This happened to me this morning about 7am just after sunup, I'm still processing the details in my head, but here's the short version.
I was headed out to go see some friends up north, wheels up at first crack of dawn 6am this morning, and cruising along fat dumb and happy at 9500 on VFR flight following when I noticed that my AFR (air-fuel-ratio) was quite a bit leaner than I normally run it. I tweaked my mixture a bit to get it back where it should be, but my mixture control was significantly richer than it should have been for that condition. That made me take a good long look at the engine, specifically the fuel pressure - which normally runs 40-42 psi (SDS injected engine), and it was down around 29. I watched it for a few more minutes, 28. 27, 25. Definitely slowly dropping and my low fuel pressure alarm goes off. The engine starts to stumble, the AFR indicates 18 (way too lean), so I go full rich, AFR only comes up to mid-16's and my fuel pressure continues to drop. Of course I changed tanks, changed fuel pumps, changed injector boards, all the things you are supposed to do - and it didn't do anything.
That was enough, I kicked off the autopilot and keyed the radio, declaring an emergency with Center. I had a small short grass strip TE08 at my 2 o'clock and headed for that with the engine stumbling and bumbling and started descending. I was plenty close enough and high enough to deadstick it, so I pulled the throttle back to make a no-power approach - and the engine got happy again. Throttle back in, and it's not happy - back out and I get some power - about 10 seconds of this and I realize I've got about 30%-40% partial power - and that means I have options. I can almost maintain my current cruise altitude of 9500 on that.
I called Center and advised them I will be holding altitude with the partial power I have, and will attempt to overfly my known good grass strip in order to stretch my deadstick glide ring to include 77F, Winters Tx, with a paved runway and a least a fighting chance of some type of assistance. I would not have been able to do this if I was lower down - but at 9500 it was possible to include both airports in my deadstick range - so I made the decision to press on another dozen miles and try to milk the engine that far. This is exactly why I like to cruise high - it gives you time and options when things go bad.
It worked, I got within comfortable deadstick range of 77F, advised Center of my intentions, they gave me a number to call on landing and I switched to advisory. By the time I had copied down the number and gotten back on task, with the engine still happily making partial power, I was well high and had loads of energy to dissipate. I pulled the throttle all the way off (don't need it now - and can't trust it - so it no longer exists and I'm a glider) and made a few spacing turns, got into a good position for final on 17 with a 10 knot direct cross, declared intentions on the local frequency and used flaps to manage my energy for a delicious squeaker of a landing that, of course, nobody was around to see. Engine was still running so I taxied clear and shut down by the hangars.
First call was to Center on the number they gave me, advised them I was down safe, no injuries, no damage, and would have assistance on the way shortly and thanks very much. Zero drama there.
Next call was to my wife, you can pretty much guess how that one went. Next call was for help, and within 20 minutes I had a 172 loaded with tools airborne in my direction.
So - that was fun. Long story short, the cause was tracked down to a plugged 10-micron final fuel filter between my pumps and the injectors. My 50-micron pre-pump filters were dirty but not completely plugged - and the stuff in them was like muddy lint. Cleaned those out, reassembled, engine made excellent power and fuel system was doing its original thing again - so I took off and climbed in a circle over the field (with the 172 close by watching me) to about 7500 feet on my way to higher and then pointed it home. On arrival I pulled apart the entire fuel system and flushed the tanks - and found the smoking gun - which is why I'm sharing this here for you other guys that fuel yourself.
On my 125-gallon fuel transfer tank and pump, I have a 10-micron fuel filter prior to the hose, as most of us do - but I do not (yet) have any type of protection for the hose end - it is hung on a peg and open to the air. A mud-dauber had come in and started building a nest in the open hose end, and I didn't see it this morning when I was fueling my plane in the dark at 5:30, and pumped that nest into my left wing. On draining the wing tanks I ran the fuel into a filter funnel and found a fair bit of the evidence coming out of my left sump, so the chain of events is well established.
So - a good fuel system flush, another cleaning of the filters, another load of good fuel in the plane, and it's happy again. All's well that ends well - but the message here to you guys that fuel yourself with a home-brew fuel setup - PROTECT your stuff against insects. Those little buggers can kill you dead.
I was headed out to go see some friends up north, wheels up at first crack of dawn 6am this morning, and cruising along fat dumb and happy at 9500 on VFR flight following when I noticed that my AFR (air-fuel-ratio) was quite a bit leaner than I normally run it. I tweaked my mixture a bit to get it back where it should be, but my mixture control was significantly richer than it should have been for that condition. That made me take a good long look at the engine, specifically the fuel pressure - which normally runs 40-42 psi (SDS injected engine), and it was down around 29. I watched it for a few more minutes, 28. 27, 25. Definitely slowly dropping and my low fuel pressure alarm goes off. The engine starts to stumble, the AFR indicates 18 (way too lean), so I go full rich, AFR only comes up to mid-16's and my fuel pressure continues to drop. Of course I changed tanks, changed fuel pumps, changed injector boards, all the things you are supposed to do - and it didn't do anything.
That was enough, I kicked off the autopilot and keyed the radio, declaring an emergency with Center. I had a small short grass strip TE08 at my 2 o'clock and headed for that with the engine stumbling and bumbling and started descending. I was plenty close enough and high enough to deadstick it, so I pulled the throttle back to make a no-power approach - and the engine got happy again. Throttle back in, and it's not happy - back out and I get some power - about 10 seconds of this and I realize I've got about 30%-40% partial power - and that means I have options. I can almost maintain my current cruise altitude of 9500 on that.
I called Center and advised them I will be holding altitude with the partial power I have, and will attempt to overfly my known good grass strip in order to stretch my deadstick glide ring to include 77F, Winters Tx, with a paved runway and a least a fighting chance of some type of assistance. I would not have been able to do this if I was lower down - but at 9500 it was possible to include both airports in my deadstick range - so I made the decision to press on another dozen miles and try to milk the engine that far. This is exactly why I like to cruise high - it gives you time and options when things go bad.
It worked, I got within comfortable deadstick range of 77F, advised Center of my intentions, they gave me a number to call on landing and I switched to advisory. By the time I had copied down the number and gotten back on task, with the engine still happily making partial power, I was well high and had loads of energy to dissipate. I pulled the throttle all the way off (don't need it now - and can't trust it - so it no longer exists and I'm a glider) and made a few spacing turns, got into a good position for final on 17 with a 10 knot direct cross, declared intentions on the local frequency and used flaps to manage my energy for a delicious squeaker of a landing that, of course, nobody was around to see. Engine was still running so I taxied clear and shut down by the hangars.
First call was to Center on the number they gave me, advised them I was down safe, no injuries, no damage, and would have assistance on the way shortly and thanks very much. Zero drama there.
Next call was to my wife, you can pretty much guess how that one went. Next call was for help, and within 20 minutes I had a 172 loaded with tools airborne in my direction.
So - that was fun. Long story short, the cause was tracked down to a plugged 10-micron final fuel filter between my pumps and the injectors. My 50-micron pre-pump filters were dirty but not completely plugged - and the stuff in them was like muddy lint. Cleaned those out, reassembled, engine made excellent power and fuel system was doing its original thing again - so I took off and climbed in a circle over the field (with the 172 close by watching me) to about 7500 feet on my way to higher and then pointed it home. On arrival I pulled apart the entire fuel system and flushed the tanks - and found the smoking gun - which is why I'm sharing this here for you other guys that fuel yourself.
On my 125-gallon fuel transfer tank and pump, I have a 10-micron fuel filter prior to the hose, as most of us do - but I do not (yet) have any type of protection for the hose end - it is hung on a peg and open to the air. A mud-dauber had come in and started building a nest in the open hose end, and I didn't see it this morning when I was fueling my plane in the dark at 5:30, and pumped that nest into my left wing. On draining the wing tanks I ran the fuel into a filter funnel and found a fair bit of the evidence coming out of my left sump, so the chain of events is well established.
So - a good fuel system flush, another cleaning of the filters, another load of good fuel in the plane, and it's happy again. All's well that ends well - but the message here to you guys that fuel yourself with a home-brew fuel setup - PROTECT your stuff against insects. Those little buggers can kill you dead.
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