Aviation safety investigations & reports

Near collision involving Morgan Cheetah, 19-5456, and Grob G115, VH-ZTA, 15 km NW of Serpentine (ALA), WA on 15 April 2016

Investigation number:
Status: Completed
Investigation completed

Final Report

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On 15 April 2016, an instructor and student of a Grob G115C2 aircraft, registered VH-ZTA (ZTA), were conducting a local training flight in the training area south of Jandakot Airport, Western Australia. Two aerodromes were situated in the training area – Serpentine and Murray Field, and they shared a common traffic advisory frequency (CTAF).

When ZTA was north-west of Serpentine aerodrome and tracking south, the instructor broadcast that they were 10 NM from Serpentine at 2,500 ft and intended to pass abeam the aerodrome tracking south.

At about that time, a Morgan Cheetah aircraft, registered 19-5456 (5456), departed Serpentine for a private flight to Rottnest Island with a pilot and one passenger on board. The pilot reported that they made the following broadcasts on the CTAF: taxiing at Serpentine for runway 23; entering and rolling on runway 23 for a departure to Rottnest Island; and when departing overhead the aerodrome at 1,500 ft climbing to 3,000 ft heading to Rottnest via Carnac.

The pilot then changed the aircraft’s only VHF radio from the CTAF to the area frequency about 5 NM from Serpentine. The aircraft was then climbing through about 2,800 ft and tracking north-west when the pilot sighted an aircraft (ZTA) about 10–15 ft above, on a reciprocal track and about 100 m away. The pilot of 5456 immediately turned left and descended.  

The student of ZTA sighted an aircraft (5456) in close proximity and alerted the instructor. The instructor saw 5456 making a steep left turn at about the same height as ZTA, took control of the aircraft from the student, and conducted a left turn to increase separation between the two aircraft. The aircraft passed at the same level and about 20 to 30 m horizontally from each other.

A search for other traffic is eight times more effective when a radio is used in combination with a visual lookout than when no radio is used. In areas outside controlled airspace, it is the pilot’s responsibility to maintain separation with other aircraft. For this, it is important that pilots use both alerted and un-alerted see-and-avoid principles.


Aviation Short Investigations Bulletin - Issue 51

Download Final Report
[Download  PDF: 289KB]
Alternate: [Download  DOCX: 274KB]

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General details
Date: 15 April 2016   Investigation status: Completed  
Time: 10:00 WST   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): Serpentine (ALA), 15 km NW    
State: Western Australia   Occurrence type: Near collision  
Release date: 08 September 2016   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Grob - Burkhart Flugzeugbau  
Aircraft model G-115C2  
Aircraft registration VH-ZTA  
Serial number 82048/C2  
Type of operation Flying Training  
Sector Piston  
Damage to aircraft Nil  
Departure point Jandakot, WA  
Destination Jandakot, WA  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer Morgan Aero Works  
Aircraft model Cheetah  
Aircraft registration 19-5456  
Serial number Unknown  
Type of operation Private  
Sector Piston  
Damage to aircraft Nil  
Departure point Serpentine, WA  
Destination Rottnest, WA  
Last update 14 November 2018