Circular No. 52/2023/TT-BGTVT Amending and supplementing certain Articles of Circular No. 29/2021/TT-BGTVT dated November 30, 2021 of the Minister of Transport detailing the management and operation of civil airports

CIRCULAR

Amending and supplementing some articles of Circular No. 29/2021/TT-BGTVT dated November 30, 2021, issued by the Minister of Transport on detailed regulations regarding management and operation of civil airportsClause on management and operation of civil aviation airports

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Pursuant to the Civil Aviation Law of Vietnam dated June 29, 2006 and the Law Amending and Supplementing Some Articles of the Civil Aviation Law of Vietnam dated November 21, 2014;

BASED ON THE DECREE NO. 56/2022/ND-CP dated August 24, 2022 of THE GOVERNMENT stipulating the functions, tasks, powers, and organizational structure of THE MINISTRY OF TRANSPORT;

Pursuant to Decree No. 66/2015/NĐ-CP dated August 12, 2015, issued by the Government on Civil Aviation Authority;

Pursuant to Decree No. 05/2021/NĐ-CP dated January 25, 2021, issued by the Government on management and operation of civil airports;

At the proposal of the Director of the Infrastructure Department under the Ministry of Transport and the Director General of the Civil Aviation Administration of Vietnam;

The Minister of Transport issues this Circular amending and supplementing some articles of Circular No. 29/2021/TT-BGTVT dated November 30, 2021, issued by the Minister of Transport on detailed regulations regarding management and operation of civil airports.

 

Article 1. Amending and supplementing some articles of Circular No. 29/2021/TT-BGTVT dated November 30, 2021, issued by the Minister of Transport on detailed regulations regarding management and operation of civil airports (hereinafter referred to as Circular No. 29/2021/TT-BGTVT)

1. Amending and supplementing Clause 17, Clause 21, and adding Clauses 27, 28, 29, 30, 31, and 32 of Article 2 as follows:

a) Amending and supplementing Clause 17 of Article 2 as follows:

"17. Historic Baseline Date is the date from which historical slot data has been confirmed to serve as the basis for determining historical slots according to the IATA slot coordination schedule.";

b) Amending and supplementing Clause 21 of Article 2 as follows:

"21. Slot is the departure time (Off Block Time) or arrival time (In Block Time) of a flight planned on a specific day, month, and year for the flight to be able to use the airport infrastructure for departure or arrival.";

c) Adding Clause 27 of Article 2 as follows:

"27. Fully coordinated airport is an airport with infrastructure capacity that does not meet the demand for slot usage by airlines.";

d) Adding Clause 28 of Article 2 as follows:

"28. SHL Deadline is the deadline for the Civil Aviation Administration of Vietnam to notify historical slots to airlines according to the IATA slot coordination schedule.";

đ) Adding Clause 29 of Article 2 as follows:

"29. Agreed Historics Deadline is the deadline for airlines to respond to historical slots notified by the Civil Aviation Administration of Vietnam according to the IATA slot coordination schedule.";

e) Adding Clause 30 of Article 2 as follows:

"30. Initial Submission Deadline is the deadline for airlines to submit telegrams proposing initial season flight slot chains to the Civil Aviation Administration of Vietnam according to the IATA slot coordination schedule.";

g) Adding Clause 31 of Article 2 as follows:

"31. SAL Deadline is the deadline for the Civil Aviation Administration of Vietnam to coordinate the initial season flight slot proposals submitted by airlines according to the IATA slot coordination schedule.";

h) Adding Clause 32 of Article 2 as follows:

"32. Series Return Deadline is the deadline for airlines to return unused initial season flight slot chains according to the IATA slot coordination schedule.";

2. Adding Clauses 19 and 20 of Article 3 as follows:

a) Adding Clause 19 of Article 3 as follows:

"19. AOBT (Actual Off-Block Time): actual departure time of the flight.";

b) Adding Clause 20 of Article 3 as follows:

"20. AIBT (Actual In-Block Time) is the actual time of flight completion.";

3. Replacing Section 12 of Chapter II as follows:

"SECTION 12. COORDINATION OF TAKE-OFF AND LANDING TIMES AT CIVIL AIRPORTS"

Article 83. Slot Council

1. The Civil Aviation Authority of Vietnam shall establish the Slot Council to seek opinions on matters related to slot coordination work, including:

a) Slot coordination parameters, changes to slot coordination parameters;

b) Solutions to increase operational capacity at Vietnamese airports and airfields;

c) Adjustments and changes to the length of slot chains; the correct usage rate for each slot chain; the slot usage rate over confirmed slots and the correct slot usage rate over confirmed slots as a basis for considering additional slot proposals from airlines during the flight schedule season; the correct slot usage index; historical slots of airlines when reducing slot coordination parameters; deadlines in the IATA slot coordination schedule;

d) The correct slot usage index, the correct slot usage rate related to determining historical slots and timeframes according to the IATA slot coordination schedule and the length of slot chains for countries with two-country airlines operating flights, ensuring the balance of interests between the two countries;

đ) List of airports subject to full slot coordination.

2. The Slot Council's membership includes representatives of Vietnamese airlines, airport operators, service providers ensuring flight operations, and units under the Civil Aviation Authority of Vietnam.

Article 84. Principles for Determining Slot Coordination Parameters

1. Airport operators have the responsibility to develop capacity limitation indices for terminal and aircraft parking areas.

2. Service providers ensuring flight operations have the responsibility to develop capacity limitation indices for runways and air traffic control services.

3. Based on the capacity limitation indices stipulated in Clause 1 and Clause 2 of this Article and the Slot Council's opinions, the Civil Aviation Authority of Vietnam will decide on slot coordination parameters and changes to these parameters.

4. Slot coordination parameters at airports are determined based on the following principles:

a) Slot coordination parameters related to terminals and aircraft parking areas must not exceed the capacity limitation indices for terminals and aircraft parking areas stipulated in Clause 1 of this Article;

b) Slot coordination parameters related to runways and air traffic control services for fully coordinated airports must not exceed 80% of the capacity limitation indices stipulated in Clause 2 of this Article. For airports not fully coordinated, slot coordination parameters must not exceed the capacity limitation indices for runways and air traffic control services stipulated in Clause 2 of this Article.

5. The Civil Aviation Authority of Vietnam will consider and decide to adjust increases in runway and air traffic control service slot coordination parameters at fully coordinated airports up to the capacity limitation indices stipulated in Clause 2 of this Article during the following periods:

a) Lunar New Year from the 15th day of the last lunar month to the 15th day of the first lunar month;

b) Summer peak from May 15 to August 15 of the Gregorian calendar;

c) Holiday periods as prescribed;

d) Cultural, economic, political events and other peak periods as required by the Government and the Ministry of Transport.

Article 85. Historical Slots

1. A historical slot for a flight season is a slot chain used correctly with a minimum usage rate of 80% for international slot chains or a minimum usage rate of 70% for domestic slot chains as stipulated in Clause 2 of this Article.

2. Slot chains considered as the basis for calculating historical slots include:

a) Slot chains confirmed until the base date for calculating historical slots;

b) Domestic slot chains changed before September 15 for winter schedules and before February 15 for summer schedules;

c) Domestic slot chains changed from international slot chains and vice versa, confirmed before September 15 for winter schedules and before February 15 for summer schedules;

d) Newly proposed slot chains (codes N, B) confirmed for the first time, and newly proposed slot chains (code N) implemented simultaneously with the cancellation of slot chains (code D) after the base date for calculating historical slots;

đ) Slot chains specified in points b and c of this clause must be proposed no later than February 10 for summer schedules and September 10 for winter schedules.

3. Priority order for determining historical slots when the number of eligible slot chains exceeds the slot coordination parameters:

a) Slot chains confirmed until the base date for calculating historical slots;

b) Slot chains specified in point b and point c of Clause 2 of this Article;

c) Slot chains specified in point d of Clause 2 of this Article.

4. Correctly Used Slots

a) For departure slots, it is a slot actually operated without being earlier or later than the confirmed slot: 30 minutes for domestic flights; 60 minutes for international flights with a distance between two airports less than 6,000 km measured along the great circle of the Earth; and 120 minutes for international flights with a distance greater than or equal to 6,000 km measured along the great circle of the Earth;

b) For arrival slots, it is a slot with actual operation time;

c) Confirmed slots affected by natural disasters, epidemics, airport closures at the request of authorities or departure/arrival airports;

d) Confirmed slots directly affected by flight schedule changes to serve special aircraft or cargo flights or at the request of authorized agencies.

5. The correct slot usage rate is the ratio of the total number of correctly used slots to the total number of confirmed slots (for summer schedules: calculated from the start date of the chain to the end date of the chain but not exceeding August 20; for winter schedules: calculated from the start date of the chain to the end date of the chain). Slot chains starting after August 20 will not be notified of historical slots.

6. The Civil Aviation Authority of Vietnam will notify historical slots to airlines based on slot chains confirmed in points a, b, and c of Clause 2 of this Article according to the IATA published schedule.

7. The Civil Aviation Administration of Vietnam shall examine and notify the airline prior to the allocation of the initial schedule slot for the new season regarding the possibility that the slots specified in point d, Clause 2, Article this are historical slots in cases where the airline submits a request and supporting documentation.

8. Airlines are responsible for submitting supporting documentation:

a) Regarding flights affected as specified in point d, Clause 4, Article this to the airport operator at least fourteen days before the announcement date of historical slots according to the IATA schedule publication;

b) Within seven days from the announcement date of historical slots according to the IATA schedule publication as stipulated in Clause 7, Article this.

9. The provisions of Clause 1 and Clause 2, Article this shall be applied starting from October 26, 2025, of the 2025 winter flight schedule to serve as the basis for determining historical slots for the 2026 winter season and subsequent scheduling seasons.

Article 86. Priority Order for Coordinating Takeoff and Landing Times

1. The Civil Aviation Administration of Vietnam shall coordinate the initial schedule slot for the new season in the following priority order:

a) Historical slots and changes to historical slots that do not affect slot coordination parameters;

b) Changes to historical slots that affect slot coordination parameters;

c) Extended slots from the previous operational season;

d) Slots for airlines operating at an airport for the first time (only prioritizing confirmation of six slots per day);

đ) New proposed slots by currently operating airlines.

2. The Civil Aviation Administration of Vietnam shall use additional priority criteria to coordinate the remaining unconfirmed slots as specified in Clause 1, Article this and new proposed slots by currently operating airlines in the following order:

a) The duration of the extended slot chain from the start to the end of the season;

b) Longer slot chains are given priority;

c) Flights to and from new countries;

d) Slots for routes serving economic and social purposes;

đ) International flights with longer flight distances;

e) Flights to and from new airports;

g) Slot chains returned by airlines in the corresponding previous season no later than the deadline for returning slot chains at the start of the new season;

h) Flights using wide-body aircraft with large commercial configurations.

3. In cases where the initial schedule slot for the new season is coordinated according to the priority order specified in Clauses 1 and 2, Article this and not all slots are confirmed, they shall be allocated sequentially on a one-to-one basis by day and specific time frame, based on the order of airlines with the highest slot usage rate in the corresponding previous seasonal period of the relevant airport.

Article 87. Procedures for Coordinating Takeoff and Landing Times at Fully Coordinated Airports

1. The Civil Aviation Administration of Vietnam shall notify historical slots to airlines before each new season according to the historical slot notification deadlines in the IATA slot coordination schedule.

2. Airlines shall respond with agreement or disagreement to the historical slots in the IATA slot coordination schedule. If no response is received from the airline within the deadline, it will be considered as agreeing to the historical slots.

3. Airlines shall send an electronic message proposing the initial schedule slot coordination for the new season to the email address published on the Civil Aviation Administration of Vietnam's website. The proposal submission deadline follows the IATA slot coordination schedule.

4. The Civil Aviation Administration of Vietnam shall coordinate the initial schedule slot for the new season based on the priority order specified in Article 86 of this Circular and send an electronic message with the results of the initial schedule slot coordination to the airline according to the slot allocation deadline in the IATA slot coordination schedule.

5. After the slot allocation deadline for the initial schedule slot for the new season, the Civil Aviation Administration of Vietnam shall compile a list of proposed slot chains from new airlines and new routes as specified in Clause 3, Article this that have not been confirmed. These slot chains in the list shall be prioritized for confirmation when available slots become available according to the priority order specified in Article 86 of this Circular until the historical slot calculation base date.

6. In cases where airlines submit proposals for slot chains after the proposal submission deadline for the initial schedule slot for the new season, the Civil Aviation Administration of Vietnam shall coordinate them according to the following principles:

a) They shall only be considered after the slot allocation deadline for the initial schedule slot for the new season and after the slot chains specified in Clause 5, Article this;

b) Airlines that submit proposals earlier shall be considered first;

c) Slot chains proposed after September 15 for the winter schedule and after February 15 for the summer schedule shall be coordinated together with non-chain slots according to the principle of first come, first served.

7. For proposals for non-chain slots, the Civil Aviation Administration of Vietnam shall coordinate them according to the following principles:

a) They shall only be coordinated after September 15 for the winter schedule and after February 15 for the summer schedule;

b) Airlines that submit proposals earlier shall be considered first.

8. In cases where the coordination parameter decreases at an airport:

a) In cases where the coordination parameter decreases, the Civil Aviation Administration of Vietnam shall reduce the number of slots currently being used by airlines proportionally to their slot holding ratio at the airport for each specific time frame during the adjustment period;

b) In cases where the decreased coordination parameter has recovered to a level equal to or less than the original level, the Civil Aviation Administration of Vietnam shall increase the number of slots for airlines proportionally to their slot holding ratio at the time before the reduction was implemented.

9. In cases where the coordination parameter increases during the periods specified in Clause 5, Article 84 of this Circular, the Civil Aviation Administration of Vietnam shall coordinate as follows:

a) Additional slots shall form a pool;

b) Fifty percent of the slots specified in point a of this clause shall be coordinated based on the slot holding ratio of airlines corresponding to the increased parameter period at the historical slot calculation base date, without applying the provisions of Clause 12 of this Article;

c) Fifty percent of the slots specified in point a of this clause shall be coordinated according to the priority order specified in Clauses 2 and 3 of Article 86 of this Circular and the provisions of Clause 12 of this Article.

10. The coordination parameters are adjusted to increase due to the enhanced service capacity of the airport and flight operation support services:

a) In the case where the coordination parameters increase before the allocation period for the initial schedule slot chain according to the IATA slot coordination schedule, the Civil Aviation Authority of Vietnam shall coordinate in accordance with the initial schedule slot chain coordination process specified in Clause 4 of this Article;

b) In the case where the coordination parameters increase after the allocation period for the initial schedule slot chain according to the IATA slot coordination schedule, the Civil Aviation Authority of Vietnam shall coordinate in accordance with the provisions set out in Clause 9 of this Article.

11. Airlines are responsible for returning confirmed slots that are not used via telegraph to the Civil Aviation Authority of Vietnam. The return of unused slots shall be carried out as follows:

a) If an airline returns slots by the deadline for returning the initial schedule slot chain according to the IATA slot coordination schedule, the corresponding time for the returned slots will be deducted when calculating historical slot usage. Airlines returning slot chains will be recorded and listed;

b) If an airline returns a confirmed slot at least ten days prior to the planned operational date, the returned slot will be deducted when determining the slot usage rate based on the most recent confirmed slot month to serve as the basis for confirming additional slots.

12. The Civil Aviation Authority of Vietnam shall implement the process of coordinating additional slots (if applicable) under the following conditions:

a) An airline has a take-off slot usage rate of 85% or higher and a correct take-off slot usage rate of 75% or higher for the most recently published month;

b) The daily operational slot usage rate of an airline matches the slot confirmed by the Civil Aviation Authority of Vietnam for the most recent month at 85% or higher;

c) The provisions of points a and b of this clause shall not apply to airlines with an average historical slot usage of six slots or fewer per day or as required by the Ministry of Transport.

Article 87a. Slot Coordination Process at Airports Not Fully Coordinated

1. The Civil Aviation Authority of Vietnam is responsible for notifying airlines of the recorded initial schedule slot chains at the end of the winter season and the recorded slot chains on August 20 for the summer season, respectively, according to the historical slot notification deadlines in the IATA slot coordination schedule.

2. Airlines must respond with agreement or disagreement to the notified slot chains at the airport within the historical slot acceptance deadlines in the IATA slot coordination schedule. Failure to receive a response from the airline within this period shall be deemed as agreement with the recorded slot chains at the end of the previous season.

3. Airlines must send a telegram proposing the initial schedule slot chain coordination to the email address published on the Civil Aviation Authority of Vietnam's website no later than fifteen days before the deadline for submitting initial schedule slot chain proposals in the IATA slot coordination schedule.

4. The Civil Aviation Authority of Vietnam is responsible for coordinating the initial schedule slot chains or seeking the opinion of the airport operator (if necessary). For new proposals (Code N), the Civil Aviation Authority of Vietnam shall coordinate according to the priority criteria for additional slot supplementation as stipulated in Clause 2 of Article 86 of this Circular.

5. The Civil Aviation Authority of Vietnam shall coordinate slot chains submitted after the deadline specified in Clause 3 of this Article together with non-chain slots according to the principle that airlines submitting proposals earlier will be considered first after completing the slot coordination process specified in Clause 4 of this Article.

Article 88. Disclosure of Information

1. The Civil Aviation Authority of Vietnam shall be responsible for compiling information on airports that are fully coordinated as follows:

a) Slot coordination parameters of airports and airfields;

b) Results of slot confirmation updated to the start date of the schedule season;

c) Statistics on the ratio of slot usage over confirmed slots, and the ratio of correct slot usage over confirmed slots monthly.

2. The information stipulated in Clause 1 of this Article shall be publicly disclosed on the Civil Aviation Authority of Vietnam's website.

Article 89. Provisions on Building a Slot Database and Applying Information Technology

1. Slot Coordination Database

a) The Civil Aviation Authority of Vietnam shall be responsible for building a database for slot coordination. Key parameters of the database include slot coordination parameters, telegrams exchanging slots, historical slot data of airlines by season, updated confirmed slot data, remaining updated slot quota, and other necessary parameters decided by the Civil Aviation Authority of Vietnam;

b) Airport operators, service providers ensuring flight operations, and related organizations participating in transportation and operation at fully coordinated airports shall be responsible for providing periodic data as prescribed in Article 90 of this Circular or ad hoc data upon request from the Civil Aviation Authority of Vietnam.

2. The Civil Aviation Authority of Vietnam shall grant access rights to the slot management software system to domestic airlines, airport operators, service providers ensuring flight operations, and Air Navigation Service Providers. Units shall be responsible for securing their access accounts to the Civil Aviation Authority of Vietnam's slot management software system.

Article 90. Reporting and Information Provisioning System for Building a Database

1. Airport operators and airfield operators shall report and provide the following information:

a) Terminal and apron capacity limits, reported twice annually, when changes occur, or upon request, using Form No. 5.1.1 of Appendix I issued with this Circular;

b) Domestic and international flight slot usage and daily operational planning compared to monthly confirmed slots, reported using Form No. 5.1.2 of Appendix I issued with this Circular on the fifth day of the following month;

c) Number of aircraft overnight parking slots confirmed for airlines, reported using Form No. 5.1.4 of Appendix I issued with this Circular before April 15 each year for winter schedule data and before September 15 each year for summer schedule data;

d) Serial slot usage according to flight number during the schedule season, reported using Form No. 5.1.5 of Appendix I issued with this Circular; reports shall be sent to the Civil Aviation Authority of Vietnam ten days prior to the historical slot announcement date according to the IATA slot coordination schedule for consolidated data according to the schedule season. The Civil Aviation Authority of Vietnam shall be responsible for providing the IATA slot coordination schedule to airport operators and airfield operators;

đ) Monitoring of slot recovery according to flight number during the schedule season, reported using Form No. 5.1.6 of Appendix I issued with this Circular; reports shall be sent to the Civil Aviation Authority of Vietnam on the tenth day of each month for consolidation of slot recovery as prescribed in Article 92 of this Circular.

2. Air Navigation Service Providers shall report and provide monitoring information on outbound flight slot usage using Form No. 5.2.1 of Appendix I issued with this Circular on the seventh day of the following month.

3. Service providers ensuring flight operations shall report and provide capacity limit indices for runway operations and air traffic control services, reported twice annually or when changes occur or upon request using Form 6.1 of Appendix I issued with this Circular.

Article 91. Mechanism for Supervising and Managing Slot Usage at Fully Coordinated Airports

1. Slot Implementation Oversight

a) The Civil Aviation Port Authority shall be responsible for overseeing the implementation of slots at airports under its jurisdiction and reporting to the Vietnam Civil Aviation Administration.

b) Airport operators shall be responsible for establishing databases and investing in information technology systems to receive and process slot implementation data from airlines, and report to the Vietnam Civil Aviation Administration and the Civil Aviation Port Authority.

c) Airlines or ground service providers authorized by airlines shall be responsible for providing accurate data on AOBT and AIBT times to airport operators to fulfill the requirements stipulated in point b, Clause 1, Article 91 of this Circular.

2. Ticket Sales and Seat Reservations Without Confirmed Slots

3. Overnight Aircraft Parking Management

a) Airport operators shall be responsible for confirming the number of aircraft parked overnight for each airline based on the registration of airlines, in accordance with the operational capacity of the airport as specified in point c, Clause 1, Article 90 of this Circular.

b) Vietnamese airlines shall be responsible for developing appropriate operational plans and adhering to the number of aircraft parked overnight as specified in point a of this clause.

c) Airlines that have been confirmed the number of aircraft parked overnight for a given season shall continue to maintain this number of overnight parking positions in the subsequent season.

d) In cases where airlines fail to comply with the number of aircraft parked overnight, leading to airport apron overload, airport operators may refuse to accept flights from the airline causing the overload and notify the air navigation service provider, the airline, and report to the Vietnam Civil Aviation Administration and the Civil Aviation Port Authority.

4. The Vietnam Civil Aviation Administration shall provide airport operators with data on confirmed slots immediately after sending it to the airlines to enable airport operators to compare, verify, and process data as required by point a, Clause 3, Article 91 of this Circular.

5. Airport operators shall provide accounts to the Civil Aviation Port Authority to access the flight management database system of the Civil Aviation Port Authority.

Article 92. Situations for Revoking Slot Chains

1. An airline that does not commence operations or ceases operations continuously for a period corresponding to 30% of the confirmed slot chain but not exceeding six weeks.

2. An airline that improperly uses slots (including confirmed slots that are not utilized and not returned on time) continuously for a period corresponding to 40% of the confirmed slot chain but not exceeding eight weeks.

3. Airlines whose slot chains are revoked will not be credited with historical slots for the subsequent season.

4. The Vietnam Civil Aviation Administration shall implement the revocation of slot chains as specified in Clauses 1 and 2 of this Article.

Article 93. Slot Chain Swap Between Airlines

1. Airlines are permitted to swap slot chains on a 1:1 basis within the same airport under the following conditions:

a) The entire slot chain must be swapped;

b) The slot chain can only be swapped once per operating season.

2. Airlines proposing to swap slot chains shall send a telegram to the Civil Aviation Authority of Vietnam at least one week before the start date of the slot chain with the following contents:

a) Names of the airlines proposing to swap slots;

b) Proposed slot chains for swapping;

c) Period of the swap (operating period, operating season).

3. Swapped slot chains will be considered historical slots according to the provisions of Article 85 of this Circular.

Article 93a. Responsibilities of the Civil Aviation Authority of Vietnam

1. Organize the management and coordination of slots to ensure transparency and non-discrimination.

2. Publish the IATA slot schedule before the operating season on the Civil Aviation Authority of Vietnam's website.

3. Decide to adjust or change the contents specified in points c and d of Clause 1 of Article 83 of this Circular in unforeseen cases beyond control that affect air transport operations, including:

a) Impact of natural disasters, weather, epidemics, war, armed conflict, terrorism, and embargo;

b) Impact of strikes, demonstrations;

c) Suspension of operations at the request of competent state authorities or airports serving departure and arrival;

d) Aircraft or engine manufacturers recalling aircraft or engines for technical reasons.

4. Report to the Ministry of Transport for consideration and decision to change or adjust the contents specified in points c and d of Clause 1 of Article 83 of this Circular in cases affecting air transport operations other than those stipulated in Clause 3 of this Article.

5. Announce the list of airports subject to full slot coordination.

6. Decide on the operation of the Slot Council.

4. Amend and supplement Article 99 as follows:

"Article 99. Transitional Provisions

1. Licenses for air traffic controllers, equipment operators, and restricted area vehicle operators issued before the effective date of this Circular remain valid until their expiration date.

2. Slot chains of Vietnamese airlines confirmed up to February 28, 2023, for the Summer 2023 flight schedule will serve as the basis for historical slot notifications for the Summer 2025 and Summer 2026 flight schedules, except for slot chains revoked due to non-use as provided in Clause 1 of Article 92 of this Circular.

3. For slot chains of foreign airlines confirmed up to the historical slot calculation base date for the Summer 2024 flight schedule, they will serve as the basis for historical slot notifications for the Summer 2025 and Summer 2026 flight schedules.

4. Slot chains confirmed up to the historical slot calculation base date for the Winter 2023 flight schedule will serve as the basis for historical slot notifications for the Winter 2024 and Winter 2025 flight schedules for airlines, except for slot chains revoked due to non-use as provided in Clause 1 of Article 92 of this Circular.

5. In cases where new slot chains of foreign airlines in the Summer 2024 flight schedule meet the conditions for historical slot notifications for subsequent seasons and exceed slot coordination parameters, the Civil Aviation Authority of Vietnam will coordinate slots for Vietnamese airlines based on the holding ratio at the time of the historical slot calculation base date as specified in Clause 2 of this Article.

6. Slot chains returned prior to the historical slot calculation base date will be notified for historical slots for the corresponding flight seasons from Summer 2024 to Summer 2026."

5. Repeal Clause 5 of Article 100 of Circular No. 29/2021/TT-BGTVT.

Article 2. Replace, supplement, and abolish the forms attached as Appendix I issued together with Circular No. 29/2021/TT-BGTVT.

1. Replace Form No. 5.1.2, Form No. 5.1.5, and Form No. 5.2.1 in Appendix I of Circular No. 29/2021/TT-BGTVT with Forms 5.1.2, Form No. 5.1.5, and Form No. 5.2.1 respectively, attached as Appendix to this Circular.

2. Supplement Form Report No. 5.1.6 to Appendix I of Circular No. 29/2021/TT-BGTVT corresponding to Form 5.1.6 attached as Appendix to this Circular.

3. Abolish Form No. 5.1.3, Form 5.2.2, and Form 6.2 in Appendix I issued together with Circular No. 29/2021/TT-BGTVT.

Article 3. Effectiveness and Responsibility for Implementation

1. This Circular takes effect from February 15, 2024.

2. The Director of the Office, the Inspector General, the Departments and Bureaus of Civil Aviation of Vietnam, and the Heads of agencies, units, and related organizations and individuals are responsible for implementing this Circular./.