License to Learn

When a student pilot finally gets his ticket, he's traditionally told "Here's your license to learn." I did just that. Specifically, I learned several ways to run out of gas.

Six months after I got that ticket, I rented a Cessna 172 for a 4000-mile trip: Boulder, Colorado to Brownsville, Texas to Lansing, Michigan and back to Boulder. Each leg was planned for at least two days and was scheduled for Christmas. I loaded N80893 with Christmas gifts, took off from Boulder, and pointed the nose toward Texas.

Believe Your Instruments

The first leg was uneventful, skirting around the Denver class B airspace and stopping at Dalhart, Texas for fuel and food (lunch). Along the way, I tried to use a "Johnny-Jar" and decided it is a bad idea. Much better to stop every two or three hours for fuel and other needs.

I left Dalhart with both fuel tanks full, headed for San Angelo. Along the way, I noticed that the right tank's fuel gauge was dropping steadily, but the left tank's gauge stayed at full. I tapped the gauges, like most people do, and wondered why. (Why do people tap?) My first thought was that something was wrong with the gauges - the fuel valve was on "both" (I checked) but only the right gauge was dropping. But my analysis was followed immediately by another thought: "What if the gauges were right? I'd be running out of gas with one full tank." I decided I'd better stop somewhere and check.

There was a small airport nearby but when I overflew the runway, I could see big "X's" at each end. I checked my charts again and discovered I was looking at an old, abandoned strip at Big Spring. The new one was a few miles further on.

I landed and taxied up to the fuel pump, and checked each tank with my trusty stick. The left tank was full, just as the gauge said, and the right tank was low. Not dangerously low, but I filled it just to be safe, and flew on to San Angelo, just 25 miles or so further on. Before heading for a motel, I arranged for a mechanic to meet me in the morning.

The next morning was the day before Christmas, but a mechanic came over, just we'd arranged. He walked up to the airplane and immediately went to the vent under the left wing, and tweaked it. He grabbed it with his hand and bent it back just a little, and said "There, that oughtta take care of your problem! No charge."

When my jaw dropped, he laughed and explained. Sometimes the vent under a Cessna's left wing is misaligned, and the prevailing wind is just right, the airflow around the strut immediately in front of the vent sets up just enough suction to hold the fuel in the tank. He pointed to a faint fuel stain on the under side of the wing that I hadn't noticed. Before I took off, I called my home base and discussed it with the mechanics there. They acknowledged that the left tank had been replaced just before I rented the airplane. The vent could have been knocked slightly out of alignment in the process.

The trip from San Angelo to Brownsville was uneventful except for being about 15 miles off course at one point. I was using "flight following" and ATC asked if I was following the correct VOR.

Nope. Thank you very much.

I spent Christmas in Brownsville, with my parents. On Christmas Day, I took Mom and Dad for a ride, much to their enjoyment. The next day I took my sister and her boyfriend up. He'd been a P-51 jockey in WWII and enjoyed the ride but declined to take the controls when I offered. I've met other vets for whom flying is not fun; it's related to a bad time that they survived.

Check Those Caps

But when I switched to just the higher-reading tank, the engine stopped. Now that's a sound that instantly grabs your full attention: the sound of silence. I immediately switched back to "both" and the engine roared back to life.

Whew!

I called Flight Watch and explained that I was nervous about the fuel situation and wanted to stop at the next small airport to check it out more carefully. ATC objected that the runway was closed for resurfacing but offered to clear a taxiway so that I could effect an emergency landing. I declined because I had no firm evidence of an emergency and my intended refueling stop was only about 30 miles further along, but asked if they'd keep an eye on me.

I landed uneventfully at College Station, Texas, and refueled.

I pushed on to Walnut Grove and refueled again, but as I passed into Missouri, my fuel gauges became abnormally low. I circled one small town, looking for the airport but couldn't find it. My charts showed an abandoned strip nearby; I was becoming desperate and went looking for it. I found it quickly and landed. My fuel gauges read near empty and sticks into the tanks showed less than five gallons total onboard.

But this was a deserted strip: not so much as an outhouse remained. I walked two miles to a service station on a nearby highway, where I made telephone calls until I could find someone who could bring me aviation fuel. He brought ten gallons and we both inspected the airplane carefully without finding anything wrong. My charts showed a larger airport, big enough to have mechanics about 40 miles north so I took off and made that hop uneventfully. I handed the plane to the mechanics and found a motel.

The next morning I conferred with the mechanic, who said he could find nothing wrong. He speculated that I might have gotten one of the caps mistightened and air flowing over the wings might have sucked the fuel out. Possibly. There were plenty of airports along the route north so I continued on.

The weather report showed a weak cold front just south of Fort Wayne, but the outlook indicated that it would dissipate before I could get there.

Ask for Help

Once I could see some distance ahead, it was apparent that the "weak cold front" wasn't dissipating as forecast, but rather was gathering strength. I decided I'd better turn back.

But when I reversed direction, I discovered that the weather had closed in behind me as well! There were no longer any holes through the cloud cover. I had made a bad decision and now was about to make another bad decision.

I reasoned that I could risk descending to my original flight altitude without running into rocks, and decided that maybe then I could see where to go. Down I went, without clearance from ATC. I did have enough sense to watch my instruments carefully to ensure that I entered no abnormal attitudes.

Fortunately, I broke out of the clouds at about the altitude I expected, but now I was in rain, and visibility was about five miles. Somewhat rattled, I tried to find the right frequency for Terre Haute, which I knew to be about 15 miles west. I couldn't find the approach frequency but did find ground frequency. At this point, I was beginning to feel a little panic, so I called Terre Haute Ground.

Terre Haute Ground gave me a little static about my miscall but quickly said he'd help. He told me how to approach Terre Haute. I should have done that before I entered the clouds; they could have talked me through my difficulty - maybe even help me avoid it in the first place.

The next day, it was an uneventful hop from Terre Haute to Lansing, Michigan, where I'd planned to spend a few days with my ex-wife and my daughter.

Winter Weather

The next morning the poor Cessna was frozen and I couldn't get it started. The local airport manager and I pulled it into a hanger and spent the morning trying to warm it up, and I finally got out about noon. I stopped at a small strip on the edge of Nebraska to re-fuel but no one was around. (Later I learned that the airport had been closed in favor of a new airport four miles south.) After calculating the remaining fuel, I elected to press on.

Fuel calculations showed I could get to Beatrice, NE, with enough fuel to spare, but I hadn't counted on 35 Kt headwinds. I should have diverted to any of the larger airports in Eastern Nebraska, but I was uneasy about flying into congested airspaces so I opted for Beatrice.

I regretted that decision as I watched the gauges inching down toward empty. When I got to the Beatrice VOR, I turned onto the appropriate radial but called Beatrice Unicom, declaring my fuel crisis and asking about nearby landmarks that might help me find the unfamiliar airport. The female voice said, "How's this?" as she flipped on the "rabbits" - flashing indicators for an ILS approach - and I was thrilled to discover that I was on a perfect track. I made a conventional approach and rolled up to the pumps with the engine still running.

Weather kept me in Beatrice for a couple of days. Once I called to file a flight plan and as I declared my destination, the voice said, "Isn't that a coincidence? I just had an experienced pilot cancel that same route due to icing conditions. Now what can I do for you?" I thanked him and hung up. (For non-pilots: ATC is not allowed to advise when pilots call to file a flight plan, but when appropriate, they often find a way to skirt that rule.)

Finally conditions warmed up a bit, flyable but with turbulence. I headed for Colorado and immediately encountered an intriguing pattern, which I should have recognized but didn't.

I'd fly for about ten miles under clear skies and very little turbulence, and then the next ten miles would be cloudy and very turbulent. One bump set me up on one wing tip and I was grateful that there are no known cases of a Cessna 172 breaking apart in the air.

I was experiencing a phenomena called "gravity waves" or "mountain waves." Anyone who flies near Boulder is very familiar with them, but I'd never seen it this far away from those mountains.

Briefly, the mountains cause eddies in the wind streams, much as rocks do in a river. Downwind of the mountains, large waves appear in the air, with the crests and troughs marked by bands of clouds. Under a crest, clouds form as the air rises and cools. and the air is turbulent as rotors are created below that crest. A trough, however, has no clouds as the moisture descends to warmer air, and little turbulence below the flow.

This pattern continued across western Nebraska and into Colorado. I stopped at McCook for fuel and continued toward home. ATC called me and asked if I had the turbulence advisory, which I acknowledged and continued on. As I drew abreast of Greeley, the skies cleared and I debated stopping in Greeley. I could see the mountains beyond Boulder and the skies were clear all the way, so I elected to continue.

I was remembering that all the way from Beatrice, clear skies had signaled calmer air. But I neglected the "waterfall" effect as the wind spills over the front range.

I crossed I-25 and was close enough to home to cancel flight following, which I did. As I reached for the radio, to change frequency to Boulder UNICOM, all hell broke loose.

It was the worst turbulence I have ever experienced. I had no control whatsoever and it was all I could do to merely hold on. Fortunately the plane held together and as the bouncing eased slightly, I saw Longmont Airport (six miles from Boulder) below me - so down there I went.

Surface winds at Longmont were only 10 knots and my landing was uneventful. I called Boulder via telephone to let them know that I wouldn't make it home that night. They said "We wondered if you'd dumb enough to try it. Winds on the runway right now are 90 knots!"

The wind had subsided the next morning and I finished my trip.

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