Navigation strategy on a short flight

Mike Ash writes:

If you check it just before you depart, it'll be even more accurate than
it was the night before!

Yes. I simply meant that I don't plan flights very far in advance. I do all
the planning just before the flight. I also don't make very long flights,
because it's boring to sit in a cockpit for hours, so I don't generally need
forecasts beyond 60 minutes or so.

Nevertheless, I've bookmarked it as another useful resource.

FlyCherokee writes:

I like about 3000 AGL over hospitable terrain (flat, plenty of fields
to land in, etc.). Over mountains, cities, etc, I'd be happier
higher, and I don't fly over water outside of gliding range to land.

I've tried to figure out what is safe for trips over water, although the only
flights I've done over water are relatively short ones, such as flights
between Los Angeles and Avalon on Santa Catalina Island, or between St. Bart's
and Sint Maarten.

The shortest distance over water to Avalon is about 18 nm, which would require
at least 10 nm or so of gliding distance, so I'd have to be at 6000 feet at
the midpoint of the crossing, which is doable, but I don't feel comfortable
flying the C152 over water except experimentally. (An experimental flight is
one that I wouldn't fly for real and in which I have often voluntarily
overlooked certain real-world considerations; a practical flight is one that I
might be willing to carry out in real life.)

Coincidentally, TFFJ to TNCM is also about 17 nm. I have also flown the C152
experimentally on that route. For practical flights, I prefer something with
more than one engine (but landing a Baron on St. Bart's is quite a challenge).

Don't count on the published glide ratio to estimate your glide
distance. You need to save some altitude for what you lose during the
initial moments when you're getting yourself together, acknowledging a
failure, and establishing the glide, then allow some for maneuvering
when your chosen landing spot starts looking not-so-good when you get
closer to it, then allow for some more altitude to maneuver for the
actual landing. I use 1 NM max per 1000 ft of altitude when I
practice, preferably less. 1 NM per 1000 ft also just happens to be
how far I can see over the cowling when in normal cruise attitude.

OK, I'll try to add some margin for safety.

If I'm remembering it correctly, the one in Flight Simulator is good
enough.

I've never looked at it, but I will take a look. If it pauses the simulator,
though, I won't be able to use it. I don't use most of the default features of
the sim.

The electronic aides are becoming very popular, but I'm a dinosaur and
like paper charts.

I would keep paper charts on hand even with an electronic flight bag, even if
that would partially defeat their purpose.

No, you only need one, you just keep changing frequency to do your
cross checks. I did all my Private training 34 years ago in a 150/152
with only one VOR, it's a little more work, that's all.

But you move while you are changing frequencies, so it seems to me that you'd
never be able to do better than an estimate with just one VOR.

Yes, the winds aloft predictions and resolution are good enough for
flight planning, have you tried aviationweather.gov?

Yes, that's what I use for winds aloft, although Active Sky (which generates
real-world weather for the sim) also will give me winds aloft for my route.

The general process for planning is to establish your desired course,
then use the predicted winds and your known aircraft performance to
determine your heading angle and predicted ground speed along your
flight. Then take off and fly that heading. When you get near your
first waypoint you use the difference between predicted and actual
time vs. position to make a correction for the rest of the flight. In
practice, it works pretty well, and the predicted winds are good
enough to get you near your first waypoint.

But how do you locate waypoints, if you don't have radio navigation aids? And
conversely, if you do have radio navigation aids, why wouldn't you just aim
for them instead of relying on dead reckoning from some previous reference
point?

I did the KPHX-KCGZ flight yesterday, but I "cheated" and used pilotage alone,
which made it very easy in the perpetual VMC of the region, with the
interstate leading me directly from one airport to the other. This time I flew
it at 5500, although it took so long to reach that altitude that I was quite
far along by the time I got there.

In article ,
wrote:
Andy Hawkins writes:

You can do a VOR cross perfectly well with a single NAV radio.

How?

Tune the first VOR, work out which radial you're on, plot that line on a
chart. You should have a rough idea of where you are so you don't need to
draw a line that stretches all the way out to the coverage of the VOR. Next,
tune in the second VOR and repeat the process. Unless you're flying at Mach
3.5 you're unlikely to have moved too far so as to make too much difference
in the position fix.

If absolute accuracy is required, once you work out which radial you're on
from the first VOR, turn to track that radial (either too or from is fine)
and make the second measurement.

Andy

In article ,
Mxsmanic wrote:

But you move while you are changing frequencies, so it seems to me that you'd
never be able to do better than an estimate with just one VOR.

Er, you can never do better than an estimate with TWO VORs either, you
know. These things aren't exact. The question is not whether it's an
estimate (it always is), but whether your margin of error is small
enough to be useful. You don't move that far in the few seconds it takes
to change the frequency on a VOR.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

In rec.aviation.piloting Mxsmanic wrote:
FlyCherokee writes:

I like about 3000 AGL over hospitable terrain (flat, plenty of fields
to land in, etc.). Over mountains, cities, etc, I'd be happier
higher, and I don't fly over water outside of gliding range to land.

I've tried to figure out what is safe for trips over water, although the only
flights I've done over water are relatively short ones, such as flights
between Los Angeles and Avalon on Santa Catalina Island, or between St. Bart's
and Sint Maarten.

You are flying a desk in a dark apartment.

It is impossible for you to do anything that is not "safe".

snip

No, you only need one, you just keep changing frequency to do your
cross checks. I did all my Private training 34 years ago in a 150/152
with only one VOR, it's a little more work, that's all.

But you move while you are changing frequencies, so it seems to me that you'd
never be able to do better than an estimate with just one VOR.

It is done by real pilots all the time.

You don't need position accuracy to multiple decimal places.

snip

But how do you locate waypoints, if you don't have radio navigation aids? And
conversely, if you do have radio navigation aids, why wouldn't you just aim
for them instead of relying on dead reckoning from some previous reference
point?

You pick waypoints that are easy to identify in the first place.

When your clock says you should be getting close according to the information
on your flight planning form, you start looking for it.


--
Jim Pennino

Remove .spam.sux to reply.

On Jul 5, 4:13*am, Mxsmanic wrote:
... (An experimental flight is
one that I wouldn't fly for real and in which I have often voluntarily
overlooked certain real-world considerations; a practical flight is one that I
might be willing to carry out in real life.)
I use Flight Sim for this also, I suspect it's common. I fly into/out
of small strips in mountainous terrain, fly long distance over water
using just compass and clock and try to find islands, etc.


I've never looked at it, but I will take a look. If it pauses the simulator,
though, I won't be able to use it. I don't use most of the default features of
the sim.
No, just use it to make your navigation plan before you start, then
print it out, then that paper becomes your nav log for the flight. It
should have times and magnetic headings to all of your waypoints. I
also put any relevant frequencies and other important info on mind,
e.g., pattern altitude and direction, etc.


No, you only need one, you just keep changing frequency to do your
cross checks. *I did all my Private training 34 years ago in a 150/152
with only one VOR, it's a little more work, that's all.

But you move while you are changing frequencies, so it seems to me that you'd
never be able to do better than an estimate with just one VOR.

No, there are lots of sources of error when doing this for position
estimation. The error due to your movement between VOR checks is
small and not a problem, unless you are a really slow frequency
changer. Position estimates derived from VOR cross checks are fairly
sloppy; I wouldn't count on better than a mile or so, probably worse.
If a remember correctly, the VOR accuracy requirement is +- 4 deg (?),
that's +- 2 NM at 30 NM from the VOR, then you have to draw a pencil
line on your sectional by lining up the proper radial in a bouncing
airplane. There's lots of error in this process, but the answer is
plenty good enough for general VFR navigation.


The general process for planning is to establish your desired course,
then use the predicted winds and your known aircraft performance to
determine your heading angle and predicted ground speed along your
flight. *Then take off and fly that heading. *When you get near your
first waypoint you use the difference between predicted and actual
time vs. position to make a correction for the rest of the flight. *In
practice, it works pretty well, and the predicted winds are good
enough to get you near your first waypoint.

But how do you locate waypoints, if you don't have radio navigation aids?

You just fly the heading that's on your flight plan until the clock
says you're there. Then you look around until you find the landmark's
actual position. (Actually, you'll be looking for the landmark all
along, eventually you'll spot it as you get close).


conversely, if you do have radio navigation aids, why wouldn't you just aim
for them instead of relying on dead reckoning from some previous reference
point?

I don't understand.

Stephen! writes:

snip

Stephen! wrote:
wrote in :

You are flying a desk in a dark apartment.

Correction... a desk in his mother's dark basement.

Nope, it is a hovel apartment in France where he eeks out a living giving
English lessons.

--
Jim Pennino

Remove .spam.sux to reply.

On Jul 3, 2:47*pm, Mxsmanic wrote:

. I didn't have a written plan, nor did I log my
progress. In general I eschew anything that might require writing, because
there is no space on the table for writing things by hand, and because the
room is generally dark except for the monitor, making writing difficult.



It works well for me. My failure or success in the sim should accurately
mirror what my result in real life would be.

So, you have a night rating... LOL

Cheers

Flaps_50! writes:

So, you have a night rating...

A night rating?