Unicom

February 1999 Issue




Cruisin’ for Bruisin’

Are new cruising altitude rules needed, or is that just heading for trouble?

I really like Aviation Safety, but after I read “Climb and Maintain What?” [Risk Management, December] I wondered how it got there. Then I thought it might have really been a “plant” to get readers to write on this topic.

I agree that the hemispherical rule has its problems, exactly as outlined. To address these, I was taught during my primary instruction to “fudge” a bit on the altitude. Therefore I might cruise at 4400, or 5650, within 250 ft of the xx,500 ft levels during VFR. In fact, my instructor never wanted us at an even height of x,500 or x,000, even when too low for the hemispherical rule, and I stay away from those altitudes still. In 500 hours, I have had 3 near-misses, separated by only altitude, when I was at a non-even height, and the other airplane was. So, I agree with the premise that the hemispherical rule has its problems.

However, the ACCAR solution proposed has its serious flaws. First and foremost, it requires either a vertical card heading indicator (magnetic or gyroscopic), or some serious mental arithmetic (read: increased cockpit load), particularly during turns near an airport (Phases 5-7) when our primary concern should be eyeball use.

Although the author may always fly with a vertical card heading indicator, they are by no means universal. I have a magnetic compass (standard drum type) and an older AN style DG in my Tripacer. Many older airplanes, even up to the mid ’60s came equipped with the AN style. This requires a smaller panel hole than the vertical type, making substitution non-trivial. Many, many aircraft out there have only the drum type magnetic compass, and no gyro capability. Replacement of all these with a vertical card is not feasible in these aircraft. In addition, if the photo of the altimeter and vertical card are in the same aircraft, it is at the wrong altitude. The heading says N, the altimeter 300 feet. If the DG reads the heading (110), as it should, then N would be at 8 o’clock, but the hundreds needle should point to 4 o’clock. (300 feet). Once we install vertical card compasses in every aircraft, shouldn’t we at least reward these irate owners with an easier rule? Did the article mean to say the hundreds needle should point where N is? That would be the mirror image of what I read, but one heck of a lot easier to calculate from a vertical card. Furthermore, if Phases 5-7 were ever implemented, there would be a lot of climbing and diving in the traffic pattern. This would be entertaining from the ground, complete with burning mid-airs, but as a pilot I would find it not very much fun. Within 5 miles of an airport is not the time/place to be carving out a piece of sky 1,000 feet thick, as a 360 degree turn would require. I did find the article interesting, but after reading it I rather like the hemispherical rule.

-Tom Lubben
Via e-mail


Mr. Patlovany’s plan would not require the addition of a vertical card. If the rules were adopted, it would be a simple matter to create a transparent sticker that could be placed right on the altimeter glass, since the inner half of the altimeter face isn’t used anyway. As for the confusion in the photograph, the intent was to show the relative angle between the 100’ hand and the proper heading of 110 degrees. The bright orange heading bug on the DG washed out to white, making it less obvious than we had hoped. As for traffic pattern operations, the proposals on page 10 clearly gives priority to headings/altitudes assigned by ATC, as is now the case.

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What Now for ACCAR?
Your article “Climb and Maintain What?” was truly interesting and thought-provoking. I’ve been reading Aviation Safety very appreciatively for years, and the ACCAR is the first really new practical idea for promoting the safety of general aviation that I’ve seen in a long while.

I didn’t write only to convey my thanks and compliment you, however. As a retired federal government lawyer, as well as current general aviation pilot, I’m both interested and concerned about the FAA and its rulemaking practices. It is no surprise that the FAA gave you the back of its hand. A good idea alone is not enough; you need to have a political organization to promote it. I mean, you’ve got to get the organizations with you, such as EAA. You probably already know this. Do you have a plan to promote the ACCAR idea further? Do you have an expanded write-up, perhaps with more examples than were in the article? What could general aviation pilots such as myself do to help push ACCAR?

-Pierre Hartman
Tehachapi, Calif.


For more detail on the mathematics that justify the proposal, Mr. Patolvany’s original technical analysis of the cruising altitude rules appears in the April 1997 issue of Risk Analysis, the monthly journal of the Society for Risk Analysis (703-790-1745). As for furthering the idea politically, we think informing readers is the place to start. The rest, we hope, will follow naturally.

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ACCAR Plan Needs Some Work
Robert Patlovany’s suggestions for new cruising altitude rules to minimize the risk of midair collisions is an excellent idea, however, it needs some additional development work.

Execept for the special case where you are flying due north, 360 is not on the top of your compass. Except for an ADF with a non-rotating card, what is on top is your actual heading. So you would either have to reset the card to north, with the attendant risk of error in resetting it back to where it belongs, or so some mental arithmetics, with risk of its own.

Would it not be better to leave the card where it is – indicating the actual heading – and fly so that the 100’ needle is where north is on the compass? The problem of light aircraft with nothing beyond a whiskey compass should be easily solved with a rotatable piece of cardboard with a compass rose on it. Having to fly an altitude where the 100’ needle points to where north is would eliminate several points of potential error, or at least unnecessary distraction.

The article also does not mention altitudes above FL 290, where current rules call for 2,000-foot separation between opposite traffic. Also, how would ACCAR work where it is ATC who assigns the altitude? Would a 747 cruising at FL 390 need a clearance to climb or descend 100 feet when the course changes by 10 degrees? What about the transition to oceanic rules? IFR and VFR mix?

Good idea, but it needs work.

-K.A. Skapa
Denver, Colo.


Aircraft operating in Class A airspace would not need ACCAR except during periods of radar outage because they do not rely on “see and avoid,” nor do they contain a mix of VFR and IFR traffic. ATC could still assign an altitude of its choice, as happens now when you are assigned altitudes that do not follow the hemispheric cruising altitude rule.

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ACCAR an Unnecessary Solution
I am still enjoying your Aviation Safety magazine after 45 years flying. I fly IFR almost all of the time, and use ATC flight following as much as possible when VFR. See and avoid is difficult. There are times, when the sun is low, that it blinds us so much we can only hope that someone else can see better than we can. There are times when both of us look at the same thing inside the cabin for periods of a half minute. There are times when the pilot not flying is dealing with paperwork, and the pilot flying is tuning a radio, or trying to get his trim set, or doing something besides looking out the window for traffic. When I fly single pilot I have to do all of this myself. So, when one is available, I enlist a passenger to sit up front and look out too.

Concerning establishing a greater number of VFR altitudes: let me say that the author’s proposal to match one’s altitude with the relative position of one’s heading on the compass rose would be only a little more likely to provide more separation between cruising aircraft. At the same time, the confusion factor is raised again for the pilot trying to memorize another rule.

Now, lets see if actually a lot of people are flying at the same altitude, after all. How many of you know how accurate your altimeters are at any given altitude above 1000 ft? Is the current FAR keeping us apart, is it errors in the altimeters?

As a quick check, dial in the local altimeter setting and see how close you are indicating to field elevation, then go down the flight line and check out 10 more airplanes. If they have all been checked within the last 24 months, as required, two of them may be within 20 feet of each other on the ground. Next check all of the navigation radios and see how accurate they are, then get 10 pilots to see if they can all maintain the same altitude and exact course for over two minutes. In fact, launch them for the same destination at the same time and see if you don’t have more random separation than you have random collision factor.

My point is, that actually there is no truth to an equation that assumes that aircraft supposed to be maintaining a given altitude and course line are actually doing so!

There’s nothing wrong with staying slightly off of one’s selected cruising altitude, except for the potential rule violation, is there? I don’t need a computer to do this, nor an FAR, all I need is to pick my own random correction of say 50 feet up or down and I have further decreased the odds of hitting someone else using the same FAA approved altitude. Don’t leave out the part where I am saying that we still need to look out and maintain contact with ATC! The next time you survive a near miss, and see another aircraft go just under or over you, wipe your brow and thank the law of natural randomness. It’s an automatic separation, that has allowed us to keep things simple and still survive.

-John C. Miller
Randleman, NC


We certainly agree with your strategy of introducing an element of randomness, and Mr. Patlovany covers this in his article. Under his plan, however, your risk would decrease even more. Yes, it is more complicated, but his point is that the more closely you conform to the regs the more likely you are to be in a mid-air collision. That’s not exactly what we call good incentive for precise flying.

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ACCAR Too Extreme a Solution
Robert Patlovany has done an excellent job of documenting the need for a rules change, and his proposed ACCAR, if used properly, would improve altitude separation.

When trying to effect needed change, it may help to consider not only what would be ideal, but also what is most likely to receive serious consideration in an environment where any change is difficult. I speculate that one reason the ACCAR proposal was turned down by the FAA is that it is a radical change that could also be perceived as being too complex to be consistently used properly. Perhaps a compromise proposal could be found that would be more acceptable to the FAA and still be a significant improvement over the current hemispheric rule.

For example, one could substitute a “quadrant rule” in which a magnetic course of 0-89 degrees corresponds to an MSL flight altitude ending in 250, eg. 3,250, 7,250, or 11,250, and then add 250 feet every 90 degrees.

Please continue all your efforts to make aviation as safe as possible.

-Geoffrey Swain
Grafton, Wisc.

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Keep Berge Coming
I am writing to you to congratulate you on publishing the writing of an absolutely engaging author.

Perhaps you knew the humor potential when you signed up Paul Berge to write the “Pattern of Abuse” article [Proficiency, December]. If true, you are to be commended for knowing how much humor can add to the impact of communications. You earn a Laugh-Out-Loud award for “... the controller tells you how to enter the pattern: ‘Make straight in,’ ‘Enter left base,’ ‘Go away’...” To know that it’s a controller writing the article adds immeasurably to the enjoyment.

Those who lampoon themselves truly know their subjects well.

Perhaps you didn’t know about his sense of humor, but had to make an executive decision on whether or not to abide a decidedly off-beat delivery in your august publication, for which I have an enduring respect. If so, good call. Five points and a few options for you, five more if you had to override some stuck-up knucklehead somewhere in your organization...

Awesome job. I read this from start to finish, something I don’t always do. Keep this coming.

-Brian Heuckroth
Via e-mail

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Real Accident Cause Uncertain
I enjoy reading Aviation Safety and many times learn very useful information. You mention an accident at Linden Airport [Preliminary Reports, January] on Oct. 25 that led me to believe the cause was pilot error and the sun was in the pilot’s eyes.

I know a few of the people there and they told me that it was unfortunate that the pilot who died had a heart attack on final and slumped forward on the yoke. The gentleman sitting in the right seat could not get him off before they crashed.

John was a good friend to many at Linden and will be missed. Keep up the good work at Aviation Safety.

-Joe Chociemski
Via e-mail


The Preliminary Reports section is taken from the preliminary reports filed with the NTSB. As such, they include the information the investigators had immediately available. The investigation takes months and typically includes autopsies and background on the pilot, the airplane, the weather, and any other factors the investigators pursue. By the time the final report is completed, much of the information will have changed. If, in fact, this was a medical emergency, we’ll update you when the final report is issued.

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Flight Plan Might Have Helped
I am a student pilot with about 50 hours, all in taildraggers, and I am an avid reader of your publication. I was reading the Aug. 3 crash in Red Lodge, Mont., involving a Cessna 177 [Preliminary Reports, November], and what caught my attention is the fact that the pilot did not file a flight plan. One bit of information I was not able to glean from the article is whether or not he could have survived the accident itself, but subsequently died from exposure and/or injuries due to the fact that no one found him for 9 days, and he wasn’t even reported missing for 6.

As I understand it, if the pilot had filed a flight plan, people would have started looking for him when he was 24 hours overdue. And if my experience is any indication, maybe even sooner.

The reason I say sooner has to do with a cross country I went on the other day. I was flying to an airport about 50 miles from my home base and back on a solo flight. I had microphone problems, and was unable to talk to ATC. I did manage to get enough through to one controller so that he could contact the FSS and inform them that I was returning to base and was OK. By the time I got back to the FBO where I take lessons and called the FSS, my flight plan had been closed by ATC as soon as I landed without my having to say anything, there was a message on the FBO answering machine, and in short ATC was right on top of things. If I had gone down, I’m sure I would have been found before the sun went down, not days later.

My story illustrates my point: How much sooner would someone have started looking for this particular pilot if he had filed a flight plan?

-Robert ‘Rex’ Shearer
San Jose, Calif.


The NTSB has not released any additional information on the accident you cite since our original report.

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Township Technicality
I’m an avid subscriber to Aviation Safety and thought I should bring to your attention a minor, but important, technicality.

The Cessna T337G report [Preliminary Reports, November] is listed as occurring in Windsor Township, Pa. I have seen townships listed as locations in other reports in the past and this is fine. However, states like Pennsylvania, Michigan and New Jersey all have township jurisdictions and often contain more than one township of the same name.

Therefore, I think it should be incumbent upon the editorial staff to specify (at the least) the name of the county in which the township is located. Otherwise, the reader may be left scratching their head as to what part of the state the accident occurred.

Thanks, and keep up the great work on your even greater trade journal.

-Matthew Tyson
Catharpin, Va.


To some extent we’re handcuffed by the sketchiness of the preliminary NTSB report. But we’ll make more effort at identifying nearby airports or other fixes that will help define just where the accidents happen.

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Ruinous Runway Conditions
Scott Schleiffer’s article “Fly ’er Till She Stops” [Airmanship, December] caught my eye, particularly his comments on slush and aircraft on skis.

Slush increases the probability of “surf-boarding” disconnect between gear and ground, something I definitely watch for when driving and feel is equally hazardous when landing or taking off – especially in Minnesota.

I hasten to add that slush is even more hazardous on takeoff because the landing gear will freeze in flight, creating the potential for disaster at the next landing. For those reasons, I would consider slush on a runway something to be avoided if there is any way to do so.

As regards aircraft on skis, he correctly observes that one must allow for increased “runout” distance when using them. But there is also the problem of crosswind, for skis have greatly reduced side-movement resistance, and this must be carefully watched if one is constrained to a fixed runway heading.

My own experience with them goes back to the ’40s, when during the winter we operated light planes on skis off Wold-Chamberlain Airport in Minneapolis, now Minneapolis/St. Paul International. If the wind was not aligned with one of the several runways available, we customarily took off and landed in the snow between the cleared runways.

The only problem then was looking out for and avoiding the banked snow along the runway edges. This, if encountered at slow speed, could be coped with.

-Noah Rosenbloom
New Ulm, Minn.

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Float, Yeah, But Not Like This
Most everyone flying around the coast or Great Lakes finds the need for life preservers. Living in Florida, I see a lot of aircraft carrying non-inflatable personal flotation devices (PFD) suitable for boats. These are dangerous in aircraft.

A career in naval aviation with its attendant water survival training taught me that you want to leave a ditched aircraft before inflating your vest. A PFD won’t allow that. Someone who dons a PFD before a ditching will drown if the aircraft sinks, as he or she will be stuck on the ceiling when the machine descends. No one can swim down hard enough to overcome the buoyancy.

“But,” you say, “I tell my passengers to put on their PFDs after exiting the aircraft.” Ever try it? It is at best difficult since you’re more or less vertical in the water, and the PFD is horizontal.

If you’re injured in the ditching, forget about it. Get rid of those things or put them on a friend’s boat.

With an inflatable “Mae West” on, you are not encumbered exiting the aircraft and can inflate it with only one hand once you’re clear. That difference may keep you alive. And don’t put them in seat pockets or other clever places when flying over water. Wear them.

I seriously question if any pilot can don a vest while descending engine-out and setting up a water landing. Something won’t get done when everything has to get done.

It’s a matter of survival for crew and passengers.

-Darrell M. Lowe
Vairico, Fla.

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Baro Cheat Sheet
Regarding “Mountain of Trouble” [Accident Probe, October], I keep a Mooney 252 based in Meeker, Colo. The local pilots there live by the following rules when flying through, and over mountain passes, and over the Continental Divide.

Check barometric pressure on both sides of the mountain pass or Continental Divide. If the difference between the barometric pressures at the two check points is 0.10, it’s OK to go, 0.20 expect low to moderate turbulence, 0.30 moderate turbulence (don’t go), 0.40 moderate to severe turbulence and 0.50 severe to terrifying.

-William G. Levy
Mt. Kisco, NY