Annex A - Civil Aviation Safety Authority

Notice of Proposed Rule Making

IFR minima and low visibility operations

Annex A Consolidated Summary of Comments / Responses Received, CASA’s Response and Disposition Actions to Discussion Paper (DP) 0805AS – Low Visibility Operations in Australia

Document NPRM 0906AS

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Comments relating to the Key Proposals made in Discussion Paper (DP) 0805AS (Low Visibility Operations in Australia)

Introduction The format of the summary is comment received, followed by the CASA response and a summary of the disposition of that comment. Comment 1 – General An aircraft operator said that the proposals were a ‘cherry pick’ of a number of international standards and were not entirely reflective of ICAO SARPs. The operator recommended modelling Australian Low Visibility rules after JAR-OPS1, as this regulation effectively embodied ICAO SARPs. This approach would provide overseas operators with a familiar operating environment. Another aircraft operator recommended that reference to FAA Order 8400.13B be changed to 8400.13C, and that provision should be made for Global Navigation Satellite System (GNSS) Landing System (GLS) operations at least for Cat I, but preferably for all categories. In response to the proposed standards for runway visibility assessments, a meteorological services provider made the following comments: • •

• •

If the aerodrome operator must produce a visibility markers chart, then airport maps must also be published for pilot use. A person who assesses runway visibility must be authorised under CAR 120 to report an assessment of runway visibility at the aerodrome. In this regard, the procedures, training material and practices used by the aerodrome for runway visibility needs to be authorised by the Director of Meteorology or by a person or persons approved for the purpose by CASA. There needs to be an additional dot point noting that there is a requirement for an ongoing audit process under CAR 120 to ensure that competences have been met for assessing runway visibility. It is preferable that observations not be made through a window, especially at night. This particular note is difficult for pilots to make an assessment of runway visibility, as all their observations will be performed through the cockpit windscreen. CASA Response During the initial stages of the low visibility project, a brief comparative review was done of the low visibility requirements of JAR-OPS1 (now known as EUOPS1), FAA regulations, Canadian regulations, Australian regulations and ICAO SARPs. From the review, it was apparent there is no consistency between regulations around the world.


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Each country has adapted regulations to local conditions, and none can be held up as the ideal regulation for worldwide adoption. EU-OPS1, for instance, does not envisage operations by Commercial Air Transportation (Aeroplanes) into noncontrolled aerodromes; a limitation not acceptable in the Australian context. European regulations also do not always address airport infrastructure requirements in a manner consistent with the operational requirements of EUOPS1. For example, some European countries require runway centreline lighting to be provided at aerodromes for takeoffs in visibility conditions of less than 400 metres and yet EU-OPS1 only requires runway centreline lighting for take-offs when the visibility is 250 metres or less. Accordingly and consistent with European practice, CASA’s approach has been to adopt ICAO standards and selected overseas practices, modified for consistency across all aviation operations. The comment referring to the latest edition of FAA Orders is noted; however it is not CASA’s intention to refer to particular FAA Orders in the proposed low visibility standards. Provision for GNSS Landing System (GLS) operations is appropriate given current developments in this regard. However, it is understood that GLS minima will be consistent with ILS minima. For example, a GLS Category I approach would have a decision height of not less than 200 feet and an RVR minimum of not less than 550 metres or visibility not less than 800 metres. The proposed changes to MOS Part 173 are tabulated according to precision approach category, rather than precision approach type. This means both GLS and ILS precision approach types will be provided for, and there is no requirement for specific mention of GLS minima. Consistent with Canadian practice, CASA does not believe it is necessary to provide specific visibility charts for pilot use. The aerodrome chart as well as proposed provision of specific information on runway light spacing should be sufficient for pilot use. The need for CAR 120 approval and approval of procedures for assessment of runway visibility is noted. CASA intends to cover the CAR 120 regulatory requirement within the MOS Part 139 standards for conduct of a runway visibility assessment. With regard to audit, any permission granted by CASA or any aviation activity undertaken under the authority given by Civil Aviation Regulations 1988 (CAR) or Civil Aviation Safety Regulations 1998 (CASR) are subject to CASA audit or surveillance. This will include runway visibility assessments. While it is noted that meteorological observations should not be made through a window, the intention of runway visibility assessments is intended to provide an indication of the visibility that a pilot in an aircraft can expect when looking through the cockpit windshield. Accordingly, CASA considers a runway visibility assessment through a windshield or windscreen acceptable. Disposition In the NPRM, CASA proposes to cover CAR 120 regulatory requirement within the MOS Part 139 standards for conduct of a runway visibility assessment. No other changes will be made to the original proposals. Document NPRM 0906AS

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Comment 2 – Key Proposal 1: Proposed definitions An aircraft operator made a number of comments against proposed definitions as follows: • • •

There should be no variation to the ICAO definitions and specifications for runway visual range (RVR) and that the proposed runway visibility and visibility definitions should not be progressed. The proposed class of low visibility operations including definitions are non-ICAO and should not be progressed. The definition for controlling zone should read ‘The RVR of the runway zone(s) that shall be above the applicable minima for a nominated take-off or landing operation to occur.’

A meteorological services provider made the following comments against the proposed definitions: •

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Qualified observer: The reference made to the standards in MOS 139 for a person qualified to make an assessment of runway visibility could not be found in the document. Also any standard or process to have a person qualified to provide runway visibility assessment should be made under CAR 120. Ground Visibility: The term ‘accredited observer’ could have several meanings, is the real meaning accredited or is qualified or authorised? Rather than say that the observer is accredited it should state that observations taken by an observer have been authorised under CAR 120. The proposed definition should be Aerodrome Visibility rather than Ground Visibility. Low Visibility Operations: The acronym Low Visibility Procedures (LVP) must be defined. Also, the ground visibility mentioned here should also be changed to aerodrome visibility and there should be mention of a reduction in sector and/or segment rather than zone. These changes would reflect the terminology used in the section Key Proposal 2: Point of commencement of low visibility operations and procedures.

An air traffic service (ATS) provider said there is a need for an alignment of definitions for ILS ‘protection areas’ across the current and any future regulations and guidance provided for Australian aviation in relation to the use of ILS associated with low visibility operations. The provider described the lack of consistent definition between AIP, MOS Part 139 and ATS regulations. The provider also highlighted pending changes to ICAO Annex 10 Volume I that will have an effect on these issues. The provider recommended a number of definitions that would be useful for defining the various protection areas. CASA Response As mentioned in the DP, there are significant differences in quality and availability between electronic RVR and human visibility assessments. Accordingly, the USA requires electronic RVR for operations below 800 metres visibility, while the UK limits human assessments to Category I minima.


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However, there is still value in the provision of human assessment of visibility along a runway particularly to support take-off operations. The Canadian terminology of runway visibility assessment provides a useful method for retaining the practice while clearly distinguishing between the electronic and human assessment. Accordingly, CASA intends to proceed with the RVR/runway visibility proposal; however, the words of the ICAO definition for RVR will be retained. The suggested change to the definition for controlling zone is noted. CASA does not intend to proceed with the change to definition for controlling zone. Regarding the meteorological service provider’s comments: • • • •

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The proposed definition ‘qualified observer’ is intended to apply once the appropriate standards for assessment of runway visibility have been included in MOS Part 139. ‘Ground visibility’ is an existing definition from AIP, however it is agreed that the term ‘accredited’ is unclear and a clearer definition will be proposed for the final regulations. Low Visibility Procedures were defined at page A-5 of the DP, and this definition will be included in the NPRM. CASA will retain the term ‘ground visibility’ as opposed to the suggested ‘aerodrome visibility’ because the former is an existing definition used in ICAO SARPs. The term is also an appropriate contrast to the existing term ‘flight visibility’. The term ‘zone’ in the definition for low visibility operations refers to the location along a runway (touchdown point, mid point, or rollout/ stop end) at which an RVR or runway visibility assessment can be provided. This differs from the use of the term ‘section’ when referring to the visibility reducing in a particular section of an aerodrome.

Disposition In the NPRM, ground visibility will be defined as the visibility at an aerodrome as reported by a person authorised under CAR 120 for that purpose. Comment 3 – Key Proposal 2: Point of commencement of low visibility operations and procedures An aircraft operator said that, contrary to the assertion in the discussion paper, there is broad agreement between ICAO and JAR-OPS. It is important that Low Visibility Procedures be in-effect prior to RVR decreasing to CAT II (550-350 m), but not too soon as to have an adverse impact on aerodrome flow rates. The operator suggested that the 800 m threshold for onset of low visibility operations was high and that such a figure will have a major impact on operations without any measurable safety benefit. The operator recommended that the JAR-OPS1 definitions for low visibility operations and procedures be adopted completely and without amendment.


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A meteorological services provider queried whether the terminology for the visibility in a particular direction should be ‘segment’ or ‘sector’, and suggested the rules should be made plainly clear that the reduction below 800m is for not just aerodrome visibility but for RVR or Runway Visibility. CASA Response As mentioned in the Discussion Paper, there is no broad agreement between the major aviation nations or ICAO for the onset of low visibility procedures or operations; therefore there is no clear and consistent standard that can be adopted. However, on reflection, CASA accepts the suggestion that 800 metres visibility is too high a value for onset of low visibility operations. What is apparent from international practice is that low visibility operations generally equate to operations in less than Category I visibility conditions – in other words less than 550 metres visibility. This visibility value will be proposed for the onset of both low visibility take offs and low visibility landings. Regarding the comment on meteorological terminology, CASA’s intent is for low visibility procedures to be fully in effect when the visibility on any part of the aerodrome movement area is 800 metres or less. This value can be a segment or sector observation. Disposition In the NPRM, CASA will propose: • Low visibility operations means an operation involving an approach with minima less than Category I or a take-off in a runway visual range or runway visibility less than 550 m; and • Low visibility procedures must be in effect when the runway visual range, runway visibility or ground visibility is 800 metres or less. Comment 4 – Key Proposal 3: Point of commencement of low visibility operations and procedures An aircraft operator said the proposed take-off minima table is unnecessarily complicated and does not represent ‘commonly accepted’ values used by a significant number of ICAO contracting states. The operator recommended that CASA adopt JAROPS 1 take-off minima and associated requirements. An ATS provider asked if CASA intended to approve low visibility departures requiring localiser guidance. If so, such approval would require notification to ATC for the purpose of protecting critical and sensitive areas. The provider said protection of these areas for all low visibility departures may be unnecessarily restrictive. The ATS provider also asked for clarification on the lowest possible visibility for take-offs (