On 12 February 2004 a Blackhawk S-70-A helicopter was conducting a training exercise with a Lead-In-Fighter (LIF) Hawk Mk 127 aircraft. During the exercise, at 0021 UTC (1021 Local Time), the Blackhawks tail rotor contacted a tree and the helicopter subsequently collided with the ground. Six of the eight occupants were injured.
The Directorate of Flying Safety Australian Defence Force (DFS-ADF) was responsible for investigating this accident. DFS-ADF requested assistance from the ATSB to produce a computer animation of the flight paths of the Blackhawk and the Hawk. Details of that request were published on the ATSB website in accordance with the requirements of the TSI Act 2003, section 22(3). The Executive Director of the ATSB approved the request.
3. INVESTIGATION PROCEDURE
Recorded data was available from the following sources:
3.1 Secondary Surveillance Radar (SSR)
DFS-ADF obtained radar data from AirServices Australia for the Mount Hardgrave SSR located on North Stradbroke Island. The Mode A codes assigned to the aircraft were:
- Blackhawk 4624
- Hawk 4637
Data recorded between 00:06:45 UTC and 00:57:38 UTC was provided for the Hawk. Data recorded between 23:50:55 UTC and 00:15:37 UTC was provided for the Blackhawk.
3.2 Flight Data Recorders (FDRs)
DFS-ADF downloaded the FDRs from both aircraft.
The Blackhawk was equipped with a model F1000 FDR manufactured by Loral Data Systems. Indicated airspeed, pressure altitude, radio altitude, main rotor RPM, magnetic heading, pitch attitude and roll attitude parameters were provided to the ATSB for a 5 minute and 58 second period prior to the accident.
The Hawk was equipped with a model MCR500 FDR manufactured by Aerospace Monitoring and Systems. Indicated airspeed, ground speed, pressure altitude, radio altitude, magnetic heading, pitch attitude and roll attitude parameters were provided to the ATSB for the entire flight from takeoff at Amberley at 0004 UTC until return to Amberley at 0059 UTC.
DFS-ADF obtained a laptop from Flight Data Systems Pty Ltd which had the GRAF Vision software (Version 2.0) installed. This software was used to perform the animation.
Aircraft animations have 6 degrees of freedom and require position data (3 axes) plus roll, pitch and yaw (magnetic heading) data.
4.1 Blackhawk Flight Path
Prior to the accident the Blackhawk had taken off from the summit of Mount Walker and commenced a descent. As it descended radar coverage was lost. The derived animation commenced at the time the Blackhawk took off from the summit and the track was then dead-reckoned using indicated airspeed, pressure altitude and magnetic heading. Magnetic heading, pressure altitude, pitch attitude and roll attitude parameters were obtained from the FDR.
4.2 Hawk Flight Path
The Hawk track was based on the radar track, including interpolation between radar paints when radar coverage was lost while the Hawk was at low altitudes. Magnetic heading, pressure altitude, pitch attitude and roll attitude parameters were obtained from the FDR.
A computer animation was produced of the flight paths of both aircraft covering the 5 minute and 58 second period from the time the Blackhawk took off from Mount Walker until the Blackhawks FDR ceased recording. This period corresponded to 0015 UTC until 0021 UTC.
The animation was produced at the ATSB during the period 2 to the 19 March 2004.
The laptop containing the animation was handed over to DFS-ADF on 23 March 2004 for their continuing investigation. A report on this accident will be produced by DFS-ADF.
|Date:||12 February 2004||Investigation status:||Completed|
|State:||Queensland||Occurrence type:||Miscellaneous - Other|
|Release date:||16 May 2004||Occurrence category:||Technical Analysis|