It was June 1995. The place was Santa Cruz, Bolivia. I was a pilot and mechanic for Wings of the Wind, the aviation ministry of the Baptist Missionary Association in Bolivia. The airplane was a Piper Aztec, a twin engine, six-place airplane built in 1966. This story started with an oil leak on the left engine. It was not a huge oil leak, but it was not supposed to be there.

I have heard that the radial engines used on World War II era aircraft always leaked oil, to the point that the crew was alarmed if there was not any oil on the hangar floor after it had sat there overnight. Our engines were Lycoming IO-540’s with six cylinders, 540 cubic inches, produced 250 horsepower each and we depended on them to get us over the jungles and back. Our engines were not supposed to leak oil.

I was not okay with the oil leak, even though it was not more than a tablespoon or so after each flight. I should be able to find the problem, fix it, and move on. The last Monday in June I removed the cowl, cleaned the engine, ran it and didn’t see any leaks. But there were a couple of gaskets that could have been the problem, so I replaced them. Next day I flew the airplane around the airport a bit, removed the cowl again and still there was oil. I removed the propeller to change the oil seal in it, saw an access plug with a copper crush washer that looked like it had some oil on it. I took the access plug out, and found a loose half-moon key in the plug. This half-moon key… 

There are several half-moon keys in the engine, but there is not supposed to be one laying loose in one of the access plugs! That particular access plug was to access a shaft that holds a gear that operates the propeller governor. The parts manual for the engine showed that there is supposed to be a half-moon key in the middle of the shaft. I put my magnet tool into the hole and the shaft came out with it. I should say that half of the shaft came out with the magnet! You’ve heard it said that the only thing worse than finding a worm in your apple is finding half a worm in your apple…half a shaft on the end of my magnet was not good news. 

The airplane was grounded. 

Pastor Edilberto Rodriquez was expecting me that weekend. He, his wife, and two small sons were planning to see me and the supplies that I would have in the airplane for them in the small village of Versalles on the Bolivia/Brazil border. This was not supposed to happen. I was not a “happy camper.” 

I talked to my friend Earl Horton in Lubbock, Texas on the phone. Earl started Horton Aero Service in 1950… the year before I was born. Earl had forgotten more about airplanes and their engines that I will ever know. When it came to airplanes, Earl was my best friend. I told him about the shaft and he had never seen one break like that before. He offered to call one of his friends at the Lycoming factory to ask what to do next. He called back the next day to say that they had never seen that before either, but outlined what they thought I should do in order to get the shaft out of the engine without losing the thrust washer on the other end of the shaft. If that thrust washer came out, it would mean a complete engine “tear-down/overhaul.” They sent a fax with a drawing of a special tool that I could make that should hold it in place. If everything went well it should work… according to the people who built the engine. 

By the following Monday, July 3, I had found a spare shaft…all in one piece… built the special “tool” and very carefully pulled the other half of the shaft out. As I placed the good shaft back in I heard the most sickening sound possible. It was the sound of the thrust washer falling down deep into the innards of the engine. I had to sit down. I called Earl back and told him the sad news. We started a list of parts that I would need to make the engine airworthy again. I found that there was a missionary team coming to Bolivia from Florida that was willing to bring some spare parts as “extra baggage.” If everything worked well the airplane should only be grounded for about a month…if everything went well…and it certainly had not gone well so far.

That night all I could think was, “Why is this happening to me? It is not supposed to be this way. What did I do to deserve this? What is going to happen to Edilberto and his family? What about the others in the Bolivian countryside that are counting on the airplane for their supplies?” 

There was a July 4th celebration in Santa Cruz among all the Americans. There were several missionaries, others worked for American oil companies, and some American “ex-pats” living in Bolivia. I took the day off to celebrate.

Beginning July 5th and working from 6 a.m. to 8 or 9 p.m. most days, I removed the engine from the airplane for disassembly to find the thrust washer. When I removed one of the magnetos that provides spark to the spark plugs there were tiny balls from a ball bearing lying where the bearing should have been. The bearing on the other magneto (each engine has two magnetos) was in bad shape, but still intact. I called to ask Earl to add these to the list, but Earl was not in the shop that day. His son Mike, whose primary job was to rebuild engines, answered the phone instead. When I told Mike about the loose balls that had been part of the bearing the phone went silent for a few seconds. I thought I had lost my connection. When Mike spoke again, he said, “Hendren, now you have scared me. We have never seen a shaft break like that, but I have seen a bearing shell out like that when we did an autopsy on an engine that had caused a crash. Just one of those little balls will ruin the oil pump and that will destroy the engine. I need you to count the balls in the intact bearing, then you have to account for all the balls that are loose in the engine. Those little loose balls will go through an oil passage and ruin the oil pump, destroying the engine. We will send you four bearings instead of two, you have to change both of them on both engines before you try to fly the airplane again! Promise me you’ll do that!” I counted (and recounted…twice…) the little balls. They were all there. 

That’s when I remembered this verse:

The left engine was minutes of operation away from complete and total failure. At the same time I thought, boy, that’s an expensive and time consuming way to learn a lesson of thanksgiving!

The 6th of August is Bolivia’s Independence Day. That was the day that the left engine was completed, installed on the airplane and ran for the first time. That was also the day that I saw fuel squirting up from the fuel injector when I started it! I shut it down immediately! A little rubber diaphragm had dried out, cracked and would have to be replaced. Another call to Earl had a replacement on the way. The following day I found that a Bolivian mechanic friend, Mono Chavez, had a spare diaphragm he was willing to loan me until my package arrived from Lubbock.

Meanwhile, the little bearings on the magneto drives on the right engine…the “good” engine…needed to be replaced. I had promised Mike Horton that I would replace them before flying again. I carefully removed the magnetos, pulled the bearing out, and found that one of them was almost completely “frozen up.” I had to sit down. The reason for flying a twin-engine airplane was in the unlikely event that an engine quit, we could continue the flight to the nearest airport. I had already realized that the left engine would not have gone much further, and now realized that the right engine…the “good” engine… was not much better. 

I had some tears in my eyes that day, sitting in a chair at the right engine, as I said:

“Thank you Lord, for an oil leak that lead to a loose half-moon key that lead to a broken shaft that lead to a thrust washer in the innards of the engine that lead to a bad bearing that lead to a bad bearing in the other engine. I’m sorry Lord, for getting so angry and depressed at the oil leak, and the key, and the thrust washer, and the shaft, and everything else. Thank you for friends in Lubbock that kept me grounded and for a family that brought me lunch, and supper, and put up with my cranky mood.” 

P.S. We still had the oil leak after the engine overhaul. Earl suggested a fix that involved an epoxy glue similar to JB Weld in a particular spot about as big as a quarter. That solved the oil leak!