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 heightsMETRES (m) or FEET (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 refernce 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.  Horizontal reference system

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

4.1 Name/designation of system

The vertical reference system corresponds to mean sea level (MSL).

4.2 Geoid model

The geoid model used is the Earth Gravitational Model 1996 — (EGM-96).

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 2026
Additional holiday Announced by Thai Govt.2 January 2026
Makha Bucha Day3 March 2026
Chakri Memorial Day6 April 2026
Songkran Festival Days13 - 15 April 2026
Royal Coronation Ceremony4 May 2026
The Royal Ploughing Ceremony13 May 2026
Visakha Bucha Day31 May 2026
Substitution for Visakha Bucha Day1 June 2026
H.M. Queen Suthida Bajrasudhabimalalakshana's Birthday 3 June 2026
H.M. King Maha Vajiralongkorn Phra Vajiraklaochaoyuhua’s Birthday28 July 2026
Asarnha Bucha Day29 July 2026
Buddhist Lent Day30 July 2026
H.M. Queen Sirikit The Queen Mother’s Birthday and National Mother Day12 August 2026
H.M. King Bhumibol Adulyadej The Great Memorial Day13 October 2026
King Chulalongkorn Memorial Day23 October 2026
H.M. King Bhumibol Adulyadej The Great's Birthday, National Day and
National Father Day		5 December 2026
Substitution for H.M. King Bhumibol Adulyadej The Great's Birthday, National Day and National Father Day7 December 2026
Constitution Day10 December 2026
New Year’s Eve31 December 2026