[TowerTalk] Tower VS aeroplane suit dropped....

[Jim Lux]

Rich wrote:



>Then there is the ambiguity of "over unpopulated areas."  If I live here is
>it unpopulated?  What density per square mile constitutes "unpopulated?"  I
>live in a lower density part of a densely populated county, but the argument
>could be made that there is nowhere in this county that is "unpopulated."
>Or, if he flies over my backyard, 200' behind my house, is that
>"unpopulated," but directly over my house is "populated?"  I don't know that
>this has ever been defined.
k4sb wrote:


> > Well, it's been some time, but the absolute minimum altitude for any
> > aircraft except the military is 500 feet above your location.(
> > exception for air shows ) The military is allowed to go as low as 200
> > feet, but only on clearly established routes. An exception also exists
> > for military flights over unpopulated areas in clearly designated


FAR (14CFR91.119)

Except when necessary for takeoff or landing, no person may operate an 
aircraft below the following altitudes:

(a) Anywhere. An altitude allowing, if a power unit fails, an emergency 
landing without undue hazard to persons or property on the surface.

(b) Over congested areas. Over any congested area of a city, town, or 
settlement, or over any open air assembly of persons, an altitude of 1,000 
feet above the highest obstacle within a horizontal radius of 2,000 feet of 
the aircraft.

(c) Over other than congested areas. An altitude of 500 feet above the 
surface, except over open water or sparsely populated areas. In those 
cases, the aircraft may not be operated closer than 500 feet to any person, 
vessel, vehicle, or structure.

(d) Helicopters. Helicopters may be operated at less than the minimums 
prescribed in paragraph (b) or (c) of this section if the operation is 
conducted without hazard to persons or property on the surface. In 
addition, each person operating a helicopter shall comply with any routes 
or altitudes specifically prescribed for helicopters by the Administrator.


---

Looks like you get to make some decisions about "sparsely populated 
areas"... in (c)

It used to be, when 12inch N-numbers were required, that if you could read 
the N number it was closer than 1000 ft (visual acuity is about 1 part in 
1000).  With 3" numbers, though...


It is exceedingly difficult to accurately estimate vertical angles and 
sizes of flying things.  If you ask 100 people to point up at an angle of 
45 or 60 degrees, more often then not, they will be way off.  Likewise, 
there's the "moon illusion" where the moon looks bigger close to the 
horizon (where you have a distance cue) than overhead.

Even trying to compare against known objects (antennas in the foreground) 
is iffy.

Jim, W6RMK