Fairchild Industries Inc SA227-DC , VH-DMO, 2 km NNE Latrobe Valley, Aero. 25 July 1999

The pilot of the Chipmunk did not see the Metroliner. It is likely that the pilot commenced his take-off roll when the Metroliner was at least 3 NM from touchdown. At that distance, the Metroliner may not have been readily detectable by the Chipmunk pilot. His lookout for possible traffic would most likely have been directed towards the circuit and approach of runway 03 rather than towards runway 21 and he would not have been expecting to see traffic approaching from the opposite direction. With the aircraft in the level attitude during takeoff, he would have been looking along the runway and his attention would have been focused on maintaining directional control. The Metroliner would most likely have been obscured from the Chipmunk pilot's view by the nose of his aircraft when he subsequently rotated to the climb attitude.

The crew of the Metroliner did not see the Chipmunk until that aircraft was almost overhead theirs. As they had not received any response to their broadcasts on the CTAF, they were relying on visual acquisition of any unalerted traffic as their only defence against a conflict. However, the Chipmunk was a small visual target with little relative movement. In addition, it had no anti-collision lighting and would initially have been below the Metroliner crew's horizon. The contrast between the background and the colour of the Chipmunk was minimal and would have made the aircraft difficult to discern.

The straight-in approach procedure at CTAF aerodromes did not appear to adequately address the limitations of unalerted "see and avoid" principles. The assumption of two pairs of eyes being more likely to detect unalerted aircraft than one pair of eyes, did not prove to be an adequate defence in this incident.

In this instance, the crew of the Metroliner elected to make a straight-in approach in wind conditions that most probably favoured a reciprocal runway direction. Without any response to their broadcast intentions, the crew probably assumed that there was no traffic and believed it was safe to use runway 21. As regulations in force at the time of the occurrence did not include a requirement for an airline operator to assess the circumstances and the likelihood of encountering non-radio traffic at individual locations, it was likely that many crews were conducting straight-in approaches as an expected routine. Had the crew been aware, for example, of the potential for greater numbers of recreational movements at weekends and on public holidays, they may have decided not to conduct the straight-in approach.

Although the company had provided a radiocommunication service to comply with the requirements for this procedure, its effectiveness to alert the crew to other aircraft was restricted by company procedures and by the physical location of the radio operator. The radio operator was not familiar with aircraft movements and had never been instructed to provide runway-in-use information. Had the radio operator been afforded a full view of the entire runway and the approach path of the Metroliner and permitted to issue traffic information, a timely warning may have been broadcast to the crew of the Metroliner about the presence of the Chipmunk.

The pilot of the Chipmunk chose to continue his flight without radio communication and without knowledge of a procedure that could place him in potential conflict with a passenger-carrying aircraft. Knowledge of scheduled aircraft movements at that location may have influenced the pilot to avoid commencing a non-radio flight when the arrival of a scheduled service was imminent.

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.