A guide to what some of that jargon means….

Have you ever wondered what all the acronyms, jargon and terminology mean? Well, there’s so many that covering them all in one blog is impossible. For now, we’ll look at some popular ones.

ACARS – Aircraft Communications Addressing and Reporting System. It’s a digital system used to exchange information between aircraft and ground stations. It facilitates message transmission related to various aspects of flight operations. This includes aircraft performance, maintenance and ATC communications.

ADS-B – Automatic Dependent Surveillance-Broadcast. The main technology used to track aircraft by companies such as FR24. Automatic means data sent from an aircraft without pilot intervention. Dependent, it relies on the aircraft’s navigation system for position information. A transponder that is ADS-B equipped allows extensive flight details to be sent. These include altitude, call sign, ground speed, wind and temperature. As you know, FR24 has a global network of receivers that can use these transmissions to provide a unique flight tracking service.

Airway – the route along which an aircraft travels to its destination. It connects set locations using navaids and waypoints. If you’ve ever seen a map of airways, they can be fascinating just for the names used. A standard format of 5 uppercase letters is utilised, the name often having a meaning depending on the country. USA uses DUMBO, JAFAR and PIGLT near MCO. In the UK, names are more straightforward. CHASE, HEMEL and KIDLI some of the easier ones to understand due to their location. FlightAware is a good site for seeing a flight’s airways routing; it’s available without paying any extra!

Automatic Terminal Information Service – known as ATIS. It’s a continuous recorded broadcast providing information such as weather, active runway, runway state, NOTAMs and other information needed by pilots. Typically the broadcast is also coded with a reference letter, for example Information Alpha. This denotes the current version. ATC provide approaching aircraft with this information, but it can also be heard on transmissions from pilots when requesting departure clearance.

Contrails – just including this as a reminder. They are not chemicals being pumped into the atmosphere to “drug” a country’s population! It’s nothing more basic than visible lines that sometimes form behind an aircraft in flight. Hot exhaust gases combine with cold, moisture laden air in the upper atmosphere. The water vapour condenses into tiny ice crystals which then freeze into small particles, hence the visible cloud. It may appear white or slightly grey, depending on the ice particles size and density. If you follow any pilots on social media, this explains why a passing aircraft appears to be creating mid to dark grey trails.

Displaced Threshold – DTHR is one for our members who spot at DUB. It’s a runway marking that indicates a point on the runway other than the beginning or end. They can be temporary or permanent, reducing the length available for landings in one direction. The area behind a DTHR can be used for take-offs in either direction and landings from the opposite direction. It doesn’t always work as planned. Recently, it was introduced at DUB at around 1400 hours. Then 30 minutes later, withdrawn because of worsening crosswinds. However, not until several aircraft had entered a holding pattern or diverted to another airport. As you can probably guess, it’s not popular with pilots!

Extended Range Operations – ETOPS will be displayed on the side of the aircraft. It’s a certification allowing operation on routes that are farther away from diversion airports than would be allowed by standard regulations. Used to be known as Extended Range Twin-Engine Operations when 757 and 767 operators developed long-haul flights over water or remote areas. Therefore allowing the airlines to operate more efficient and cost-effective routes.

Holding Pattern – if you’re watching activity at a certain airport on FR24, you will often see a holding pattern. LHR ones can be interesting to watch. Reasons include wind out of limits for landing, runway still occupied, other weather-related issues. Most common non-UK airport for this is FNC. Holding patterns, whether a circular orbit or oval shaped, occur over a fixed waypoint, usually a VOR.

Localiser – a fundamental component of the Instrument Landing System (ILS). It operates on a lateral axis, providing horizontal guidance to an aircraft during approach and landing. Located at the far end of the runway, it transmits a radio signal used by pilots to align their aircraft with the runway centreline.

Precision Approach Path Indicator – or PAPI for short. A visual aid for pilots during approach to landing. Located beside the runway, these light project a 2-colour signal of white and red. When an aircraft is on the correct glide path, the pilot sees 2 red and 2 white. If too high, 3 or more white, signalling a descent adjustment is needed. Too low, then more red lights show.

QNH and QFE – both are aeronautical “Q” codes. QNH provides a barometric altimeter setting relating to airfield elevation above mean sea level. QFE is also an aeronautical “Q” code which provides a barometric altimeter setting which causes an altimeter to read 0 when at the airfield’s reference datum point.

In other news –

Boeing – FAA has issued a new Airworthiness Directive for the B717. It will have a substantial impact on operations of at least 2 US airlines. The AD was prompted by the Delta incident in 2023, which landed without nose gear. Repetitive inspections for cracking of the upper lock link assembly are now required. This additional maintenance burden may hasten the aircraft’s imminent retirement.

And finally –

American Airlines – drew a frenzy of speculation recently when the company’s name appeared beside Spirit, sparking many reports of a takeover. The real reason for the link is Spirit recently transferred 2 gates at ORD to AA for $30m. However, this hasn’t quashed the opinion that the low-cost carrier is unlikely to survive into 2026.

Information courtesy of FR24, FlightAware

Images courtesy of Time & Navigation, Pilot Mall

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