The Australian Transport Safety Bureau (ATSB) is recommending that sports parachuting organisations review aircraft used in parachuting operations to identify and mitigate potential aircraft equipment-related crash survivability issues.

The bureau's recommendation follows its investigation into the January 2006 crash of a Cessna 206 in Queensland on a tandem parachuting flight, during which it determined that some sports parachuting aircraft could be made safer in the event of a crash.

The Cessna 206, with six parachutists and the pilot on board, crashed into a tree and landed in a dam shortly after take-off from the parachuting centre at Willowbank. Four passengers and the pilot died in the crash, with two survivors seriously injured.

The ATSB concluded that the crash was due to engine power loss, with a number of anomalies believed to have reduced the available engine power on the highly modified aircraft.

Sports parachuting in Australia is self-administered, with oversight delegated to the Australian Parachute Federation (APF), but funding provided by the Civil Aviation Safety Authority for oversight is reported to be insufficient to meet the organisation's operating costs, says the report.

Audits by the APF of the operator involved in the crash did not cover a number of operational anomalies found, including the fact that the aircraft was operating in excess of its maximum take-off weight.

In addition, insufficient aircraft emergency procedures and performance information was available to the pilot, not enough information was available to the pilot on an engine modification and there were too few aircraft cabin floor harness attachments for the number of occupants.

The APF has already addressed a number of these issues, including increasing the oversight of parachuting aircraft during audits and reviewing tandem student parachutist hooking up procedures, aircraft emergency procedures briefings, single point restraint requirements, the use of helmets and pilot training requirements.

The investigation resulted in seven safety recommendations relating to airworthiness bulletins regulations, parachutists' safety and survivability, aircraft maintenance documentation and pilot training in emergency procedures.

After a number of incidents involving loss of control following engine power loss, the ATSB has also launched a special investigation into the factors involved.