AMC1 NCO.OP.142(b)(5) Destination alternate aerodromes — instrument approach operations

CAA ORS9 Decision No. 47

Text in magenta in force from 30 October 2025

APPROPRIATE CONTINGENCY ACTION

  1. An appropriate contingency action is an alternative offered in NCO.OP.142(b)(5) to completion of the planned flight to a safe landing, either at the planned destination or a destination alternate, using normal procedures and using navigation equipment meeting the requirements of NCO.IDE.A/H.100, installed for redundancy or as a backup.

  2. The contingency action should be considered before flight and take into account the information identified by flight preparation according to NCO.OP.135. It may depend on the flight and availability of navigation solutions (satellites, ground navaids, etc.) and weather conditions (IMC, VMC) along the flight.

  3. The contingency action addresses partial loss of navigation capability, such as:

  • loss of the stand-alone GNSS equipment;

  • local loss of GNSS signal-in-space (e.g. local jamming at destination); and

  • loss of GNSS signal-in-space.

  1. It should take into account what options remain in case of loss of GNSS signal; for instance, (non-GNSS-based) radar vectoring by ATC, non-GNSS-based navigation systems or the possibility to reach VMC.

  2. Examples of contingency actions include:

  • seeking navigational assistance from ATS, using communication and surveillance systems that remain operational, to enable safe descent to VMC;

  • the emergency use of navigation equipment not meeting the requirements of NCO.IDE.A/H.100 by making use of the provisions in NCO.GEN.105(e);

  • descent over water or very flat terrain to levels with reduced (but reasonable) obstacle clearance; and

  • unusually long periods of dead reckoning.