In-Flight Re-Planning

033-06-02Pablo Asensio Martínez2026-04-011 min

Reasons for Re-Planning

  • Weather: Deterioration at destination or alternate.
  • Fuel Shortage: Use of contingency fuel exceeding limits or unforecast headwinds.
  • Technical Failure: Loss of engine, pressurization, or navigation equipment.
  • Passenger Medical: Requirement to land at nearest suitable airport.

The Re-Planning Process (1-in-60 Rule)

For navigation deviations:

  • Track Error Angle (TE): $\frac{Distance Off}{Distance Flown} \times 60$.
  • Correction Angle: To return to track in same distance: $2 \times TE$.
  • To fly direct to destination: Use new track and distance.

Fuel Re-Assessment

When re-planning to a new destination (diversion):

  1. Current Position: Treat as the new "Departure Point".
  2. Fuel on Board: Treat as the new "Take-off Fuel".
  3. Calculation: Calculate Trip Fuel from Current Position to New Destination + Reserves.
    • Is Current Fuel > Trip to Alternate + Reserves?
    • If YES: Proceed.
    • If NO: Land at nearest suitable aerodrome immediately.
Written and reviewed by

Pablo Asensio · 2026-04-01

Aeronautical engineer. Passed the thirteen EASA ATPL(A) theoretical knowledge exams studying from these very notes. Writes and reviews each topic against the Part-FCL Learning Objectives.

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