Mountain flying

[iflyforpie]

That's what death looks like.

Meh....

[Shiny Side Up]

Are you taking the pictures, or are you in the pictures Pie?

That second picture also looks familiar, where's that at?

[iflyforpie]

Bugaboos. I was taking the pictures.

[Big Pistons Forever]

Training and experience is what matters. CS could scare IFP to death with some low level aeros's while CS would be crapping his pants going through some of the mountain passes that are ops normal to a good mountain pilot.

There is no short cut to experience and it doesn't matter how good you are at the home drome, the PDM you use dealing with flights that are outside of your comfort zone separate the good from the not so good, and sometimes the living and the dead....

[Colonel Sanders]

Messing with something you don't understand
is a good way to get killed.

Both Sparky Imeson and Steve Fossett knew
100x as much about mountain flying as I ever
will. I am a creature of flat lands, and half the
year, negative density altitudes.

[LousyFisherman]

negative density altitudes.

I'm sorry I don't understand?

I agree on the weather though, I would never fly in that. However, I would go in 2 seconds with
STL. I would be bouncing on the co-pilots seat (in my ski boots)
- "Can I have the stick for a bit?"
STL - Have you ever flown a helicopter before?
- "No, (still bouncing) but can I have the stick?

The main reason I will not go if the mountain tops are in the cloud is I cannot see the weather in the next valley. Since it can move in in 15 minutes, that is too much risk for me. STL said it best,, so add my +1 to the others

And the partnership vetoed the afterburner on the 150, sorry

LF

[Beefitarian]

When it is warm the air thins and we calculate the density altitude because of the loss of performance especially on takeoff.

The only time I really experienced it was in a place called RapidCity near RushMore I think it was 107 degrees F. I calculated it then watched the perimeter fence on climb out. It looked way too close asI climbed at a few feet per minute.

When it is cold the air will do the opposite. We don't care because it makes take off easier so we just enjoy it when the plane flys better, worrying about other things like keeping the frost off the windows and the engine temperature from dropping too fast. If you calculated it the density altitude would be less than sea level, negative density altitude.

Hope I made sense of that.

[iflyforpie]

negative density altitudes.

I'm sorry I don't understand?

He means that when you calculate density altitude it is below sea level. Entirely possible in a part of the country that is near sea level and gets horrific winters (at least compared to BC ). The net result would be like putting afterburners on the 150.

[Colonel Sanders]

correct - a negative number is a number that
is less than zero. Whenever the temperature
is less than 10C here, the density altitude is
sea level (zero) or less. The performance of
aircraft at -20C here is unbelievable. So are
the EGT's.

Thinking about this - are you guys pulling my
chain about not knowing what a negative number
is? You got me!

[Shiny Side Up]

The performance of
aircraft at -20C here is unbelievable. So are
the EGT's.

Out of curiousity, what sort of EGTs are we talking here? I ask because I don't think I've ever experienced a negative d.alt day, mostly because any time I've been near SL its always been summer and in the +30 range. Well actually that one time near New Orleans, it was near that in February.

[Colonel Sanders]

what sort of EGTs are we talking here?

EGT's, unlike CHT's, do not have a sensible absolute
value.

For example, a CHT over 400F is worrisome.

However, the EGT value will depend where I drill the hole
in the exhaust stack, to insert the thermocouple.

Anyways, at sea level and -20C, the EGT's will be
hundreds of degrees hotter than during the summer.
I am sure that the exhaust valves are glowing red
from the lean mixture. More than rated sea level
power is being produced.

What blows my mind is that no one gives this a
thought. However, if I did the same thing to the
engine with a dry shot of nitrous in the summer,
TC would put me in jail for being a VERY BAD MAN
and an avionics tech in Winnipeg would jump for
joy because TC was attacking me again

[iflyforpie]

[However, if I did the same thing to the
engine with a dry shot of nitrous in the summer,
TC would put me in jail for being a VERY BAD MAN
and an avionics tech in Winnipeg would jump for
joy because TC was attacking me again

[LousyFisherman]

....... because I don't think I've ever experienced a negative d.alt day.

I ran the math once: 3000 feet, -10 Celcius, 30.3 Hg and it came out around 250' ASL.
At -12 the density altitude = sealevel but that's starting to get a little too cold for 1960's
Volkswagons and similar machinery

LF

[sky's the limit]

Given this is a mountain flying discussion, the opposite end of the DA conversation is the one that we should be talking about. It's a very big deal each summer as we find out time and again in the Penticton area with private pilots crashing enroute to the Lower Mainland. DA is second only to wind in determining the performance of the aircraft at a given time in the mountains.

[Shiny Side Up]

....... because I don't think I've ever experienced a negative d.alt day.

I ran the math once: 3000 feet, -10 Celcius, 30.3 Hg and it came out around 250' ASL.
At -12 the density altitude = sealevel but that's starting to get a little too cold for 1960's
Volkswagons and similar machinery

LF

Its starting to get too cold for me anymore too. I used to tell myself I liked winter, but that was before I went somewhere where it was actually warm. I'll confess I never have figured it out on that end, so I could be exaggerating about never having seen it.

I think the worst I seen it here one day was where on the field it was a d.alt of 8000'. Not a great day for small airplanes, too much drag to fly with the window open and only hot air comes in. I could be a little bit off on my whiz wheel calc with a temp of +35C. Thankfully we haven't got up to that for a while.

Perfect banner towing weather.

[LousyFisherman]

Given this is a mountain flying discussion, the opposite end of the DA conversation is the one that we should be talking about.

Very true, given that the usual grass strip is 3000' in the Alberta foothills and mountains, 7500' density altitude is usually the limit for me. If I am relatively light (no passenger) I may try a takeoff but even then the climb out is very slow. Remember, I'm talking a 150 here, the climb out is pretty slow all the time

YMMV
LF

[New_PIC]

My initial hours, nearly 30 years ago, towards the PPL that I'm working on finishing now, were flown in a mountain valley. The thing I recall struggling with the most was holding my altitude steady in steep turns when there is no horizon. The mountain ridges on both sides were higher and uneven, and the valley turned not far off too so there was no usable reference there either.

[sky's the limit]

My initial hours, nearly 30 years ago, towards the PPL that I'm working on finishing now, were flown in a mountain valley. The thing I recall struggling with the most was holding my altitude steady in steep turns when there is no horizon. The mountain ridges on both sides were higher and uneven, and the valley turned not far off too so there was no usable reference there either.

What you are/were experiencing is one of the other major topics in mountain flying - the hazards associated with optical illusion. There are many, but the reason you struggled with steep turns in a valley is the result of one of the most common mistakes made because of these illusions.

Flying parallel to the valley wall, ie. up or down valley, if you initiate a turn out into the valley away from the sides the nose will drop significantly and you will lose height and gain airspeed. Conversely, if you make turn into the valley wall you will gain altitude and lose airspeed. It all has to do with the way the eyeball perceives what is going on outside, and the natural desire to have the nose or reference point on the aircraft follow the terrain.

The best way to mitigate this particular illusion at first, is to look at your Altimeter and force yourself to hold the altitude you have when you initiate your turns. Attitude is EVERYTHING when trying to make an aircraft do anything, and once you learn to judge the correct attitude the instrument becomes secondary or can be avoided almost entirely. After a while I think it becomes second nature and the propensity to lose the nose up or down reduces or goes away. It's similar to learning IMC flight, in that you have to learn to trust a gauge briefly instead of your eyes.

There are plenty of other mountain illusions, and many of them can and will get you in the take-off/landing phase of flight if you are unaware of them and how to eliminate their effects.

stl

[New_PIC]

Yeah, I learned pretty quick that chasing the VSI doesn't work well.