Skip to main content

Aircraft Knowledge

Aircraft Description

ICAO Doc 8643 provides data on aircraft such as the Manufacturer, Model, Type designator, etc. One of the items is called Description and is a three-symbol code containing basic data about the aircraft:

  • The first symbol describes the aircraft type:
    • L - Landplane, e.g. A320. Note: A floatplane, which can temporarily be converted to a landplane or vice versa, is described as a landplane and not a seaplane or amphibian in ICAO Doc 8643.
    • S - Seaplane, e.g. HARBIN SH-5 (ICAO designator SH5)
    • A - Amphibian, e.g. LA4
    • G - Gyrocopter, e.g. A002
    • H - Helicopter, e.g. A109
    • T - Tiltrotor, e.g. V22
  • The second symbol specifies the number of engines 1, 2, 3, 4, 6, 8 or C, where C means that two engines are coupled to drive a single propeller system (e.g. C08T). The C symbol is only used for fixed-wing aircraft.
  • The third symbol specifies the engine type:
    • J - jet
    • T - turboprop/turboshaft
    • P - piston
    • E - electric
    • R - rocket
Examples
  • L2J - a landplane with two jet engines
  • H2T - a helicopter with two turboprop/turboshaft engines
  • S1P - a seaplane with one piston engine

ICAO Aerodrome Reference Code

The ICAO Aerodrome Reference Code is a two part categorisation of aircraft types which simplifies the process of establishing whether a particular aircraft is able to use a particular aerodrome. It is included in ICAO Annex 14. It has two 'elements', the first is a numeric code based on the Reference Field Length for which there are four categories and the second is letter code based on a combination of aircraft wingspan and outer main gear wheel span.

Element 1 of the Code is as follows:

Code number Aeroplane reference field length Typical aeroplane
1 < 800 m DE HAVILLAND CANADA DHC-6/PIPER PA-31
2 800 m but < 1200 m ATR ATR-42-300/320/BOMBARDIER Dash 8 Q300
3 1200 m but < 1800 m SAAB 340/BOMBARDIER Regional Jet CRJ-200
4 1800 m and above BOEING 737-700/AIRBUS A-320

Field length means the balanced field length (which is when the take-off distance required is equal to the accelerate-stop distance required) if applicable, or take-off distance in other cases. Aeroplane reference field length is defined as "the minimum field length required for take-off at maximum certificated take-off mass, at sea level, in International Standard Atmosphere conditions in still air and with zero runway slope as documented in the Aircraft Flight Manual (AFM) or equivalent document.

Element 2 of the Code is derived from the most restrictive of either the aircraft wingspan or the aircraft outer main gear wheel span. The categories are as follows:

Code letter Wingspan Typical aeroplane
A < 15 m PIPER PA-31/CESSNA 404 Titan
B 15 m but < 24 m BOMBARDIER Regional Jet CRJ-200/DE HAVILLAND CANADA DHC-6
C 24 m but < 36 m BOEING 737-700/AIRBUS A-320/EMBRAER ERJ 190-100
D 36 m but < 52 m B767 Series/AIRBUS A-310
E 52 m but < 65 m B777 Series/B787 Series/A330 Family
F 65 m but < 80 m BOEING 747-8/AIRBUS A-380-800

It should be noted that Element 2 is often used on its own since it has direct relevance to detailed airport design. It also has a parallel but differently defined code use by the FAA, the Airplane Design Group (ADG)

Wake Turbulence Category

The ICAO wake turbulence category (WTC) is entered in the appropriate single character wake turbulence category indicator in Item 9 of the ICAO model flight plan form and is based on the maximum certificated take-off mass, as follows:

  • J (Super) aircraft types specified as such in Doc 8643 (Aircraft type designators). At present, the only such type is the Airbus A380-800 with a maximum take-off mass in the order of 560 000 kg. (see Airbus A380 Wake Vortex Guidance)
  • H (Heavy) aircraft types of 136 000 kg (300 000 lb) or more (except those specified as J);
  • M (Medium) aircraft types less than 136 000 kg (300 000 lb) and more than 7 000 kg (15 500 lb); and
  • L (Light) aircraft types of 7 000 kg (15 500 lb) or less.

Variants of an aircraft type may fall into different wake turbulence categories, (e.g. L/M or M/H). In these cases, it is the responsibility of the pilot or operator to enter the appropriate wake turbulence category indicator in the flight plan.

Back to top