GEN 2  TABLES AND CODES

GEN 2.1  MEASURING SYSTEM, AIRCRAFT MARKINGS, HOLIDAYS

1.  Units of measurement

1.1 Units of measurement to be used in flight operations and air-ground communications are as follows:

QUANTITY

UNIT OF MEASUREMENT

Distance used in navigation, position reporting, etc.-generally in excess of 2 to 3 nautical milesNAUTICAL MILES (NM)
Relatively short distances such as those relating to aerodrome (e.g. runway lengths) METRES (M)
Altitudes, elevations and heightsFEET (FT)
Horizontal speed, including wind speedKNOTS (KT)
Vertical speedFEET PER MINUTE (FT/MIN)
Wind direction for landing and take-offDEGREES MAGNETIC
Wind direction except for landing and take-off DEGREES TRUE
VisibilityKILOMETRES (KM)
Runway visual rangeMETRES (M)
Altimeter settingHECTOPASCALS (hPa)
TemperatureDEGREES CELSIUS (°C)
Mass (Weight)KILOGRAMES (KG) or METRIC TON (T)
TimeHOURS AND MINUTES, THE DAY OF 24 HOURS BEGINNING AT MIDNIGHT (UTC)

Visibility of less than 5 km may be given in metres.

2.  Temporal refernceime system

Co-ordinated Universal Time (UTC) is used in the air traffic and communication services and in documents published by the Aeronautical Information Services. When reporting time, the nearest full minute is used, e.g., 12 hr 40 min 40 sec is reported as 1241. Time checks to aircraft are accurate within 30 sec.

3.   Geodetic Horizontal rreference systemdatum

3.1 All published geographical coordinates in the Bangkok FIR indicating latitude and longitude are expressed in terms of the World Geodetic System-1984 (WGS-84) geodetic reference datum.
3.2 The area of application for the published geographical coordinates coincides with the area of responsibility of the Aeronautical Information Services, i.e. the entire territory of Thailand as well as the airspace over the high seas encompassed by the Bangkok Flight Information Region in accordance with the Regional Air Navigation Agreement.
3.3 Aerodromes with coordinates which have been transformed into WGS-84 coordinates but whose accuracy does not meet the requirements in Appendix 1. Aeronautical Data Catalogue in Doc 10066 PANS-AIM, are listed below:

VTUN — Nakhon Ratchasima / Khorat

VTSN — Nakhon Si Thammarat / Cha - Ian

4.  Vertical reference system

5.  Aircraft nationality and registration marks

The nationality mark for aircraft registered in Thailand consists of the letters HS. The nationality mark is followed by a Hyphen and a registration mark consisting of 3 letters, e.g., HS-TDD.

6.  Public holidays

NAME

Date
New Year’s Day1 January 20220254
Makha Bucha Day 24 12 February 20242025
Chakri Memorial Day6 April 20242025
Substitution for Chakri Memorial Day 7 8 April 20242025
Songkran Festival Days13 - 15 April 20242025
Substitution for Songkran Festival Days16 April 20242025
Royal Coronation Ceremony4 May 20242025
Substitution for Royal Coronation Ceremony 5 May 2025
Substitution for Royal Coronation Ceremony The Royal Ploughing Ceremony 6 May 2024 9 May 2025
Visakha Bucha Day 11 22 May 20242025
Substitution for Visakha Bucha Day 12 May 2025
Additional holiday Announced by Thai Govt. 2 June 2025
H.M. Queen Suthida Bajrasudhabimalalakshana's Birthday 3 June 20242025
Asarnha Bucha Day 20 10 July 20242025
Buddhist Lent Day 21 11 July 20242025
H.M. King Maha Vajiralongkorn Phra Vajiraklaochaoyuhua’s Birthday28 July 20242025
Substitution for H.M. King Maha Vajiralongkorn Phra Vajiraklaochaoyuhua’s Birthday Additional holiday Announced by Thai Govt. 29 July 2024 11 August 2025
H.M. Queen Sirikit The Queen Mother’s Birthday and National Mother Day12 August 20242025
H.M. King Bhumibol Adulyadej The Great Memorial Day13 October 20242025
King Chulalongkorn Memorial Day23 October 20242025
H.M. King Bhumibol Adulyadej The Great's Birthday, National Day and
National Father Day		5 December 20242025
Constitution Day10 December 20242025
New Year’s Eve31 December 20242025