General Rules of the Air: Flight Plans, Lights, SSR Codes, and Lost Communications

010-05-03Pablo Asensio Martínez2026-03-271 min

Flight Plan

A flight plan shall be submitted prior to operating any flight to which air traffic control service is to be provided.

Adherence to Flight Plan: Flights must adhere to the current flight plan. Deviations must be reported to ATC:

  • Deviation from track: Correct the heading immediately.
  • Variation in TAS: If true airspeed varies by +/- 5%.
  • Time estimate: If the time estimate for the next reporting point changes by more than 2 minutes.

Signals and Lights

At night, all aircraft in flight shall display:

  1. Anti-collision lights to attract attention.
  2. Navigation lights to indicate relative path.
    • Red: Left wing (110°).
    • Green: Right wing (110°).
    • White: Tail (140°).

Transponder Codes (SSR)

  • 7500: Unlawful Interference (Hijack).
  • 7600: Radio Failure.
  • 7700: Emergency.

Semicircular Rule (Cruising Levels)

For vertical separation, flight levels (FL) or altitudes are used based on magnetic track:

  • 000° - 179° (East): ODD levels (e.g., FL50, FL70, FL290, FL330).
  • 180° - 359° (West): EVEN levels (e.g., FL40, FL60, FL280, FL320).

Note: In RVSM airspace (between FL290 and FL410), separation is reduced to 1000 ft, but the odd/even logic is maintained.

Communication Failure

If radio failure occurs in IFR conditions or if it is not likely to complete the flight in VMC:

  • Maintain the speed and level assigned for a period (usually 7 or 20 min).
  • Proceed according to the current flight plan.
  • If being vectored, proceed in the most direct manner possible to rejoin the current flight plan route.