Private pilot · ACS PA.VI.C
Diversion
A diversion is changing your destination in flight, because the plan no longer works.
The skill is making the decision early, and then getting to the new airport without losing control of the airplane, the navigation or the fuel.
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.
Can’t miss
- •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)
What you should know
When to divert K2 · R3
- 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 K1 · R4
- 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 R5
- 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 R1 · R2
- 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)
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.
Scenarios
Decide what you would do first, then see the worked answer.
Halfway there, the destination ASOS shows ceilings dropping below your personal minimums. A field 15 miles to the right has good weather but a short runway.
How do you decide? See the worked answer
Check whether the short runway works for your airplane and conditions using the POH performance data. If it does and the weather is good, divert there now. If not, pick another airport or return to where you came from.
Risk Management Handbook (FAA-H-8083-2A)
A passenger becomes sick and anxious.
What do you do? See the worked answer
Divert to the nearest suitable airport, tell ATC (declare an emergency if it’s serious) and keep flying the airplane calmly.
14 CFR 91.3
ATC gives you a heading that would take you toward a cloud bank.
What do you do? See the worked answer
Tell ATC you’re unable because of weather and ask for another heading. You must not fly into clouds VFR. Say "unable" before you deviate, give the reason, and request an amended clearance or another heading; outside an emergency, don't simply fly contrary to an instruction.
14 CFR 91.123
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.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice diversion out loud with our examiner.
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Teaching this? The instructor lesson plan →
Sources
- Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C): Navigation; Flight Instruments
- Aeronautical Information Manual (AIM): Chapters 1, 4, 6 and 7
- 14 CFR Part 91: 91.3, 91.119, 91.123, 91.151, 91.159, 91.171, 91.215, 91.225
- AC 90-48: Pilots' Role in Collision Avoidance
- Private Pilot ACS (FAA-S-ACS-6C): Area VI
- VFR sectional chart and Chart Supplement: for your route
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-12.