"Tony Cox" wrote in message
ink.net...
"Barry" wrote in message
...

How would the TLS be affected if the Big Sky theory were relied upon
for aircraft separation as John T. suggested?

I'm not very familiar with this subject, but you can read "Safety
Considerations for Operation of Small Unmanned Aerial Vehicles in
Civil Airspace" produced by the MIT International Center for Air
Transportation:

http://icat-server.mit.edu/Library/f....cgi?idDoc=205

They studied both midair collisions and exposure to people on the
ground.
The
relevant conclusions for midairs:

Significant Amount of Airspace with Exposure Risk
Below the Target Level of Safety
- Areas around major airports are above the TLS

Opportunities may exist to allow a class of small
UAV's to operate with limited restrictions
- Limiting operation in airspace near airports
may achieve TLS

Mitigation Strategies Are Available to Further Reduce the Risk
-Vehicles can be designed with capabilities to limit
likelihood of midair collisions

This study attempts to 'bound' the danger through a Bayesian
analysis of engine failure probability and chances of hitting
something at random in the airspace 'per flight hour'. In high
traffic areas, the probability is small (10-8). But the total
accident rate will depend on how many of these things are
flying around. There is nothing about 'accountability' in the
"Mitigation Strategies", which is very odd since accountability
looms very large in current aviation practice (and FAA regulation).

I'm concerned that the model for this sees a UAV "pilot" as a
sort of hands-on air traffic controller, rather than as a proper
"pilot" with the attendant certification and responsibility
requirements. This is a major departure from existing practice,
and potentially devastating for GA.

I had an opportunity to speak with a Marine who operates UAVs as the remote
pilot. He said he and others doing that job must be instrument rated pilots
and the UAV must be on an IFR flight plan. Given that, why would the
accident rate for UAVs be any different than normal IFR traffic?