Embraer-Empresa Brasileira De Aeronautica EMB-110P1 , VH-UQF

Local safety action

Airservices Australia advised that the following procedures
were to be implemented with immediate effect (27 August 1998):

" A coordinator shall be assigned to FS1 at least 15 minutes
prior to expected multiple movements at MOK whether inbound or
outbound.
Communications shall be managed by FS1 and FS5 so that all
aircraft at A100 and below shall be in HF contact with FS1 when
crossing the FIA boundary north/south between 122.4 and 125.7 or at
top of descent into MOK from flight levels.
VHF transfers between 125.7 and 122.4 shall not be attempted in
either direction with aircraft at or below A100.
Aircraft not capable of continuous two-way contact with either
FS1 or FS5 shall be advised that "IFR operations are not permitted
without continuous two-way comms, advise intentions". Pilots should
be expected to proceed VFR at a VFR level, with a SARTIME.
If considered of value and as a prompt, primary and secondary
HF frequencies may be given to IFR flights arriving at MOK as
follows;

When aircraft report arrival at MOK, they may be
instructed to "report taxying and departure on ... (HF frequency)
as primary, with ... as secondary".
IFR aircraft that fail to report departure MOK within 10 NM of
the aerodrome or prior to climbing through A050 shall be the
subject of an immediate phone call to their company. This shall be
done by the Group Leader if on duty or the TLDR or OCA officer at
all other times.
If considered of value in difficult communications conditions,
traffic information may be directed to IFR flights on anticipated
MOK departures that may not have reported taxying.
The situation with MOK traffic, communications, frequency
congestion and pilot movement reports will be reviewed over a trial
period of 28 days. Further action will be taken as circumstances
warrant."

Bureau of Air Safety Investigation safety action

As a result of this and a similar occurrence, the Bureau of Air
Safety Investigation is currently investigating a perceived safety
deficiency relating to the air traffic service operational
limitations of Brisbane Flight Service 1 position.

Any safety output issued as a result of this analysis will be
published in the Bureau's Quarterly Safety Deficiency Report.

The pilot of one aircraft did not report taxiing at Mitton
Creek to the FS1 officer.
VHF radio coverage did not extend to the Mitton Creek
airfield.
HF radio operation was intermittent on the morning of the
occurrence.
The large number of flights being managed on retransmitted
frequencies by the FS1 officer made radio communication
difficult.
The delay in the transmission of the departure reports by three
of the aircraft limited the ability of the FS1 officer and pilots
to fully appreciate the amount of aircraft traffic in the
area.

Had the pilots of all the departing aircraft persisted with
attempts to report taxiing at Mitton Creek to the FS1 officer it is
probable that they would have received the necessary traffic
information. While this would have delayed some flights, it would
have ensured that the required traffic information was received by
pilots prior to departure. While two pilots were able to have their
taxi report relayed through the pilot of airborne aircraft, there
was no confirmation that they had received the required traffic
information.

The complexity of the traffic and the number of pilots operating
on the FS1 frequencies made it difficult for the officer to
communicate the required traffic information to pilots. The ability
to transfer the retransmitted frequency to another operating
position within the flight service centre would have reduced the
number of radio communications being received/transmitted by FS1.
This would have assisted the officer to manage the traffic
situation.

The crew of the instrument flight rules (IFR) EMB110 did not
receive traffic information on two IFR category aircraft that had
departed Mitton Creek. The crews of the departing aircraft did not
report taxiing prior to departure.The flight service (FS) frequency
for the area was congested and it was difficult to communicate.
Consequently, the crew was unable to coordinate the use of lateral
or vertical separation techniques with the crews of the departing
aircraft.