I departed my home field around 2:30 on the afternoon of August 4, 2012 for a flight out to our daughter's place, about a 10 minute flight across town and northwest of my home. On my way out there, about a two miles south of her place and around 800 feet AGL, my engine died like there was a fuel problem. I turned on my backup fuel pump and tried to start the engine. It started normally so I figured I had a main fuel pump failure and turned back toward home to fix it.
As I passed over the northeast part of town, the engine quit again. Realizing there was no probable way both fuel pumps were bad, I turned away from town and looked for a landing spot. I decided on the hillside behind Menards, a big box hardware store here. There was an access road near the pasture which would make recovery easy if necessary. As I flew toward the hill, I traded altitude for speed which I knew I'd need to flare landing uphill. My biggest concern was the presence of large rocks hidden in the tall grass but the landing and rollout turned out to be uneventful. Field landings are normal for me as I'm used to landing in my neighbor's pasture which butts up to our back yard and is also my home strip.
When I realized I would be landing deadstick, I called the Rapid City Regional tower and told them I had an engine or fuel system problem and would be landing behind Menards to check it out. I wanted the tower to be aware of my situation in case someone thinking they were witnessing an aircraft accident due to seeing me come down toward a hillside with no prop turning, would call it in to someone.
The tower asked if I was declaring an emergency to which I told them "No", and that I was just landing to check out the problem. I tried calling again upon landing but couldn't make contact due to the hillside being between me and the tower. So I got out and checked the fuel pumps by switching each one on individually and listening for its running. Both were good so I removed the fuel bowls from each carburetor and each one was full. I tried to start the engine again and it started normally.
NOTE: For anyone wondering about the "both fuel pumps running" comment, I had removed the Mikuni pump years ago due to problems I was having with it in the way my fuel system was installed. I did have a Facet electric pump as a backup which I later found would overcome the fuel delivery problem I was having with the Mikuni. So I plugged off the pulse port on the engine and replaced the Mikuni with a Facet which resolved my problems. I wrote an article for the challengers101.com website about troubleshooting those problems and my solution.
Anyway, I taxied up to the top of the hill where I could get radio contact and called the tower. I let them know I was down and okay but would be a while troubleshooting the problem. She acknowledged the transmission and I shut down to go see what I could find. I then called my wife to let her know of my problem, that everything was okay, and what I would be doing to find the problem.
A few minutes later I heard sirens so went to look over the hill and down toward Menards. "Surely this wasn't for me", I thought.... well, it was. There were 5 or 6 city police cars, a fire engine, 2 or 3 Search & Rescue vehicles, and a couple of unmarked Suburbans. I'm guessing they were the Feds but don't know. I found out later that the tower had declared an emergency on their own when they hadn't heard from me after a few minutes.
I walked down the hill toward the police officers and Search & Rescue vehicles that were coming into the pasture and waved that I was okay. Search & Rescue met me about mid-way and they wanted to take me for a medical checkout. I replied that I was fine and it was a normal landing for me. They were insisting but again I told them that there was no aircraft damage nor personal injury and a mostly routine landing for me. They asked if anyone was with me and I said no. They asked what happened and I told them I evidently had an engine or fuel problem of some sort that I needed to check out. They asked if there was a fire to which I again said it was a routine landing for me and nothing else was wrong with the plane.
Well, they wanted to see it and I said okay so I got in and we drove up to the top of the hill where they checked the plane over. Satisfied, they asked how I would get it out of there and I said that would depend on what I found. If I found nothing, I would run the engine for a while to see if it was reliable and, if so, I'd fly out and get it home which was about 4 miles away to the southeast. If I found a problem, I'd call my wife to get a trailer and we'd trailer it out. They said "Okay" and headed back down the hill.
Once again I checked over the fuel system seeing nothing in the fuel sump bowl, no loose or leaking fuel lines, nor anything else that was readily apparent. So I started the engine again and ran it up to take-off rpm, cruise rpm, idle, and everywhere in between I could think. I ran it for about 8 or 9 minutes mostly at cruise and take-off rpms with no problems. I brought it back to idle, set the brake and walked back down the hillside. I'd decided that I'd have to take-off in that direction due to fencing and quite tall high-lines near the hilltop. Even though I'd have a slight tailwind, that was the only way back out. I was looking for rocks or anything that would cause a problem as I departed.
Finding nothing, I got back in, checked my controls, then ran the throttle up to take-off rpms. I waited a few moments, released the brakes and departed. There were still two police officers down at the street so I waved to them as I departed and they acknowledged. Turning to the southeast and home, I called the tower for permission to enter their Class D airspace and transition to my home strip. Permission was granted as requested and I proceeded toward home.
A few minutes later, about a mile and a half northwest of home, the engine died again so, once more, I set it down in a pasture without incident. I called the tower to let them know I was down again but everything was just fine and I'd be trailering the plane home this time. They acknowledged my call, asked me to let them know when we got it home and I shut down. I started checking things again just for grins and giggles. Both fuel bowls were full as before but this time as I rotated the prop through, I noticed that I had only one compression "bump" whereas I usually have two as the cylinders fire alternately. I decided that I had a failed cylinder so called my wife that I'd need to get a trailer for the plane. She called our daughter and they came out with a gooseneck trailer. We loaded the plane, tied it down, and drove home where it was unloaded and put back in the hangar.
Checking compression again at home, I did have two compression "bumps" but the bad cylinder was about 30 psi lower than the good cylinder. Pulling the engine off and taking it apart, I found that the PTO cylinder had stuck rings due to carbon build-up. This probably caused blowby and heated the skirts enough to expand and seize a bit. Oddly enough, when things cooled off, it would run normally for a while. There was some scoring of the cylinder wall which will have to be honed. I'll also be replacing the seals during the rebuild.
I had 192 hours on the engine and the problem was my own fault for not decarboning at 150 hours as well as running EGT's around 1020 - 1030 degrees the previous winter instead of the normal 1130 - 1150 I normally run. I'm fairly well convinced that this allowed carbon to build much faster. My first engine had been run with synthetic 100:1 mix and I had a shelled-out PTO bearing probably due to too tight a drive belt tension my first couple of hundred hours. That in turn, probably contributed to the broken crankshaft as I had about an eighth inch play in the PTO shaft when it was checked. At the time, I wasn't sure whether or not the lean oil mix was a contributing factor so, on this new engine I decided to go back to a 50:1 mix with organic oil.
With the synthetic oil, I didn't show any signs of carbon build-up until about 450 hours when there was just a hint of it. The rings were always free not to mention hardly any oil residue on the prop and tail feathers. When I get this one repaired, I'll most likely be going back to synthetic oil after the break-in run.
What I learned from this was to follow my maintenance checklist no matter what issues (or lack of) I've experienced in the past. I completely forgot about carbon build-up issues when I decided to change oil types and I failed to properly inspect the engine during the 50 hour inspections. While this was an expensive lesson to learn, it could have been much worse.