What do I do? What do I do?

[Ed Cesnalis]

First the simple flight plan is KMMH - O26 - KVNY

 

Enroute I fly a bit west to take advantage of the view and lift. First I get a look at the Palisades Glacier.

 

 

BTW the 2 couloirs are named 'V notch and U notch' and are pretty interesting skiing above 13,000'

 

Turns out there is a mountain wave and I utilize it for energy so I am flying at 15,000' and making very good speed.

 

As I approach Mt Whitney I am arguably legal at 16,500' but the wave is giving me so much energy that I have to violate a limitation. What should it be?

• pitch attitude? I could pitch down more than 30 degrees.
  
• speed? I might have to violate Vne in terms of TAS or even IAS
  
• altitude? Do I call Joshua Approach and tell them that I cannot avoid busting class A?
  
• Turn off my transponder
  

I think that pitch attitude limitations in this case are artificial limitations and are the first to violate. If I can pitch down without violating Vne and stay out of Class A that is my first choice.

 

Beyond that I will bust Class A before busting Vne in terms of TAS.

 

What would you do?

 

Violating Vne and pitch attitude could be the same consideration but not necessarily

[Jim]

Turn 45 degrees to the wave?

[Ed Cesnalis]

Turn 45 degrees to the wave?

 

Into the wind to avoid the rotor? What if that turn just increased my vertical speed?

[mocfly]

Vne is one thing I would do everything I could to avoid exceeding. The engineers put it down for a reason and don't just pull it out of the air. I would concede that this number is probably owner than the actual Failure Mode number. But I am not going to test that theory.

 

[Ed Cesnalis]

Vne is one thing I would do everything I could to avoid exceeding. The engineers put it down for a reason and don't just pull it out of the air. I would concede that this number is probably owner than the actual Failure Mode number. But I am not going to test that theory.

 

At high altitude (~15,000') would you avoid exceeding Vne with IAS or TAS?

[chanik]

IAS is the only one that matters to aerodynamic loading. But in a monster updraft, I would presume severe turbulence so Va is what I would stay under (98kts IAS at -6 flaps). Adjust flaps to max negative (-12 if you can) as that increases stall speed by 5kts over -6 flaps and therefore Va by ~11kts. It is the one way that -12 flaps are safer.

[FastEddieB]

I will think on this but my first reaction:

 

The phrase that came to mind is "Hobson's Choice". http://en.wikipedia.org/wiki/Hobson's_choice

 

Glancing through that entry, perhaps a better word for what you're putting forth is a "dilemma". http://en.wikipedia.org/wiki/Dilemma

 

In flying, I'm often suspect of these dilemmas. Do I take off over gross or start the leg with inadequate fuel? If I find myself in freezing rain, better to climb or descend? That sort of thing.

 

While perhaps worthwhile as thought exercises, in real life these choices often show a lack of planning or disregard for limitations.

 

Sure, once in that situation it's good to think out what is the best of out of a bunch of bad options. But if a pilot finds himself in a spot where only bad options present themselves, maybe the decision making that put him or her there is what really needs examination.

 

But, again, I will take a look at the options put forth and see which I think is the best of a bad lot.

[FlyingMonkey]

I don't think violating the pitch angle limitation is going to break anything or make the FAA cross with you. Of course, you can always declare a weather emergency and violate whatever you need to!

[bseager]

In Canada operating a 2006 CTSW, the VNE is 162 knots, I know it is less for LSA (145?). It is the same airframe so I always wondered about the difference. In Canada we are restricted to 1232 pounds max weight. I point this out because that VNE buffer may be much larger than you think operating as an LSA. Anyone have any ideas about the difference, is it just the maximum weight allowed?

[Roger Lee]

Hi beseager,

 

Do you have a BRS chute?

 

By the way did the struts get there yet?

[Ed Cesnalis]

 

While perhaps worthwhile as thought exercises, in real life these choices often show a lack of planning or disregard for limitations.

 

 

 

 

 

Monster lift ( and sink ) is a reality in the eastern sierra. Think Bob Fosset.

 

Some situations are easier to avoid than others, entering a cloud on a dark night is harder to avoid than when not too dark.

 

Big lift or sink is one of those things that you typically can't see to avoid and like favorable winds, lift in high mountains can be quite useful and usually isn't more than enough to enhance your rate of climb.

 

Assuming that I have O2, and that the wave's leading edge is smooth isn't my biggest danger busting Class A? More of a technicality than a real risk.

 

The eastern escarpment of the Sierra Nevada mountain range generates the world's strongest and most reliable mountain wave conditions throughout the year. Most commonly remarked from the ground by lines of standing lenticular clouds marking its presence, the mountain wave gives rise to powerful air currents that are sought after by sailplane pilots from all over the world who come to Minden, Nevada and other airports along the eastern side of the Sierra Nevada range to make record high altitude and long-distance soaring flights without the use of an engine.

These pilots and modern day explorers turn to the experts at Soaring Nevada for a bird's eye and thrilling ride, a mile above the ground. Visitors can choose several rides like the Tahoe SkyRide, a motor-less glider flight with breathtaking views of Lake Tahoe. Or, they can have their FAA-certified ride pilot guide them through taking control of the glider. Either way, visitors can custom tailor the ride they want. Or they can learn to fly with an FAA certificated instructor

 

Soaring flights above 25,000' MSL and cross country flights in excess of 500 miles are fairly common when the mountain wave is working, and sailplane pilots from all over the world make a pilgrimage to Minden as part of their "bucket list" of flights they hope someday to experience.

 

The strength of the rising air that creates the lenticular clouds has to be experienced to be believed. Climbs of 1,500 feet per minute in the strongest wave conditions are common, and experiencing this kind of lift in a silent glider leaves a pilot in awe of Mother Nature's raw power. Curiously enough the wind that results in the best lift frequently remains stationary over the ground so a successful wave flight is frequently can often accomplished by "parking" the glider above some feature on the earth and staying right there, all the time climbing as if on a silent elevator.

 

The FAA has recognized the special nature of our soaring conditions above Minden by designating a special high altitude "window" where sailplanes can soar into Class A airspace without being under the control of Air Traffic Controllers.

http://www.sierranevadageotourism.org/content/glider-rides-soar-above-the-sierra-nevada/sieDDD6C765822CA5522

[bseager]

Roger, yes I have a BRS1350 HS chute, maximum deployment speed is 180 mph I believe. and no, no struts yet. Must be help up in Canadian Customs. Do you have any way to trace it?

[bseager]

I should point out that my CT did not come equipped with a BRS, I added it later so perhaps that explains the placarded higher VNE for the aircraft when it was delivered.

[Roger Lee]

That would explain the 20knt difference, but now you're like the others with a BRS.

 

Does it really make a difference? FD and BRS thought so.

[sandpiper]

My BRS, as stated on the device, is 184K. As for the Vne being 162 for a plane without a BRS vs 145 for one with a chute, that seems strange. It would be nice to know if that is the reason or if it is something else.

[Ed Cesnalis]

Perhaps the normally aspirated limitations combined with the apparent 17kt buffer created by using BRS deployment max speed caused Flight Design to think it not necessary to address a lowering of Vne at altitude either by supplying IAS as most do or instructing to convert to TAS as Pipistrel does. The 17kt buffer probably covers you up to the service ceiling but it is possible to soar higher than that. It would be nice to know the flutter speed.

 

Another question: Does the BRS speed lower at high altitude?

[Ed Cesnalis]

We can look to Austrailia for the answer on adjusting Vne for high altitude.

 

"If there is insufficient manufacturer's information available for the aircraft you fly — and you are uncertain about the appropriate Vne for an operating altitude — then multiply the density altitude, in thousands of feet, by a factor of 1.5 to get the percentage decrease to apply to the specified Vne to establish a safe Vne appropriate to the altitude. For example if density altitude is 8000 feet and specified Vne is 100 knots then 8[000] × 1.5 = 12%. Corrected Vne = 88% of 100 = 88 knots IAS/CAS."

 

http://flysafe.raa.a...2.html#too_fast

 

 

The conversion chart approach comes from the FAR on ASIs:

 

"Where the aircraft designer selects a true air speed value as a limiting airspeed applicable when flying above a nominated altitude, FAR Part 23.1545 © requires that "If Vne varies with altitude, there must be means to indicate to the pilot the appropriate limitations throughout the operating altitude range". The 'means' is normally a placard next to the ASI."

 

I wonder if my TAS value on my EFIS qualifies?

[mocfly]

Based on this outline I don't see why you couldn't use it. Of course every instrument has some sort of error. Depending how close you plan on getting to Vne I would find out what that error is.

 

 

The airspeed indicator (ASI), driven by a Pitot tube and a barometric static port, shows what is called indicated airspeed (IAS). By the static port the IAS is corrected for the surrounding air pressure, but not for air density. The ratio between pressure and density is temperature dependent — as per the ideal gas law.

 

At sea level in the International Standard Atmosphere (ISA) and at low speeds where air compressibility is negligible, IAS corresponds to TAS. When the air density or temperature around the aircraft differs from standard sea level conditions, IAS will no longer correspond to TAS, thus it will no longer reflect aircraft performance. The ASI will indicate less than TAS when the air density decreases due to increase in altitude or temperature.

 

For this reason, TAS cannot be measured directly. In flight, it can be calculated either by using an E6B flight calculator or its equivalent. For low speeds, the data required are static air temperature, pressure altitude and IAS (or CAS for more precision). Above approximately 100 knots, the compressibility error rises significantly and TAS must be calculated by the Mach speed. Mach incorporates the above data including the compressibility factor.

 

Modern aircraft instrumentation use an Air Data Computer to perform this calculation in real time and display the TAS reading directly on the EFIS.

[Ed Cesnalis]

The reason I picked violating pitch attitude 1st is because when there is a big vertical component to the wind (updrafts, thermals, down-currents, downdrafts, microbursts, macrobursts and lee waves) you could have to violate pitch limitations to keep from stalling or overpeeding. Consider this Chart:

 

 

In big lift or sink my AOA could increment or decrement 10-20 degrees.

[Flying C Farms]

Charlie, who is Bob Fosset ? Did you mean Steve ?

[Roger Lee]

Hi Bob,

"Think Bob Fosset."

 

He did mean Steve. He's getting old like the rest of us. Some sooner than others....

 

Sorry Ed I just couldn't resist.

[Mac Bowden]

Bob Fosset? . . . . . . . . . He's a painter with frizzy hair.

[Tom Baker]

Bob Fosset? . . . . . . . . . He's a painter with frizzy hair.

 

I think that's Bob Ross. I used to watch him on PBS 20 years ago when I was on lunch break. Think, "happy little cloud".

[WmInce]

I think that's Bob Ross. I used to watch him on PBS 20 years ago when I was on lunch break. Think, "happy little cloud".

 

Yes . . . I remember . . . "happy little cloud."

He was a landscape master.

Each time I started watching him, I couldn't get away until he finished the painting.

A very soft spoken guy . . . just like most of the guys on this forum.

[sandpiper]

Speak softly and carry a big stick!! :angry: