Extended Diversion Time Operations (EDTO)

Amendments to Part I of Annex 6 to the Chicago Convention introduced Extended Diversion Time Operations (EDTO) requirements replacing Extended-range Twin-engine Operational Performance Standards (ETOPS) requirements currently in force. Updating the UK Regulatory framework, notably Assimilated Regulation (EU) No. 965/2012 (the UK Air Ops Regulation), by transposing the relevant ICAO Standards and Recommended Practices (SARPS) from ICAO Annex 6, Part I would ensure compliance with the UK’s international obligation and realise the safety benefits these provisions are designed to achieve.

We ran a consultation asking for feedback on the proposed amendments to the UK Air Ops Regulation that would adopt these ICAO Standards in full. The consultation ran from 23 April 2025 to 21 May 2025.

We asked if the proposed transition period of 9 months following the publication of the Statutory Instrument would be a sufficient to implement the required changes.

We also sought feedback on the draft Acceptable Means of Compliance (AMC) and Guidance Material (GM) that would support these new requirements.

The consultation results were intended to guide regulatory development, refine the AMC and GM and assess if there was a significant monetary impact on industry.

We received a total of 62 comments from 5 respondents with one respondent contributing the majority of comments.

60% of respondents supported the proposed amendments with a strong overall consensus that incorporating EDTO requirements would have a positive impact on safety.

20% thought it might have a negative impact on efficiency noting the potential for longer routes for 3 and 4 engined aircraft.

80% thought the financial impact would be negligible with only one respondent concerned with the increased administrative burden for 3 or 4 engined aircraft.

The majority of respondents indicated that there would be no impact on security and anticipated either a negligible or positive effect on environmental and equality considerations.

3 respondents were expressing their own views, and 2 respondents were representing an organisation. One of the 3 respondents, who was expressing their own views, was commenting on an issue regarding flight dispatcher qualifications that was outside of the scope of the consultation.

The clear majority were in support of the underlying policy and most of the comments related to the proposed changes to AMC and GM.

Some of the suggestions included re-wording or the addition of further information to improve clarity, and some comments queried the definitions and applicability of current ETOPS approvals.

A specific query was raised concerning the provision to increase an operator’s diversion time by up to 15%, subject to approval, and whether such an extension could be granted without an upper limit of 180 mins.

A common concern raised by two respondents relates to the removal of AMC 20-6B, specifically regarding where the new requirements—those not included within the Air Operations regulations—will be published, as well as the anticipated timeline for their release.

The CAA has carefully considered all the consultation responses and would like to thank all contributors, in particular, the substantial technical insights received from one Original Equipment Manufacturer.

The majority of substantive comments have been accepted and will be taken into account when drafting the AMC and GM material which will be further developed to coincide with the publication of the Statutory Instrument later this year.

Comments reviewed include but are not limited to the following:

• Transition period - we have listened to the feedback regarding the transition period and as such have amended this from 9 months to 12 months to allow operators greater time to make any required updates.
• Request to retain ETOPS terminology - The term ‘EDTO’ will replace ‘ETOPS’ in UK Regulation (EU) No 965/2012. However, the use of ‘ETOPS’ may not have been updated in other regulations and documentation (e.g. manufacturer documentation) and should be considered as equivalent to EDTO.
• Clarification requested on whether existing ETOPS approvals remain valid under EDTO - the CAA confirms that all current ETOPS approvals will remain valid. As stated in the proposed Annex 1 Definitions section, ETOPS and EDTO are built on the same concepts, therefore when an EDTO type design and reliability approval is required, it is acceptable to perform EDTO flights with an aeroplane that is certified for ETOPS. The EDTO operational approval of an operator of ETOPS-certified aeroplanes does not require that these aeroplanes are re-certified for EDTO, nor that the aeroplane documentation is updated to refer to EDTO instead of ETOPS.
• Request to clarify EDTO and EDTO ERA definitions, particularly regarding aerodrome adequacy – the definitions used are aligned with ICAO Doc 10085. Aerodrome adequacy is addressed through existing provisions on aerodrome selection and fuel planning policy.
• Concern that the document structure is unclear, with certification, operations, and maintenance topics dispersed - this consultation was focused on Air Operations regulations. Airworthiness and maintenance elements will be addressed in subsequent consultations.
• Request to consolidate AMC20-6B and related maintenance requirements into a single reference - Whilst this consultation focused on proposed amendments to UK Regulation (EU) No. 965/2012 (the UK Air Operations Regulation), it was observed that a significant proportion of responses related to areas beyond the remit of Flight Operations. In response, the CAA is collaborating with colleagues across Airworthiness and Design and Certification to ensure that all relevant information and references particularly those linked to EASA publications such as AMC 20-6B are appropriately reviewed and updated. This coordinated approach aims to maintain consistency and continuity across departmental regulatory frameworks.
• Suggestion to explicitly include runway length and adequacy criteria – the CAA considers that runway adequacy and performance considerations are already addressed through the aerodrome selection policy requirements.
• Recommendation to limit the 15% diversion time extension to a maximum of 180 minutes for two-engine aeroplanes – this recommendation has been accepted, and the wording has been revised accordingly to establish an upper limit of 180 minutes for such an increase.
• Aircraft specific queries, CMP requirements, APU monitoring, and engineering approvals - these matters have been acknowledged and will be addressed in future airworthiness guidance and AMC material.

Comments not specifically addressed in this response have been duly considered and where appropriate will be used to develop and refine the Acceptable Means of Compliance and Guidance Material.