EU All-Weather Operations Rules (2022)

All-weather operations (AWO) is the name European rules give to the take-offs and approaches flown when fog, low cloud or precipitation restrict what the crew can see. Since 30 October 2022 they have been governed by Commission Implementing Regulation (EU) 2021/2237, which amended the Air Operations Regulation (EU) No 965/2012, together with acceptable means of compliance and guidance material issued by EASA in ED Decision 2022/012/R and the airworthiness standards of CS-AWO. The package replaced rules that went back to JAR-OPS and EU-OPS, renamed several operations, and introduced a new way of describing approaches and the credit an aircraft's equipment can earn.

This article deals with the regulation: how operations are classified, which of them need an approval, and what the operator has to show. The operational technique, from low visibility procedures and alert height to the visual segment, is covered in low visibility operations, and the way minima are established and applied in aerodrome operating minima.

Why the AWO rules were rewritten

European all-weather rules grew out of JAR-OPS 1 and were carried into EU-OPS. The Air Operations Regulation, which replaced EU-OPS in 2014, largely carried them over, so until 2022 crews flew to definitions inherited from JAR-OPS. Two things had moved on:

• ICAO's terms. ICAO had reorganised its classification of approach operations into Type A and Type B and merged Category III into a single category. EU-OPS still divided CAT III into IIIA, IIIB and IIIC, and older ICAO texts used an RVR of 800 m as the threshold for low visibility operations.
• Aircraft capability. Head-up guidance, enhanced vision and automatic landing systems allowed lower minima than a runway's ground equipment alone would justify, but the rules recognised them piecemeal, in the lower than standard CAT I (LTS CAT I) and other than standard CAT II (OTS CAT II) operations and in a few take-off and single-pilot concessions.

The result follows ICAO's terms and leaves the operator responsible for establishing minima for every aerodrome it plans to use, by a method set out in its operations manual (CAT.OP.MPA.110). Every operation below standard CAT I, and every take-off below 400 m RVR, needs the specific approval SPA.LVO. How the other rules changed at the same time is summarised in from EU-OPS to Part-CAT.

Approach classification: Type A and Type B

Instrument approach operations are classified by their lowest minima, not by the type of guidance:

A 2D approach, with lateral guidance only, is flown to an MDA/H; such non-precision approaches are Type A operations in the alternate planning tables. A 3D approach is flown to a DA/H and may be either type: an approach with vertical guidance whose minimum is 250 ft or higher is Type A, while an ILS to 200 ft is Type B, CAT I.

The classification is used well beyond the approach itself. Alternate planning minima under CAT.OP.MPA.182, introduced alongside it by the fuel rules of Regulation (EU) 2021/1296, add increments by type: under the basic fuel scheme, DA/H + 200 ft and RVR + 800 m for a Type B approach, and + 400 ft and + 1,500 m for a Type A approach (see alternate aerodromes).

CAT I, CAT II and CAT III under the new rules

Low visibility operations (LVO) are defined as approach or take-off operations with an RVR below 550 m or a DH below 200 ft. Standard CAT I therefore sits just outside them, while CAT II, CAT III, SA CAT I and SA CAT II sit inside.

Four changes from the EU-OPS rules are examined most often:

• One CAT III. There is no longer a CAT IIIA, IIIB or IIIC. The lowest RVR for a DH between 50 ft and 100 ft fell from 200 m to 175 m, in line with ICAO.
• The more demanding category. Where the DH and the RVR fall into different categories, the operation is conducted to the requirements of the more demanding one. Under EU-OPS the RVR decided the category.
• Controlling RVR. The touchdown zone RVR is controlling, or the midpoint value if no touchdown value is reported; midpoint and stop-end values are advisory. EU-OPS also made the midpoint and stop-end values controlling where reported and relevant, with minimums of 125 m at the midpoint, or the touchdown value if lower, and 75 m at the stop end.
• New names. LTS CAT I and OTS CAT II became SA CAT I and SA CAT II.

Operations with operational credits

An operational credit is a reduction in minima, or a relief from a facility requirement, earned by the aircraft's equipment, the crew's training or both. The rules group these as operations with operational credits:

• SA CAT I (special authorisation category I). A DH not lower than 150 ft and an RVR not lower than 400 m, the exact value depending on the approach lighting. CS-AWO now contains an airworthiness standard for aircraft used to these minima.
• SA CAT II (special authorisation category II). A CAT II approach to a runway that does not meet all the infrastructure requirements of CAT II. The aircraft makes up the difference: on the A320 an SA CAT II approach without a head-up display must end in an automatic landing, while with a HUD the crew monitors the approach on it and may land automatically or manually.
• EFVS 200. Under CAT.OP.MPA.312 an aircraft with an approved enhanced flight vision system may use reduced RVR minima, but never below 550 m, and the DH may not go below 200 ft. EFVS 200 is therefore not a low visibility operation and needs no specific approval.

All operations with operational credits other than EFVS 200 need an SPA.LVO approval. The aircraft's flight manual states which operations it is certified for, and items inoperative under the MEL can downgrade the capability for a given flight (see head-up display and vision systems).

Low visibility take-off

A low visibility take-off (LVTO) is a take-off in an RVR below 550 m. Under EU-OPS the threshold was 400 m, and that figure survives in a new role:

Without a specific approval, the AMC to CAT.OP.MPA.110 gives a multi-engine aeroplane 500 m by day on a runway with no lighting, as long as the pilot can identify the take-off surface and keep directional control, and 400 m with edge lights or centreline markings by day, or edge or centreline lights and runway end lights at night. States publish the result on aerodrome charts: France shows take-off minima for RVRs above 75 m and warns that an LVTO approval may be needed below 400 m, and at Lyon Saint-Exupéry runways 35L and 35R allow 125 m.

The SPA.LVO approval

Part-SPA, Subpart LVO, is the single gateway to the lowest minima. An operator needs the approval for:

• take-offs in an RVR below 400 m;
• CAT II and CAT III approach operations;
• operations with operational credits, except EFVS 200.

Part-SPA approvals are not tied to commercial air transport: any operator conducting these operations needs one, whatever Part it flies under, and for an air operator certificate holder the approval appears in its operations specifications (see specific approvals). To obtain it the operator shows that each element of the chain is in place: aircraft certified for the operation under CS-AWO or an equivalent, with the capability stated in the flight manual; operating procedures and MEL provisions; trained and qualified crews; and aerodromes whose facilities and low visibility procedures support the minima it intends to use.

Published minima set the floor without approval. France's AIP states that the minima on its approach charts, for CAT I, approaches with vertical guidance, non-precision approaches and visual manoeuvres, are the lowest usable without an operational approval from the operator's authority. It also shows the kind of checks the operator owns: before practising automatic landings on a CAT I or CAT II runway outside low visibility procedures, it must confirm that the ILS classification's second character is D or E, that the glide path is set at no more than 3° and meets CAT III structure requirements, and that its autoland system suits the terrain before the threshold and the runway profile (see autoland).

Crew training and qualification

The approval covers people as well as equipment. CAT II and CAT III operations require a flight crew of at least two pilots, both trained and qualified for the operation, as EU-OPS 1.440 did before. The operator's procedures, training and records for each approved operation are part of what the authority approves, and operations with credits add training on the equipment that earns them, such as a head-up guidance system. Pilots must also remain current in the operations they fly: the minima are not available to a crew that is not trained and qualified for them, even when the aircraft, the runway and the weather allow.

Comparison with the FAA

The FAA reaches similar minima through operations specifications rather than a regulation of this kind, with its criteria consolidated in AC 120-118 (2018):

The FAA also ties credits closely to type-specific training. For the 737 head-up guidance system, for example, its Flight Standardization Board requires a captain to fly 25 HUD approaches to CAT II/IIIa minima in visual conditions, and 25 HUD-assisted take-offs, before using the HUD in instrument conditions below RVR 1,800 ft.

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.