Norman Vine writes: > > Six statue miles is the generally-accepted cutoff for good VFR. > > Terminal area forecasts (TAF's) don't bother with anything over that, > > and just report P6SM (plus six statue miles). > > Nice to know but does that have any bearing on anything other then > what is considered good enough to call 'good enough visibility' to > not require 'instruments' when flying :-)
Legally, good enough visibility not to require IFR ranges from 3 SM in a control zone to 1 SM in class G airspace during the day or in a control zone under SVFR. MVFR isn't much fun, though -- even with 3 SM, a control tower might not be able to see all parts of a large airport. On the other hand, 6 SM is considered so good that it's not worth mentioning anything higher in a forecast. I was just mentioning that we can go as low as six miles if needed. > FWIW > 10 miles seems a little low to me but this is easily adjusted That depends on where and when. I think that most pilots in the eastern U.S. (you're there, aren't you, Norm?) would have been happy even for 3 SM for much of this spring and summer, and L.A., of course, has its smog. Somewhere like Arizona, on the other hand, 10 SM would probably be considered a foggy day. It's also worth noting that the purpose of visibility requirements is not to allow navigation by pilotage, but to allow aircraft to provide their own separation from terrain, obstacles, and especially other aircraft -- that's all the FAA (and Transport Canada) really care about. Finding her way to the destination is the pilot's problem. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
