ANSS Advisory Circular 1 of 2025 • ATC Unit Log Books

The circular links ATC unit log books directly to Watch Duty Time Limitations and safety investigations.

                        
1. Introduction

                      DGCA CAR Section 9 Series L Part VII on Watch Duty Time Limitations
                      mandates that the ATS provider shall:
                      Ensure that records of ATCOs regarding the start, duration and end of each duty period are maintained.

                      The circular states that log books maintained at ATS units:
                      Form an essential piece of evidence required during a safety investigation.
Must be maintained in a correct and uniform format at all manned positions in an ATS station (airport).

                        Text: Section 1 – Introduction, ANSS Advisory Circular 1 of 2025

2. Applicability

The circular is applicable to all ATS stations.
It applies to personnel of Air Navigation Services Provider, Airports Authority of India engaged in provision of Air Traffic Services.

The intent is that every manned ATS position at every ATS station keeps a log book that is fit for duty-time verification and for use in any safety investigation.

Section 3.1 defines how ATC unit log books are to be provided, stored and issued.

                        
                      
3.1 • Distribution & Maintenance

                      (a) The ATS-in-Charge of an airport should maintain
                      sufficient number of ATC unit log books as per requirements of the ATS station.


                      (b) ATS-in-Charge should also issue extra unit log books to be kept in custody of
                      the Watch Supervisory Officer (WSO) / Shift In-charge, to be utilised:
                      As and when required at the ATS unit during holidays or
For other urgent requirement(s).

                      The Shift In-charge should issue a new unit log book to an ATC unit:
                      (i) When the earlier unit log book has been filled up completely.
(ii) On 01 Jan of every year.
(iii) When a log book is sealed for investigation purposes.

                      When any existing ATC unit log book is filled completely,
                      a new unit log book should be opened immediately.
                    

3.1 • Positions & Master List

(c) Each ATC position within an ATC unit where an ATCO carries out ATS responsibilities (directly exercising licence privileges or indirectly via coordination / supervision) should have an ATS unit log book.
(d) For ATS units functioning only during specific watch hours, the unit log book(s) are to be maintained only during such watch hours.
(e) The ATS-in-Charge shall maintain a master list of all ATS unit log books issued.

No gap in records: stock, extra books with WSO/Shift In-charge, and a master list ensure every manned position is always covered.

Section 3.2 standardises the format and certification of ATC unit log books.

                        
                      
3.2 • Format of ATC Unit Log Books

                      (a) ATC unit log books must be:
                      Properly bound, and
All pages serially numbered.

                      Log books are to be serially numbered in the format:
                      XX/NN/YY where:
                          XX = Name of the ATC position,
NN = Serial number,
YY = Year.

                        

                      Example given in the circular:
                      First unit log book: ACC(W)/01/25
Second unit log book: ACC(W)/02/25, and so on.

                      At smaller stations where only one position exists for each ATC unit,
                      the name of the ATC position may be omitted.
                    

Certification by WSO / Shift In-charge

(b) The WSO / Shift-in-charge should certify the log book on the first page as:

“Certified that this log book contains (number) pages numbered serially”.

XX/NN/YY serial numbering format

First-page certification mandatory

Section 3.3 describes how entries are to be made: columns, ink, corrections, chronology and use of UTC.

                        
                      
3.3 • Columns & Basic Entry Rules

                      (a) Every ATC unit log book shall contain four columns:
                      1st column – Time
2nd column – Details of entries
3rd column – Name and signature of the ATCO
4th column – Countersignature of responsible official

                      At stations operating a 24-hour watch:
                      The change of date occurs at 0000 UTC.
The new date shall be written at the centre of the page in the next blank line below the last entry of the previous date.

                      (b) ATC unit log book entries:
                      Shall only be made in blue or black ink.
No coloured ink or pencil entries are permitted.
No overwriting should be resorted to.

                    

Corrections, Chronology & UTC

(c) No entry shall be erased. If alteration is absolutely necessary:
- Previous entry should be struck off by drawing a fine line over it in ink.
- New entry must be made and duly signed in the log book by the ATCO modifying the entry.
- Multiple strikethroughs of the same entry are not permitted.
(d) Entries should be made in chronological order and, as far as possible, concurrently with occurrences and actions.
During emergencies or busy times, if detailed entry at the moment is not possible:
- Rough notes with exact times should be kept.
- A detailed log entry as a late entry should be made as soon as possible thereafter.
(e) Under no circumstances shall a page or pages be torn, defaced, obliterated or removed from the ATS-unit log book.
(f) Entries are to be made by the controller on duty.
(g) Time of entries should be recorded in UTC and in sufficient detail to give a complete understanding of actions; strict attention to:
- Time an incident occurs, and
- Time at which action is initiated.
(h) Every ATCO making an entry should ensure entries are made within the allotted columns.

3.3 also prescribes supervisory log books, recording of other ATCO duties, types of information to record, and clarity of wording.

                        
                      
3.3 • Supervisory & Other Duties

                      (i) Where supervisory positions are established (e.g. Tower Supervisor, Approach Supervisor, WSO):
                      Separate log books for each supervisory position should be maintained.
Entries should include, apart from hand-over and take-over timings, the compilation of important log entries of all log books for which the supervisor is responsible.
Example given: A tower supervisor log book at a major ATS station should contain significant entries of all Aerodrome Control Tower units such as:
                          Clearance Delivery,
Surface Movement Control,
Tower Controller positions.

                        

                      (j) Other duties performed by the ATCO should also be recorded, such as:
                      On-the-Job Training Instructor (imparting training),
On-the-Job Trainee,
Conduct of Proficiency Check,
Skill Assessment Board / Pre-rating Board.

                      (k) All time periods during watch hours must be covered by an ATCO having taken over watch in the log book.
                      
No ATCO should take over two active units at the same time unless units are treated as combined and considered as one.
                    

3.3 • Type & Clarity of Information

(l) The type of information recorded shall be, but not limited to:
- (i) Incidents, accidents, non-compliance with regulations or ATC clearances, regardless of whether an additional separate report is required.
- (ii) Essential aerodrome information.
- (iii) A change in status of navigation facilities, services and procedures.
- (iv) Changes in runway-of-operation.
- (v) Low Visibility Procedure (LVP) operations.
(n) Log-entries such as “inform all concerned” do not convey relevant information and should be avoided.
- Specific details of the name of the agencies / persons to whom the information was passed must be recorded in sequence.
- ATCO should make log entries in a clear and concise manner so that all pertinent information are recorded.
(o) The ATS-in-Charge or ATS official to whom responsibility for counter-signature(s) is delegated shall be responsible for deviation / non-conformance of ATC-unit log book entries.

Section 3.4 details the Handover–Takeover procedure linked with log book entries.

                        
3.4 • Before Taking Over Watch

                      (a) All ATCOs shall ensure that:
                      The necessary briefing has been received.
Monitoring of the prevailing traffic scenario has been accomplished before logging-in the “Time-in-position”.

                      The relieving ATCO shall use all possible means to acquire the required situational awareness and information for safe discharge of duties.
                      
                      (b) The ATCO to be relieved shall brief the entire traffic scenario to the relieving controller.
                      The relieving ATCO shall first “take over watch” in the log book and sign.
This is followed by the “handing over watch” by the relieved ATCO.

3.4 • Items to Familiarise Before Watch

(c) Before taking over watch, ATCOs must familiarise themselves with:
- (i) Current weather report and forecast (METAR).
- (ii) Serviceability status of communication facilities (VHF channels, intercoms, etc.).
- (iii) Status of special user airspaces and special exercises, if any.
- (iv) Current NOTAMs, bulletins and AUP/UUP.
- (v) Status of serviceability of radio-nav aids / landing aids / visual aids, etc.
- (vi) Status of crash and fire alarm siren and bell.
- (vii) Details of aircraft parking and other information about aerodrome infrastructure (taxiways, runway, apron, lighting, etc.).

Any unserviceability of the above facilities shall be recorded in the ATC unit log book.

(d) ATCOs shall write and sign above their name in a legible way after Handover (HOW) / Takeover (TOW).

Sections 4, 5 and 6 cover correctness of entries, countersignature, retention periods, access control and overall responsibility.

                        
4. Correctness & Countersignature

                      (a) Every ATCO taking over respective ATS positions shall:
                      Promptly sign against each entry made in the ATC-unit log book during which he/she had been in the position prior to leaving.
The ATCO will be responsible for the correctness of his/her entries.

                      (b) The ATS-in-Charge / designated official shall countersign the unit log books of all ATC units regularly.
                      In large ATS stations where more than ten ATC unit log books are maintained, ATS-in-Charge may delegate the responsibility of countersignature and verification to a suitable number of senior ATCOs.
Each such senior ATCO should be responsible for not more than ten log books.
Where countersigning responsibility is delegated, a local directive shall be issued including details of alternate / link ATCOs authorised to countersign in their absence.

5 & 6 • Retention, Access & Responsibility

The ATC unit log books shall be preserved for not less than the retention periods specified:
- ATS Unit Log Book – 2 years.
- Aircraft movement records (log book form or automation system in Aerodrome Control Tower) – 2 years.
- Runway inspection log book maintained in Aerodrome Control Tower – 2 years.
Log-book data are safety-critical entries and shall not be shared as part of general information; confidentiality shall be maintained.
Only authorised ATCOs and DGCA officials shall have access to ATS unit log books.
Section 6: The ATS-in-Charge of the aerodrome shall be responsible for the upkeep and maintenance of all ATS unit log books.

Safety-critical & confidential data

2-year retention requirement

ATS-in-Charge overall responsible