Unicom

August 2000 Issue




More on Mountains

Mountain flying is a specialty that takes study and a new approach to flying

I enjoyed Wally Miller’s article “Big Pile of Trouble” [Weather Tactics, June], but I was sorry to see that he did not list my favorite pre-flight planning guideline and flying technique for handling wind and the mountains. At my flying club in Seattle, they teach us to plan for at least 1,000 feet of ridge clearance for each 10 mph of wind at altitude. If your airplane cannot fly at that altitude, take a different one (we have a pressurized Centurion) or do not go. Following this guideline does not assure that you will stay out of trouble – as pointed out in Miller’s article – but it does give the pilot a minimum altitude to fly and reasonable basis for a go/no-go decision.

-Daniel Wisehart
Redmond, Washington

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Think Glider When Winds Attack
After reading the article “Sometimes You Win” [Learning Experiences, June] about the pilot caught in mountain wave near Palm Springs I found myself asking the following question: Why do pilots with engines come to grief with it when pilots without an engine (glider pilots) seek it out?

This is not to say it is never harmful, but understanding its dynamics can enable a pilot to minimize its risks, and even use it to his/her advantage. The following technique is not foolproof, but will frequently work better than trying to overpower sinking air.

First, a general practice when caught in sinking air should not be to pitch up, unless ground impact is imminent. A better technique is to go to full power and pitch a few degrees nose down, being careful not to exceed a safe airspeed.

The atmosphere cannot create a vacuum, so any time there is sinking air, there will be rising air as well. If you think you are in an isolated column of sinking air (usually marked by turbulence) continue your current heading. If you have a GPS, the best airspeed is one that gives the highest ground speed. The technique is to fly out of it, rather than to out-climb it.

If you think you are in mountain wave, as marked by eerily smooth air and predicted by certain conditions, the following technique is recommended: Pitch down as described above. Choose a heading that is the best combination of heading for better terrain and parallel to the winds aloft. Heading into the wind may be the best option.

When you get into rising air, turn directly into the wind, and slow to minimum airspeed and, if you are in powerful conditions, your altimeter will spin upwards like the blades on a fan. If you find yourself in sinking air again, repeat as above until you seek out an area of maximum lift. Mark your spot on the ground or your position with your GPS.

The ideal is to maintain zero ground speed, headed into the wind. This may not be possible, requiring repeat turns down wind, then back upwind. Once you have enough altitude, consider your options for escape. This technique requires excellent positional awareness, a clear understanding of winds aloft, and a lot of nerve if you are in IMC, but it is essentially the same technique glider pilots use to achieve altitudes well into the flight levels.

-F. X. Del Vecchio
Via e-mail

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Slow Speed Didn’t Help at All
In “Sometimes You Win,” the pilot makes the statement while in a severe downdraft that “The Centurion’s best angle of climb speed at 10,000 feet is 80 KIAS. I kept the airspeed needle between 70 and 80 knots, which stopped the descent at 9,500 feet.” He would have been much better served to fly the best rate of climb speed, since it was his descent rate that was a problem. Also, flying at less then Vx is the worst thing he could do for himself.

Vy is at the top of the airspeed vs. rate of climb curve where it is fairly flat, and a couple of knots variation makes little difference in performance. Vx, however is located where a tangent from zero touches the steep part of the curve, and any speed below Vx results in a dramatic loss of performance. By flying below Vx, the author reduced his performance and prolonged his anxiety.

-Chuck Daly
Via e-mail

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VMC, FL250 or grounded
The pilot and his passengers in “Sometimes You Win” were very lucky. The flight should never have been undertaken, but not for the reasons stated in the account. This flight should not have been taken into IMC in mountainous terrain.

I am convinced that no light aircraft should ever proceed into IMC or at night over mountainous terrain unless it is capable of attaining FL250 and staying there until clear of the mountains.

I’m sure there are many pilots who would disagree with me and say that a prudently planned flight in a properly equipped aircraft and with a competent pilot should be able to safely fly an IFR flight plan in the mountains, but I’m sticking to my guns.

In order to be able to apply weather knowledge to the flight, you must be able to see the terrain. It is hard to say if you are on the windward side or the lee side of a ridge, for example, if you are in the middle of a cloud. This should be reason enough.

The second basic safety lesson is that altitude is your friend. While many mountain flying seminars say that 1,000 feet agl is a good safety margin, I think 2,000 should be the minimum.

I have made many mountain flights in my 1956 Cessna 172, going in and out of airports such as Eagle, Leadville, Aspen and others. It is an exhilarating experience and especially beautiful in the winter.

At the same time, virtually all of the aircraft lost within 50 miles of the Rocky Mountain National Park area in the last 10 years have been more beefy and powerful than the 210 in the “Sometimes You Win” account. Light aircraft are simply no match for some of the powerful weather conditions found in the mountains on even a nice day. They can be flown safely, but the pilot has to be trained and has to be able to see the terrain.

-Michael Kellam
Estes Park, Colo.


While you make some good points, we suspect many people will find FL250 just a tad on the conservative side, especially given the situational awareness allowed by GPS.

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Practice What You Preach
I find it ironic that the June cover photo that invites readers to follow the great safety example of airline pilots shows an unsafe practice.

It appears that neither pilot is using the installed shoulder harnesses and it looks like they are on approach. This is a common risk behavior – not using the available safety equipment.

I don’t think we should be learning from their example.

-George Heath
Via e-mail


Good catch. Even though the photo was taken of a simulator ride, the habits we practice are the habits we use.

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George, I Promise I Won’t Sue
I just had to respond to George Abbott’s e-mail about CFIs [Unicom, June]. It’s too doggone bad we live in a world where the lawyers rule, they’ve made flying very expensive and very tough to get into.

I would love to have an instructor like George! We need more instructors like George. I know this CFII in Truckee who would be an awesome instructor but he does not want to instruct for the same reasons as George. He’s afraid of the liability issue if something were to go wrong. I’ve begged him.

He tells me he has many assets and only would be a target in the aviation industry. I believe there are many instructors in George’s position. You see, if I took lessons from a person like George and something happened I would probably blame myself instead of blaming George. I would be a man about it! So I think there are many people like me also.

I challenge all pilots and CFIIs in George’s position to go after this issue. Bond together somehow. We need you guys more than ever. Isn’t there something these people can do?

-David Achiro
Via e-mail


We know a number of excellent instructors who have given up instruction – especially primary training – because the cost of insurance made it uneconomical for them to continue. While it’s easy to blame the lawyers, remember that they can’t do it without a client. Let’s face it, there are a lot of unfortunate pilots who want to turn their own accident into a winning lottery ticket and a lot of families who think money will ease their anger and grief.

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Don’t Worry, Be Happy
Congratulations on “Weathering a Check” [Legal Matters, June] and thanks for bringing such valuable info to me.

Why fear a check? To an excellent article, I would like to add, like Napoleon Hill would say, “A ramp check? That’s good!”

I have worked at the “delivery end” as an inspector with a large European ships and aircraft register for 12 years. I have also been at the “receiving end” of inspection as a shipyard director. Now, at 57, I find myself as a new pilot and ask myself why I should be afraid of a ramp check.

The matter is really simple: Either my plane and myself do conform to the requirements of safety, common sense and regulations, or we don’t. If we do not and I still intend to fly, I certainly have something to learn.

If I do conform why worry? If one chooses to ignore the requirements of safety, common sense and/or regulations, that’s what one should worry about. The chief goal of the inspector is safety; regulations are the support of safety.

If an inspector found something wrong with my aircraft or myself, I could only view that as an opportunity to learn about aviation … or about myself. To me, “A ramp check? That’s good!”

-Alain Gauthier
Via e-mail


In an ideal world, you’d be right. But this isn’t one. Recall the incidents of the airplane with new Q-tip props that was grounded for a “prop strike” and the unfortunate soul who was grounded because his yoke-mounted portable GPS was deemed an illegal installation. Knowing what you’re required to do and what you’re not required to do will make the entire experience less intimidating, which can only be good for everyone.

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One Size Doesn’t Fit All
In “Weathering a Check” it is stated: “I keep W&B sheets with ‘worst case’ aft c.g./max weight cases with the required W&B documents; anything lighter or more forward is guaranteed ‘in the zone.’”

That statement while true for some airplanes, does not apply in general. For example on my Geronimo the max weight limit of 4,000 lbs and most rearward c.g. 100 inches cannot be applied simultaneously. If the weight exceeds 3,800 lbs the rearward limit moves to 98 inches and if the c.g. is beyond 98 inches the max. weight is reduced to 3,800 lbs. In other words the envelope has a notch (reentrant corner), which is off-limits.

There is another effect that also needs to be considered. If the moment arm of the fuel is not the same as that of the c.g. of the loaded airplane the c.g. will move during flight as fuel is used. Depending on the location of the fuel tanks it is therefore possible for the c.g. to shift beyond either the forward or the rear limits.

When the various tanks have different moment arms fuel may have to be used in a prescribed sequence in order to keep the c.g. within the envelope for the entire flight. Again using the Geronimo as an example the c.g. shifts forward in flight and can easily go beyond the forward limit when only the two front seats are occupied. I routinely ask my “copilot” to move to the rear seat to avoid this problem.

While exceeding the rearward limit, which reduces the stability margin, is universally recognized as a problem, exceeding the forward limit must also be considered. A forward c.g. reduces pitch and yaw control authority which can be a problem particularly when landing at a short field. I use a computer program to assure that the c.g. location stays within limits for the entire trip.

-John Lawton
Seville, Ohio


Good points, all. While Mr. Levy’s specific advice reflects his airplane and certainly doesn’t apply to all airplanes, it does illustrate some ways you can satisfy the inspector that you’ve considered W&B in your loading. In our Lance, we keep copies of W&B calculations for the aircraft as it is typically loaded: two occupants/no bags and five occupants/full fuel.

We include figures for full fuel, half fuel and fuel remaining after 4 hours of flight. Anything other than that, and we either interpolate from the prepared calculations or run a new set.