FAR Ninety-One Point Three, the Final Authority Rule, and the Two Sentences That Let You Break Any Regulation in the Book to Save the Airplane

FAR 91.3 is one of the shortest and most powerful regulations in the entire Federal Aviation Regulations. In two sentences, it names the pilot in command (PIC) as the final authority over the aircraft and grants the power to deviate from any rule in Part 91 when an in-flight emergency requires it. Understanding it changes how you sit in the left seat.

What Does FAR 91.3 Actually Say?

The regulation is titled “Responsibility and authority of the pilot in command,” and it runs just three short paragraphs.

Paragraph (a) states that the pilot in command is directly responsible for, and is the final authority as to, the operation of that aircraft.

That word - final - is the whole point. Not the tower. Not your instructor in the right seat. Not dispatch, not the chief pilot, not the confident voice on the radio. When you are pilot in command, the buck stops in your seat.

What Does “Final Authority” Really Mean?

Final authority cuts both ways, and both edges matter.

First, it means nobody can make you do something unsafe. If a controller issues a clearance you cannot safely fly, you are not merely allowed to say “unable” - you are expected to. “Unable” is a complete sentence. You owe no explanation in the moment. You fly the airplane first and sort out the paperwork on the ground.

Second, it means final responsibility. If it goes wrong, it’s yours, and you can’t hand it to anyone afterward. The same rule that protects you from a bad clearance also means you can’t blame the briefer, the mechanic, or the weather forecaster when the outcome lands in your lap. Authority and responsibility come welded together - you don’t get one without the other.

What If the Tower Tells Me to Keep My Speed Up?

Picture a long final into a towered field. You’re configured and stable, right where you want to be. The tower calls: “Cleared to land, keep your speed up, you’ve got a regional jet behind you.”

So you push it up. Now you’re fast, floating, and eating up runway as the numbers slide by underneath you.

This is FAR 91.3 in action. The controller asked you to keep your speed up. He did not - and cannot - order you to fly an unstable approach onto a runway you’re going to run off the end of. The moment the approach goes bad, you key the mike, announce “going around,” and go. You don’t ask; you tell.

If the spacing gets ugly for the jet behind you, that is the controller’s problem to solve - that’s the controller’s job. Your job is the safe operation of your aircraft.

Can I Really Break Any Rule in an Emergency?

Yes - and this is the famous part. Paragraph (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 required to meet that emergency.

Any rule. You can bust an altitude. You can enter airspace you’re not cleared into. You can exceed a speed limit. You can land on a road, in a field, at a closed airport, downwind, or opposite direction - whatever the emergency requires. When the airplane is in genuine trouble and immediate action is needed, every other rule in Part 91 becomes advisory. Your only job is to meet the emergency and get everyone down alive.

But this is not a license to freelance on a normal Tuesday. Three phrases do the heavy lifting, and you need all three:

• “Emergency” means a real one - an engine failure, a fire, ice you can’t shed, a passenger medical event, a control problem. Something where the safe outcome is genuinely in doubt. Being behind on your flight plan or simply uncomfortable does not qualify.
• “Immediate action” means there isn’t time to negotiate. If you have time to request, you request. Paragraph (b) is for when the situation is moving faster than the radio.
• “To the extent required” is the leash. You deviate as much as the emergency demands and no more. If busting an altitude by 500 feet saves you, you don’t climb 3,000 feet just because the rule is suspended. Take exactly what you need and give the rest back the moment you can.

How Does This Work in a Real Engine Failure?

Here’s the classic scenario every instrument student meets. You’re in solid IMC. Your engine starts running rough, then quits. You’re gliding now. There’s a field or highway beneath you, and an airport eight miles away you know you cannot reach. You are cleared to fly the airway - but the airway does not go to that field.

FAR 91.3(b) says: go to the field. Leave the airway. Descend below your assigned altitude. Do whatever the glide requires. Tell ATC as soon as you can key the mike - declare the emergency, state you’re gliding with an engine failure - and then fly the airplane. If they can’t hear you, you go anyway. The regulation gave you permission before you ever left the ground.

Will I Get in Trouble? Understanding Paragraph (c)

Paragraph (c) is short and pilots dread it more than they should. It states that a pilot in command who deviates under paragraph (b) shall, upon the request of the Administrator, send a written report of that deviation.

Notice: upon request. You are not required to file anything automatically. You send a report only if the FAA asks for one.

Take the fear out of it. If you had a genuine emergency, deviated only to the extent required, and brought the airplane down safely, the report is simply you explaining a good decision. The FAA is not trying to violate a pilot who saved an airplane. The rule is built to let you act first and explain later - usually a phone call and maybe a letter. Pilots who handle real emergencies by the book almost never have trouble with the report. Trouble comes from pilots who did something reckless and called it an emergency to cover for it - a different situation entirely.

Shield, Not Sword

Draw the line clearly: FAR 91.3(b) is a shield, not a sword. It protects you when you had to break a rule to stay alive. It does not give you cover to do something dumb and then declare an emergency afterward to escape the consequences. The FAA can tell the difference - and honestly, so can you.

How Does FAR 91.3 Show Up on the Checkride?

On the private and instrument checkrides, the examiner won’t quiz you on the exact wording. They’re looking for something deeper: proof that you understand you are the final authority.

They’ll watch how you handle a clearance you shouldn’t accept, and whether you’ll say “unable” when a scenario calls for it. A favorite setup: on the cross-country portion, the examiner applies pressure - asking you to descend into terrain you can’t see, accept a clearance into weather you didn’t plan for, or continue when your gut says turn around.

The bust isn’t refusing the clearance. The bust is the applicant who does something unsafe because a more confident voice told them to. In the airplane, the pilot in command is you. The examiner is a passenger. Act like it.

On scenario-based emergency questions, the answer examiners want to hear, in your own words, is this: “I’m going to do whatever I need to do to fly this airplane safely to the ground, and I’ll deal with the airspace, the altitudes, and the paperwork after everyone is safe.” That is 91.3(b) living in your decision making.

Practical Steps for Your Next Flight

1. Read the whole regulation tonight. It’s three short paragraphs. It takes ninety seconds and it will change how you sit in the left seat.
2. Practice the word “unable.” Say it out loud in the car. The first time you need it shouldn’t be the first time you’ve spoken it. When a clearance doesn’t work: “Unable” - and if you have a second, “unable, request the following.”
3. Know that the emergency authority is already yours. You don’t have to earn it in the moment or ask for it. It’s granted the second things go wrong. Your only decisions are what the emergency requires and how much deviation it takes to meet it.
4. Lose the fear of paragraph (c). The report isn’t a punishment. It’s the price of an authority that let you save the airplane - paid on the ground, with everyone alive, after the hard part is over.

Buried in the middle of all the checklists and callouts is this one small regulation that says: when it really counts, all of that steps aside and it comes down to your judgment. That’s a lot of trust the system places in you. Grow into it. Don’t be reckless with it, but don’t be afraid of it either. The final authority is yours.

Key Takeaways

• FAR 91.3(a) makes the pilot in command the final authority over the aircraft - a power that carries equal, non-transferable responsibility.
• Final authority means you can - and should - say “unable” to any clearance you cannot safely fly, with no explanation owed in the moment.
• FAR 91.3(b) lets the PIC deviate from any rule in Part 91 during an in-flight emergency requiring immediate action, but only to the extent required.
• FAR 91.3(c) requires a written report of the deviation only upon the FAA’s request - it is not automatic and not a punishment.
• 91.3(b) is a shield, not a sword - it protects sound emergency decisions, not reckless acts disguised as emergencies.