Unicom

April 1999 Issue




Beauty and the Beast

That Beautiful Moonless Night Could be Siren Song

All right, you finally scared me. After years of reading your excellent articles as a low time pilot and thinking “I’ll never do that,” you sent me one on spatial disorientation that I probably would have done: launch into a dark, moonless, featureless night without anything even remotely resembling an instrument rating [What If?, February].

Perhaps I’ve been lulled into a false sense of confidence by instructors who tell me my instrument skills are pretty good for a non-rated pilot. Perhaps it’s because there are almost always lights around to provide a ground reference in Northeastern New Jersey. Maybe because most of my 12 hours per year are flown at night and that I periodically spend time practicing partial panel flying on a PC training device at home, but I would have launched into that “beautifully clear moonless night” at Van Nuys.

Night flying is so beautiful, and I’ve found it such a great way to simulate/practice instrument navigation without actually flying under IFR, that I do it whenever I can. I’ve never gotten into trouble yet, even over the darkened landscapes of the Northwestern parts of the state. But then, in retrospect, I don’t think I’ve ever been over them without a moon to gently light the way.

So, you got me. Your magazine did what it’s supposed to. Thank you. The life you save may be my own.

-Jim Kemp
Madison, N.J.


You’re welcome. But you also have to thank yourself for realizing the potential for trouble. Now, about those 12 hours a year…

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Angle of Attack Was Risky
With respect to “Wicked Assumptions” [Accident Probe, February], there were a couple of things that caught my eye.

In 1956 I was taking dual for my commercial certificate and was taught the same soft field takeoff technique. I think back at how the tailwheel was forced down into the mud and how much drag it must have produced. In this case, since Telluride, Colo., has a hard-surfaced runway, a soft-field technique is not indicated – and certainly not a wrong one.

But never mind, we are now in the air. What ever happened to the story of the back side of the power curve or, as the old books called it, the “region of reversed command” – the speeds between Vs and Vy where you have to put the nose down and let the airspeed increase for the rate of climb to increase. And then, a 1650-pound airplane with a 219-pound overload, the actual Vy would be well above the book value. And maybe there would be no climb rate at 10,000 feet and out of ground effect.

One last thing, the examiner said the pilot liked to lift off nose high and climb with a steep angle of attack. In an overloaded low-powered airplane, a nose-high attitude would result in a low airspeed, which would result in a high angle of attack. Yeah, right next to the stall angle of attack.

-Billy Gibson
Farmingdale, N.J.


Mr. Gibson is a Designated Pilot Examiner.

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Kilos, Not Liters, an Issue in Crash
I just got my first issue of Aviation Safety and was pleasantly surprised. The articles seemed more substantive and detailed than I expected. I like the journal and have subscribed for the year.

Two quibbles about the “Gasping for Gas” article [Airmanship, February]. On page 3, the reference to the 767 fuel exhaustion incident, the issue was kilos versus pounds, not liters versus gallons. The latter would have resulted in overfilling. On page 4, the author says that airline and professional pilots seldom, “if ever,” run out of fuel. Strange to say this, having just documented such a case on the preceding page.

Keep up the good work, this looks like a fine publication.

-Bill Stanley
Albuquerque, N.M.


Quibbles noted. We hope your flying is as sharp as your eyes.

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Is Auto Fuel a Wimpy Alternative?
“Gasping for Gas” is an excellent article. One thing I noted was that the Cessna 150 used in the article had the “auto fuel” STC.

Just what is “auto fuel”, leaded, unleaded, oxygenated, or the MTBE stuff we are burning in California?

I have two VWs that I purchased new in 1973 and 1974. I maintain the engines to aircraft quality and have careful records on every mile and gallon of gas they have ever used.

When these VWs were new they got 24 miles per gallon on “leaded” regular gas. They were designed to use “leaded” gas. This is just what the book said they got for mileage.

Then they outlawed “leaded” gas and we got only “unleaded.” The miles per gallon decreased.

Next they eliminated “unleaded” and gave us MTBE oxygenated gas only which also probably contains alcohol of some kind. Now the gas mileage on these carefully maintained VW engines is down to 18 miles per gallon or only 75% of what they originally got.

The 10 gallon tank now gives a range of only 180 miles instead of 250 miles.

How is a pilot supposed to know what the fuel burn per hour is in these “auto fuel” STC airplanes? Is there really readily available data?

I fly only Cessna 150 and 152 airplanes and have not encountered one converted for “auto fuel.” If I do I sure won’t expect the same fuel economy the POH claims for 100LL.

-Donald W. Pray
Via e-mail


We posed your question to the experts at the Experimental Aircraft Association and were told that auto fuel actually has slightly more available energy than does avgas, but that it’s so similar that in most applications power and fuel burn will be identical.

With some low-pollution formulations of auto fuel, you may get at most a 2% reduction in power compared to avgas. (For more on auto fuel STCs, see the EAA’s web site at www.eaa.org.)

We suspect the troubles with your aging VW engines come from some other source than the gasoline you’re buying.

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Metering Fuel Solves Gas Crisis
The article “Gasping for Gas” reminds us once again that there is only one way to know how much gas is left: Measure it. There is one way of doing this with near certainty – count the drops as they go by. That is, use one of the fuel flow measuring systems that are on the market.

At a cost of around $1,000 or less, this is an expenditure that every owner of a serious cross-country airplane ought to make. Those who regularly rent that kind of aircraft should lean on the owner or the FBO to have one put in.

My own experience is that, after calibration on a few tanks of gas, the accuracy is better than 1 percent. This means that you can know your current consumption of fuel to within a few tenths of a gallon. Further, since the burn rate is also available, you can easily check that you have leaned as well as you had planned. It is of real comfort to know your used and remaining fuel for sure. It could be life saving!

Clearly, a bad leak, loose gas cap or simply forgetting to reset the total fuel available after fueling can negate the utility of a fuel flow system. Screw-ups happen. But it is mighty reassuring to check the refill after a long flight and have it come to within a few tenths of a gallon of the measured total fuel flow.

-David Fox
Minneapolis, Minn.

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Politics and Flying Do Mix
The articles “Gasping for Gas” [Airmanship, February] and “Earning Trust” [Learning Experiences, February] were excellent reminders that fuel gauges should never be trusted. Our Cessna 172 has two fuel gauges. I have labeled the one on the left Democrat and the one on the right Republican because they both lie to me.

So before every flight I “stick” the tanks to learn the truth, then fly by time rather than by distance.

-W.R. Messinger
Webster, Texas