[NSRCA-discussion] Mid-Air discussion

[Earl Haury]

I did a very quick drawing with pilot stations 75' apart (probably the max at local meets - most closer) and each centerline skewed 10 deg, then added flight paths at 150 & 175m. This creates a "diamond of death" between the center poles and each flight path that represents roughly 10% of the flight area between the paths. The centers are roughly 350' apart at the 175m poles. (However, the "point" of the diamond is only half that.) Flight data show that a typical loop diameter is on the order of 300' (150' radius), so many center maneuvers would occupy the diamond for some period of time.

Interestingly, this would work at many fields as the 175m path only extends to around 250m out and the 150m comes in to around 50m. More area in the footprint - but not more than generally available.

Certainly, the chance for turnaround mid-airs is eliminated and, generally, only half of a center maneuver would be exposed to the diamond. 

I'm all for reducing the risk of mid-airs, but also don't wish to rush into something that increases that risk. Parallel paths don't cross - hard for both pilots to maintain that orientation (especially in a cross-wind). Crossing flight paths kinda reminds me of the old county fair figure 8 jalopy races.

Earl



----- Original Message ----- 
  From: Bob Richards 
  To: NSRCA Mailing List 
  Sent: Friday, September 28, 2007 7:51 AM
  Subject: Re: [NSRCA-discussion] Mid-Air discussion


  IMHO, this is sort of like the old saying that a stopped clock has the exact time at least twice a day. :-)

  If the planes are flown at a 10 degree (or 20 or whatever) offset, then their paths DO cross on every pass. If they are flown parallel, there is the possibility that their paths NEVER cross, if flown at slightly different distances. Therefore, one might conclude that if the pilots are proactive about collision avoidance, flying parallel is safer. If they fly without any measure of avoidance in mind, flying offset might be safer. I suspect most of the competitors don't fly with avoidance in mind.

  As for the existing situation (flying parallel) where have most of the midairs occurred? Center, turnarounds, other? Of the midairs that I can remember, most of them occurred with at least one plane in a turnaround manuever.

  When flying an offset, the turnarounds would be shifted away from each other somewhat. Also, with an offset, a pilot would only have to think about collision avoidance in certain parts of the sky (where the flight paths cross) instead of the whole box if flying 0 offset.

  I think it would be interesting to try this, but for it to reveal any useful data it would have to be done over a long period of time and statistics collected. Who wants to be a statistic??? :-)

  Bob R.


    -----Original Message-----
    From: nsrca-discussion-bounces at lists.nsrca.org
    [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of george w.
    kennie
    Sent: Thursday, September 27, 2007 10:27 PM
    To: NSRCA Mailing List
    Subject: Re: [NSRCA-discussion] Mid-Air discussion

    While it may be true that the flight paths cross on every pass, the cross 
    point is of a momentary nature, whereas without the 10 degree offset the 
    time spent in the same flight plane is magnified by a significant factor 
    greatly increasing/multiplying contact opportunities. Where the offset 
    capability exists it presents the possibility of reduced incidents. While I 
    acknowledge that this is my "opinion" I am more than willing to listen to 
    persuasive arguements to the contrary. Maybe there's something I'm not 
    seeing here.
    G.





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