All Weather Operations

Updated version on 7 March 2024 with the latest All Weather Ops Guidelines - download at the bottom of the page.

This is produced by EUSPA in collaboration with ESSP aim to promote and provide high level material to facilitate the implementation of EFVS operations based on SBAS technology, which will greatly contribute to the increased availability of suitable destination and alternate aerodromes during periods of reduced visibility. 

The objective of this publication is ensuring harmonised solutions and a common approach in accordance with Single European Sky (SES) Regulation. In this context, this document is mainly intended for aircraft operators but also includes relevant information for other affected stakeholders, such as aerodrome operators, Air Navigation Service Providers (ANSPs) and aircraft manufacturers / design organisations.”

Updated version of the EASA All Weather Ops Implementation Manual (version 1.2) published with effect from 7 August 2023 - download at the bottom of the page. 

Air operations need to happen safely in all weather conditions. EASA Rulemaking Task RMT.0379 has recently been completed to introduce a more performance-based and technology neutral approach to enabling all weather operations.

More specifically RMT.0379 has introduced the ICAO concept of operational credits meaning that with an advanced aircraft (having enhanced capabilities) you can either:

• Reduce your approach minima at airports having standard ground and navigation infrastructure while the ‘basic aircraft’ maintains the standard minima or
• Maintain the standard approach minima at airports having reduce airport infrastructure while the ‘basic aircraft’, must use higher minima.

The new regulatory framework makes it easier to enable CAT II and CAT III approaches by reducing the operational demonstration needed by the operator, for some cases the operational demonstration can be removed. There are also new rules on Enhanced Flight Vision Systems (EFVS) that reduces approach possibilities to 200ft without prior approval, then also to 100ft and even 0ft depending on the equipment available on the aircraft and at the aerodrome.

The material available to help you with implementation

In addition to this article, there is lots of information to support you with the implementation. The main things are:

• The All Weather Operations (AWO) Implementation Manual (at the bottom of this page). 
• 3rd Webinar on AWO held on 24 October with the focus on EFVS. Presentations and partial recording available. 
• 2nd Webinar on AWO held on 7 September with presentations on the NAA and operators view as well as navigation system providers. Presentations and full recording available.
• 1st Webinar on AWO held on 19 June - AMC and GM information available. 

Overview of All Weather Operations

So let’s go back to the very beginning. All weather operations is the ability of aircraft to take off and land in an airport under low visibility conditions, this means below 550m Runway Visual Range (RVR). In these circumstances, technology can really help to enable safe operations in situations that would otherwise be impossible or pose considerable safety challenges.

The challenge of all-weather operations is a great example of the different parts of our aviation system coming together to achieve something amazing. It also highlights how the 6 parts of the Safety Map of the World will help you to understand this topic in more detail. <Mindset, People, Resources, Compliance, Risks and Learning>

• The start of the story – Compliance. The rules are obviously new so we are firmly in the compliance box. The main purpose of this article, the implementation guide and the different webinars is to help you to understand and comply with these new rules.
• Mindset. Everything in aviation requires the right mindset and culture in your organisation. Considering safety as a key part of every aspect of what you do is vital. This is particularly important when operating in difficult weather conditions. Ask yourself important questions about where your risks lie and encourage everyone in the organisation to talk openly about safety. 
• People. The new rules have a particular focus on the competencies of your people. To operate in low visibility requires specific proficiency checks that are covered in the Air Ops Rules. 
• Resources. A key part of operating in low visibility are the technical capabilities onboard the aircraft and then also those available at the aerodrome. Knowing these are vital to implementation of the new rules.
• Risks. The purpose of the new rules is clearly to help manage risks around operating in poor weather conditions. However, like any change in your operation it can also create new risks that you need to understand and manage.
• Learning. The end of the story of all weather operations is really that you never stop learning. Continually monitor your implementation and seek to identify new risks and mitigate them effectively. Share experiences with other organisations and with your staff so they can learn from each other.

A total system approach with 4 aspects impacted 4 different EASA Rules

The new EASA rules follow a total system approach, which splits things into 4 parts:

1. Your operation: Aircraft operators are impacted by changes to operational requirements – you will find these in Regulation (EU) 965/2012 on Air Operations. This includes any new approvals that you need as an organisation and linked to this is the specific training for the flight crew.
2. Pilots and their training: As we mentioned already, the training for pilots is changing with regards to all weather operations. While the rules for training are laid down in Regulation (EU) 1178/2011 on Flight Crew Licencing the big change in the new rules is that the requirements for training on Low Visibility Operations (LVO) are moved into the Air Ops rules to ensure a clear link to the different operational activities being performed. This approach is not new, back in the JAR-OPS time and EU-OPS LVO training was in the OPS domain.
3. The aerodrome: It also impacts Aerodrome operations and infrastructure in Regulation (EU) 139/2014 on Aerodromes Safety.
4. The aircraft: Finally, there are specific requirements for the equipment and capabilities of the aircraft as laid down in CS-AWO (ED Decision 2022/007/R) on Airworthiness.

This means that all weather operations assesses the combination of the aircraft’s capability, the aerodrome’s ground infrastructure and the approach minima.

Different Types of Approach and Landing under the new Rules

Before getting into the different aspects of the operation, training, aerodrome and aircraft requirements, its worth having a quick overview of the different types of approach we are talking about.

• CAT II Approach: A precision instrument approach and landing with a decision height below 200ft but not less than 100ft and with a Runway Visual Range (RVR) of 300m (1000ft).
• CAT III Approach: A precision instrument approach and landing with a decision height below 100ft and with a Runway Visual Range (RVR) of 200m (700ft).
• EFVS 200 Approach: An operation in which the approach continues without reliance on the pilot’s natural vision to a height not lower than 200 ft above threshold elevation and in visibility conditions equivalent to RVR not lower than 550 m.
• EFVS Approach (EFVS-A): An operation in which the approach continues without reliance on the pilot’s natural vision to a height above the threshold elevation not lower than 100 ft above and in visibility conditions equivalent to RVR less than 550 m but not lower than 75 m.
• EFVS Landing (EFVS-L): An operation in which the approach continues without reliance on the pilot’s natural vision and any restriction to a height above the threshold elevation and in visibility conditions equivalent to RVR less than 550 m but not lower than 75m.

The Operation

As mentioned at the beginning, from an ops perspective the new rules introduce the ICAO concept of operational credits. This means that with an advanced aircraft (having enhanced capabilities) you can either reduce your minima provided that the ground infrastructure at the airport is the same or that you can maintain the minima where the infrastructure is reduced.

Removing the need for an operational demonstration

This makes it easier to enable CAT II and CAT III approaches by reducing the operational demonstration needed by the operator. It also reduces the operational demonstration requirements needed for CAT II and CAT III approaches. The new rules remove the need for each aircraft type and runway end to have an operational demonstration. This has lots of benefits. It increases the availability of alternate aerodromes, which in turn reduces the environmental impact. In these tough economic times is helps to save money for operators and provides more flexibility for the route network.

Currently 90% of runways are within the certification assumptions for both CS-AWO Issue 1 and Issue 2. For the remaining 10% you can use any previous operational data you have, data from another operator or use of data for other models from the same aircraft manufacturer, provided they provide a supporting statement. It’s also possible to use computer/ full flight simulations from the manufacturer. If none of the above works a traditional operational demonstration is required.

The challenge of course is how to know if a particular aircraft/ aerodrome combination is in the 90% that are already covered. To to this, you will need to compare the AFM data and certification assumptions with the airport data. If they are within the certification assumption and AFM data, you can operate without any operational demonstration.

If it is not within the assumptions/AFM data, then you have to use previous data or undertake a traditional operational demonstration.

It is worth noting that with CS-AWO issue 2 there are new requirements to provide certification assumptions and to be more transparent with the AFM data. Additionally, the new Aerodrome rules increase the requirements in the AIP to provide more airport data. This tries to make sure that the AFM data and airport data comparison can be done.

In terms of special authorisations, you need to apply for specific authorisations or approvals from your National Aviation Authority for:

• CAT II and CAT III
• SA CATI, SA CATII
• EFVS-A or EFVS-L

Pilot Training

When it comes to flight crew training and all-weather operations, there have been some clarifications and improvements on route and aerodrome knowledge requirements, a great link to Evidence Based Training (EBT) and alignment of validity periods to the end of the month.

When it comes to the operators conversation course (OCC) there is increased flexibility for new AOCs, new aircraft type or other operational circumstances.

The biggest change is that the specific requirements for LVO training are now linked into the Ops rules for the operator.

Aerodromes and Their Equipment

When it comes to the aerodrome, the updates in Regulation (EU) 2022/208 help the implementation of all weather operations by ensuring the availability of the appropriate visual and non-visual aids, the availability of the required information of the operator to have access to for their decision making and then the implementation of the appropriate procedures for this type of activity.

More specifically this includes the provision of traditional aids such as ILS and then also the procedures needed to enable GPS/ GNSS approaches that make many smaller aerodromes accessible in poor conditions.

The Aircraft

Finally from an aircraft perspective, the publication of CS-AWO Issue 2 has a number of building blocks including high altitude landing system performance, head-up guidance landing systems, structural limit loads and lateral touchdown performance, autobrake – these were laid out in a number of AWO NPAs.

There were also a number of Certification Review Items (CRIs) covering automatic landing distance, GBAS landing system for Cat 1 operations, extrapolation of wind limits for Autoland demonstration and landing distances using HUDs.

You can find out more about the structure and new elements of the CS-AWO in the powerpoint and 1^st EASA Webinar on all weather operations. However, you can see some examples below of new design HuDs, EFVS and Synthetic Vision Guidance Systems (SVGS). 

Summary

So that gives you a basic overview of the key parts of the new EASA all weather ops rules. Check out the PPTs from the Webinars, the Webinar recordings themselves and the draft EASA Guide on All Weather Ops for more information.