Responsibility and Authority of the Pilot in Command

Section 91.3 is the cornerstone responsibility-and-authority rule of the FARs. It establishes two things that every pilot needs to internalize: the pilot in command is directly responsible for, and is the final authority as to, the operation of the aircraft. Those are not the same concept and the FAA treats them differently.

Direct responsibility (paragraph a): The PIC carries the legal weight for the conduct of the flight. The FAA's enforcement history is full of cases where a pilot tried to deflect responsibility — a dispatcher told them to go, the controller cleared them, the operator pressured them — and lost. The Administrator's view is consistent: once you accepted PIC, the buck stops with you.

Final authority (paragraph a): The PIC can refuse an ATC clearance, refuse to operate an unairworthy aircraft, refuse to depart with unsafe weather, and refuse a company-mandated routing if safety requires it. This authority isn't optional — it's the legal counterweight to the operational pressures pilots face. The NTSB and FAA have repeatedly upheld PIC authority decisions in enforcement and accident cases.

Emergency deviation (paragraph b): In an in-flight emergency requiring immediate action, the PIC may deviate from any rule of Part 91 "to the extent required to meet that emergency." This is not a blanket get-out-of-jail card — the deviation has to be required by the emergency, and the PIC must be prepared to defend the reasonableness of the deviation. Common applications: descending below MEA to escape icing, landing on a closed runway to avoid loss of control, busting airspace to avoid a midair.

Written report on demand (paragraph c): When a PIC has deviated from a rule under § 91.3(b), they must, upon the request of the Administrator, send a written report of that deviation to the Administrator. The trigger is the FAA's request, not the deviation itself. Pilots are not required to volunteer a § 91.3(c) report — but if the FAA asks, the obligation is mandatory.

Reference: See also FAA-H-8083-25 (PHAK) Chapter 1 on the role of the pilot in command. The FAA also addresses PIC authority extensively in its enforcement decisions; see NTSB Order EA-5101 (Slack) for a foundational discussion of how 91.3 interacts with company procedures.

PIC Authority Is the Cornerstone of Part 91

If you only memorize one regulation in Part 91, make it this one. § 91.3 is the reg every other rule in Part 91 sits on top of — it tells you who's accountable, what powers you have, and what happens when the situation goes sideways and the book doesn't have an answer for it.

The reg is three short paragraphs, each doing distinct work:

• (a) — Responsibility and final authority. One undivided block. You are directly responsible for the operation of the aircraft, and you are the final authority as to that operation. Two ideas, one sentence. Responsibility is the legal accountability. Final authority is the decision-making power. They come together. You can't have one without the other.
• (b) — Emergency deviation. In an in-flight emergency requiring immediate action, you may deviate from any rule of Part 91 to the extent required to meet that emergency. Not "any rule you feel like." Any rule of Part 91. To the extent required. Not more.
• (c) — Written report on demand. If you deviated under (b), you send a written report — but only if the Administrator asks. You don't have to volunteer one. The FAA decides when they want it.

Enforcement reality: Pilots have spent decades trying to deflect responsibility onto dispatchers, controllers, flight schools, and operators. The NTSB has rejected those arguments consistently. In cases reviewed under NTSB Order EA-5101 and others, the line has been clear — when you accept the controls, you accept § 91.3(a). An ATC clearance is not a regulatory exemption. A dispatcher's release is not a get-out-of-jail card. The PIC can be violated even when ATC made the mistake.

What authority feels like in the cockpit: Authority sounds powerful on paper. In practice, it usually means saying an awkward "unable" to a controller who's busy, or telling the chief pilot you're not taking the airplane, or pressing the missed approach button when the airline captain next to you is descending. Authority is the willingness to be the one who's wrong about the weather and right about the airplane. § 91.3(a) doesn't ask you to be heroic. It asks you to be the person whose name is on the certificate.

What an Examiner Asks About § 91.3

Every checkride — private, instrument, commercial, ATP, CFI — has a § 91.3 question in it. Sometimes the DPE asks it cold. More often it's woven into a scenario. Examiners aren't testing whether you can recite three paragraphs — they're testing whether you understand the weight of them.

Common questions, in roughly the order they come up:

• "What does PIC authority actually mean?" Don't just say "I'm in charge." The answer the examiner wants: "I'm directly responsible for the operation of the aircraft, and I'm the final authority as to that operation — which means I can refuse a clearance, refuse the aircraft, refuse the flight, or change the plan in flight if safety requires it. And I carry the legal accountability whether I delegate or not."
• "When can you deviate from a rule?" Only under § 91.3(b) — in an in-flight emergency requiring immediate action, to the extent required to meet that emergency. Three triggers, all required: in-flight, emergency, immediate action. Convenience doesn't cut it. Schedule pressure doesn't cut it.
• "If you deviate, what's required after?" Trick question. Nothing is required automatically. Under § 91.3(c), you submit a written report upon request of the Administrator. You don't have to self-report. (Separate issue: NTSB Part 830 reporting for accidents and serious incidents is a different reg and may still apply.)
• "ATC tells you to descend into known icing and you have no anti-ice. What do you do?" "Unable." Then offer an alternative — a different altitude, a turn, a deviation. § 91.3(a) means the controller's instruction doesn't override your responsibility for the airplane. The clearance is a coordination tool, not a command.

A Real Authority Call, Under § 91.3

You're a freshly minted instrument pilot in a Cessna 172, no anti-ice, no de-ice, flying a 200-nm IFR cross-country in late October. You're level at 8,000 in solid IMC. Outside air temp is +2°C. Center calls: "Climb and maintain one zero thousand." You check the PIREPs you pulled before departure — light-to-moderate rime reported at 9,000 along your route within the last 30 minutes. The freezing level is at 6,000.

What § 91.3 makes you do: § 91.3(a) puts the decision on you, not the controller. The clearance to 10,000 is legal — but it would take you into known icing in an airplane that isn't certified for it, which independently violates § 91.9 (POH limitations) and § 91.13 (careless operation). Your answer is "N12345, unable ten thousand, request to remain at eight thousand or descend to six thousand due to icing." If the controller can't accommodate and you start picking up ice climbing through, § 91.3(b) authorizes you to deviate from the clearance — descend, turn, divert — to the extent required to escape the ice.

What competent adds: You don't wait for the climb instruction to be the moment you start thinking about icing. Before you launched, you knew the freezing level, you knew the airplane's limits, and you'd already decided what altitudes and conditions would trigger a diversion. You briefed your "out" — KXYZ, 30 miles south, MVFR, no ice. So when Center calls, your "unable" is calm and quick. You're not negotiating with yourself at 8,000 feet — you're executing a decision you already made on the ground.

The reg gives you the authority. Preparation is what makes the authority easy to use.