Jump to Content

The crew of VH-XDZ, a SAAB 340 operating an IFR category flight taxiing at Mt Isa was not passed traffic information on VH-XDA, another SAAB 340 operating an IFR flight inbound to Mt Isa on the same track to be used by the departing aircraft. The flight service officer was not aware of this omission until the aircraft had passed in flight at 1750 EST.

The incident occurred during a peak in traffic movements, with multiple transmissions from aircraft on both VHF and HF frequencies in airspace that encompassed a large and complex geographical area. The work position comprised 2 HF networks, each with three frequencies, as well as four VHF repeaters. Because of the size and complexity of the airspace, the console needed a large chart display on a mobile trolley placed at 90 degrees to the console operator's position to supplement the overhead map display. The flight service officer reportedly had about 15-18 active flight progress strips for aircraft movements within his area of responsibility at the time of the occurrence and 12 aircraft on frequency. Geographical display bays were not used for the flight progress strips; they were sequenced in a chronological order.

The flight service officer had been on duty for five hours before the incident and had worked the position for most of that time. During the previous three days, the officer had worked a 10-hour shift, a 7-hour shift and a 9.5-hour shift, none of which agreed with the planned roster. Staffing throughout the day of the occurrence had been difficult as three staff were on sick leave.

Team leader coverage was required in the centre between the hours of 0600 and 2000 daily. The sole team leader available for duty on the day of the occurrence had worked from 0700 to 1700 hours and was required to stand-down because 10 hours was the maximum shift length allowable. A relief team leader was not available.

The flight service officer elected not to ask for support during the increased workload because of staff availability. Three other flight service officers were on duty. One was absent from the centre preparing a meal; one was working the FIS 3 position; and, the evening shift officer was eating a meal at the utility position. The evening shift officer intended to provide relief at one of the two consoles and had completed a 7-hour night shift earlier that morning.

Earlier that day, all flight service officers on duty at the Brisbane centre were briefed at a meeting on the imminent closure of the flight service function and the potential ending of their employment with Airservices Australia.

 

The incident occurred during a high workload period for the flight service officer. Analysis of the audio transmissions revealed frequency congestion, with multiple calls from aircraft and associated inter-unit coordination. The officer may have been suffering the effects of fatigue having worked unexpected periods of overtime on the preceding days, as well as concern stemming from the meeting held earlier during the day. The imminent closure of the flight service function had lessened motivation and morale and heightened general levels of uncertainty and anxiety. The detrimental impact of excessive anxiety, stress and high workloads on human performance has been well documented. These factors appear to have had a significantly adverse influence on the flight service officer's ability to perform effectively.

The console needed a large chart display on a mobile trolley placed at 90 degrees to the operating position to complement the overhead map display. The arrangement of this workstation was ergonomically undesirable, requiring the flight service officer to continually change physical position to correlate the flight progress strip display with the chart display. Moreover, the chart display was a physical barrier between the operating position and the supervisor/utility position. This barrier may have prevented the evening shift officer from noting the flight service officer's increasing workload.

The number of active flight progress strips for aircraft movements within the flight service officer's area of responsibility was considerable. Because the geographical display bays were not used and the strips were sequenced in chronological order, this adversely affected the situational awareness on the flight service officer

 
  1. The flight service officer did not provide directed traffic information to the crew of VH-XDZ about the disposition of VH-XDA.
  2. The workstation design complicated traffic management, the maintenance of an accurate air picture, and oversight of the flight service officer's workload.
  3. The absence of three staff on sick leave.
  4. Management of the flight service officer was inadequate by allowing the officer to continue working for long periods, with a high workload, without satisfactory supervision.
  5. Management of the flight service centre roster did not provide properly endorsed and rested staff to provide an effective flight service function
 

Local Safety Action

Airservices Australia's Occurrence Investigation Report (V4) dated 7 May 1999 under the heading of recommendations stated:

"Actions Taken
The officer concerned and his team leader have been interviewed to obtain their perspective on the occurrence. The officer was suspended and undertook 2 days of training and assessment by his team leader.

Other officers on duty at the time of the occurrence have been counselled to confirm the need for close scrutiny and oversight of traffic disposition, officer relief and coordinator support.

Actions to be taken.
All Flight Service Officers will be made aware of the findings of this investigation".


ATSB Safety Action

As a result of this and other occurrences the Australian Transport Safety Bureau (ATSB) investigated a safety deficiency. The deficiency was identified as: "Human factor issues in flight service centres are creating an environment in which safety may be compromised".

Air Safety Recommendation R19990220 was released to the public on 27 January 2000 and stated:

"The Australian Transport Safety Bureau (formerly BASI) recommends that Airservices Australia address flight service related issues that have the potential to seriously compromise safety, including those relating to incidents where there was a "failure to pass traffic" or a "failure to coordinate."

Air Safety Recommendation R19990220 was formally rejected by Airservices Australia in their response dated 28 February 2000. The ATSB considered the Airservices' rejection and because of developments with another "failure to pass traffic" occurrence asked "whether Airservices' rejection of the recommendation stands".

Airservices Australia confirmed their formal rejection of R19990220 on 29 March 2000. The rejection was considered by the ATSB and, due to the subsequent closure of the Flight Service Centres, categorised the response as "Closed - Not Accepted".

 
General details
Date: 23 April 1999 Investigation status: Completed 
Time: 1750 hours EST Investigation type: Occurrence Investigation 
Location   (show map):Mount Isa, Aero. Occurrence type:ANSP info/procedural error 
State: Queensland Occurrence class: Airspace 
Release date: 02 April 2001 Occurrence category: Incident 
Report status: Final Highest injury level: None 
 
Aircraft 1 details
Aircraft manufacturer: S.A.A.B. Aircraft Co 
Aircraft model: 340 
Aircraft registration: VH-XDZ 
Serial number: 340B-328 
Type of operation: Air Transport Low Capacity 
Damage to aircraft: Nil 
Departure point:Mount Isa, QLD
Destination:Townsvile, QLD
Aircraft 2 details
Aircraft manufacturer: S.A.A.B. Aircraft Co 
Aircraft model: 340 
Aircraft registration: VH-XDA 
Serial number: 340B-333 
Type of operation: Air Transport Low Capacity 
Damage to aircraft: Nil 
Departure point:Townsvile, QLD
Destination:Mount Isa, QLD
 
 
 
Share this page Provide feedback on this investigation
Last update 13 May 2014