Aviation safety investigations & reports

Boeing Co 737-700, VH-VBV

Investigation number:
Status: Completed
Investigation completed


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On 24 December 2003, a Boeing 737-7BK (737) operating under the instrument flight rules (IFR) was en route from Sydney and descending for a landing at Launceston, Tasmania. A Socata TB10 (Tobago) operating under the visual flight rules (VFR) was en route from Hobart, Tasmania, to Sydney at about 7,500 ft. As the 737 was descending through about 8,300 ft, at around 1333:53 ESuT1, the crew received a traffic advisory (TA) from their traffic alert and collision avoidance system (TCAS) about the Tobago. This was followed approximately 15 seconds later by receipt of a TCAS resolution advisory (RA) to climb. The crew responded to the RA and after arresting the aircraft's rate of descent, climbed the aircraft to approximately 9,200 ft. The pilot in command of the 737 reported that the TCAS indicated that the Tobago passed the 737 within about 200 ft vertically, slightly to the left, and certainly less than 1 NM horizontally.

Both aircraft were operating in Class E airspace that was introduced as part of the National Airspace System (NAS) phase 2b on 27 November 2003. As no prescribed separation standards are applicable in these circumstances, there was no infringement of separation standards. However, TCAS data and information obtained from the pilots of both aircraft indicate that the aircraft came into such close proximity that a threat to the safety of the aircraft may have existed. Therefore, the occurrence has been classified by the ATSB as an airprox2 event, which is a type of serious incident.


1 Eastern Summer Time.
2 Under the Transport Safety Investigation Regulations 2003, an 'airprox is defined as an occurrence in which two or more aircraft come into such close proximity that a threat to the safety of the aircraft exists, or may exist, in airspace where the aircraft are not subject to an air traffic separation standard, or where separation is a pilot responsibility.

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Download Final Report
[Download  PDF: 749KB]
General details
Date: 24 December 2003   Investigation status: Completed  
Time: 1335 hours ESuT    
Location   (show map): 19 km N Launceston, Aero.    
State: Tasmania   Occurrence type: Near collision  
Release date: 19 January 2004   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer The Boeing Company  
Aircraft model 737  
Aircraft registration VH-VBV  
Serial number 33015  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Sydney, NSW  
Destination Launceston, TAS  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer S.O.C.A.T.A.-Groupe Aerospatiale  
Aircraft model TB  
Aircraft registration VH-TBA  
Serial number 18  
Type of operation Private  
Damage to aircraft Nil  
Departure point Hobart, TAS  
Destination Sydney, NSW  
Last update 13 May 2014