Plane spotting glossary: the key terms from approach to wet lease

“The reg came in on a wet lease, then a go-around on final – and on the second approach I had the sun at my back.” If you are new, a sentence like that makes little sense at first. This plane spotting glossary explains the key terms of the scene, sorted by topic, with a short definition and often an example of how the term actually gets used at the fence or in the chat. By the end you will understand not just individual words but also how they fit together.

Why spotters use so much English

Civil aviation is organized internationally. Procedures, radio phrases and many technical designations go back to standards of the International Civil Aviation Organization (ICAO) and are used in English worldwide. That is why even in Germany hardly anyone reaches for a German word when they mean final or line-up. On top of that come abbreviations from photography and a remainder of genuine scene slang.

This very mixture makes getting started tough at first. Some of the terms are official technical language, some are spotter jargon – and in the group chat the two sit right next to each other. If you are just starting out, read the guide Plane spotting for beginners alongside this one.

Airport and operations

This area answers the question: where and how is the aircraft moving right now? It determines which spot you stand at.

• Approach – the arrival toward the runway. On the radio, this is also the name of the approach control unit that sequences traffic before handing it over to the tower. “The 747 is already on approach, it will be down in ten minutes.”
• Final / Short Final – the final approach on the extended runway centerline; short final is the last few miles before that. Classic approach spots like the Affenfelsen at Hamburg Airport live off this stretch.
• ILS – the instrument landing system, which guides aircraft precisely onto the runway with radio signals. Explained in detail in the guide to the ILS approach.
• Departure – the takeoff phase; on the radio, also the control unit that takes over departing aircraft.
• Runway direction in use – the direction in which an airport is currently taking off and landing. It depends mainly on the wind, because aircraft take off and land into the wind whenever possible. More in the article Understanding the runway direction in use.
• Runway number – the magnetic heading of a runway rounded to ten degrees, divided by ten. Runway 26 points roughly west; L, C and R distinguish parallel runways. See Runway designations explained.
• Taxiway – the connecting routes between apron and runway, usually named with letters and numbers. How signs and holding points work is covered in the guide to taxiways and holding points.
• Holding Point – the stop line in front of the runway where an aircraft waits for clearance.
• Line-up – moving onto the runway into takeoff position. “Line up and wait” means: onto the runway, but do not take off yet.
• Rotation – the moment when the pilot raises the nose during takeoff. For many spotters the favorite moment.
• Go-Around – an aborted landing approach. A normal procedure, not an emergency. Details in the article Go-arounds explained.
• Holding – a holding pattern flown in a fixed shape when the airport does not have enough capacity at the moment. See Holding and holding patterns.
• Diversion – the rerouting to an alternate airport, for example because of weather or a medical emergency on board. More in the guide to diversions.
• Turnaround – the time on the ground between landing and the next departure, with deplaning, cleaning, refueling and boarding. Background in the article on the turnaround.
• Apron – the parking area for aircraft. Outlying positions without a jet bridge are often called remote stands; more under Gates and apron positions.
• Slot – an allocated time window for takeoff or landing at a heavily congested airport. See Airport slots.

Aircraft and technology

Here the question is: what exactly did I just see?

• Reg (Registration) – an aircraft’s registration, for example D-AIXA. The prefix reveals the country of registry, with D standing for Germany. The basics are explained in the guide Understanding aircraft registrations. “Which reg was that?” is the most common question at the fence.
• Type and variant – the aircraft type (such as A350) and the sub-variant (A350-900 or -1000). Many discussions revolve around exactly this fine detail.
• Hex code – the globally unique 24-bit address of the transponder. Receivers use it to identify an aircraft even when no registration is transmitted. See ICAO hex code explained.
• Fleet number – an airline’s internal number for an aircraft, often on the nose gear door or the tail. More under Airline fleet numbers.
• Narrowbody / Widebody – a narrowbody has a single aisle (such as the A320 family), as opposed to a widebody with two aisles.
• Winglets and sharklets – upturned wingtips that reduce fuel consumption. Sharklet is Airbus’s name for them. Differences in the guide to spotting winglets and sharklets.
• APU – the auxiliary power unit in the tail, which supplies electricity and air conditioning on the ground. The connection to ground power is described in the article APU and ground power.
• Reverser / Thrust reverser – flaps on the engine that redirect thrust forward after landing. Easy to hear, and on wet days visible as a cloud of spray.
• V1, VR, V2 – speeds during takeoff: from V1 the takeoff is generally continued, at VR the rotation begins, and V2 is the speed at which the aircraft can climb safely even with an engine failure.
• Heavy / Super – ICAO wake turbulence categories. Aircraft with a maximum takeoff mass of 136 tonnes or more count as heavy, and the Airbus A380 is classified as super. These aircraft state the category directly after the callsign on first radio contact.
• Wake turbulence – the air vortices behind the wingtips that force aircraft to keep their distance. See Wake turbulence and separation.

Radio and data

This area answers: how do I know what is coming next?

• Callsign – the identifier of a flight on the radio, in flight data usually made up of the airline’s three-letter ICAO code and an identifier (such as DLH plus a number), and on the voice radio the airline’s radio name. It is not always identical to the flight number on the ticket; the article Callsign and flight number explains the difference.
• Delivery, Ground, Tower, Approach, Center – the main radio units a crew talks to during a flight: route clearance, taxi traffic, takeoff and landing, approach, and en route. Overview in the guide Tower, Ground and Approach.
• ATIS – an automatic broadcast with weather, runway direction in use and active runways, updated and tagged with an identifying letter. See ATIS explained.
• METAR and TAF – the coded weather report and weather forecast for an airport. How to read them is shown in the guide METAR and TAF for spotters.
• Squawk – the four-digit transponder code. 7500 means hijacking, 7600 radio failure, 7700 a general emergency. Background under Squawk codes 7500, 7600, 7700.
• ADS-B – the system with which aircraft broadcast their position, altitude and identification themselves. The basis of all flight tracker services; more under Flight tracking with ADS-B.
• ACARS – a data link for short text messages between aircraft and ground. See ACARS explained.
• ETOPS – rules mainly for twinjets on routes far from alternate airports, typically over oceans. More in the article ETOPS explained.

Airline and business

Here the question is: why is this aircraft flying here in the first place? The leasing terms in particular explain many apparent puzzles.

• Wet Lease (ACMI) – an airline rents an aircraft with crew, maintenance and insurance, hence ACMI for aircraft, crew, maintenance, insurance. The flights operate under the lessee’s flight number, but the aircraft often flies in the lessor’s colors. Typical for seasonal peaks or maintenance outages. Covered in detail in the guide Wet lease explained. “Today the leisure flight showed up in someone else’s livery – wet lease.”
• Damp Lease – an in-between form in which the lessor provides the aircraft, the cockpit crew and maintenance, and the lessee provides the cabin crew.
• Dry Lease – only the aircraft is provided, without staff. The lessee operates it with its own crew and its own air operator certificate (AOC), usually for several years. More on the principle under Aircraft leasing explained.
• Codeshare – a flight sold under several flight numbers of different airlines but operated by only one. See Codeshare explained.
• Alliance – a grouping of several airlines with a coordinated network and shared frequent flyer benefits, such as the Star Alliance.
• Charter – flights that are chartered wholly or partly by a tour operator or client, as opposed to scheduled flights. Differences under Charter vs. scheduled flights.
• Ferry Flight – a repositioning flight without passengers, for example for deliveries or shipyard visits. How to find them is shown in the guide to delivery and ferry flights.
• Livery – an aircraft’s paint scheme. A special livery is a special paint scheme for anniversaries, events or advertising; a hybrid livery mixes elements of two operators, often after a change of ownership. See Finding special liveries and Spotting hybrid liveries.

Photography and the scene

The last area describes how a picture comes about and how the community talks about it.

• Spot – the specific location you shoot from, from the visitors’ hill to a gap in the fence. What is allowed there is summarized in the article Is plane spotting allowed?
• Sighting – the documented observation of an aircraft with reg, type, place and time.
• Side view and three-quarter view – the pure profile shot as opposed to the angled perspective on nose and flank.
• Panning – swinging the camera with the aircraft at a longer exposure so that propellers or the background show motion. Instructions under Panning technique.
• Heat haze – rising warm air above asphalt, which blurs details at long distance.
• Backlight and front light – sun behind or in front of the subject. How to find your time window is shown in Planning the sun position.
• Rarity – an aircraft, airline or type that rarely shows up at an airport. How to judge that is described in the guide Judging how rare a sighting is.
• Bus – scene shorthand for Airbus aircraft, especially the A320 family. “Nothing but Buses today, not a single heavy.”

Terms that are regularly mixed up

Pair of terms	The difference	How to tell
Wet lease vs. dry lease	In a wet lease the crew comes along, in a dry lease only the aircraft	Wet lease: someone else’s livery, the lessee’s flight number; dry lease: usually the operator’s own colors
Callsign vs. flight number	The callsign applies on the radio, the flight number in ticket sales	On flight tracker maps both often appear side by side and differ
Reg vs. hex code	The reg is on the outside of the aircraft, the hex code is inside the transponder	You read the reg off the fuselage, the hex code only through receivers and databases
Go-around vs. holding	A go-around aborts a landing, holding is waiting before the approach	A go-around happens low over the runway, holding usually farther away and higher in oval holding patterns
Approach vs. final	Approach is the entire arrival, final only the last straight stretch	Final runs on the extended runway centerline
Codeshare vs. wet lease	A codeshare is only a sales arrangement, in a wet lease an aircraft with crew is rented	Codeshare flights have several flight numbers, wet lease flights usually only the lessee’s

Common mistakes when using the terms

• Mixing up identifiers. Posting a flight number as a reg causes confusion – a flight number is flown by different aircraft every day.
• Treating every go-around as an emergency. Go-arounds are part of everyday operations. You are more likely to recognize real emergencies by squawk 7700 and official reports, not by speculation in the chat.
• Equating type and variant. “A321” is not the same as “A321neo”. For clean sightings, the variant counts.
• Confusing the livery with the operator. An aircraft in the colors of airline X may be flying on a wet lease for airline Y. When in doubt, check the flight number.
• Reporting sightings without context. “Something rare today” helps nobody. Without reg, type, place and time, a report is worth very little.

Conclusion

The language of plane spotters seems at first like a radio call without a translation, but it follows a clear logic. If you keep the five areas apart – airport operations, technology, radio and data, the airline business and photography – you will understand most conversations after a few spot visits. Many terms are official aviation vocabulary, and that is exactly why it pays to use them correctly. Even so, the fastest way to learn them is not from a list but at the fence, with the radio in your ear and a live map on your phone.