Special investigation report 79-1
This Accident Investigation Report prepared by the Dept while appearing to be extensive and detailed in its investigation of this accident is in fact deficient in its pursuit of the subject matter to its logical extension of the ramifications of the total assessment of all the facts.
The Dept have touched on the matter of pilot strength when they investigated control system failure caused by pilot input loads but chose to not detail in a similar manner the requirements of FAR 23-143© which limit the force required to be exerted by a pilot on a temporary basis not to exceed 75 pounds.
This report also omits to detail any reference to the fact that the position of the trim tab actuator was in a position that indicated that the trim tab travel was other than that certified in Australia
This report omits to admit to the fact that the Dept failed to obtain flight test reports as required by ANO 101-22 prior to certifying the Autopilot/Electric Trim system.
This report omits to detail that the Trim Tab Travel Range was excessive to that required to comply with FAR23-689(f) which establishes total trim capacity required for an aircraft.
This report fails totally to address the fact that the Electric Trim System was never flight tested correctly as required.
This report by not completely investigating all aspects of the Electric Trim System was able to minimize the design and certification deficiencies to enable the claim of pilot error to be raised by stating. “However, the more likely explanation is that the command trim switch was activated unknowingly.”
This cannot be supported by any evidence as the coroner found at the inquest.
The CAUSE as listed in this report is incorrect and misleading and would be more accurate if listed similar to the following.-
Cause
The cause of the accident was that the aircraft became grossly out of trim at a height which did not permit time for the crew to affect recovery. The trim system design allowed control forces to be generated that exceeded pilot control force limits to be exceeded by a substantial amount. The manner in which the out of trim condition occurred has not been determined and the pos- sibility of a trim system malfunction cannot be eliminated.
This is the short answer!
Alan C Baskett - P_6317alan.
This Accident Investigation Report prepared by the Dept while appearing to be extensive and detailed in its investigation of this accident is in fact deficient in its pursuit of the subject matter to its logical extension of the ramifications of the total assessment of all the facts.
The Dept have touched on the matter of pilot strength when they investigated control system failure caused by pilot input loads but chose to not detail in a similar manner the requirements of FAR 23-143© which limit the force required to be exerted by a pilot on a temporary basis not to exceed 75 pounds.
This report also omits to detail any reference to the fact that the position of the trim tab actuator was in a position that indicated that the trim tab travel was other than that certified in Australia
This report omits to admit to the fact that the Dept failed to obtain flight test reports as required by ANO 101-22 prior to certifying the Autopilot/Electric Trim system.
This report omits to detail that the Trim Tab Travel Range was excessive to that required to comply with FAR23-689(f) which establishes total trim capacity required for an aircraft.
This report fails totally to address the fact that the Electric Trim System was never flight tested correctly as required.
This report by not completely investigating all aspects of the Electric Trim System was able to minimize the design and certification deficiencies to enable the claim of pilot error to be raised by stating. “However, the more likely explanation is that the command trim switch was activated unknowingly.”
This cannot be supported by any evidence as the coroner found at the inquest.
The CAUSE as listed in this report is incorrect and misleading and would be more accurate if listed similar to the following.-
Cause
The cause of the accident was that the aircraft became grossly out of trim at a height which did not permit time for the crew to affect recovery. The trim system design allowed control forces to be generated that exceeded pilot control force limits to be exceeded by a substantial amount. The manner in which the out of trim condition occurred has not been determined and the pos- sibility of a trim system malfunction cannot be eliminated.
This is the short answer!
Alan C Baskett - P_6317alan.