IFR just 5.4% of the time

On Mar 3, 8:24 am, Matt Whiting wrote:
Andrew Sarangan wrote:
On Mar 2, 12:03 pm, Mxsmanic wrote:

Andrew Sarangan writes:

Not necessarily. For driving, you only need a clear view of the road
and traffic ahead. Whether you can see the scenery around you is
irrelevant for safe driving. Except for the darkness inside the cabin,
which makes it harder to read maps, the darkness outside is not a big
factor. As long as you can see the horizon, airports, runways and
other airplanes, it does not make a big difference how much of the
scenery you can see.

What about terrain?

Terrain avoidance at night becomes a problem only in unpopulated areas
under an overcast moonless sky. It has happened, so it is a real
issue, but most pilots fly in areas where there are at least some
ground lights, moon or stars, and it is really not that hard to tell
if you are heading towards a mountain. On the other hand, unlit towers
are a real concern, regardless of whether it is day or night, and this
is why they get NOTAM'd.

If you are flying the minimum IFR altitudes, it still should not be a
problem, unless there is a chart error.

Matt- Hide quoted text -

True, but we are talking about flying VFR at night and how to avoid
terrain under those circumstances.

Matt Whiting wrote:

If you are flying the minimum IFR altitudes, it still should not be a
problem, unless there is a chart error.

Matt, you have provided a great leadin to what I think got missed in
this discussion. Yes, flying the minimum IFR altitude is ok...
PROVIDED you can MAINTAIN that altitude.

One of the most insidious things about mountain flying is the wind!
You can be going DOWN (or UP) over 2000 FPM in the laminar flow and
not feel a thing! This can be a VERY BAD (TM) thing at night.

As you remember, in the mountains, the minimum IFR altitude is only
2000' above the highest terrain in the area. But, at 2000 FPM down,
you are at mountain top level in one minute.

4000 FPM down is not uncommon. Day or night!

I profess that until you are flying at over 18000 MSL, AND you can
overcome a 4000 FPM downdraft, IFR in the mountains should be
avoided.

Conversely, VFR in the mountains, day or night, if you choose your
route carefully, and the winds are less than 25 knots at mountain
top level and you and stay about 2000' above the canyon floor, you
are rarely out of gliding distance to a survivable landing spot.
Not an airport, but a survivable landing spot.

Best regards,

Jer/ "Flight instruction and mountain flying are my vocations!"
--
Jer/ (Slash) Eberhard, Mountain Flying Aviation, LTD, Ft Collins, CO
CELL 970 231-6325 EMAIL jer'at'frii.com http://users.frii.com/jer/
C-206, CFII Airplane&Glider, FAA-DEN Aviation Safety Counselor
CAP-CO Mission&Aircraft CheckPilot BM218 HAM N0FZD 247 Young Eagles!