# 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](https://skybrary.aero/node/17548). 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](https://skybrary.aero/node/17927)
    - **G** - Gyrocopter, e.g. [A002](https://skybrary.aero/node/17528)
    - **H** - Helicopter, e.g. [A109](https://skybrary.aero/node/17530)
    - **T** - Tiltrotor, e.g. [V22](https://skybrary.aero/node/18078)
- 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](https://skybrary.aero/node/18087)). 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](https://skybrary.aero/index.php/International_Civil_Aviation_Organisation_(ICAO) "International Civil Aviation Organisation (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:

<table border="2" cellpadding="3" cellspacing="4" class="zebra-ivory-blue tablesaw tablesaw-stack" data-tablesaw-minimap="" data-tablesaw-mode="stack" id="bkmrk-code-number-aeroplan"><thead><tr><th data-tablesaw-priority="persist" role="columnheader" scope="col">Code number</th><th role="columnheader" scope="col">Aeroplane reference field length</th><th role="columnheader" scope="col">Typical aeroplane</th></tr></thead><tbody><tr><td><span class="tablesaw-cell-content">1</span></td><td><span class="tablesaw-cell-content">&lt; 800 m</span></td><td><span class="tablesaw-cell-content">[DE HAVILLAND CANADA DHC-6](https://skybrary.aero/index.php/DHC6 "DHC6")/[PIPER PA-31](https://skybrary.aero/index.php/PA31 "PA31")</span></td></tr><tr><td><span class="tablesaw-cell-content">2</span></td><td><span class="tablesaw-cell-content">800 m but &lt; 1200 m</span></td><td><span class="tablesaw-cell-content">[ATR ATR-42-300/320](https://skybrary.aero/index.php/ATR42 "ATR42")/[BOMBARDIER Dash 8 Q300](https://skybrary.aero/index.php/DH8C "DH8C")</span></td></tr><tr><td><span class="tablesaw-cell-content">3</span></td><td><span class="tablesaw-cell-content">1200 m but &lt; 1800 m</span></td><td><span class="tablesaw-cell-content">[SAAB 340](https://skybrary.aero/index.php/SF34 "SF34")/[BOMBARDIER Regional Jet CRJ-200](https://skybrary.aero/index.php/CRJ2 "CRJ2")</span></td></tr><tr><td><span class="tablesaw-cell-content">4</span></td><td><span class="tablesaw-cell-content">1800 m and above</span></td><td><span class="tablesaw-cell-content">[BOEING 737-700](https://skybrary.aero/index.php/B737 "B737")/[AIRBUS A-320](https://skybrary.aero/index.php/A320 "A320")</span></td></tr></tbody></table>

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](https://skybrary.aero/index.php/ISA "ISA") conditions in still air and with zero runway slope as documented in the [Aircraft Flight Manual (AFM)](https://skybrary.aero/index.php/AFM "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:

<table class="zebra-ivory-blue tablesaw tablesaw-stack" data-tablesaw-minimap="" data-tablesaw-mode="stack" id="bkmrk-code-letter-wingspan"><thead><tr><th data-tablesaw-priority="persist" role="columnheader" scope="col">Code letter</th><th role="columnheader" scope="col">Wingspan</th><th role="columnheader" scope="col">Typical aeroplane</th></tr></thead><tbody><tr><td><span class="tablesaw-cell-content">A</span></td><td><span class="tablesaw-cell-content">&lt; 15 m</span></td><td><span class="tablesaw-cell-content">[PIPER PA-31](https://skybrary.aero/index.php/PA31 "PA31")/[CESSNA 404 Titan](https://skybrary.aero/index.php/C404 "C404")</span></td></tr><tr><td><span class="tablesaw-cell-content">B</span></td><td><span class="tablesaw-cell-content">15 m but &lt; 24 m</span></td><td><span class="tablesaw-cell-content">[BOMBARDIER Regional Jet CRJ-200](https://skybrary.aero/index.php/CRJ2 "CRJ2")/[DE HAVILLAND CANADA DHC-6](https://skybrary.aero/index.php/DHC6 "DHC6")</span></td></tr><tr><td><span class="tablesaw-cell-content">C</span></td><td><span class="tablesaw-cell-content">24 m but &lt; 36 m</span></td><td><span class="tablesaw-cell-content">[BOEING 737-700](https://skybrary.aero/index.php/B737 "B737")/[AIRBUS A-320](https://skybrary.aero/index.php/A320 "A320")/[EMBRAER ERJ 190-100](https://skybrary.aero/index.php/E190 "E190")</span></td></tr><tr><td><span class="tablesaw-cell-content">D</span></td><td><span class="tablesaw-cell-content">36 m but &lt; 52 m</span></td><td><span class="tablesaw-cell-content">[B767 Series](https://skybrary.aero/index.php/B767 "B767")/[AIRBUS A-310](https://skybrary.aero/index.php/A310 "A310")</span></td></tr><tr><td><span class="tablesaw-cell-content">E</span></td><td><span class="tablesaw-cell-content">52 m but &lt; 65 m</span></td><td><span class="tablesaw-cell-content">[B777 Series](https://skybrary.aero/index.php/B777 "B777")/[B787 Series](https://skybrary.aero/index.php/B787_Series "B787 Series")/[A330 Family](https://skybrary.aero/index.php/A330 "A330")</span></td></tr><tr><td><span class="tablesaw-cell-content">F</span></td><td><span class="tablesaw-cell-content">65 m but &lt; 80 m</span></td><td><span class="tablesaw-cell-content">[BOEING 747-8](https://skybrary.aero/index.php/B748 "B748")/[AIRBUS A-380-800](https://skybrary.aero/index.php/A388 "A388")</span></td></tr></tbody></table>

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)](https://skybrary.aero/index.php/Airplane_Design_Group_(ADG) "Airplane Design Group (ADG)")

### Wake Turbulence Category

The [ICAO](https://skybrary.aero/index.php/International_Civil_Aviation_Organisation_(ICAO) "International Civil Aviation Organisation (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](https://skybrary.aero/index.php/A388 "A388") with a maximum take-off mass in the order of 560 000 kg. (see [Airbus A380 Wake Vortex Guidance](https://skybrary.aero/index.php/Airbus_A380_Wake_Vortex_Guidance "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.