Saturday, October 3, 2009

Death & Destruction - The TAIC Report

I had previously written about a crash that killed a cousin of mine and the delay on behalf of NZ's TAIC in producing a report.
On 1 October the TAIC finally released their report. It can be found here as report 08-001.
The report is a simple thing and yet it tells a damning story and has a lesson for regulators, aerodrome operators and pilots.Briefly the facts of the crash as set out in the report are:
  • The C152 was on a solo flight and had departed from sealed rwy 34;
  • It departed the circuit and performed airwork to the north;
  • The R22 was conducting flight test operations from parallel rwy 34 grass with a student and testing officer onboard;
  • The C152 returned and made a standard overhead join for a left hand circuit on 34 seal.
  • As the C152 completed its turn on the "dead" side and began its crosswind entry at 1000' AGL it collided with the R22 which was on a right downwind for 34 grass;
  • All required radio calls had been made. The aerodrome was not controlled;
  • It appears that no avoiding action was taken by either pilot;
  • All 3 occupants were killed.
What is salutary is that as far back as 1996 the potential for conflict with respect to contra circuit operations at the crash airfield had been identified. It was proposed that a modified circuit joining procedure be developed. This had never been done - for reasons that remain unclear.
In contra direction circuit operations - certainly as they are practiced here and and in NZ - the potential for serious conflict exists at two main points:
  • Overhead the airfield at a height of 1500' AGL as aircraft from each circuit cross to their respective "dead" sides; and
  • In the downwind position for each circuit as aircraft from the "other" circuit cross at 1000' AGL towards their own downwind.
Circuit operations are specifically designed to avoid placing aircraft in conflict with each other. However contra circuit operations with un-modified overhead joins create real conflict. They are in my view inherently dangerous, yet nobody had done anything to alleviate this situation despite knowing that it existed.
The lessons for me from this crash are:
  1. Whilst the pilot of the C152 was notionally the give way pilot all pilots had a responsibility to see and avoid. This accident shows that, as other studies have found, see and avoid has serious limitations;
  2. Systems of operation create the conditions within which a crash can occur. In this case the accepted system of operation created dangerous potential for conflict which remained unaddressed. So whilst the pilots had primary responsibility for collision avoidance, they were hampered in safe operations by the system within which they were operating;
  3. That the various parties had failed to address the safety issues suggests that familiarity had bred an acceptance of risks which prima facie would appear to be unacceptable. Call it perception fatigue if you like but it's the reason we have regulators. They claim in this case limited ability to act. Is that good enough?
The bottom line is that there is a better way to join when contra circuit operations are taking place. I personally would never join overhead in that situation unless absolutely compelled to do so. If there is no real dead side then in my view you cannot conduct a safe overhead join. My choice would always tend to be an oblique downwind after taking care of spacing.
A history of conducting overhead joins in a contra circuit environment without incident does not mean that it is safe to continue to do so. Are your circuit operations as safe as they could be?

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