In the United States, private aviation operates under two primary regulatory frameworks established by the Federal Aviation Administration (FAA): Part 91 and Part 135 of the Federal Aviation Regulations (FARs). Understanding the distinction between these two sets of rules is important for anyone who flies privately, owns an aircraft, or operates a charter business.

Part 91: Private Operations

Part 91 governs the general operating and flight rules for all civil aircraft within the United States. When you fly your own aircraft for personal or business purposes without offering flights for hire, you operate under Part 91.

Key Characteristics of Part 91

• No commercial operations: You cannot sell seats or charter flights under Part 91
• Owner flexibility: The aircraft owner has greater operational flexibility in areas like maintenance scheduling and pilot qualifications
• Pilot requirements: Minimum requirements are lower than Part 135 — though responsible owners typically exceed them
• Maintenance: The owner is responsible for maintaining airworthiness, but the specific inspection intervals and requirements are less prescriptive
• No Air Carrier Certificate required: Part 91 operators do not need FAA approval beyond standard pilot and aircraft certificates

Part 135: Charter Operations

Part 135 governs on-demand air carrier and commercial operations — essentially, any operation where passengers or cargo are carried for compensation. This is the regulatory framework under which all legitimate US charter operators function.

Key Requirements of Part 135

Part 91 vs Part 135: The Key Differences

Obtaining a Part 135 Certificate

Establishing a Part 135 operation is a substantial undertaking:

• Timeline: Typically 12-18 months from application to certificate issuance
• Cost: $200,000-$500,000+ in setup costs including legal, compliance, and training
• FAA process: Five phases — pre-application, formal application, document compliance, demonstration and inspection, and certification
• Key personnel: Must hire qualified Director of Operations, Director of Maintenance, and Chief Pilot before certification
• Manuals: Comprehensive General Operations Manual and General Maintenance Manual must be developed and approved

What This Means for Passengers

As a charter passenger, Part 135 certification provides important protections:

• Your pilots meet higher qualification and training standards
• The operator is regularly inspected by the FAA
• Drug and alcohol testing programs are in place
• Duty time limitations reduce fatigue-related risks
• Maintenance standards are more prescriptive
• Insurance requirements are higher

Gray Areas and Illegal Charter

One of the most significant safety concerns in private aviation is illegal charter — situations where an aircraft operating under Part 91 carries passengers for compensation without Part 135 certification. This is both illegal and dangerous:

• Pilots may not meet Part 135 qualification standards
• The aircraft may not be maintained to Part 135 requirements
• Insurance may not cover passengers in a commercial operation
• Drug testing and duty time rules may not be followed

To protect yourself, always verify that your charter operator holds a valid Part 135 certificate. You can check operator status on the FAA's website.

International Equivalents

Outside the United States, similar regulatory frameworks exist:

• EASA (Europe): Air Operator Certificate (AOC) for commercial operations
• GCAA (UAE): AOC required for charter operations
• TCCA (Canada): Air Operator Certificate under Canadian Aviation Regulations
• CAAC (China): Commercial operating certificate

Verify Operator Credentials