A BREAKDOWN in radio communications has been blamed for a near head-on collision in January by two planes taking off from Tyabb airfield.
Each plane had to veer away just after taking off from opposite ends of the same runway.
Investigators have found that neither pilot heard that the other was about to use the runway and the club says it remains a mystery why their respective radio broadcasts were not received.
However, a bystander hearing both broadcasts on a hand-held radio quickly sounded the alarm, but that too was not heard by either pilot.
A student pilot in one of the planes – broadcasting “rolling runway 35” at the same time – “may have over-transmitted the call”, Australian Transport Safety Bureau investigators have found.
While the pilots elected to veer left to avoid collision, regulations state they should turn right.
Peninsula Aero Club vice-president Jack Vevers said radio problems were “the root cause” of the incident. These are being investigated. He confirmed the pilots’ evasive action was reasonable in the circumstances and “worked out well”.
The near disaster occurred about 2pm on 2 January when the pilot of a Starduster SA300 aircraft began pre-flight preparations for a local private flight. Unknown to him, a Cessna 152 was moving towards the other end of the same runway (No. 17) – and would soon be pointing straight at him.
An safety bureau investigation – concluded on 22 April – found the Starduster pilot had followed airfield procedures on the calm day and used runway 17, which he confirmed on the usual common traffic advisory radio frequency. At about the same time, an instructor and student pilot in the Cessna radioed that they were about to use runway 35 – the other end of the same runway – but the pilot of the Starduster did not hear that broadcast, nor see the Cessna at the time.
Taxiing to runway 35, the student pilot broadcast he was lining up and getting ready to go. The pilot of the Starduster did not hear him and was by then at runway 17 where he broadcast that he was lining up and about to depart. The pilots of the Cessna did not hear him, either.
As the Cessna lifted off, the instructor saw the Starduster on its take-off run straight ahead and, taking control, began a left banking turn while keeping the other plane in sight. Approaching, three metres off the ground, the Starduster pilot saw the Cessna and – taking his cue – also banked to his left. The two aircraft passed about 50 metres apart with the Starduster slightly higher. It then joined the circuit for runway 35 on the crosswind leg, and broadcast that it was returning to land at Tyabb.
Mr Vevers said an “out clause” in the regulations meant the instructor in the Cessna had “done the right thing” in turning left first up. “This allowed him to maintain visual contact with the other plane as well as avoid flying over built-up areas,” he said. “That decision worked out well and he had a good reason for making it.
“Different situations allow for different actions. I would have done the same thing myself.”
The aero club self-reports to the ATSB any serious safety incidents as a way of retaining the investigative services of a high-level team of experts and to educate its pilots.
“It is important that we work out why this incident happened and implement improvements straight away,” Mr Vevers said. “We have found that we are getting radio interference at either ends of the runway and we have not been able to identify why.
“We investigated perceived problems with line-of-site but that is not the problem. Something else is interfering with our radios and we are unsure what it is but we are working on it.
“That’s why we went to ATSB – the on-ground radio broadcast was only heard by the Cessna. Something was blocking it from the other aircraft.”
Mr Vevers said new procedures initiated as a result of the incident, such as pulling holding points back to before pilots enter the runway, would open up their line-of-site in future. The club will review installation of an Aerodrome Frequency Response Unit to assist in selecting the correct VHF frequency, as well as a means of recording the Common Traffic Air Frequency. It will also review its Emergency Management Plan.
The airport’s En Route Supplement Australia entry (the aviation “bible” relating to runway use) will be amended as the documented runway layout “may have been misleading”.
Both the pilot of the Starduster and the instructor of the Cessna are aware of the local instruction for the preferred runway in nil or cross wind conditions, the ATSB found.
“The risk of reduced separation events can be minimised through good communication by pilots. Most importantly, a good visual lookout should be maintained at all times,” it said.
Despite both pilots banking left in this incident, one in response to the other, Civil Aviation Regulations 1988 – Regulation 162 ‘Rules for Prevention of a Collision’ – state: “When two aircraft are approaching head-on … and there is a danger of collision, each shall alter its heading to the right.”
However, the ATSB said that, in this case, the pilot of the first aircraft elected to turn left “to keep the other aircraft in sight and clear of his aircraft and successfully avoided the potential for collision. The other pilot responded equally and turned left when he saw the opposing aircraft turning left”.
The spokesman reiterated that the ATSB “investigates to improve safety, not to apportion blame or determine liability (or fault)”. It is responsible for investigating incidents and other transport safety matters involving civil aviation, marine and rail operations in Australia that fall within Commonwealth jurisdiction, as well as participating in overseas investigations involving Australian registered aircraft and ships.
The object of a safety investigation is to identify and reduce safety-related risk. ATSB investigations determine and communicate the safety factors relating to the transport safety matter being investigated.
