← Train

Private pilot · ACS PA.VI.C · lesson pack

Diversion

Why this one matters

Pressing on when the weather or fuel says stop is behind many fatal accidents, especially VFR flight into instrument conditions. A diversion is a plan B you make before you need it, executed without hesitation. Pilots who divert early land with options; pilots who wait run out of them.

1 · Know these cold

  • •Divert early: deteriorating weather, low fuel, a sick passenger, a rough engine, darkness or fatigue are all reasons.(Risk Management Handbook (FAA-H-8083-2A))
  • •Turn toward the new destination first, then work out heading, distance, groundspeed, time and fuel.(PHAK (FAA-H-8083-25C), Navigation)
  • •Pick an airport that suits you: runway length and surface, weather, fuel, services, terrain and airspace.(PHAK (FAA-H-8083-25C), Navigation)
  • •As pilot in command you are the final authority. In an in-flight emergency requiring immediate action you may deviate from Part 91 to the extent required (91.3(b)). An ATC clearance is separate: deviate only with an amended clearance, in an emergency, or for a TCAS resolution advisory, and tell ATC as soon as possible (91.123).(14 CFR 91.3(b); 91.123(a), (c))
  • •Use your resources: ATC, Flight Service, the GPS "nearest" function and your passengers.(PHAK (FAA-H-8083-25C), Navigation)
  • •Update the weather in flight with ATIS/ASOS, Flight Service and data-link weather, and check its age.(AIM, Chapter 7, Safety of Flight (in-flight weather and FIS-B))
  • •Checkride standard: promptly divert, make a reasonable estimate, altitude ±200 feet and heading ±15°.(Private Pilot ACS (FAA-S-ACS-6C), PA.VI.C.S2-S3, S6)

2 · The lesson

When to divert
  • Weather worse than forecast, a lowering ceiling, fuel burn higher than planned, a mechanical problem, a sick passenger, fatigue or darkness are all reasons to change the plan.(Risk Management Handbook (FAA-H-8083-2A))
  • Set personal limits before the flight (ceiling, visibility, fuel at landing) and divert when you reach them, not when the situation becomes critical.(Risk Management Handbook (FAA-H-8083-2A))
  • In an in-flight emergency requiring immediate action you may deviate from the Part 91 rules, only to the extent required. To deviate from an ATC clearance you need an amended clearance, an emergency, or a TCAS resolution advisory; outside those, say "unable" and ask for an amended clearance first.(14 CFR 91.3(b); 91.123(a)-(b))
  • Afterwards: tell ATC as soon as possible after an emergency deviation; if asked, send a written report to the FAA after a 91.3 deviation, and a detailed report to the ATC facility manager within 48 hours if you were given emergency priority.(14 CFR 91.3(c); 91.123(c)-(d))
  • Fuel is a planning rule you keep in the air: you began with enough to reach the first landing plus 30 minutes by day (45 at night) at normal cruise, considering wind and forecast weather. If the projection drops below that, divert to a nearer suitable airport while you still have options.(14 CFR 91.151(a))
Choosing where
  • Before the flight, note airports along the route you could use. In flight, check runway length, weather, fuel, services, terrain, airspace and NOTAMs for the one you pick.(PHAK (FAA-H-8083-25C), Navigation)
  • Choose the airport (or, in a seaplane, the seaplane base) that makes the situation better: an easy runway and good weather beat a slightly closer airport with a crosswind and low clouds.(Risk Management Handbook (FAA-H-8083-2A))
Flying it
  • Turn toward the new destination right away, using an estimated heading from the chart. Note the time.(PHAK (FAA-H-8083-25C), Navigation)
  • Then refine it: measure the true course and distance, apply the wind correction (then variation) to get a magnetic heading and groundspeed, and work out the time en route and fuel. Flying the chart course as a heading in a crosswind drifts you off the airport. The GPS "direct to" and "nearest" functions help; check them against the chart.(PHAK (FAA-H-8083-25C), Navigation)
  • ATC can help with vectors, weather and the airport’s information. Ask early.(AIM, Chapter 4, Air Traffic Control (radar services for VFR aircraft))
  • Once established toward the alternate, tell ATC or Flight Service you're diverting, with the new destination and ETA, and amend (or close and refile) your VFR flight plan so search and rescue isn't working from the old one.(AIM, Chapter 4, Air Traffic Control (radar services for VFR aircraft); AIM 5-1)
  • Pick an altitude for the new course: if you're more than 3,000 feet AGL, the VFR cruising altitude for the new magnetic course (0-179°, odd thousands plus 500; 180-359°, even thousands plus 500) unless ATC assigns otherwise, that clears terrain and obstacles and meets 91.119. Then hold it ±200 feet, and the heading ±15°.(14 CFR 91.159; 91.119)
  • Update the weather in flight from ATIS or ASOS, Flight Service, or FIS-B, and remember data-link weather is not real time.(AIM, Chapter 7, Safety of Flight (in-flight weather and FIS-B))
Staying ahead of the airplane
  • A diversion adds workload at a stressful moment. Fly the airplane first, hold altitude and heading, then do the math.(Risk Management Handbook (FAA-H-8083-2A))
  • A new route can put you near unfamiliar traffic, airspace, terrain, obstacles and wires, especially when lowering ceilings are pushing you down. Keep an altitude that clears them and meets 91.119, keep scanning, and use flight following if you can.(AC 90-48, Pilots' Role in Collision Avoidance; 14 CFR 91.119)

Want it all on one page, with scenarios? Read the full lesson.

On the flight

ACS standards

  • Make a reasonable estimate of heading, groundspeed, arrival time and fuel to the new destination, and promptly divert.(Private Pilot ACS (FAA-S-ACS-6C), PA.VI.C.S2, S6)
  • Altitude ±200 feet and heading ±15°.(Private Pilot ACS (FAA-S-ACS-6C), Area VI)

What your instructor is watching for

Your instructor watches whether you decide promptly, turn toward a sensible airport before doing calculations, keep the airplane under control while you work, and use the resources you have.

3 · Say it out loud

Answer each one out loud, then check yourself and mark how it went.

  1. Remember Recall it

    “Name three reasons to divert.”

  2. Understand Explain why

    “Why do you turn toward the new airport before doing the calculations?”

  3. Apply Use it on a flight

    “The clouds ahead are lowering and you’re already lower than you planned. What do you do?”

4 · Common mistakes

  • Waiting too long to decide.

    Weather and fuel problems get worse, and options disappear while you hope.

    Instead: Set a decision point and limits before the flight, and act when you reach them.

  • Doing the math before turning.

    You fly further the wrong way while you calculate.

    Instead: Turn to an estimated heading first, then refine.

  • Losing altitude while plotting.

    Heads-down work in a stressful moment.

    Instead: Trim, set the heading bug, then work, and look up often.

5 · Quick check

Answer, then reveal. Flag anything you want to see again.

  1. 1. What should you do first when you decide to divert?

  2. 2. May you deviate from an ATC instruction in an emergency?

  3. 3. What do you check about a diversion airport?

  4. 4. Where can you get updated weather in flight?

  5. 5. What are the checkride tolerances for a diversion?

  6. Scenario6. Your fuel burn is higher than planned and you’ll land with 20 minutes of fuel in daylight. What do you do?

Trained it? Now prove it: practice diversion out loud with our examiner.

Start a practice oral on this task

Your progress is saved in this browser. Create a free account to keep it on every device, with your shaky spots and mock oral results in one place.

Connect it

One situation that runs across this lesson and its neighbors in the same ACS area. Decide first, then check.

Connect it · Navigation

Halfway through a cross-country, the clouds ahead are lowering and pushing you down. You turn toward an airport off to your right, and ten minutes later you can't match the ground to the chart.

How do the diversion and the lost procedure connect? Decide, then see the worked answer

Divert early, while you still have altitude and options, and to a suitable airport, not just the nearest: terrain and weather on the way, runway length and surface, and fuel to get there with your reserve. As you turn, note the time and your heading, estimate the new heading, time and fuel, then refine. Hold an altitude that keeps you clear of terrain and meets the 91.155 cloud clearances. That note at the turn is what the lost procedure starts from: dead-reckon from the turn point, and the elapsed time multiplied by your groundspeed bounds how far you can be from it, your circle of uncertainty. Then the five Cs, in order. Climb, if the clouds allow, for a better view and radio reception. Communicate: ATC for radar assistance, flight following or vectors; Flight Service for communications and direction-finding help (Flight Service doesn't provide flight following). Confess that you're unsure of your position. Comply with the help you get, but keep the controller advised that you're VFR and not instrument rated: radar assistance doesn't authorize you to break the regulations or the VFR cloud clearances, so declare an emergency rather than accept a vector into cloud. Conserve fuel with an endurance power setting. Cross-check with a VOR cross-fix or GPS. Declare an emergency early, on 121.5 or by squawking 7700, if you can't stay VFR or the help isn't resolving it.

PHAK (FAA-H-8083-25C), Navigation; AIM 6-2; 14 CFR 91.155

Brings together: Pilotage and Dead Reckoning · Navigation Systems and Radar Services · Diversion · Lost Procedures

Teaching this? The instructor lesson plan →

Study aid, not FAA guidance. Sources: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C); Aeronautical Information Manual (AIM); 14 CFR Part 91; AC 90-48; Private Pilot ACS (FAA-S-ACS-6C); VFR sectional chart and Chart Supplement. Checked against current sources 2026-11-12.