Setting altimeters with no radio

How about doing a touch and go at an airport with a known altitude,
while you are retracting flaps, quick twist of the dial to set field
elevation and away you go.

(this was a joke by the way, much as the original question)

Neil Gould wrote:
Recently, Mxsmanic posted:


"Jim Macklin" writes:


GPS, even a $100 hikers model will solve the problem. But I
just say, look at the ground, you can judge 1,000 feet
pretty well and you only need to apply the hemisphere rule
above 3,000 AGL.

GPS is far less accurate than an altimeter, and I don't think the
regulations say "if you have no radio, use GPS."


I'm not sure why you think that "GPS is far less accurate than an
altimiter...", as an altimeter only need be accurate to 75' to be legal.
GPS can do much better than that, and are unaffected by barometric
pressure; the result is a potential source of problems that require pilots
to fly by the altimeter, not the GPS. None of this has anything to do
with regulations, of course.

To answer your original question, the prudent pilot will take the
barometric pressure of their destination into consideration during
preflight planning, and adjust the altimeter accordingly. Most of the
time, the pressure won't change all that drastically at the destination in
the time it takes to fly 100 miles, and non-radio VFR pilots aren't likely
to fly in weather where the pressure is changing too rapidly.

Neil

"Mxsmanic" wrote in message
...
"Jim Macklin" writes:

GPS, even a $100 hikers model will solve the problem. But I
just say, look at the ground, you can judge 1,000 feet
pretty well and you only need to apply the hemisphere rule
above 3,000 AGL.

GPS is far less accurate than an altimeter, and I don't think the
regulations say "if you have no radio, use GPS."

--
Transpose mxsmanic and gmail to reach me by e-mail.

The regs don't say a lot of things. You asked the question. Besides the OT
debate, you got two basic responses 1) It doesn't matter 'cause you're VFR
anyway and 2) any old GPS could give you an altitude to use a reference in
the case where the local pressure was significantly different from the
departure.

-------------------------------
Travis
Lake N3094P
PWK

you land every 100 miles or less
reset your altimeter to field elevation
and then fly another 100 miles

"Mxsmanic" wrote in message
...
Since it is possible to fly without voice radio equipment, and given
that (if I understand correctly) pilots are supposed to have their
altimeters set correctly to a reference located not more than 100
miles from their position, how does an aircraft without a radio keep
its altimeter properly set as it travels?

--
Transpose mxsmanic and gmail to reach me by e-mail.

"BT" wrote:
you land every 100 miles or less
reset your altimeter to field elevation
and then fly another 100 miles

I presume you're trying to pull his leg?

he's flying a friggin sim..

"Jim Logajan" wrote in message
.. .
"BT" wrote:
you land every 100 miles or less
reset your altimeter to field elevation
and then fly another 100 miles

I presume you're trying to pull his leg?

"BT" wrote:
he's flying a friggin sim..

This forum is open to everyone, clued and clueless, sane and insane, so
it's impossible to tell by the absurdity of a post whether it is being
posted in jest or is sincerely believed by the poster. Hence my question.


"Jim Logajan" wrote in message
.. .
"BT" wrote:
you land every 100 miles or less
reset your altimeter to field elevation
and then fly another 100 miles

I presume you're trying to pull his leg?

There is no 100 mile rule, IFR or VFR. There is a rule that IFR you
have to have a radio, and an adjustable altimeter (and a bunch of other
stuff).

Like the guy said. Land and set the altimeter to the field elevation.

Mxsmanic wrote:
Since it is possible to fly without voice radio equipment, and given
that (if I understand correctly) pilots are supposed to have their
altimeters set correctly to a reference located not more than 100
miles from their position, how does an aircraft without a radio keep
its altimeter properly set as it travels?

You can find the answer in FAR 91.121(a)(iii).

Jim Logajan writes:

You can find the answer in FAR 91.121(a)(iii).

Found it, thanks. I'm surprised that just setting it at the airport
would suffice--one could conceivably fly for hundreds of miles VFR,
and the altimeter could change significantly along the way.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Recently, Mxsmanic posted:

Jim Logajan writes:

You can find the answer in FAR 91.121(a)(iii).

Found it, thanks. I'm surprised that just setting it at the airport
would suffice--one could conceivably fly for hundreds of miles VFR,
and the altimeter could change significantly along the way.

That really isn't as likely as you think, as the flights you're referring
to only takes a couple of hours. If the pressure is changing significantly
faster than that, it's likely to look pretty ugly outside either before
you leave or en-route.

Neil