Commercial pilot · ACS CA.VI.C · Instructor lesson plan
Diversion
Student pack: Train: Diversion · Full lesson: Prepare guide
1 · Objective
By the end of this lesson your student can explain diversion in their own words, apply it in a realistic situation, and fly it to the ACS standard for CA.VI.C.
Why it matters for safety: For a commercial pilot, the hardest part of a diversion is often deciding to do it: the client expects to arrive where they paid to go. Weather and fuel accidents are usually the story of a diversion made too late. Setting the decision criteria before the flight, and acting on them, keeps the choice a calm one.
2 · Assign before the lesson
Pre-work: the free Train pack, Diversion. Decide early, turn first, then compute: a suitable airport, a reasonable estimate, and a prompt diversion.
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Pack: pilotprep.pro/train/cpl/diversion · Full lesson: pilotprep.pro/prepare/cpl/diversion
3 · Teach sequence
Key points to land
- Divert early: weather worse than forecast, fuel burn above plan, a mechanical concern, a sick passenger, fatigue or darkness 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 the airport that makes the situation better: runway length and surface, weather, fuel, services, terrain and airspace, not just the closest.(PHAK (FAA-H-8083-25C), Navigation)
- Routine diversion on a clearance or in controlled airspace: get an amended clearance first (91.123). In an emergency, the PIC may deviate from the rules or a clearance to the extent required, telling ATC as soon as possible, and must send a written report if the FAA asks (91.3(b)-(c)).(14 CFR 91.3; 91.123)
- Use your resources: ATC, Flight Service, the GPS nearest and direct-to functions, data-link weather, and passengers for simple tasks.(Advanced Avionics Handbook (FAA-H-8083-6))
- Data-link NEXRAD shows where the weather was: what it depicts can be 15 to 20 minutes older than the age on the display. Use it only for strategic avoidance with wide margins, never to thread between cells.(AIM, Chapter 7, Safety of Flight (in-flight weather and FIS-B); NTSB Safety Alert SA-017)
- Commercial standard: select a suitable destination and route (S1), estimate heading, groundspeed, arrival time and fuel (S2), hold altitude ±100 feet and heading ±10° (S3), and divert promptly (S6).(Commercial Pilot ACS (FAA-S-ACS-7B), CA.VI.C.S1-S3, S6)
When to divert
- Weather worse than forecast, a lowering ceiling, an unexpected headwind, fuel above plan, a rough engine, a sick passenger, fatigue or approaching darkness.(Risk Management Handbook (FAA-H-8083-2A))
- The legal floor is 91.151: before you begin a VFR flight, fuel to the first point of intended landing plus, at normal cruise, 30 minutes by day or 45 at night, considering wind and forecast weather. The in-flight divert decision should come from a higher personal minimum (ceiling, visibility, fuel at landing) set before the flight; divert when you reach it.(Risk Management Handbook (FAA-H-8083-2A); 14 CFR 91.151)
- Not an emergency: ask ATC for an amended clearance before turning. An emergency: deviate to the extent required, tell ATC as soon as possible, and file a report if asked.(14 CFR 91.3; 91.123)
- With passengers who paid for the trip, decide by the criteria, explain it plainly, and offer the alternative (a later arrival, ground transport).(Risk Management Handbook (FAA-H-8083-2A))
Choosing the airport
- Before the flight, note suitable airports along the route. In flight, check runway length and surface, weather, fuel, services, terrain, airspace and NOTAMs for the one you choose.(PHAK (FAA-H-8083-25C), Navigation)
- Choose the airport that improves the situation: a long runway into the wind with good weather beats a slightly closer one with a crosswind and low clouds. The exception is time-critical (a seriously ill passenger, fire, a failing engine): the closest suitable airport with help (road access, EMS, a usable runway) usually wins; tell ATC, ask for priority, and declare if you need it.(Risk Management Handbook (FAA-H-8083-2A))
Doing it
- Turn toward the new destination right away (once cleared, if on a clearance), on an estimated heading from the chart or the GPS direct-to; note the time. Pick an altitude for the new route that clears terrain, obstacles and wires (check the maximum elevation figures) and fits the cruising rule for the new magnetic course.(PHAK (FAA-H-8083-25C), Navigation; 14 CFR 91.159)
- Then refine it: distance, groundspeed from the known wind, time and fuel. Check the GPS against the chart.(PHAK (FAA-H-8083-25C), Navigation)
- Tell ATC; they can give vectors, weather and airport information.(AIM, Chapter 4, Air Traffic Control (radar services for VFR aircraft))
- Update the weather from ATIS/ASOS, Flight Service or FIS-B, and check the data's age.(AIM, Chapter 7, Safety of Flight (in-flight weather and FIS-B))
Workload and traffic
- A diversion adds workload at a stressful time: distraction, poor task priorities and lost situational awareness are the risks. Fly the airplane first, then the math.(Risk Management Handbook (FAA-H-8083-2A))
- A new route may cross unfamiliar traffic and airspace: keep scanning, and use flight following.(AC 90-48, Pilots' Role in Collision Avoidance)
Watch for in the airplane: Your instructor watches for an early decision, an immediate turn on an estimated heading, a sensible airport choice, a reasonable estimate of time and fuel, ATC used, and altitude and heading held within commercial tolerances.
4 · Ask your student
In order: recall, then understanding, then applying it. Move up only when the answer shows it.
Recall · What do you do first when you decide to divert?
A strong answer: Turn toward the new destination on an estimated heading, then compute distance, time and fuel.
Understand · Why decide on diversion criteria before the flight?
A strong answer: In the air, with a paying client and the destination close, the pressure is to continue. Pre-set limits make the decision a check, not a debate.
Apply · Halfway, the destination's ceiling is dropping toward your minimum and your client has a meeting there. What do you do?
A strong answer: Divert to an airport with good weather now, explain plainly, and help with ground transport. A late diversion into worsening weather is how accidents happen.
Scenarios to talk through
The FIS-B radar picture shows your route clear of a storm, but the image is 12 minutes old. Can you rely on it?
Sound decision: No: storms move and develop in 12 minutes. Use it for strategic avoidance only, keep a wide margin, and check with ATC or Flight Service.
Two nearby airports: one 8 nm away with a 2,600-foot runway and a 15-knot crosswind, one 15 nm away with a long runway into the wind. Which do you choose?
Sound decision: Usually the second: it improves the situation (longer runway, into the wind). The extra 7 miles is a few minutes.
Your fuel burn is 10% above plan and the headwind is stronger than forecast. What do you do?
Sound decision: Recompute fuel at the destination with reserve; if it drops below your personal minimum, divert to a fuel stop now.
5 · Common student errors
Computing before turning.
Why it matters: You fly further the wrong way while you work.
How to correct it: Turn first on an estimate, then refine.
Choosing the closest airport automatically.
Why it matters: It may not improve the situation.
How to correct it: Pick the one that does: runway, wind, weather, services.
Waiting too long.
Why it matters: Options shrink with fuel, weather and daylight.
How to correct it: Divert when a pre-set limit is reached.
6 · Completion standard
- Select a suitable destination and route; estimate heading, groundspeed, arrival time and fuel; promptly divert.
- Altitude ±100 feet, heading ±10°; update and interpret weather in flight; use digital weather and aeronautical displays.
- Your student answers each "Ask your student" question in their own words, up to the Apply level, without prompting.
- They talk through the scenarios and reach a safe, legal decision, explaining why.
- They complete the pack’s quick check and can say what they flagged.
Area trained? Close out with a practice oral focused on CA.VI.C: pilotprep.pro/exam?exam=CPL&focus=CA.VI.C
7 · References
- Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Navigation; Flight Instruments
- Advanced Avionics Handbook (FAA-H-8083-6)
- Aeronautical Information Manual (AIM), Chapters 1, 4, 6 and 7
- 14 CFR Part 91, 91.3, 91.103, 91.123, 91.151, 91.171, 91.215, 91.225
- AC 90-48 and AC 91-78
- Commercial Pilot ACS (FAA-S-ACS-7B), Area VI
- Airman Certification Standards, task CA.VI.C
PilotPrep instructor lesson plan, from the Diversion lesson (checked against current FAA sources 2026-11-13). A study and teaching aid, not FAA guidance; teach to your own judgment and the current ACS.