Aviation safety investigations & reports

Piper PA25-235/A1, VH-BSB, Blanik L13, VH-GGF, Woodbury TAS, 5 August 1984

Investigation number:
198402338
Status: Completed
Investigation completed

Summary

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The student glider pilot had carried out three previous flights during the day. Her instructor had informed her that she was at a suitable stage of training to be introduced to practice emergency procedures. After sighting her training log book, the instructor for the final flight left the glider to speak to the pilot of the tug aircraft. The instructor returned to the glider and preparations for take-off were then continued. Witnesses observed that the tug and glider became airborne and subsequently carried out normal turns to position the aircraft on a downwind leg at about 500 feet above ground level. The tug aircraft was then seen to waggle its wings sharply three times. Almost immediately this aircraft assumed a steep nose-down attitude, its tail apparently being pulled into a vertical position by the tow rope which was still attached to the glider. The glider then also assumed a steep nose-down attitude and both aircraft spun or spiralled towards the ground. The tow rope was released from both aircraft, but neither pilot regained control before impact with the ground. The subsequent investigation did not disclose any defect or malfunction with either aircraft that might have contributed to the development of the accident. During glider towing operations when the pilot of the tug waggles the aircraft wings it is a signal to the glider to immediately release from the tow. This "wave-off" signal would normally be given when the tug pilot detects some malfunction or when the glider is sufficiently far out of position behind the tug to affect the tug pilot's control of his aircraft. On this occasion it was considered possible that the instructor in the glider had arranged for the tug pilot to simulate an emergency by giving a wave-off signal. The wave-off signal was observed to be given in the normal position relative to the strip for such training manoeuvres to be performed. The reason for the subsequent loss of control of both aircraft could not be determined, however it was evident that when the aircraft released the tow rope there was insufficient height remaining to permit recovery to normal flight.

Download Final Report
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General details
Date: 05 August 1984   Investigation status: Completed  
Time: 1541    
Location: Woodbury    
State: Tasmania   Occurrence type: Loss of control  
Release date: 26 May 1986   Occurrence category: Accident  
Report status: Final   Highest injury level: Fatal  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Piper Aircraft Corp  
Aircraft model PA-25  
Aircraft registration VH-BSB  
Type of operation Aerial Work  
Damage to aircraft Destroyed  
Departure point Woodbury TAS  
Departure time 1541  
Destination Woodbury TAS  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer Let National Corporation  
Aircraft model Blanik  
Aircraft registration VH-GGF  
Type of operation Gliding  
Damage to aircraft Destroyed  
Departure point Woodbury TAS  
Last update 13 May 2014