Background
From 31 March to 20 May 2025, taxiway construction works were carried out at Adelaide Airport, South Australia. To accommodate the works, the runway 23 start of take-off (SOT) position was temporarily displaced 650 m beyond the normal runway start, and the runway 23 landing threshold was displaced a further 508 m beyond the temporary SOT position.
Occurrences
Thirteen occurrences were identified in which aircraft commenced take-off from the displaced threshold instead of the intended SOT position. The first incident occurred on 31 March 2025, and the last on 20 April 2025. The occurrences took place during both daylight and night-time hours and involved several aircraft operators. Several other potential occurrences were prevented by intervention from air traffic control (ATC) or by flight crews contacting ATC or their flight operations support personnel before departure to confirm the correct SOT position.
Flight Crew Experiences
Two flight crews interviewed by the ATSB had read available documentation regarding the aerodrome works and received the automatic terminal information service (ATIS) prior to taxiing. They had identified the works and displaced threshold as threats and were aware of different runway positions for landing and take-off. Both crews had landed on the runway less than 35 minutes earlier, successfully identifying the displaced threshold. They also noted a reminder in the operational documentation not to commence take-off before passing the runway end. However, after receiving clearance to enter the runway at the B2 holding point and taxi to the displaced runway end (SOT position), the flight crews did not identify the white line indicating the SOT position as stated in the revised NOTAM (and elsewhere). Due to bright sunny conditions, they did not see the start of red edge lights (specified as visual cues for night and low visibility conditions), which commenced at the SOT position. Consequently, they taxied to the displaced threshold before commencing take-off. In one incident, this was likely influenced by observing an aircraft ahead commence take-off from the displaced threshold. The flight crews later realized the error and reported the occurrences.
For the other 11 occurrences, identified by aircraft operators' analysis of recorded flight data, it was unknown how much of the related documentation flight crews had reviewed or whether they were aware that the aircraft had departed from the incorrect position.
Visual Cues and Confusion
Given the high number of occurrences, both day and night involving different aircraft operators and the combined significant experience of the involved flight crews, the visual cues for the SOT position were almost certainly confusing. By day, the white arrows and threshold lights were more prominent than the white runway end line designating the SOT position. However, there was no mention in the documentation of the white arrows, which pointed towards the displaced (landing) threshold. Flight crews found that these arrows indicated to continue moving forwards before commencing take-off. The red runway edge lights were illuminated day and night from 4 April 2025 but were not readily visible in daylight. At night, the start of runway being a transition from green taxiway lighting to red edge lighting was insufficiently distinct. Additionally, being red (intended to indicate to pilots of landing aircraft not to land before the displaced threshold), the edge lights did not intuitively indicate the start position for take-off. The runway end line, while perceptible, did not identify the line as an indication of the start of runway position to many flight crews, and it had the same characteristics as the white displaced threshold line.
Additional Observations
The ATIS did not contain any information relating to the SOT position other than a difference between the stated take-off and landing distances, so it did not offer a means to correct an incorrect understanding of its location. Many pilots queried ATC as to the correct SOT position.
Analysis
The source analysis discusses the effectiveness of the works information provided to flight crews, including aerodrome works lights and markings, and the required aerodrome standards. It also reviews the contents of the NOTAM and its effectiveness in describing the SOT position. ATC phraseology is discussed, along with strategies used by controllers to assist pilots in identifying the SOT position. Finally, the Civil Aviation Safety Authority's (CASA) review of the method of working plan and the timeliness of that review is analysed.