or a maximum payload capacity of 7,500 pounds or less.

Part 91

regulation

Federal Aviation Regulation covering general aviation operations, including private, recreational, and corporate flights. Part 91 operations cannot carry passengers for compensation or hire, making them distinct from commercial Part 135 operations.

PIC (Pilot in Command)

crew

Pilot responsible for the operation and safety of an aircraft during flight. The PIC has final authority and responsibility for the aircraft and must meet specific experience and training requirements under Part 135.

Progressive Inspection

maintenance

Maintenance program dividing required inspections into smaller segments performed over time rather than during single lengthy maintenance events. This allows Part 135 aircraft to remain in service more consistently.

R

Recent Experience

training

Currency requirements for Part 135 pilots including recent takeoffs, landings, instrument approaches, and route qualifications. Recent experience ensures pilots maintain proficiency for safe operations.

RVSM (Reduced Vertical Separation Minimum)

airspace

Airspace where aircraft are separated by 1,000 feet instead of 2,000 feet between FL290 and FL410. RVSM requires specially equipped aircraft and pilot authorization for operations in designated airspace.

S

SIC (Second in Command)

crew

Required copilot on Part 135 operations with certain aircraft or under specific conditions. The SIC assists the PIC and must be qualified to serve as copilot on the specific aircraft type.

SMS (Safety Management System)

safety

Formal, top-down business approach to managing safety risk. Required for some Part 135 operators, SMS includes safety policies, risk management processes, safety assurance, and safety promotion activities.

STC (Supplemental Type Certificate)

certification

FAA approval for modifications to aircraft that change the original type design. STCs allow Part 135 operators to install approved modifications for specialized equipment or performance improvements.

T

TFR (Temporary Flight Restriction)

airspace

Restriction on aircraft operations in specific areas for security, safety, or other reasons. TFRs can affect charter flight routing and scheduling, particularly around major events or VIP movements.

Type Rating

training

Authorization on a pilot's license to operate specific aircraft types. Part 135 pilots must have appropriate type ratings for aircraft they fly, ensuring they are trained and qualified for each aircraft's unique characteristics.

V

VFR (Visual Flight Rules)

operations

Flight rules requiring pilots to maintain visual contact with the ground and see-and-avoid other aircraft. VFR operations are limited by weather conditions and visibility requirements.

W

Wet Lease

business

Aircraft leasing arrangement where the lessor provides the aircraft, crew, maintenance, and insurance. Wet leases allow Part 135 operators to expand capacity without owning additional aircraft.