Unicom

August 2003 Issue




Not So Perfect

Power-off landing calculations off a bit, making that ‘Perfect Landing’ come up short

It would seem “The Perfect Landing” article [Stick & Rudder, June] contains less than perfect information.

The author emphasizes that the pilot “execute a 180-degree standard rate turn, roll out on final and land the airplane.” According the sidebar figures his airplane descends at 750 feet per minute, which would give you 80 seconds of flight time. A standard rate, 180 degree turn requires 60 seconds; so if you time 25 seconds outbound, you’d be on the ground five seconds before you roll out on final.

A closer look at the formula’s derivation reveals that it is predicated on turning 180 degrees in 30 seconds, or double the standard rate turn. There is obviously a disconnect here, but it is not clear where the error lies. The author is quite emphatic about flying standard rate turns.

-Steve Lehr
Bellevue, Nebraska

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Close, But No Cigar
I really enjoyed the article entitled “The Perfect Landing.” As a glider pilot, I can attest to how important “getting it right” on approach is. I don’t get a chance to go around if I botch the approach.

However I think there is an error in the calculations presented in the Applying Theory sidebar to the story. In this case, the outbound time in calm winds in the example should be about 10 seconds, rather than the stated 25.

I hope that you either clarify that the turn is double the standard rate or that the outbound leg calculations are grossly inaccurate. If not, there may be a rash of landing-short accident reports in the near future.

All in all, I believe that the power-off 180-degree accuracy approach and the steep spiral are good additions to the CSEL PTS.

-Howard Burhanna III
Trenton, Ill


You are right. We screwed up the formula. All the better to crunch the numbers for your own airplane rather than trusting what you read anywhere. The maneuver, at least as described in the Commercial Pilot Practical Test Standards, should use a standard-rate turn.

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Forget That Rote Approach
In “The Perfect Landing,” I happen to disagree with the technique described. The bank angle for a standard rate turn at 68 knots will be about 12 degrees, which in many high wing airplanes will block the pilot’s view of the landing target for a very long time.

This technique also throws all the crosswind correction into only the initial key selection and the 10-15 second final segment, and any initial position that is not the perfect distance from the runway will result in not being lined up on final as the turn is completed.

Or did I miss the point and he was joshing with us?

Since I disagree with this technique perhaps it is only fair to offer something for Brian and others to disagree with. Make the turn from downwind to final when “it looks about right to be on base.” Use an aggressive turn to minimize the time in the turn, say a 30-degree bank.

Visually acquire the aim point just a little short of the desired touchdown. Adjust the base by angling in or out. Be less aggressive with the bank angle on the turn from base to final and play the bank angle as necessary to become aligned.

If flaps become necessary to increase the descent angle, lower the nose simultaneously to maintain speed and not get that balloon. Keeping the speed allows you to retract flaps and still be at no flap glide speed if you are settling short.

Slowing to normal flaps-down final approach speed should be delayed until making the distance is assured. If you keep the flaps up, know that slowing somewhat will increase the descent angle. As Brian noted, slips are a great tool. If the headwind is significant know that increasing speed will help get you there.

Practice seeing the “stationary point” on the ground where the airplane’s flight path will reach the ground. Use these techniques to move that “stationary point” to the aim point.

-Jaime Alexander
Council Bluffs, Iowa

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Who’s the Idiot?
I enjoyed “IFR Without ATC” [Instrument Flight, June] immensely, but I must take issue with a statement written in a sidebar regarding IFR arrival tactics.

The author states in paragraph 1 that one should listen, then talk, when arriving at an uncontrolled airport after an IFR flight. I agree that every pilot should take the opportunity to listen to the frequency for a few moments before keying the mic, because all of the landing information might be presented by other airplanes.

However, the author states that the use of the “idiotic” phrase, “any traffic in the area please advise” ought to be avoided. I could not more vehemently disagree. For starters, what is so idiotic about asking for traffic advisories? If there is no one at the FBO or other airport office to provide the advisory, who else is going to do it?

My home airport is Altus, Okla., and the Unicom operator does an outstanding job of providing inbound pilots info on the winds, estimated altimeter and if there are any other airplanes in the pattern. However, I have been around when the line person is out fueling an airplane on the ramp and unavailable to provide the advisory to an inbound airplane. There happens to be another airplane in the pattern and they give the advisory. How is this idiotic?

My definition of an idiot is someone who does not use all available resources to safely complete a flight. Perhaps sounding good on the radio is a nice thing, but I’d rather have a better idea of what’s out there when I arrive at my destination.

-Neal Thompson
Altus, Okla.

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Using Common Sense
I just finished reading Ron Levy’s article on “IFR Without ATC.” I get the overall feeling that he is trying very hard to discourage any IFR flight to any airport without a control tower. Sorry Ron, but most of the airports out there are non-towered airports.

Here in the Great Plains region, our destinations are mostly non-towered, and a great percentage of them are lacking “official” weather reporting systems. However, they can all be reached via an IFR flight plan. Sometimes, due to weather conditions, we can’t make it in. That’s why we file alternates.

Also, your comment in the gray box on page 5 under item #1: about “using the idiotic phrase ‘any traffic in the area please advise..’ “

The use of that “idiotic phrase” has alerted us to traffic at many of these uncontrolled airports that we fly into. The reason is because many local pilots at their home airport really don’t expect any other traffic coming in. Therefore, they aren’t talking on the CTAF, and they won’t either, unless they are prompted by the “idiotic phrase!” It’s just good, plain aviation safety practice to find out who, if anyone else, is out there. To call to ask them to report is common safety sense.

Finally, I’m getting the feeling that Ron knows the facts and regulations, but doesn’t have the experience that comes with the practical use of the ATC system. The controllers that watch over the Dakotas, Montana, Wyoming, and Nebraska know their airspace, regular aircraft that fly there, and the kind of airport operations that are being used out there. The pilots that fly out there, working with the controllers, know how to utilize the system to the max in order to get the job done. There are some limitations, that Mr. Levy mentioned. However, it is all doable. It works and it’s safe.

Pilots shouldn’t be discouraged from IFR flying just because ATC doesn’t have coverage from the ground up.

It’s an overall good article, however, I wanted to bring up these points.

-Loren Carson
Bismarck, N.D.


Ron Levy replies: First, I did my instrument training and practical test at a nontowered airport in 1971. I’ve flown IFR around the country and around the world, including areas with very sparse or primitive ATC capability. Without a careful logbook review, I can only guess that I’ve flown IFR into more nontowered fields than those with towers. So I’ve been there, and I’ve done that, and I’ve been doing it for a long time.

I am in no way trying to discourage flying IFR in and out of nontowered airports. There are only a few hundred towered airports, and more than 10,000 without towers. Nontowered airports are a vital part of our airport/airway infrastructure, and for the majority of cities and towns in this country are the only way to connect to the air transportation system.

The purpose of the article was to educate pilots who haven’t or don’t often operate IFR into and out of nontowered airports, so they can do it well, from both procedural and safety standpoints.

Mr. Carson’s point on the lack of weather reporting is important. I did not address in depth the problems surrounding operating IFR into and out of airports without weather reporting. The short version is that without weather reporting, you have only the area forecast to guide you, and that is usually many hours old by the time you arrive. This is a particular concern in the areas in which Mr. Carson operates, as a good alternate may be a long way away from your destination, and by the time you get there, the weather may have changed a lot from the forecast you used to select it. Likewise, you can be badly fooled as to the actual weather conditions if you attempt to launch under VFR intending to pick up your IFR once airborne.

I still say that use of the phrase, “any traffic in the area please advise” is superfluous. (So maybe “idiotic” was a bad word choice.) Pilots in the pattern should respond appropriately when they hear someone call “ten miles out inbound for landing” to the airport at which they are flying. It should not require another five seconds of transmission to get them to do so. While Mr. Carson may fly in areas where you can climb to 3000 AGL and still be able to hear only one airport on a given CTAF, in more crowded airspace CTAF’s are shared between multiple airports within line-of-sight range in the pattern. In those areas, we must keep radio transmissions as short as possible or the CTAF’s become nothing but a mass of squealing interference.

And I do not hold with Mr. Carson’s assertion that lack of expected traffic is an excuse not to make the appropriate transmissions in the pattern. As a safety officer in a professional flight operation, Mr. Carson must realize the importance of standardized procedures. It is simply not possible to turn them on and off. Either you use them all the time, or you will not remember to use them when needed. Making pattern position reports only when you think someone else is out there is not recommended in any handbook or training manual I know.

Finally, we file alternates because the FAA requires us to, not because “sometimes we can’t make it in.” For many reasons, the filed alternate is merely a planning exercise, and it’s easy to find legal filed alternates that no one could rightfully expect to be usable if our destination actually went down. Alternates filed in accordance with FAR’s 91.167 and 91.169 usually provide far less than an adequate fallback plan if you hit MDA and see nothing but the inside of a cloud. This is even more important in the areas in which Mr. Carson flies, since airports with terminal forecasts and weather reporting are much farther apart then they are in more densely populated areas.

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Weather Data Details
Thank you for Ron Levy’s excellent article “IFR without ATC.” I would like to point out that in his discussion of automated weather systems, he claims the A/FD does not distinguish whether or not you can find the airport weather in a METAR.

Examination of the “weather data sources” line in the airport’s description may show ASOS, AWOS, or possibly LAWRS (limited aviation wx reporting station). One important difference between ASOS and AWOS, aside from their funding, is that ASOS is connected to the NWS network, and therefore the pilot should find a METAR for such an equipped airport in a briefing.

In addition, an ASOS equipped airport’s weather would also be available to ATC. What the careful pilot should keep in mind is whether the report was derived purely from machinery or if there was a human observer to augment the report, confirming its accuracy. Timely PIREPs can be tremendously helpful at any uncontrolled field in low weather; why not file one next time you cancel from the ground?

I also recommend reading the Air Safety Foundation’s Advisor on ASOS for folks who regularly depend on it.

-Rich Bertoli
San Francisco, Calif.

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My Arrival, My Business
I am a corporate pilot who used to fly for the airlines. I just finished reading “IFR Without ATC” – which was very good – and I can tell you from being based out of an airport with no control tower that what you said was very true.

My question is about the “IFR Arrival Tactics” portion of the article. I do not believe a recommended traffic pattern is law.

Especially if you are cleared for a visual approach, you can set up your landing however you like. Including flying in from a different side of the runway then recommended by VFR procedures. You can also do this VFR after canceling or just when flying VFR because it is only recommended procedures in the AIM. There is no FAR to my knowledge that requires you to fly a standard pattern that is published. I am not condoning this in any way nor do I fly that way in my career but I don’t think that is “illegal” as the article states.

However, you are right in that the catch all “careless and reckless” violation will be received if you do this and have some sort of incident or accident I am sure. But to my knowledge it is not illegal to set yourself up to land any way you please. It has been a while since I was an active CFI so please correct me if I am wrong.

-Mike Gavin
Rice Lake, Wisc.


There is no FAR that says you must enter a pattern in a particular way. However, FAR 91.126 says you must fly left-hand traffic unless right hand traffic is officially stipulated.

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Learning From Others
The article on the Grumman crash at VAY contained some excellent things to be thinking about. That crash occurred a month or so before I started my pilot training and was cited by a number of CFIs at the Kenmarson Aeroclub as “That’s what’s gonna happen to you if you cross-control.”

You picked a good accident to write about since it certainly could have been prevented – and that’s the kind we all can learn something from.

-Bob Bruneau
Via e-mail


While the cross-control stall may be the primary lesson here, remember that there were other dynamics at play that can just as easily bite.

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Erratum
There may be a mix up in aircraft type in the lead item in Squawk Box. So far as I can tell, AD 98-08-18 applies to PA31 aircraft, which means Navajo, not Aztec (PA23-250). Maybe that’s why I haven’t heard from the FAA?

-Robert Copeland
Via e-mail


Yup. We messed that up.

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Prop Paranoia
Regarding “Disc of Death” [Editor’s Log, May], your points are well taken. I share your paranoia of props having seen first hand what a spinning prop can do to a German shepherd while on takeoff roll. He ended up looking like a loaf of French bread sliced and ready for the oven. Didn’t even clean the insects from the blades.

One note: If you are in a hurry to stop the prop, please use the mag switch instead of using the mixture mixture if you think a second or three will matter. It really depends on the rpm at the time of decision.

I wanted to make some comments on other articles as well.

In the article about cabin altitude (Breathe the Thin Air), I was taught to be aware of your environment and to use awareness of your own physiology. Pounding heart and fingernails are also a part of your instrument cross checks as precautions against hypoxia, a fast indicator is breathing rate and the effort required to inhale and exhale.

If you pay any attention to your physiology, the difference in breathing effort is impossible to miss as is slight trouble speaking.

Think about it the next time you are snow skiing! In the same vein, lights on the ground and instrument lighting, colors are all affected.

As little as we think of our own physiology, it is a simple tool to keep in the back of your head for another angel on your shoulder. High cabin altitude is not the only cause of hypoxia. Except for breathing effort, the other checks will be effective by any type of hypoxia.

Pointing out a problem is only half the job of flight safety. Giving good usable corrective information is another.

For example, one way of preventing prop accidents would be to not even crank a single with a nose wheel chocked or twin with a main wheel chocked. Try as hard as I may, I make more mistakes than I like to think about. Thinking about them beforehand is the most painless way to take care of potential and real problems. This is why I like your publication.

-Lin Anderson
Wadesboro, N.C.


That ounce of prevention of which you speak is the most precious commodity a pilot can carry.

Frankly, we find some of the decisions we make colored by answering the question: “How will this look in print?”