Plane down on Vail Pass

"Mike Rapoport" wrote

Since you totally missed his point, perhaps you do need to take some
instruction.

What point was it that I missed? Are you telling me that mountain wave
activity is not present early in the morning?
--
Jim in NC

"Morgans" wrote in message
...

"Mike Rapoport" wrote

Since you totally missed his point, perhaps you do need to take some
instruction.

What point was it that I missed? Are you telling me that mountain wave
activity is not present early in the morning?
--
Jim in NC



No, it can be present anytime. However the time-of-day issues that Newps
brought up are more relevent 99% of the time. While it is possible for an
airplane to crash into a ridge while flying upwind because of a wave, I
don't think that I have ever heard of it happening. By the time mountain
waves are a real issue the wind is usually screaming. Perhaps we could add
"don't fly if the ridgetop winds are over XXkts to Newps' advice to fly in
the mountains. What Newps said is what 99% of mountain flying instructore
would have said.

Mike
MU-2

"Mike Rapoport" wrote

While it is possible for an
airplane to crash into a ridge while flying upwind because of a wave, I
don't think that I have ever heard of it happening.

I never saw anyone say anything about upwind or downwind in this thread, did
you?

While downdrafts due to thermals are a possibility, I can't imagine anyone
flying close enough to a ridge to not be able to get away from it's
"clutches", and flying into a ridge because of them. Flying early is
important for comfort, but beyond that, I don't see the relevance. All that
is left is wave activity, it seemed to me.

Or I could be wrong, then "nevermind."
--
Jim in NC

Morgans wrote:


While downdrafts due to thermals are a possibility, I can't imagine anyone
flying close enough to a ridge to not be able to get away from it's
"clutches", and flying into a ridge because of them.

That's entirely possible. Most flatlanders, when presented a valley to
fly in, fly right down the middle. You're supposed to fly on the
downwind side of a valley. The wind goes into the valley and rides up
the downwind side. If you fly near the rocks then you can get that lift
too.


Flying early is
important for comfort,

But mostly for safety.

Newps wrote:
Flying early is important for comfort,

But mostly for safety.

As does flying ABOVE the tree line/ridge instead of level with it

Ron Lee

There are many more foces at work in the mountains than just wave. The most
common is up and downslope winds. The upslope wind starts when the ground
begins to heat up and reaches a maximium around 5pm. Downslope winds start
as the air cools and flows down hill. First thing in the morning the
termperatures have pretty much equalized and the air tends to be calm.
These diurnal effects can be dramatic. Consider Hood River OR, possibly the
wind surfing capital of the world. Every morning it is calm and every
afternoon it is blowing around 25kts. This wind is predictable at Hood
River with one major drainage going from the low, moist coast to the high,
dry interior, but when you have numerous drainages interacting with each
other and complex differential heating the velocity and direction of the
wind becomes unpredicable and often varies 180deg from one end of a 1000'
runway to the other as well as having large up and down components.

It is not just a matter of comfort, it doesn't take much wind to produce
significant up and downdrafts in very rugged terrain as well as horizontal
shear. The problem is that the direction of these small-scale winds cannot
be predicted. When taking off or landing it is easy to be forced into the
ground by a tailwind or downdraft. Another problem is that many mountain
airports are one way and you can't take off or land unless the wind is
either calm or favorable.

Once you get above ridgetop level the wind starts to flow in a predicable
manner, thus the difference flying "over the mountains" and "mountain
flying" that Newps was making.

The best rule is to fly in the morning when none of this stuff is going on.

Mike
MU-2


"Morgans" wrote in message
...

"Mike Rapoport" wrote

While it is possible for an
airplane to crash into a ridge while flying upwind because of a wave, I
don't think that I have ever heard of it happening.

I never saw anyone say anything about upwind or downwind in this thread,
did
you?

While downdrafts due to thermals are a possibility, I can't imagine anyone
flying close enough to a ridge to not be able to get away from it's
"clutches", and flying into a ridge because of them. Flying early is
important for comfort, but beyond that, I don't see the relevance. All
that
is left is wave activity, it seemed to me.

Or I could be wrong, then "nevermind."
--
Jim in NC

"Ron Lee" wrote in message
...
Newps wrote:
Flying early is important for comfort,

But mostly for safety.

As does flying ABOVE the tree line/ridge instead of level with it

Ron Lee


The winds above the ridgeline are predicable.

Mike
MU-2

Newps wrote:
That's entirely possible. Most flatlanders, when presented a valley to
fly in, fly right down the middle. You're supposed to fly on the
downwind side of a valley. The wind goes into the valley and rides up
the downwind side. If you fly near the rocks then you can get that lift
too.


Flying early is

important for comfort,


But mostly for safety.

I the Alps we usually fly on the right side of the valley, to avoid
conflict with other traffic, unless there is strong downdraft of course.

And we cross the ridge at 45 degrees, for a quick turn around if needed.