Published date: 5 April 2022


This AC describes an acceptable means of compliance with Civil Aviation Rule Part 121, which, if included in a certificate holder’s exposition, would support an application for Extended Diversion Time Operations (EDTO) and/or polar area operations authorisation. It explains means acceptable to the Director for a New Zealand-registered twin turbine engine Part 121 aeroplane to be eligible to operate over a route, or a designated polar area, that contains a point further than 60 minutes’ flying time from an adequate aerodrome at an approved one-engine inoperative cruise speed.

This Revision also includes provisions for the authorisation of Part 121 turbine engine aeroplane with more than two engines to operate over a route beyond 180 minutes from an adequate aerodrome. Specific criteria are included for deviations up to 180 minutes, up to 240 minutes, and greater than 240 minutes from an adequate aerodrome.

Related rules

This AC relates specifically to the rules regarding EDTO (Subpart G, rule 121.407, Maintenance elements for EDTO, and Subpart N, EDTO Authorisation and Operations, and rule 121.165, Route distance limitations, and those relating to the conduct of polar area operations: rule 121.171, Requirements for Air Operations in a Polar Area, rule 121.173, Application for Air Operations in a Polar Area, and rule 121.175, Authorisation for Air Operations in a Polar Area.

Change notice

Revision 1 updates this AC to support the revised rules governing aeroplane diversions greater than 60 minutes’ flight time from an adequate aerodrome. The revised standard:

  • encompasses the operations of all turbine powered multi engine Part 121 aeroplanes, and
  • replaces the previous extended-range twin-engine operations (ETOPS) rules which applied only to extended range operations in twin turbine engine aeroplanes.