Article appeared in Flying Magazine September, 2015 by John King –
“Hey, fly the airplane.” I looked up, startled to see that we had entered a left bank. At Martha’s urging I came in with strong right rudder, ignored the left boost pump, and flew the airplane to the runway.
The checklist on a Cessna 340 calls for both fuel boost pumps to be switched on at short final. When I did, the left engine quit. There is a principle that says when you do something in an aircraft and you don’t like the result, undo it. Following that principle, I had returned my attention to the left boost pump to turn it back off. Martha rightly had objected to my lack of attention to airplane control.
On the ground we wanted to know—why had the engine quit? We drained the fuel sumps and much to our surprise found water in the fuel. This had us confused. When we had left San Diego for this flight to Cheyenne, we had drained the sumps and found absolutely no water in the fuel. Where had it come from?
We drained the sumps thoroughly, and continued to do so until long after we were no longer getting water. Then we ran the engine up with the boost pump off and on, and it ran just fine. Out of ideas, we took off again. Martha flew us without incident to Sioux Falls, South Dakota.
Our next leg was to Farmington, New Mexico. It was my turn to fly. Everything was fine until, during cruise at 22,000 feet in the pressurized 340, the left engine quit. I switched tanks and the engine came back to life. Again, I was confused. There was plenty of fuel in both tanks.
As we were talking with approach control while setting up for the approach to Farmington, the left engine started surging. Approach control cleared us for the VOR approach to runway 25, circle to land runway 7. Martha said, “You’d better not circle to land.”
I was offended. I was an ATP. I had been trained to fly a twin on one engine. I said, “Why not?” “The other engine is quitting too,” Martha explained. On the panel I could see both fuel flow gauges waving at me. The airplane was yawing back and forth wildly.
I advised approach control that we were making a straight-in to Runway 25 and we were having trouble with both engines. Each engine was putting out intermittent power. I didn’t feather either one of them on the theory that we were getting some power, and that if we feathered them, we would for sure be getting no power.
Farmington’s airport is on a plateau above the town. I wasn’t sure we were going to make it to the runway. If we weren’t going to make it, we would have to make the decision early, or risk slamming into the cliff. I looked for an emergency landing area, but couldn’t find one. The town surrounded the east end of the plateau. I committed us to land on top of the plateau.
We passed over the cliff at less than 50 feet with gear and flaps up. With the runway made, I put them down simultaneously. I idly wondered whether the gear would make it down before we touched down. My biggest concern was whether we would have brakes and steering. I didn’t really care a whole lot whether the airplane would be damaged. I was mad at it at the time—it was letting me down big time.
After landing, we found the left engine had quit completely and the right engine was idling. It produced just enough power to taxi us off the runway and into parking. Firetrucks followed us onto the ramp. One fireman with a clipboard asked, for his report, what the problem was. When I told him I had had problems with both engines, he asked if he could say I was out of fuel. “Absolutely not!” I replied. I pointed out the frost line at mid height on each of the tip tanks caused by the super-cold fuel, explaining it indicated the fuel level.
We left the airplane at a maintenance shop and asked them to investigate the problem. Even though it was only mid-afternoon, Martha and I checked into a hotel for the night.
The next morning the shop told us they couldn’t find any contamination or anything else wrong with the fuel system. I decided to make phone calls. My first call was to Cessna. I made it clear that I was not willing to fly the airplane again until I understood what the problem was, and why it wasn’t going to do that to us again.
The very kind and competent person on the other end of the line said, “It’s not in your model year’s handbook, but in subsequent years there’s an explanation of how to prevent this. When an airplane—even one using avgas—flies at altitudes where it’s very cold, the water that is regularly dissolved in the fuel precipitates out in the form of ice crystals, which then can block your fuel system. Then as your fuel system warms up, the ice melts and the water dissolves back into the fuel. When you drain warm fuel from the sumps, you won’t find water, because it is dissolved in the fuel. The solution is to use a fuel system icing inhibitor like the product called Prist, or isopropyl alcohol.”
I was stunned. This could have been prevented, if we had only known. We went out immediately and bought isopropyl alcohol, and put the recommended amount in our fuel. We used isopropyl alcohol in the fuel from then on and never had the problem again.
We learned from this that we had moved into a new flying environment, and clearly didn’t have the knowledge we needed to identify and mitigate the risks. Our training for flying at higher altitudes had been pretty much limited to a course in an altitude chamber. The rest, things like how to plan our descents and how to keep from shock-cooling our engines, we learned on our own
We took full advantage of the pressurization in the Cessna 340 and routinely flew it in the low twenties. Since our previous aircraft was Cessna 310, our 340 checkouts consisted of little more than a few trips around the pattern. Checkouts in those days were usually pretty minimal. Had we had more formal instruction, we probably would have learned about water dissolving in the fuel—and that alone would have helped us avoid unnecessarily putting our lives at risk.
Interestingly, when we moved into jets we didn’t have any similar problems. In fact it’s fair to say that in 28 years of flying jets we have not had one single “deal,” or in any way scared ourselves in a jet. The reason is that in a jet, in addition to having more redundancy and more reliable systems, we were required by the FAA to have a type rating and the training it requires. We were taught what we needed to know to manage the risks of that particular type of aircraft and the environment it flies in. Along with jet training came the high altitude training we didn’t get for the C340.
Pilots often think of flight training as the learning of physical skills. But our problem at Farmington in the 340 illustrates that getting knowledge is critically important as well. When we pilots move into new environments the FAA often helps us out by requiring specific training such as for seaplanes, gliders and helicopters. But there are many other new environments for which the FAA does not require training, such as mountain flying, off-airport flying, and as in our case, flying at altitudes in the high teens and lower twenties.
From our C340 experience we learned that it pays to use whatever resources you can find to learn about any new flying environment, whether the FAA requires training for it or not. You can look for expert instructors, type clubs, books, courses—any resource that will help you learn about the new environment. The Internet is a powerful tool to use to find these resources. If we had actively sought to learn about the environment of higher-altitude flight, we might have gained the knowledge we needed to identify and mitigate the risk that gave us such a scary experience at Farmington.