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 how a New Zealand-registered twin turbine engine Part 121 aeroplane can 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 aeroplanes 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.
This AC relates specifically to the rules regarding EDTO - Subpart G Maintenance, rule 121.407 Maintenance elements for EDTO, and Subpart N EDTO Authorisation and Operations, and rule 121.165 Route distance limitations. It also relates to the rules on 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.
Revision 3 makes minor updates to align with the redrafted rules under the Civil Aviation Act 2023 (CA Act 2023) and removes specific form numbers.
