Sequence of events
The crew of a Metroliner, conducting a scheduled passenger service from Sydney, reported that at 30 NM from Latrobe Valley, they obtained weather information from their ground agent on the common traffic advisory frequency (CTAF). They recorded the wind as light and variable. At approximately 17 NM, the co-pilot broadcast on the CTAF advising their intention to join for a 5 NM straight-in approach to runway 21. Two similar broadcasts were made, one at 10 NM and the other at 5 NM. At approximately 1 NM from touchdown, the crew saw a Chipmunk aircraft a short distance to their left and about 400 ft above them, travelling in the opposite direction. The crew continued their approach and landing as they considered that there was no further risk of collision.
The Chipmunk pilot was conducting a private flight. He reported that the aircraft radio had undergone maintenance prior to the incident flight and that he was unsure if a functional check of the radio had been made. He determined that the wind was a light north-easterly and elected to use runway 03. He broadcast on the CTAF that he was taxiing, and made a further transmission advising that he was backtracking along runway 03. He did not hear any response to either broadcast and had not heard the aerodrome frequency response unit. He assumed that his aircraft radio was not operating and proceeded with the flight without making any further radio broadcasts.
The pilot of the Chipmunk reported that he did not see any aircraft either when entering the runway or when lining up for takeoff. He departed and climbed away, unaware that the landing Metroliner had passed below him. Although he was aware that scheduled flights operated into the aerodrome, he was not familiar with those schedules. He was also unaware that such aircraft could conduct straight-in approaches to CTAF aerodromes. He reported that although his aircraft was equipped with a landing light, he was not in the habit of using it in daylight conditions.
Witness information
An instructor at the aerodrome reported that, at the time of the occurrence, the Chipmunk and the Metroliner were the only aircraft in the circuit. He added that other aircraft movements that day had been made from runway 03.
Following this incident, another instructor observed the straight-in approach procedure under similar conditions. He stationed himself at a position similar to that of the Chipmunk pilot at takeoff in order to determine the visibility of the approaching Metroliner. He reported that when the crew broadcast their 5 NM position, he was only able to see the aircraft after several seconds of looking. However, at an estimated 3 NM, with the landing gear extended and the taxi light illuminated, it was much easier to see the aircraft.
Weather
Weather conditions at the time of the occurrence were described as fine and clear with good visibility. Witnesses on the ground reported the wind as 5-8 kt from the north-east. Data recorded from the automatic weather station (AWS), indicated that a north-east wind had prevailed from 1100 Eastern Standard Time (EST) onwards. The Latrobe Valley METAR (meteorological observation) at 1304 EST indicated that the wind direction was 070 degrees magnetic and the windspeed was 7-10 kt. Those conditions favoured the use of runway 03.
Straight-in approach procedures
On 26 March 1997, the Civil Aviation Safety Authority permitted multi-crew regular public transport aircraft to conduct straight-in approaches to non-controlled aerodromes other than those within a mandatory broadcast zone. Effective from 1 May 1999, amendment 35 to the Civil Aviation Orders (CAO) part 82.3 incorporated a new sub-section 5A that required the provision of a ground-based radiocommunication service at aerodromes where straight-in approach procedures were conducted. However, following industry concerns about the operator's liability in relation to the provision of traffic information and the cost to airlines of providing such a service, that section was amended. CAO amendment 41 was issued with a new sub-section 5B that restricted the information to be given by the radiocommunication service to wind direction and runways in use at the aerodrome.
The company operating the Metroliner contracted the services of a ground-handling and booking agent to perform the required radiocommunication service, and personnel were trained and approved to provide that service. The procedure required the agent's staff to obtain weather information from the AWS and, when requested, broadcast this information to company pilots on the CTAF. Information about other traffic or the runway in use was not transmitted.
The agent advised that crews could obtain traffic and runway information from other aircraft on the CTAF. Other duties performed by the agent's staff precluded them from continuously monitoring the CTAF for information about other traffic. Additionally, the company radio was situated in the airport terminal and only a limited view of the airfield was afforded through the windows. Visual observation of aerodrome traffic from this location was not possible. The Chipmunk would not have been visible from this vantage point at any time it was taxiing or airborne.
There were no specific company instructions for crews making straight-in approaches at CTAF aerodromes. Company management personnel were satisfied that the procedures contained in the Aeronautical Information Publication were adequate. Company standard operating procedures required the landing and recognition lights to be turned on as aircraft were approaching 10,000 ft when transition checks were being completed. The taxi light was not to be turned on until after the landing gear was extended. The crew reported that that procedure had been followed.
The pilot in command advised that the crew's preferred choice of runway direction at Latrobe Valley on the flight from Sydney was runway 21. This not only reduced flying time but also allowed crews the 3-minute cooldown period for the engines while backtracking to the terminal. It also avoided running the engines near the terminal and creating unnecessary noise.
Determination of the runway in use, as required by the Aeronautical Information Publication (AIP) procedure, was assumed by crews to be either the reported runway being used by other traffic in the circuit or, in the absence of other traffic, runway 21, provided that wind conditions were favourable. The view expressed by the pilot in command was that the straight-in approach procedure offered a better level of safety than that provided by the normal circuit entry and that it was more expedient. He believed that the procedure resulted in less circuit manoeuvring and a reduced risk of traffic conflicts.
Aerodrome traffic
This incident occurred on a Sunday afternoon. The airline operated six services per week into Latrobe Valley but only one of these flights was conducted on a weekend. The pattern of activity at the aerodrome was not recorded however, staff at the Aero Club were able to confirm that most recreational flying activity took place at weekends and on public holidays. Only a small number of aircraft operating from the aerodrome were not radio-equipped. The scheduled movements at Latrobe Valley were not published in any of the aeronautical publications.