| Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation. |
What happened
On 27 April 2018 at approximately 0905 Eastern Standard Time, a Glaser-Dirks DG-1000S glider aircraft (the glider) was conducting solo training in the left-hand circuit of runway 08 at Bathurst Airport, New South Wales. As the glider made its downwind radio call, a Cessna aircraft broadcast that it was taxiing for runway 35. The pilot of the Cessna acknowledged a further call made by the glider ground controller that there was a glider training in the circuit area.
Several seconds later the glider turned onto the left base of the circuit and broadcast, “turning left base, runway 08”.
Later, as the glider was turning final for runway 08, the Cessna broadcast its rolling call on runway 35. Recognising the potential separation issue at the intersection points of runways 08 and 35, the glider ground controller called “ABORT, ABORT, ABORT, glider on final runway 08”.
The Cessna pilot brought the aircraft to a full stop prior to the intersection and the glider landed on runway 08 without incident. The Cessna pilot then backtracked and departed from runway 35.
Figure1: Diagram of Bathurst Airport showing indicative aircraft position
Related occurrences
A search of the ATSB database revealed a similar occurrence that took place at Bathurst Airport in 2016:
On 13 April 2016, an instructor and student of a Jabiru J170-D aeroplane, registered 24-7750 (7750), conducted a local training flight from Bathurst Airport, New South Wales. At about 1446 Eastern Standard Time, the aircraft arrived in the circuit, and the instructor broadcast that they were joining the circuit on an early downwind for runway 17, for a full-stop landing.
Powered aircraft were operating on runway 17 and gliders (and towing aircraft) were operating on runway 08.
Meanwhile, a student pilot of a Glaser-Dirks DG-1000S glider, registered VH-NDQ (NDQ) was conducting a solo flight at Bathurst. At about 1449, about 90 seconds after the pilot of 7750 had communicated with Glider Ground regarding glider traffic in the air, the pilot of NDQ broadcast on the Bathurst CTAF that they were on left downwind for runway 08.
After 7750 touched down on runway 17, about 100 m before the intersection with runway 08, the pilot sighted a glider (NDQ) on short final for runway 08, at an estimated 100 feet above ground level. The pilot applied full power to cross runway 08 as quickly as possible.
As 7750 landed, the pilot of NDQ assessed that there was the potential for a collision, closed the glider’s airbrakes and initiated a climb to pass over 7750. The glider then landed ahead on runway 08.
The instructor in 7750 lost sight of NDQ as it passed overhead. As 7750 accelerated with a high power setting, the instructor elected to continue a take-off and conducted a circuit before landing safely.
Safety message
While in this case, the incident did not result in a near collision, the safety message remains the same between the two occurrences.
Simultaneous operations on crossing runways can be problematic, particularly where the operation types are different (such as powered flight and gliding operations). Organisations responsible for the coordination and conduct of such activities are encouraged to carefully assess and manage the risks involved. This is particularly important when operations are likely to involve instructional flights and less experienced pilots, where workload and the potential for pilot distraction may be elevated.
This incident highlights the importance of effective communication. The primary purpose of communications on the CTAF is to ensure the maintenance of appropriate separation through mutual understanding by pilots of each other’s position and intentions. Where a pilot identifies a risk of collision, that pilot should alert others as soon as possible to allow a coordinated and effective response.
Civil Aviation Advisory Publication 166-1(3) stated that ‘whenever pilots determine that there is a potential for traffic conflict, they should make radio broadcasts as necessary to avoid the risk of a collision’.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.