Aviation safety investigations & reports

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

Investigation number:
Status: Completed
Investigation completed


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.


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.

Significant Factors

  1. The pilot of one aircraft did not report taxiing at Mitton Creek to the FS1 officer.
  2. VHF radio coverage did not extend to the Mitton Creek airfield.
  3. HF radio operation was intermittent on the morning of the occurrence.
  4. The large number of flights being managed on retransmitted frequencies by the FS1 officer made radio communication difficult.
  5. 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.

Safety Action

Local safety action

  • Airservices Australia advised that the following procedures were to be implemented with immediate effect (27 August 1998):
  1. " A coordinator shall be assigned to FS1 at least 15 minutes prior to expected multiple movements at MOK whether inbound or outbound.
  2. 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.
  3. VHF transfers between 125.7 and 122.4 shall not be attempted in either direction with aircraft at or below A100.
  4. 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.
  5. 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".
  6. 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.
  7. 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.
  8. 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.

General details
Date: 19 August 1999   Investigation status: Completed  
Time: 0745 hours EST    
Location   (show map): 30 km E Mitton Creek    
State: Queensland   Occurrence type: ANSP info/procedural error  
Release date: 20 August 1999   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Embraer-Empresa Brasileira De Aeronautica  
Aircraft model EMB-110  
Aircraft registration VH-UQF  
Serial number 110232  
Type of operation Air Transport Low Capacity  
Damage to aircraft Nil  
Departure point Mount Isa, QLD  
Departure time 0710 hours EST  
Destination Doomadgee, QLD  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer Fairchild Industries Inc  
Aircraft model SA227  
Aircraft registration VH-UZA  
Serial number AC-619B  
Type of operation Air Transport Low Capacity  
Damage to aircraft Nil  
Departure point Mitton Crek, QLD  
Destination Townsville, QLD  
Last update 13 May 2014