FAR Ninety-One Point Three, the Thirty-Seven Words That Make You Commander, and the Deviation Authority Every Pilot Forgets They Have

FAR 91.3 is the most important single regulation in Part 91. Its two subsections establish both the absolute authority of the pilot in command and an explicit legal protection for emergency deviations - authority that too many pilots never fully internalize or use.

What Does FAR 91.3 Actually Say?

Subsection A contains 28 words: “The pilot in command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft.”

Three phrases carry the weight of that sentence: “pilot in command,” “directly responsible,” and “final authority.” Each one is doing specific legal work.

Who Is the Pilot in Command?

The pilot in command is not simply whoever occupies the left seat. It is the person formally designated as such for that flight - the person who has logged it and is legally responsible for the outcome. That designation cannot be transferred to anyone else in the cockpit or on the ground.

This matters because the obligation that comes with the designation is non-negotiable. If you are the pilot in command, every decision made on that flight is yours.

What Does “Directly Responsible” Actually Mean?

“Directly responsible” is a precise legal term. Not indirectly responsible. Not partly responsible. Not responsible through a chain of command where someone above you absorbs accountability when things go wrong.

If you are the pilot in command, you own every decision made on that flight. There is no structure that dilutes that.

What Does “Final Authority” Mean in Practice?

Final authority means the last word belongs to you - not to the controller, not to the dispatcher, not to a chief pilot who called before departure, not to a more experienced pilot in the right seat, not to a passenger who outranks you professionally.

When the wheels leave the ground, the final authority on the operation of that airplane is the pilot in command. That phrase is not an honor. It is a responsibility.

Why Do Pilots Fail to Exercise This Authority?

Aviation human factors researchers identify deference to authority as one of the classic hazardous attitudes. It describes a pilot who receives an instruction from someone who appears more experienced or more confident - and complies, even when something inside them says the situation is wrong.

Crew resource management research dating to the 1980s identified this pattern as a factor in numerous fatal crashes, particularly in commercial aviation, where junior first officers recognized developing emergencies and failed to override complacent captains. The pattern appears in general aviation as well:

• A student continues into deteriorating weather because the CFI seems confident
• A new private pilot accepts an ATC altitude that compromises terrain clearance because the controller must know the area
• A passenger who is a commercial airline pilot makes an offhand remark that shifts the pilot in command’s decision on a marginal weather day

FAR 91.3 exists, in part, as the legal counterweight to that instinct.

What Practical Situations Does This Authority Cover?

Scenario 1: You are a student pilot on a solo cross-country. Cleared to land, on short final, you notice a vehicle on the runway. The tower has said nothing.

You go around. You do not wait for a clearance to deviate from your landing clearance. You exercise your authority as pilot in command and get the nose up.

Scenario 2: You are inbound to a towered airport, cleared for the visual to runway 14. The wind sock you can see from the pattern is straight down runway 32. The ATIS - from 20 minutes ago - indicated winds favoring 14, but you can see the sock with your own eyes. The controller has not updated you.

Under FAR 91.3, you have every right to tell that controller “unable” and request the runway that matches the current wind.

How Do You Say “Unable” to ATC?

The word “unable” is in the Pilot-Controller Glossary. It is professional. It is completely expected within the system. It is also one of the most underused words in student pilot radio communication.

A complete, correct call: “Unable that runway, requesting runway 32.”

That starts a conversation. It does not create a conflict. It is exactly the kind of behavior FAR 91.3 was designed to protect.

What Does FAR 91.3(b) Authorize in an Emergency?

Subsection B reads: “In an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule of this part to the extent necessary to meet that emergency.”

Any rule. That is a sweeping grant of authority. It means a pilot in an emergency can:

• Bust an assigned altitude
• Enter airspace without a clearance
• Land at an airport where the runway is officially closed
• Enter Class B without a clearance
• Do whatever is necessary to preserve the safety of the flight

Subsection B exists to break a specific pattern: a pilot sees a problem developing, recognizes the deteriorating situation, but stays inside the box because they are unsure they are authorized to deviate. They try to handle it quietly and run out of options before they run out of altitude. The emergency deviation clause says the box gets bigger when you need it to.

What Happens After an Emergency Deviation?

The reporting requirement is stated directly in subsection B. If you deviate and ATC requests a report, you must submit a written report to the Administrator as soon as possible. It is a written explanation of what happened, why you deviated, and what the emergency was.

It is not an enforcement proceeding. If the deviation was genuinely emergency-driven, the written report is typically the end of it. The FAA’s consistent position for decades has been that they want pilots to handle emergencies aggressively. They would rather read your paperwork than your accident report.

The only pilots who face enforcement from an emergency deviation are pilots who deviated when there was no emergency - and even then the standard is applied with judgment. When in doubt, declare. The regulation authorizes it.

How Does FAR 91.3 Apply When a CFI Is on Board?

When a certified flight instructor is acting in the capacity of flight instructor, the student can be designated as pilot in command for the purpose of logging that time. The CFI remains responsible for the safety of the flight under Part 61, but if you have been designated as pilot in command for a given flight, FAR 91.3 applies to you.

That means you have standing to raise concerns about weather, to push back on a maneuver entry that conflicts with your aircraft’s limitations, and to make final calls on the operation of that aircraft. If you are the designated pilot in command, own it.

How Is Pilot in Command Authority Tested on a Checkride?

The Airman Certification Standards require evaluators to assess pilot in command attitude throughout the practical test. That is a specific, measurable standard - not a vague phrase. The examiner is watching whether you make decisions with appropriate authority, whether you speak up when something is not right, and whether you question situations that deserve questioning.

A common checkride scenario tests this directly. The examiner suggests a descent to an altitude that would put the aircraft below the minimum safe altitude required under FAR 91.119 over a congested area.

The student who fails complies without comment.

The student who passes says: “I’d rather hold this altitude until we’re clear of that area. The regulation requires 1,000 feet above the highest obstacle in a congested area and I’m not comfortable with that descent point right here.”

The examiner is not looking for blind compliance. They are testing whether you know the regulation and whether you will exercise your authority even when someone who appears to outrank you is pushing a different direction.

What Is the Relationship Between ATC Authority and PIC Authority?

ATC has real authority over the organization and sequencing of traffic in controlled airspace. They can assign headings, altitudes, speeds, and routing, and you are generally required to follow those clearances.

But ATC authority does not reach into the cockpit to manage the safety of your aircraft. Controllers do not know your fuel state unless you tell them. They do not know about a developing alternator failure, disorientation, rough engine, or severe turbulence at an assigned altitude. They are managing traffic flow. You are managing the airplane.

ATC cannot override your responsibility for terrain clearance, your responsibility to see and avoid, or your responsibility to operate within the structural limits of your aircraft. Those responsibilities belong to the pilot in command whether or not a clearance has been issued.

When a clearance conflicts with the safety of the flight, the correct response is “unable,” followed by what you can do. “Unable that altitude, requesting 8,500 due to turbulence” is a complete, professional radio call that starts a conversation and keeps everyone in the loop.

The Hardest Point to Accept

Following an instruction you believe to be unsafe is not “safe” because you were technically following the rules. Complying with a clearance you know to be dangerous - because you did not want to push back - does not protect you. It violates the spirit and letter of FAR 91.3 by giving away the authority the regulation explicitly assigns to you.

The National Transportation Safety Board has published decades of accident reports showing this pattern: pilots had information suggesting danger, had authority under FAR 91.3 to act on it, and deferred to an external voice that felt more authoritative in the moment. The regulation was not the problem in those accidents. The problem was a failure to use the authority it provides.

Know FAR 91.3 completely - subsection A, subsection B, the reporting requirement, and what “final authority” means when your hands are on the controls.

Key Takeaways

• FAR 91.3(a) makes the pilot in command directly responsible and the final authority on every decision made during a flight - that authority cannot be delegated to ATC, a CFI, or anyone else
• Deference to authority is a recognized hazardous attitude with decades of accident history; 91.3 is the legal counterweight to that instinct
• The word “unable” is professional, expected, and one of the clearest tools available to exercise PIC authority without escalating a situation
• FAR 91.3(b) explicitly authorizes deviation from any Part 91 rule during an emergency requiring immediate action - the reporting requirement that follows is typically a written statement, not an enforcement action
• Checkride examiners actively assess pilot in command attitude throughout the practical test; knowing when to push back is part of the standard