Shielding from buildings at Geraldton Airport and inaccurate relayed information contributed to the pilots of two charter aircraft commencing their take-off runs from runways with intersecting flight paths within seconds of each other.
An ATSB investigation report details that just after 8 am on 19 March 2024, a Fairchild Metroliner was lined up on the threshold of Geraldton's runway 03 to take off to the north-east, while a Beechcraft Bonanza was lined up on runway 14, to take off to the south-east.
While the two runways do not cross each other, they form a 'y' shape in which aircraft departing runway 14 (and landing on the reciprocal runway 32) overfly runway 03 (and the reciprocal runway 21).
Geraldton Airport is a non-controlled aerodrome, where pilots are responsible for maintaining separation from other aircraft by monitoring and broadcasting radio calls on a common traffic advisory frequency, or CTAF.
After reaching their respective runway thresholds and preparing for take-off, each pilot had attempted to contact the other, but they could not hear or see one another.
The pilot of a third aircraft, from the same operator as the Bonanza, attempted to assist by passing along traffic information.
However, the aircraft began their take-off rolls within three seconds of one another, and the Metroliner crossed about 400 m in front of the Bonanza, with a vertical separation of about 250-300 ft.
The ATSB investigation confirmed the position of airport buildings made it unlikely aircraft would be able to see one another when positioned at the thresholds of runway 03 and runway 14, which are over 2,100 m apart.
Further, the investigation found aircraft in these positions may not be able to reach one another on VHF radio due to potential shielding effects.
"Each aircraft was unable to verify the other's location while lined up for take-off," ATSB Director Transport Safety Kerri Hughes said.
"While the third aircraft pilot was attempting to assist, the details provided were inaccurate and incomplete, which inadvertently resulted in misinterpretation by the Metroliner and Bonanza pilots, influencing their almost simultaneous decisions to take off."
After the incident, Geraldton Airport conducted radio checks which identified the potential for VHF shielding. The airport subsequently submitted an amendment to the En Route Supplement Australia to highlight this possibility.
"Operations at non-controlled aerodromes require pilots to monitor traffic and maintain separation through the use of VHF radio in conjunction with a vigilant lookout under the principles of alerted see-and-avoid," Ms Hughes explained.
"As such, especially where communications and visibility are limited, it is critical for pilots to take all reasonable measures to verify the position and intentions of known traffic."
CASAIR, the operator of the Metroliner, has since emphasised to its pilots to stop or slow down when communication difficulties are identified, until completely assured of the situation.
Similarly, Shine Aviation, the operator of the Bonanza, has highlighted to its pilots the importance of being completely certain of another aircraft's position and intentions, and not to make assumptions.
You can find here the report: Near collision involving Beechcraft A36, VH-CKX, and Fairchild SA226-TC, VH-KGX, at Geraldton Airport, Western Australia, on 19 March 2024
