Commission Implementing Regulation (EU) 2017/373 of 1 March 2017 laying down common requirements for providers of air traffic management/air navigation services and other air traffic management network functions and their oversight, repealing Regulation (EC) No 482/2008, Implementing Regulations (EU) No 1034/2011, (EU) No 1035/2011 and (EU) 2016/1377 and amending Regulation (EU) No 677/2011 (Text with EEA relevance. )

• (a) Whenever Voice-ATIS or D-ATIS, or both, are provided:
• (1) the information communicated shall relate to a single aerodrome;
• (2) the information communicated shall be updated immediately when a significant change occurs;
• (3) the preparation and dissemination of the ATIS message shall be the responsibility of the air traffic services provider;
• (4) individual ATIS messages shall be identified by a designator in the form of a letter of the spelling alphabet in accordance with point SERA.14020 of the Annex to Implementing Regulation (EU) No 923/2012. Designators assigned to consecutive ATIS messages shall be in alphabetical order;
• (5) aircraft shall acknowledge receipt of the information upon establishing communication with the air traffic services unit providing approach control service or the aerodrome control tower or AFIS unit, as appropriate;
• (6) the appropriate air traffic services unit shall, when replying to the message in point (5) or, in the case of arriving aircraft, at such other time as may be prescribed by the competent authority, provide the aircraft with the current altimeter setting;
• (7) the meteorological information shall be extracted from the local routine report or local special report.

• (b) When rapidly changing meteorological conditions make it inadvisable to include the meteorological information as in point (a)(7) in the ATIS, the ATIS messages shall indicate that the relevant meteorological information will be given on initial contact with the appropriate air traffic services unit.

• (c) Information contained in a current ATIS, the receipt of which has been acknowledged by the aircraft concerned, need not be included in a directed transmission to the aircraft, with the exception of the altimeter setting, which shall be provided in accordance with point (a).

• (d) If an aircraft acknowledges receipt of an ATIS that is no longer current, the air traffic services unit shall without delay take either of the following actions:
• (1) communicate to the aircraft any element of information which has to be updated;
• (2) instruct the aircraft to obtain the current ATIS information.

ATS.TR.325 VOLMET broadcasts and D-VOLMET broadcasts

When so prescribed by the competent authority, HF or VHF VOLMET broadcasts, or D-VOLMET service, or all of those, shall be provided, using standard radiotelephony phraseologies.

SECTION 4

ALERTING SERVICE

ATS.TR.400 Application

• (a) Alerting service shall be provided by the air traffic services units:
• (1) for all aircraft provided with air traffic control service;
• (2) in so far as practicable, to all other aircraft having filed a flight plan or otherwise known to the air traffic services;
• (3) to any aircraft known or believed to be the subject of unlawful interference.

• (b) Flight information centres or area control centres shall serve as the central point for collecting all information relevant to a state of emergency of an aircraft operating within the flight information region or control area concerned and for forwarding such information to the appropriate rescue coordination centre.

• (c) In the event of a state of emergency arising to an aircraft while it is under the control of an aerodrome control tower or approach control unit or in contact with an AFIS unit, such unit shall notify immediately the flight information centre or area control centre responsible which shall in turn notify the rescue coordination centre, except that notification of the area control centre, flight information centre, or rescue coordination centre shall not be required if the nature of the emergency is such that the notification would be superfluous.

• (d) Nevertheless, the aerodrome control tower or approach control unit responsible or the relevant AFIS unit shall first alert and take other necessary steps to set in motion all appropriate local rescue and emergency organisations which can give the immediate assistance required, in accordance with local instructions, whenever either of the following situations occurs:
• (1) an aircraft accident has occurred on or in the vicinity of the aerodrome;
• (2) information is received that the safety of an aircraft which is or will come under the jurisdiction of the aerodrome control tower or of the AFIS unit may have or has been impaired;
• (3) requested by the flight crew;
• (4) when otherwise deemed necessary or desirable or the urgency of the situation so requires.

ATS.TR.405 Notification to rescue coordination centres

• (a) Without prejudice to any other circumstances that may render such notification advisable, air traffic services units shall, except as prescribed in point ATS.TR.420(a), notify rescue coordination centres immediately when an aircraft is considered to be in a state of emergency in accordance with the following:
• (1) Uncertainty phase when either of the following situations applies:
• (i) no communication has been received from an aircraft within a period of 30 minutes after the time a communication should have been received, or from the time an unsuccessful attempt to establish communication with such aircraft was first made, whichever is the earlier;
• (ii) an aircraft fails to arrive within 30 minutes of the estimated time of arrival last notified to or estimated by air traffic services units, whichever is the later. Uncertainty phase does not apply when no doubt exists as to the safety of the aircraft and its occupants.
• (2) Alert phase when either of the following situations applies:
• (i) following the uncertainty phase, subsequent attempts to establish communication with the aircraft or inquiries to other relevant sources have failed to reveal any news of the aircraft;
• (ii) an aircraft has been cleared to land and fails to land within 5 minutes of the estimated time of landing and communication has not been re-established with the aircraft;
• (iii) at AFIS aerodromes, under circumstances as prescribed by the competent authority;
• (iv) information has been received which indicates that the operating efficiency of the aircraft has been impaired, but not to the extent that a forced landing is likely;
• (v) an aircraft is known or believed to be the subject of unlawful interference. Points (i) to (iv) do not apply when evidence exists that would allay apprehension as to the safety of the aircraft and its occupants.
• (3) Distress phase when either of the following situations applies:
• (i) following the alert phase, further unsuccessful attempts to establish communication with the aircraft and more widespread unsuccessful inquiries point to the probability that the aircraft is in distress;
• (ii) the fuel on board is considered to be exhausted, or to be insufficient to enable the aircraft to reach safety;
• (iii) information is received which indicates that the operating efficiency of the aircraft has been impaired to the extent that a forced landing is likely;
• (iv) information is received or it is reasonably certain that the aircraft is about to make or has made a forced landing, Distress phase does not apply when there is reasonable certainty that the aircraft and its occupants are not threatened by grave and imminent danger and do not require immediate assistance.

• (b) The notification shall contain such of the following information as is available in the order listed:
• (1) INCERFA, ALERFA or DETRESFA, as appropriate to the phase of the emergency;
• (2) agency and person calling;
• (3) nature of the emergency;
• (4) significant information from the flight plan;
• (5) unit which made last contact, time and means used;
• (6) last position report and how it was determined;
• (7) colour and distinctive marks of aircraft;
• (8) dangerous goods carried as cargo;
• (9) any action taken by the reporting office;
• (10) other pertinent remarks.

• (c) Such part of the information specified in point (b), which is not available at the time the notification is made to a rescue coordination centre, shall be sought by an air traffic services unit prior to the declaration of a distress phase where time permits and where there is reasonable certainty that this phase will eventuate.

• (d) Further to the notification specified in point (a), air traffic services units shall, without delay, furnish the rescue coordination centre with either of the following:
• (1) any useful additional information, especially on the development of the state of emergency through subsequent phases;
• (2) information that the emergency situation no longer exists.

ATS.TR.410 Use of communication facilities

Air traffic services units shall, as necessary, use all available communication facilities to endeavour to establish and maintain communication with an aircraft in a state of emergency, and to request news of the aircraft.

ATS.TR.415 Plotting aircraft in a state of emergency

When a state of emergency is considered to exist, the air traffic services unit or units aware of the emergency shall plot the flight of the aircraft involved on a chart or other appropriate tool in order to determine the probable future position of the aircraft and its maximum range of action from its last known position.

ATS.TR.420 Information to the operator

• (a) When an area control centre or a flight information centre decides that an aircraft is in the uncertainty or the alert phase, it shall, when practicable, advise the aircraft operator prior to notifying the rescue coordination centre.

• (b) Whenever practicable, an area control centre or flight information centre shall, without delay, communicate all information notified to the rescue coordination centre to the aircraft operator.

ATS.TR.425 Information to aircraft operating in the vicinity of an aircraft in a state of emergency

• (a) When it has been established by an air traffic services unit that an aircraft is in a state of emergency, other aircraft known to be in the vicinity of the aircraft involved shall, except as provided in point (b), be informed of the nature of the emergency as soon as practicable.

• (b) When an air traffic services unit knows or believes that an aircraft is being subjected to unlawful interference, no reference shall be made in air traffic services air-ground communications to the nature of the emergency unless it has first been referred to in communications from the aircraft involved and it is certain that such reference will not aggravate the situation.

Appendix 1

Identification of individual aircraft using the downlinked aircraft identification feature as required by point ATS.OR.446(b)

The downlinked aircraft identification feature shall be used as follows to establish individual aircraft identification:

• (a) The air traffic services provider shall declare to the Network Manager the airspace volumes where individual aircraft identification is established using the downlinked aircraft identification feature.

• (b) The conspicuity SSR code A1000 shall be assigned to aircraft where individual aircraft identification is established by using the downlinked aircraft identification feature.

• (c) Except when one of the conditions set out in point (d) apply, the conspicuity SSR code A1000 shall be assigned to departing aircraft or to aircraft for which, in accordance with point (g), a code change is required, where the following conditions apply:
• (1) the downlinked aircraft identification matches the corresponding entry in the flight plan for that aircraft;
• (2) the Network Manager has communicated that the particular aircraft is eligible for the assignment of the conspicuity SSR code A1000.

• (d) The conspicuity SSR code A1000 shall not be assigned to aircraft referred to in point (c) if any of the following conditions apply:
• (1) contingency measures that require the assignment of discrete SSR codes to aircraft have been put in place by an air navigation service provider that experiences unplanned ground surveillance sensor outages;
• (2) exceptional military contingency measures require air navigation service providers to assign discrete SSR codes to aircraft;
• (3) an aircraft which is eligible for the assignment of the conspicuity SSR code A1000 established in accordance with point (c) exits or is otherwise diverted outside the airspace volume referred to in point (a).

• (e) Aircraft that are not assigned the conspicuity SSR code A1000 established in accordance with point (c) shall be assigned an SSR code that complies with a code allocation list agreed by the Member States and coordinated with third countries.

• (f) When an SSR code has been assigned to an aircraft, a check shall be made at the earliest opportunity to confirm that the SSR code set by the pilot is identical to that assigned to the flight.

• (g) SSR codes assigned to aircraft being transferred from air traffic services providers in neighbouring States shall be automatically checked to see whether the assignments can be retained in compliance with a code allocation list agreed by the Member States and coordinated with third countries.

• (h) Formal arrangements with the following minimum content shall be established with neighbouring air navigation service providers that establish individual aircraft identification by using discrete SSR codes:
• (1) an obligation on the neighbouring air navigation service providers to transfer aircraft with verified discrete SSR codes assigned in compliance with a code allocation list agreed by the Member States and coordinated with third countries;
• (2) an obligation to notify accepting units about any observed irregularity in the operation of airborne constituents of surveillance systems;

• (i) air traffic services providers shall ensure that the assignment of discrete SSR codes in compliance with a code allocation list agreed by the Member States and coordinated with third countries to establish individual aircraft identification complies with the following:
• (1) the SSR codes are automatically assigned to aircraft in compliance with a code allocation list agreed by the Member States and coordinated with third countries;
• (2) the SSR codes assigned to aircraft being transferred from air navigation service providers in neighbouring States are checked to see whether the assignments can be retained in compliance with a code allocation list agreed by the Member States and coordinated with third countries;
• (3) the SSR codes are classified into different categories to allow for differentiated code assignment;
• (4) the SSR codes from the different categories referred to in point (3) are assigned according to the directions of flights;
• (5) multiple simultaneous assignments of the same SSR code are made to flights that operate in code conflict-free directions;
• (6) the controllers are automatically informed when SSR code assignments are unintentionally duplicated.;

Appendix 2

Processes to be implemented for automated coordination as required by point ATS.TR.230(c)

• A. The mandatory processes to be implemented between units that provide area control service, or when so agreed with or between other air traffic control units, shall be the following:
• (a) Notification
• (1) The flight information subject to the notification process shall include as a minimum:
• (i) aircraft identification,
• (ii) SSR mode and code (if available),
• (iii) departure aerodrome,
• (iv) estimate data,
• (v) destination aerodrome,
• (vi) number and type of aircraft,
• (vii) type of flight,
• (viii) equipment capability and status.
• (2) The content of the ‘equipment capability and status’ information shall include reduced vertical separation minima (RVSM) and the 8,33 kHz channel spacing capability as a minimum. Other items may be included in accordance with the letters of agreement.
• (3) The notification process shall be performed at least once for each eligible flight planned to cross boundaries unless the flight is the subject of the pre-departure notification and coordination process.
• (4) The eligibility criteria for cross-boundary notification of flights shall be in accordance with the letters of agreement.
• (5) When the notification process cannot be performed by a bilaterally agreed time prior to the initial coordination process, it shall be included in the initial coordination process.
• (6) When performed, the notification process shall precede the initial coordination process.
• (7) The notification process shall take place again each time there is a change to any of the following data prior to the initial coordination process:
• (i) coordination point (COP);
• (ii) expected SSR code at the transfer of control point;
• (iii) destination aerodrome;
• (iv) type of aircraft;
• (v) equipment capability and status.
• (8) If a discrepancy is identified between the transmitted data and the corresponding data in the receiving system, or no such information is available that would result in the need for corrective action upon receipt of the following initial coordination data, the discrepancy shall be referred to an appropriate controller working position for resolution.
• (9) Time criteria for the initiation of the notification process:
• (i) The notification process shall be initiated at a parameter number of minutes before the estimated time at the COP.
• (ii) The notification parameter(s) shall be included in the letters of agreement between the ATC units concerned.
• (iii) The notification parameter(s) may be defined separately for each of the coordination points.
• (b) Initial coordination
• (1) For a flight subject to initial coordination, the agreed transfer conditions of a flight shall be operationally binding for both air traffic control units unless the coordination is abrogated or revised.
• (2) The information on the flight that is subject to the initial coordination process shall include as a minimum:
• (i) aircraft identification;
• (ii) SSR mode and code;
• (iii) departure aerodrome;
• (iv) estimate data;
• (v) destination aerodrome;
• (vi) number and type of aircraft;
• (vii) type of flight;
• (viii) equipment capability and status.
• (3) The content of the ‘equipment capability and status’ information shall include RVSM and the 8,33 kHz channel spacing capability as a minimum. Other items may be included as bilaterally agreed by the letters of agreement.
• (4) The initial coordination process shall be performed for all eligible flights planned to cross boundaries.
• (5) The eligibility criteria for cross-boundary initial coordination of flights shall be in accordance with the letters of agreement.
• (6) Unless already manually initiated, the initial coordination process shall be automatically initiated, in accordance with the letters of agreement, at:
• (i) a bilaterally agreed parameter time period before the estimated time at the coordination point; or
• (ii) the time at which the flight is at a bilaterally agreed distance from the coordination point.
• (7) The initial coordination process for a flight shall only be performed once unless the abrogation of the coordination process is initiated.
• (8) Following the abrogation of the coordination process, the initial coordination process may be initiated again with the same unit.
• (9) The completion of the initial coordination process, including confirmation from the receiving unit, shall be passed on to the transferring unit – the flight is then considered ‘coordinated’.
• (10) Failure of the initial coordination process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the controller working position responsible for the coordination of the flight within the transferring unit.
• (11) The initial coordination information shall be made available to the appropriate controller working position at the accepting unit.
• (c) Revision of coordination
• (1) The revision-of-coordination process shall ensure association with the flight previously coordinated.
• (2) For a flight subject to the revision-of-coordination process, the agreed transfer conditions of a flight shall be operationally binding for both air traffic control units unless the coordination is abrogated or the conditions are further revised.
• (3) The revision-of-coordination process shall provide the following flight information, provided it has changed:
• (i) SSR mode and code;
• (ii) estimated time and flight level;
• (iii) equipment capability and status.
• (4) If bilaterally agreed, the revision-of-coordination data shall provide the following information provided it has changed:
• (i) coordination point;
• (ii) route.
• (5) The revision-of-coordination process may take place one or more times with the unit with which a flight is currently coordinated.
• (6) The revision-of-coordination process shall take place when:
• (i) the estimated time over the coordination point differs from that previously provided by more than a value bilaterally agreed;
• (ii) the transfer level(s), SSR code or equipment capability and status is (are) different from that (those) previously provided.
• (7) Where bilaterally agreed, the revision-of-coordination process shall take place when there is any change in the following:
• (i) coordination point;
• (ii) route.
• (8) The completion of the revision-of-coordination process, including confirmation from the receiving unit, shall be passed on to the transferring unit.
• (9) Failure of the revision-of-coordination process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the controller working position responsible for the coordination of the flight within the transferring unit.
• (10) The revision-of-coordination process shall take place immediately following the relevant input or update.
• (11) The revision-of-coordination process shall be inhibited after the flight is at a bilaterally agreed time/distance from the transfer control point in accordance with the letters of agreement.
• (12) The revision-of-coordination information shall be made available to the appropriate controller working position within the receiving unit.
• (13) Where the completion of the revision-of-coordination process is not confirmed in accordance with the applicable quality-of-service requirements, the transferring unit shall initiate verbal coordination.
• (d) Abrogation of coordination
• (1) The abrogation-of-coordination process shall ensure association with the previous notification or coordination process that is being cancelled.
• (2) The abrogation-of-coordination process shall take place with a unit for a coordinated flight when:
• (i) the unit is no longer the next unit in the coordination sequence;
• (ii) the flight plan is cancelled in the sending unit and the coordination is no longer relevant;
• (iii) abrogation-of-coordination information is received from the previous unit in respect of the flight.
• (3) The abrogation-of-coordination process may take place with a unit for a notified flight when:
• (i) the unit is no longer the next unit in the coordination sequence;
• (ii) the flight plan is cancelled in the sending unit and the coordination is no longer relevant;
• (iii) abrogation-of-coordination information is received from the previous unit in respect of the flight;
• (iv) the flight is delayed en route, and a revised estimate cannot be determined automatically.
• (4) The completion of the abrogation-of-coordination process, including confirmation from the receiving unit, shall be passed on to the transferring unit.
• (5) Failure of the abrogation-of-coordination process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the controller working position responsible for the coordination of the flight within the transferring unit.
• (6) The abrogation-of-coordination information shall be made available to the appropriate controller working position within the notified unit or within the unit with which the coordination is cancelled.
• (7) Where the completion of the abrogation-of-coordination process is not confirmed in accordance with the applicable quality-of-service requirements, the transferring unit shall initiate verbal coordination.
• (e) Basic flight data
• (1) The information subject to the basic-flight-data process shall provide as a minimum:
• (i) aircraft identification;
• (ii) SSR mode and code.
• (2) Any additional information provided by the basic-flight-data process shall be subject to bilateral agreement.
• (3) The basic-flight-data process shall be performed automatically for each eligible flight.
• (4) The eligibility criteria for basic-flight-data shall be in accordance with the letters of agreement.
• (5) The completion of the basic-flight-data process, including confirmation from the receiving unit, shall be passed on to the supplying unit.
• (6) Failure of the basic-flight-data process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the appropriate controller working position within the supplying unit.
• (f) Change to basic flight data
• (1) The change-to-basic-flight-data process shall ensure association with the flight previously subject to a basic-flight-data process.
• (2) Any other information subject to the change-to-basic-flight-data process and the associated criteria for its provision shall be subject to bilateral agreement.
• (3) A change-to-basic-flight-data process shall only take place for a flight which has previously been notified by a basic-flight-data process.
• (4) A change-to-basic-flight-data process shall be initiated automatically in accordance with bilaterally agreed criteria.
• (5) The completion of the change-to-basic-flight-data process, including confirmation from the receiving unit, shall be passed on to the supplying unit.
• (6) Failure of the change-to-basic-flight-data process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the appropriate controller working position within the supplying unit.
• (7) The change-to-basic-flight-data information shall be made available to the appropriate controller working position within the receiving unit.

• B. When agreed between the units concerned to conduct the pre-departure notification, the change-of-frequency or the manual-assumption-of-communication processes shall be as follows:
• (a) Pre-departure notification and coordination
• (1) The information subject to the pre-departure notification and coordination process shall include as a minimum:
• (i) aircraft identification;
• (ii) SSR mode and code (if available);
• (iii) departure aerodrome;
• (iv) estimated take-off time or estimate data, as bilaterally agreed;
• (v) destination aerodrome;
• (vi) number and type of aircraft.
• (2) The information subject to the pre-departure notification and coordination process from a terminal manoeuvring area (TMA) control unit or an ACC shall contain the following:
• (i) type of flight;
• (ii) equipment capability and status.
• (3) The content of the ‘equipment capability and status’ information shall include RVSM and the 8,33 kHz channel spacing capability as a minimum.
• (4) The ‘equipment capability and status’ information may contain other items as bilaterally agreed by the letters of agreement.
• (5) The pre-departure notification and coordination process shall take place one or more times for each eligible flight planned to cross the boundaries where the flight time from departure to the coordination point would not allow sufficient time for the initial coordination or notification processes to be executed.
• (6) The eligibility criteria for the cross-boundary pre-departure notification and coordination of flights shall be in accordance with the letters of agreement.
• (7) The pre-departure notification and coordination process shall take place again each time there is a change to any item of the data subject to the previous pre-departure notification and coordination process before departure.
• (8) The completion of the pre-departure notification and coordination process, including confirmation from the receiving unit, shall be passed on to the transferring unit.
• (9) Failure of the pre-departure notification and coordination process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the controller working position responsible for the notification/coordination of the flight within the transferring unit.
• (10) The pre-departure notification and coordination information shall be made available at the appropriate controller working position within the notified unit.
• (b) Change of frequency
• (1) The information subject to the change-of-frequency process shall include the aircraft identification and any of the following, if available:
• (i) release indication;
• (ii) cleared flight level;
• (iii) assigned heading/track or direct clearance;
• (iv) assigned speed;
• (v) assigned rate of climb/descent.
• (2) If bilaterally agreed, change of frequency data shall contain the following:
• (i) current track position;
• (ii) instructed frequency.
• (3) The change-of-frequency process shall be manually initiated by the transferring controller.
• (4) The completion of the change-of-frequency process, including confirmation from the accepting unit, shall be passed on to the transferring ATC unit.
• (5) Failure of the change-of-frequency process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the appropriate controller working position within the transferring ATC unit.
• (6) The change-of-frequency information shall be made available to the accepting controller without delay.
• (c) Manual assumption of communications
• (1) The information subject to the manual-assumption-of-communications process shall include as a minimum the aircraft identification.
• (2) The manual-assumption-of-communications process shall be initiated by the accepting unit when communication is established.
• (3) The completion of the manual-assumption-of-communications process, including confirmation from the transferring unit, shall be passed on to the accepting ATC unit.
• (4) Failure of the manual-assumption-of-communications process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the appropriate controller working position within the accepting ATC unit.
• (5) The manual-assumption-of-communications information shall be presented immediately to the controller within the transferring unit.
• (d) Crossing intention notification
• (1) The information subject to the crossing-intention-notification process shall include as a minimum:
• (i) aircraft identification;
• (ii) SSR mode and code;
• (iii) number and type of aircraft;
• (iv) identifier of sector in charge;
• (v) crossing route including estimated times and flight levels for each point on the route.
• (2) The crossing-intention-notification process shall be initiated manually by the controller, or automatically as described in the letters of agreement.
• (3) The completion of the crossing-intention-notification process, including confirmation from the notified unit, shall be passed on to the notifying unit.
• (4) Failure of the crossing-intention-notification process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning within the notifying unit.
• (5) The crossing-intention-notification information shall be made available to the appropriate controller working position within the notified unit.
• (e) Crossing clearance request
• (1) The information subject to the crossing-clearance-request process shall include as a minimum:
• (i) aircraft identification;
• (ii) SSR mode and code;
• (iii) number and type of aircraft;
• (iv) identifier of sector in charge;
• (v) crossing route including estimated times and flight levels for each point on the route.
• (2) If bilaterally agreed, a crossing clearance request shall contain the equipment capability and status.
• (3) The content of the ‘equipment capability and status’ information shall include the RVSM capability as a minimum, and may contain other items as bilaterally agreed.
• (4) The crossing clearance request shall be initiated at the controller’s discretion, in accordance with the conditions specified in the letters of agreement.
• (5) The completion of the crossing-clearance-request process, including confirmation from the unit receiving the request, shall be provided to the requesting unit.
• (6) Failure of the crossing-clearance-request process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the appropriate controller working position within the requesting unit.
• (7) The crossing-clearance-request information shall be made available to the appropriate controller working position within the unit receiving the request.
• (8) A crossing-clearance-request process shall be replied to by any of the following:
• (i) the acceptance of the proposed route/airspace crossing details;
• (ii) a counter-proposal including different route/airspace crossing details as specified in Section 6 below;
• (iii) the rejection of the proposed route/airspace crossing details.
• (9) If an operational reply is not received within a bilaterally agreed interval, a warning shall be issued at the appropriate controller working position within the requesting unit.
• (f) Crossing counter-proposal
• (1) The crossing-counter-proposal process shall ensure association with the flight previously subject to coordination.
• (2) The information subject to the crossing-counter-proposal process shall include as a minimum:
• (i) aircraft identification;
• (ii) crossing route including estimated times and flight levels for each point on the route.
• (3) The counter-proposal shall include a proposed new flight level and/or route.
• (4) The completion of the crossing-counter-proposal process, including confirmation from the original requesting unit, shall be passed on to the counter-proposing unit.
• (5) Failure of the crossing-counter-proposal process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the appropriate controller working position within the counter-proposing unit.
• (6) The crossing-counter-proposal information shall be made available to the appropriate controller working position within the original requesting unit.
• (7) The confirmation of the successful processing of the crossing-counter-proposal information by the original requesting unit shall be followed by an operational reply from the original requesting unit.
• (8) The operational reply to a crossing counter-proposal shall be acceptance or rejection, as appropriate.
• (9) If an operational reply is not received within a bilaterally agreed interval, a warning shall be issued at the appropriate controller working position within the counter-proposing unit.
• (g) Crossing cancellation
• (1) The crossing-cancellation process shall ensure association with the previous notification or coordination process that is cancelled.
• (2) A crossing-cancellation process shall be initiated by the unit responsible for the flight when one of the following occurs:
• (i) the flight previously notified by the basic-flight-data process will now not enter the airspace of the notified unit or is no longer of interest to the notified unit;
• (ii) the crossing will not be executed on the route expressed in the crossing-intention-notification information;
• (iii) the crossing will not be executed according to the conditions under negotiation or according to the conditions agreed after an airspace crossing dialogue.
• (3) A crossing-cancellation process shall be triggered automatically or manually by a controller input in accordance with the letters of agreement.
• (4) The completion of the crossing-cancellation process, including confirmation from the notified/requested unit, shall be passed on to the cancelling unit.
• (5) Failure of the crossing-cancellation process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in a warning at the appropriate working position within the cancelling unit.
• (6) The crossing-cancellation information shall be made available to the appropriate controller working position within the notified/requested unit.

• C. Between units that provide area control services required to operate the data link services as referred to in point AUR.COM.2005(1)(a) of Implementing Regulation (EU) 2023/1770, or when so agreed with or between other units, the following processes shall be supported by automation:
• (a) Logon forward
• (1) The information subject to the logon-forward process shall include as a minimum:
• (i) aircraft identification;
• (ii) departure aerodrome;
• (iii) destination aerodrome;
• (iv) logon type;
• (v) logon parameters.
• (2) One logon-forward process shall be performed for each data link logged-on flight planned to cross boundaries.
• (3) The logon-forward process shall be initiated at or as soon as possible after the earlier of the times determined, in accordance with the letters of agreement, from the following:
• (i) a parameter number of minutes before the estimated time at the coordination point;
• (ii) the time at which the flight is at a bilaterally agreed distance from the coordination point.
• (4) The eligibility criteria for the logon-forward process shall be in accordance with the letters of agreement.
• (5) The logon-forward information shall be included with the corresponding flight information in the receiving unit.
• (6) The logged-on status of the flight may be displayed at the appropriate controller working position within the receiving unit.
• (7) The completion of the logon-forward process, including confirmation from the receiving unit, shall be passed on to the transferring unit.
• (8) Failure of the logon-forward process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in the initiation of an air–ground data link contact request to the aircraft.
• (b) Next authority notified
• (1) The information subject to the next-authority-notified process shall include as a minimum:
• (i) aircraft identification;
• (ii) departure aerodrome;
• (iii) destination aerodrome.
• (2) One next-authority-notified process shall be performed for each eligible flight crossing boundaries.
• (3) The next-authority-notified process shall be initiated after the next data authority request with the aircraft has been acknowledged by the airborne system.
• (4) Following the successful processing of the next-authority-notified information, the receiving unit shall initiate a controller–pilot data link communication (CPDLC) start request with the aircraft.
• (5) If the next-authority-notified information has not been received in accordance with a bilaterally agreed parameter time, local procedures shall be applied by the receiving unit for the initiation of data link communications with the aircraft.
• (6) The completion of the next-authority-notified process, including confirmation from the receiving unit, shall be passed on to the transferring unit.
• (7) Failure of the next-authority-notified-process to confirm completion, in accordance with the applicable quality-of-service requirements, shall result in the initiation of local procedures within the transferring unit.

ANNEX V

SPECIFIC REQUIREMENTS FOR PROVIDERS OF METEOROLOGICAL SERVICES

(Part-MET)

SUBPART A — ADDITIONAL ORGANISATION REQUIREMENTS FOR PROVIDERS OF METEOROLOGICAL SERVICES (MET.OR)

SECTION 1 — GENERAL REQUIREMENTS

MET.OR.100 Meteorological data and information

• (a) A meteorological services provider shall provide operators, flight crew members, air traffic services units, search and rescue services units, aerodrome operators, accident and incident investigation bodies, and other service providers and aviation entities with the meteorological information necessary for the performance of their respective functions, as determined by the competent authority.

• (b) A meteorological services provider shall confirm the operationally desirable accuracy of the information distributed for operations, including the source of such information, whilst also ensuring that such information is distributed in a timely manner and updated, as required.

MET.OR.105 Retention of meteorological information

• (a) A meteorological services provider shall retain meteorological information issued for a period of at least 30 days from the date of issue.

• (b) This meteorological information shall be made available, on request, for inquiries or investigations and, for these purposes, shall be retained until the inquiry or investigation is completed.

MET.OR.110 Meteorological information exchange requirements

A meteorological services provider shall ensure it has systems and processes in place, as well as access to suitable telecommunications facilities to:

• (a) enable the exchange of operational meteorological information with other meteorological services providers;

• (b) provide the required meteorological information to the users in a timely manner.

MET.OR.115 Meteorological bulletins

The meteorological services provider responsible for the area concerned shall provide meteorological bulletins to the relevant users.

MET.OR.120 Notification of discrepancies to the world area forecast centres (WAFCs)

The meteorological services provider using WAFS SIGWX forecasts shall notify the WAFC concerned immediately if significant discrepancies are detected or reported in respect of WAFS SIGWX forecasts concerning:

• (a) icing, turbulence, cumulonimbus clouds that are obscured, frequent, embedded, or occurring at a squall line, and sandstorms or dust storms;

• (b) volcanic eruptions or a release of radioactive materials into the atmosphere of significance to aircraft operations.

SECTION 2 — SPECIFIC REQUIREMENTS

Chapter 1 — Requirements for aeronautical meteorological stations

MET.OR.200 Meteorological reports and other information

• (a) An aeronautical meteorological station shall issue:
• (1) local routine report at fixed intervals, only for dissemination at the aerodrome of origin;
• (2) local special report, only for dissemination at the aerodrome of origin;
• (3) METAR at half-hourly intervals at aerodromes serving scheduled international commercial air transport operations for dissemination beyond the aerodrome of origin;

• (b) Notwithstanding point (a)(3), the aeronautical meteorological station may issue hourly METAR and SPECI for dissemination beyond the aerodrome of origin, for aerodromes not serving scheduled international commercial air transport operations, as determined by the competent authority;

• (c) An aeronautical meteorological station shall inform the air traffic service units and aeronautical information service of an aerodrome of changes in the serviceability status of the automated equipment used for assessing runway visual range;

• (d) An aeronautical meteorological station shall report to the associated air traffic services unit, aeronautical information services unit, and meteorological watch office the occurrence of pre-eruption volcanic activity, volcanic eruptions and volcanic ash cloud;

• (e) An aeronautical meteorological station shall establish a list of criteria to provide local special reports in consultation with the appropriate ATS units, operators and others concerned.

MET.OR.205 Reporting of meteorological elements

An aeronautical meteorological station shall report:

• (a) surface wind direction and speed;

• (b) visibility;

• (c) runway visual range, if applicable;

• (d) present weather at the aerodrome and its vicinity;

• (e) clouds;

• (f) air temperature and dew point temperature;

• (g) atmospheric pressure;

• (h) supplementary information when applicable.

Where authorised by the competent authority, at aerodromes not serving scheduled international commercial air transport operations, an aeronautical meteorological station may report only a subset of the meteorological elements as relevant to the types of flights at that aerodrome. This data set shall be published in the aeronautical information publication.

MET.OR.210 Observing meteorological elements

An aeronautical meteorological station shall observe and/or measure:

• (a) surface wind direction and speed;

• (b) visibility;

• (c) runway visual range, if applicable;

• (d) present weather at the aerodrome and its vicinity;

• (e) clouds;

• (f) air temperature and dew point temperature;

• (g) atmospheric pressure;

• (h) supplementary information, when applicable:

Where authorized by the competent authority, at aerodromes not serving scheduled international commercial air transport operations, an aeronautical meteorological station may observe and/or measure only a subset of the meteorological elements as relevant to the types of flights at that aerodrome. This data set shall be published in the aeronautical information publication.

Chapter 2 — Requirements for aerodrome meteorological offices

MET.OR.215 Forecasts and other information

An aerodrome meteorological office shall:

• (a) prepare and/or obtain forecasts and other relevant meteorological information necessary for the performance of its respective functions for flights with which it is concerned, as determined by the competent authority;

• (b) provide forecasts and/or warnings for local meteorological conditions on aerodromes for which it is responsible;

• (c) keep the forecasts and warnings under continuous review and issue amendments promptly when necessary, and cancel any forecast of the same type previously issued for the same place and for the same period of validity or part thereof;

• (d) provide briefing, consultation and flight documentation to flight crew members and/or other flight operations personnel;

• (e) provide climatological information;

• (f) provide its associated air traffic services unit, aeronautical information service unit and meteorological watch office with information received on pre-eruption volcanic activity, a volcanic eruption or volcanic ash cloud;

• (g) provide, if applicable, meteorological information to search and rescue services units and maintain liaison with the search and rescue services unit(s) throughout a search and rescue operation;

• (h) provide meteorological information to relevant aeronautical information services units, as necessary, for the conduct of their functions;

• (i) prepare and/or obtain forecast and other relevant meteorological information necessary for the performance of the ATS units functions in accordance with point MET.OR.242;

• (j) provide its associated air traffic services unit, aeronautical information service unit and meteorological watch offices with information received on the release of radioactive materials into the atmosphere.

MET.OR.220 Aerodrome forecasts

• (a) An aerodrome meteorological office shall issue aerodrome forecasts as a TAF at a specified time.

• (b) When issuing TAF, the aerodrome meteorological office shall ensure that not more than one TAF is valid at an aerodrome at any given time.

MET.OR.225 Forecasts for landing

• (a) An aerodrome meteorological office shall prepare forecasts for landing as determined by the competent authority.

• (b) This forecast for landing shall be issued in the form of a TREND forecast.

• (c) The period of validity of a TREND forecast shall be 2 hours from the time of the report which forms part of the landing forecast.

MET.OR.230 Forecasts for take-off

An aerodrome meteorological office shall:

• (a) prepare forecasts for take-off as determined by the competent authority;

• (b) supply forecasts for take-off to operators and flight crew members on request within the 3 hours before the expected time of departure.

MET.OR.235 Aerodrome warnings and wind shear warnings and alerts

An aerodrome meteorological office shall:

• (a) provide aerodrome warnings information;

• (b) prepare wind shear warnings for aerodromes where wind shear is considered a factor, in accordance with local arrangements with the appropriate ATS unit and operators concerned;

• (c) issue, at aerodromes where wind shear is detected by automated, ground-based, wind shear remote-sensing or detection equipment, wind shear alerts generated by these systems;

• (d) cancel warnings when the conditions are no longer occurring and/or no longer expected to occur at the aerodrome.

MET.OR.240 Information for use by operator or flight crew

An aerodrome meteorological office shall provide operators and flight crew members with the latest available:

• (a) forecasts, originating from the WAFS, of the elements listed in points (1) and (2) of point MET.OR.275(a);

• (b) METAR or SPECI, including TREND, TAF or amended TAF for the aerodromes of departure and intended landing, and for take-off, en-route and destination alternate aerodromes;

• (c) aerodrome forecasts for take-off;

• (d) SIGMET and special air-reports relevant to the whole route;

• (e) volcanic ash, tropical cyclone and space weather advisory information relevant to the whole route;

• (f) area forecasts for low-level flights prepared in combination with the issuance of AIRMET, and AIRMET relevant to the whole route;

• (g) aerodrome warnings for the local aerodrome;

• (h) meteorological satellite images;

• (i) ground-based weather radar information.

MET.OR.242 Information to be provided to air traffic services units

• (a) An aerodrome meteorological office shall provide, as necessary, its associate aerodrome control tower and AFIS unit with:
• (1) local routine report, local special report, METAR, SPECI, TAF and TREND and amendments thereto;
• (2) SIGMET, AIRMET, wind shear warnings and alerts and aerodrome warnings;
• (3) any additional meteorological information agreed upon locally, such as forecasts of surface wind for the determination of possible runway changes;
• (4) information received on volcanic ash cloud, for which a SIGMET has not already been issued, as agreed between the aerodrome meteorological office and the aerodrome control tower or the AFIS unit concerned;
• (5) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the aerodrome meteorological office and the aerodrome control tower or the AFIS unit concerned.

• (b) An aerodrome meteorological office shall provide its associate approach control unit with:
• (1) local routine report, local special report, METAR, SPECI, TAF and TREND and amendments thereto;
• (2) SIGMET, AIRMET, wind shear warnings and alerts, appropriate special air-reports and aerodrome warnings;
• (3) any additional meteorological information agreed upon locally;
• (4) information received on volcanic ash cloud, for which a SIGMET has not already been issued, as agreed between the aerodrome meteorological office and the approach control unit concerned;
• (5) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the aerodrome meteorological office and the approach control unit concerned.

Chapter 3 — Requirements for meteorological watch offices

MET.OR.245 Meteorological watch and other information

Within its area of responsibility, the meteorological watch office shall:

• (a) maintain continuous watch over meteorological conditions affecting flight operations;

• (b) coordinate with the organisation responsible for the provision of NOTAM and/or ASHTAM to ensure that meteorological information on volcanic ash included in SIGMET and NOTAM and/or ASHTAM is consistent;

• (c) coordinate with selected volcano observatories to ensure that information on volcanic activity is received in an efficient and timely manner;

• (d) provide its associated VAAC with information received on pre-eruption volcanic activity, a volcanic eruption and volcanic ash cloud for which a SIGMET has not already been issued;

• (e) provide its aeronautical information service units with information received on the release of radioactive materials into the atmosphere in the area or adjacent areas for which it maintains watch and for which a SIGMET has not already been issued;

• (f) provide its associated area control centre and flight information centre (ACC/FIC), as necessary, with relevant:
• (1) METAR and SPECI, including current pressure data for aerodromes and other locations, TAF, TREND and amendments thereto;
• (2) forecasts of upper winds, upper-air temperatures and significant en-route weather phenomena and amendments thereto, SIGMET, AIRMET and appropriate special air-reports;
• (3) any other meteorological information required by the ACC/FIC to meet requests from aircraft in flight;
• (4) information received on volcanic ash cloud, for which a SIGMET has not already been issued, as agreed between the meteorological watch office and the ACC/FIC;
• (5) information received concerning the release of radioactive material into the atmosphere, as agreed between the meteorological watch office and the ACC/FIC;
• (6) tropical cyclone advisory issued by a TCAC in its area of responsibility;
• (7) volcanic ash advisory issued by a VAAC in its area of responsibility;
• (8) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the meteorological watch office and the ACC/FIC;

• (g) when available, provide the relevant air traffic services units, in accordance with local agreement, with information regarding the release into the atmosphere of toxic chemicals which could affect the airspace used by flights within their area of responsibility.

MET.OR.250 SIGMET

A meteorological watch office shall:

• (a) issue SIGMET;

• (b) ensure that the SIGMET is cancelled when the phenomena are no longer occurring or are no longer expected to occur in the area covered by the SIGMET;

• (c) ensure that the period of validity of a SIGMET is not more than 4 hours, and in the special case of SIGMET for volcanic ash cloud and tropical cyclones, it shall be extended up to 6 hours;

• (d) ensure that SIGMET are issued not more than 4 hours before the commencement of the period of validity. In the special case of SIGMET for volcanic ash cloud and tropical cyclones, SIGMET shall be issued as soon as practicable, but not more than 12 hours before the commencement of the period of validity, and updated at least every 6 hours.

MET.OR.255 AIRMET

A meteorological watch office shall:

• (a) issue AIRMET when the competent authority has determined that the density of traffic operating below flight level 100, or up to flight level 150 in mountainous areas, or higher, where necessary, warrants the issue of AIRMET in combination with area forecasts for low-level flights;

• (b) cancel the AIRMET when the phenomena are no longer occurring or are no longer expected to occur in the area;

• (c) ensure that the period of validity of an AIRMET is not more than 4 hours.

MET.OR.260 Area forecasts for low-level flights

A meteorological watch office shall ensure that:

• (a) in the case of AIRMET being issued in combination with area forecasts for low-level flights in accordance with point MET.OR.255(a), area forecasts for low-level flights are issued every 6 hours for a period of validity of 6 hours and transmitted to the meteorological watch offices concerned not later than 1 hour prior to the beginning of their validity period;

• (b) in the case where the competent authority has determined that the density of traffic operating below flight level 100, or up to flight level 150 in mountainous areas, or higher, where necessary, warrants the routine issue of area forecasts for low-level flights not in combination with AIRMET, the frequency of issue, the form, and the fixed time or period of validity of the area forecast for low-level flights and the criteria for amendments thereto, are as determined by the competent authority.

Chapter 4 – Requirements for volcanic ash advisory centres (VAACs)

MET.OR.265 Volcanic ash advisory centre responsibilities

In its area of responsibility, the VAAC shall:

• (a) when a volcano has erupted, or is expected to erupt, or volcanic ash is reported, issue advisory information regarding the extent and forecast movement of the volcanic ash cloud:
• (1) the European aviation crisis coordination cell;
• (2) meteorological watch offices serving flight information regions in its area of responsibility which may be affected;
• (3) operators, area control centres, and flight information centres serving flight information regions in its area of responsibility which may be affected;
• (4) WAFCs, international OPMET databanks, international NOTAM offices and centres designated by regional air navigation agreement for the operation of the aeronautical fixed service internet-based services;
• (5) other VAACs whose areas of responsibility may be affected.

• (b) coordinate with selected volcano observatories to ensure that information on volcanic activity is received in an efficient and timely manner;

• (c) provide the advisory meteorological information referred to in point (a) at least every 6 hours until such time as the volcanic ash cloud is no longer identifiable from satellite data, no further meteorological reports of volcanic ash are received from the area and no further eruptions of the volcano are reported; and

• (d) maintain a 24-hour watch.

Chapter 5 – Requirements for tropical cyclone advisory centres (TCACs)

MET.OR.270 Tropical cyclone advisory centre responsibilities

In its area of responsibility, the TCAC shall issue:

• (a) advisory information concerning the position of the cyclone centre, changes in intensity at the time of observation, its direction and speed of movement, central pressure and maximum surface wind near the centre:
• (1) meteorological watch offices in its area of responsibility;
• (2) other TCACs whose areas of responsibility may be affected;
• (3) WAFCs, international OPMET databanks and centres responsible for the operation of the aeronautical fixed service internet-based services;

• (b) updated advisory information to meteorological watch offices for each tropical cyclone, as necessary, but at least every 6 hours.

Chapter 6 – Requirements for world area forecast centres (WAFCs)

MET.OR.275 World area forecast centre responsibilities

• (a) The WAFC shall issue:
• (1) gridded global forecasts of:
• (i) upper wind;
• (ii) upper-air temperature and humidity;
• (iii) geopotential altitude of flight levels;
• (iv) flight level and temperature of tropopause;
• (v) direction, speed and flight level of maximum wind;
• (vi) cumulonimbus clouds;
• (vii) icing;
• (viii) turbulence;
• (2) global forecasts of significant weather (SIGWX) phenomena, including volcanic activity and release of radioactive materials.

• (b) The WAFC shall ensure that world area forecast system products in digital form are transmitted using binary data communications techniques.

SUBPART B — TECHNICAL REQUIREMENTS FOR PROVIDERS OF METEOROLOGICAL SERVICES (MET.TR)

SECTION 1 — GENERAL REQUIREMENTS

MET.TR.115 Meteorological bulletins

• (a) Meteorological bulletins shall be disseminated using specified data types and code forms appropriate to the information being provided.

• (b) Meteorological bulletins containing operational meteorological information shall be disseminated via communication systems appropriate to the information being provided and the users for which it is intended.

SECTION 2 — SPECIFIC REQUIREMENTS

Chapter 1 — Technical requirements for aeronautical meteorological stations

MET.TR.200 Meteorological reports and other information

• (a) Local routine report, local special report, METAR and SPECI shall contain the following elements in the order indicated:
• (1) identification of the type of report;
• (2) location indicator;
• (3) time of the observation;
• (4) identification of an automated or missing report, when applicable;
• (5) surface wind direction and speed;
• (6) visibility;
• (7) runway visual range, when the reporting criteria are met;
• (8) present weather;
• (9) cloud amount, cloud type only for cumulonimbus and towering cumulus clouds and height of cloud base or, where measured, vertical visibility;
• (10) air temperature and dew-point temperature;
• (11) QNH and, when applicable, in local routine and local special report, QFE;
• (12) supplementary information, when applicable.

• (b) In local routine report and local special report:
• (1) if the surface wind is observed from more than one location along the runway, the locations for which these values are representative shall be indicated;
• (2) when there is more than one runway in use and the surface wind related to these runways is observed, the available wind values for each runway shall be given, and the runways to which the values refer shall be reported;
• (3) when variations from the mean wind direction are reported in accordance with point MET.TR.205(a)(3)(ii)(B), the two extreme directions between which the surface wind has varied shall be reported;
• (4) when variations from the mean wind speed (gusts) are reported in accordance with point MET.TR.205(a)(3)(iii), they shall be reported as the maximum and minimum values of the wind speed attained.

• (c) METAR and SPECI
• (1) METAR and SPECI shall be issued in accordance with the template shown in Appendix 1.
• (2) METAR shall be filed for transmission not later than 5 minutes after the actual time of observation.

• (d) Information on visibility, runway visual range, present weather and cloud amount, cloud type and height of cloud base shall be replaced in all meteorological reports by the term ‘CAVOK’ when the following conditions occur simultaneously at the time of observation:
• (1) visibility, 10 km or more, and the lowest visibility is not reported;
• (2) no cloud of operational significance;
• (3) no weather of significance to aviation.

• (e) The list of criteria to provide local special report shall include:
• (1) those values which most closely correspond to the operating minima of the operators using the aerodrome;
• (2) those values which satisfy other local requirements of the air traffic services (ATS) units and of the operators;
• (3) an increase in air temperature of 2 °C or more from that given in the latest local report, or an alternative threshold value as agreed between the meteorological services providers, the appropriate ATS unit and the operators concerned;
• (4) the available supplementary information concerning the occurrence of significant meteorological conditions in the approach and climb-out areas;
• (5) when noise-abatement procedures are applied and the variation from the mean surface wind speed has changed by 5 kt or more from that at the time of the latest local report, the mean speed before and/or after the change being 15 kt or more;
• (6) when the mean surface wind direction has changed by 60° or more from that given in the latest report, the mean speed before and/or after the change being 10 kt or more;
• (7) when the mean surface wind speed has changed by 10 kt or more from that given in the latest local report;
• (8) when the variation from the mean surface wind speed (gusts) has changed by 10 kt or more from that at the time of the latest local report, the mean speed before and/or after the change being 15 kt or more;
• (9) when the onset, cessation or change in intensity of any of the following weather phenomena occurs:
• (i) freezing precipitation;
• (ii) moderate or heavy precipitation, including showers thereof; and
• (iii) thunderstorm, with precipitation;
• (10) when the onset or cessation of any of the following weather phenomena occurs:
• (i) freezing fog;
• (ii) thunderstorm, without precipitation;
• (11) when the amount of a cloud layer below 1 500 ft (450 m) changes:
• (i) from scattered (SCT) or less to broken (BKN) or overcast (OVC); or
• (ii) from BKN or OVC to SCT or less.

• (f) When so agreed between the meteorological services provider and the competent authority, local special reports and SPECI, when applicable shall be issued whenever the following changes occur:
• (1) when the wind changes through values of operational significance; the threshold values shall be established by the meteorological services provider in consultation with the appropriate ATS unit and operators concerned, taking into account changes in the wind which would:
• (i) require a change in runway(s) in use;
• (ii) indicate that the runway tailwind and crosswind components have changed through values representing the main operating limits for typical aircraft operating at the aerodrome;
• (2) when the visibility is improving and changes to or passes through one or more of the following values, or when the visibility is deteriorating and passes through one or more of the following values:
• (i) 800, 1 500 or 3 000 m;
• (ii) 5 000 m, in cases where a significant number of flights are operated in accordance with the visual flight rules;
• (3) when the runway visual range is improving and changes to or passes through one or more of the following values, or when the runway visual range is deteriorating and passes through one or more of the following values: 50, 175, 300, 550 or 800 m;
• (4) when the onset, cessation or change in intensity of any of the following weather phenomena occurs:
• (i) dust storm;
• (ii) sandstorm;
• (iii) funnel cloud (tornado or waterspout);
• (5) when the onset or cessation of any of the following weather phenomena occurs:
• (i) low drifting dust, sand or snow;
• (ii) blowing dust, sand or snow;
• (iii) squall;
• (6) when the height of base of the lowest cloud layer of BKN or OVC extent is lifting and changes to or passes through one or more of the following values, or when the height of base of the lowest cloud layer of BKN or OVC extent is lowering and passes through one or more of the following values:
• (i) 100, 200, 500 or 1 000 ft;
• (ii) 1 500 ft, in cases where significant numbers of flights are operated in accordance with the visual flight rules;
• (7) when the sky is obscured and the vertical visibility is improving and changes to or passes through one or more of the following values, or when the vertical visibility is deteriorating and passes through one or more of the following values: 100, 200, 500 or 1 000 ft;
• (8) any other criteria based on local aerodrome operating minima, as agreed between the meteorological services providers and the operators.

MET.TR.205 Reporting of meteorological elements

(a) Surface wind direction and speed

• (1) In local routine report, local special report, METAR and SPECI, the surface wind direction and speed shall be reported in steps of 10 degrees true and 1 kt respectively.

• (2) Any observed value that does not fit the reporting scale in use shall be rounded to the nearest step in the scale.

• (3) In local routine report, local special report, METAR and SPECI:
• (i) the units of measurement used for the wind speed shall be indicated;
• (ii) variations from the mean wind direction during the past 10 minutes shall be reported as follows, if the total variation is 60° or more, alternatively:
• (A) when the total variation is 60° or more and less than 180° and the wind speed is 3 kt or more, such directional variations shall be reported as the two extreme directions between which the surface wind has varied;
• (B) when the total variation is 60° or more and less than 180° and the wind speed is less than 3 kt, the wind direction shall be reported as variable with no mean wind direction;
• (C) when the total variation is 180° or more, the wind direction shall be reported as variable with no mean wind direction;
• (iii) variations from the mean wind speed (gusts), during the past 10 minutes shall be reported when the maximum wind speed exceeds the mean speed by, alternatively:
• (A) 5 kt or more in local routine report and local special report when noise abatement procedures are applied;
• (B) 10 kt or more otherwise;
• (iv) when a wind speed of less than 1 kt is reported, it shall be indicated as calm;
• (v) when a wind speed of 100 kt or more is reported, it shall be indicated to be more than 99 kt;
• (vi) when variations from the mean wind speed (gusts) are reported in accordance with point MET.TR.205(a), the maximum value of the wind speed attained shall be reported;
• (vii) when the 10-minute period includes a marked discontinuity in the wind direction and/or speed, only variations from the mean wind direction and mean wind speed occurring since the discontinuity shall be reported.

(b) Visibility

• (1) In local routine report, local special report, METAR and SPECI, the visibility shall be reported in steps of 50 m when the visibility is less than 800 m; in steps of 100 m when it is 800 m or more, but less than 5 km; in kilometre steps when the visibility is 5 km or more, but less than 10 km; and it shall be given as 10 km when the visibility is 10 km or more, except when the conditions for the use of CAVOK apply.

• (2) Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale.

• (3) In local routine report and local special report, visibility along the runway or runways shall be reported together with the units of measurement used to indicate visibility.

(c) Runway visual range (RVR)