Ferris,
Perhaps an example of how we might approach a change, similar to one enunciated in your latest reform efforts:
Proposed design change: Class C in the terminal transition airspace to Class E.
BENEFITS
Benefit and Value 1. Reduced separation responsibility for air traffic control potentially translates to reduced workload to controller potentially reduces staffing requirement. If tower and approach function integrated and one man tower – net benefit zero.
Benefit and Value 2: Greater freedom of access for VFR aircraft. If VFR aircraft regularly diverting around controlled airspace, or delayed in obtaining clearance or subject to restrictive clearances, potential fuel and time cost. For small and quiet tower, assume minimal disruption to VFR operations, assume cost to VFR at $200 per day times 365 days equals $75k per year.
Benefit and Value 3: Better relationship between levels of risk and services provided to mitigate risk – i.e., best practice. Value – cultural not directly monetary.
Net potential benefit: $75,000.00
RISKS
Primary Hazard: Inability to communicate with, control, or manage VFR flights in relation to IFR flights increases to potential for collision in terminal transition airspace. Class C risk calculated/estimated at [say one accident per 200 years(not validated – example only)]. Risk in Class E calculated/estimated at [say one accident per 100 years (not validated – example only)]. Cost of a hull loss equals $50M plus passenger value at $2M times 75 equals total $200M amortized over the change in risk years [$200M/100years] equals $2M per year.
RISK MITIGATION
In order for this equation to make sense, one of two things needs to happen.
1. An authority needs to state that a change in risk of this magnitude is acceptable.
2. Risk needs to be managed so that the differential between cost and benefit is reduced to a more reasonable ratio.
Examining risk mitigations:
1. Primary radar – cost $5M plus annual maintenance - unacceptable
2. Secondary radar plus transponder carriage and activation - $5M plus maintenance – unacceptable
3. Reliance on TCAS – not permitted
4. enhanced see and avoid – minimal cost [but refer 6 below]
5. training and education – cost at, say, $100,000 one off.
6. etc
Enhanced see and avoid, from what we have seen and read, means training in scanning, and activation of lights. A search of the web will immediately turn up more than a dozen studies that argue that scanning and lights are of somewhat limited value [refer previous posts]. If this means is to be pursued, the proponents of change would need to do and record substantial studies on the subject, and specifically tailor training and education to that subject.
Training and education would probably concentrate on avoidance techniques – i.e., ways to avoid the flight paths of IFR aircraft and so on [but refer the benefit argument above].
…etc…
We think you see where we are heading here.
There is little or no benefit, for a substantial initial cost, AND a substantial risk increase.
One thing that should be noted is that safety cases do not just show when it’s “safe” to do something. They are also used to tell you when you shouldn’t do something. This is a classic case where there is no benefit in a change, other than the potential cultural shift.