Quote Originally Posted by Kitfox Pilot View Post
Thanks for the heads up Jim. Just wondering what caused the emergency landing?
Harlan, its a long story, but here it is:
An engine out event I had due to a water pump drive gear failure on 4/9/2021 at 952 TTSN hours.

On April 9, 2021 I was flying low (about 400') in my Kitfox SS7 over the Deschutes River, OR in the bottom of the deep canyon, heading for Bull Run, a backcountry dirt airstrip about 5 miles ahead of me. All instruments were showing normal readings and the engine was running smooth. Suddenly without any warning the engine stopped instantly without any clank or unusual noises. With nowhere to land except the river or rocks and brush on the narrow shoreline I pitched to a 65 mph best glide speed and tried a restart; it started right up and seemed to run fine. I climbed out of the canyon and made a normal landing at a small rural airport (Wasco State) about 15 miles away. However, during this 15 mile flight, the CHT's started to climb into the red, reaching about 320 F and leveling off there. The oil pressure and temp remained entirely normal thru the whole flight until I shut off the engine. When I got out of the plane oil was dripping out of the bottom of the cowling, but no coolant had leaked out and the coolant system was full with no steam coming past the pressure cap. Oil of course was way down and didn't show on the dipstick, but there must have still been enough to maintain oil pressure and temp. With the oily mess I couldn't spot any cause, like broken hose or loose clamps or fittings. So I arranged to trailer it home to evaluate it.


After cleaning up the oil that had sprayed all around in the engine compartment I was able to see a hole punched thru the bottom of the ignition housing near the water pump weep hole. A gear tooth was partly sticking out of that new hole that had been punched. It was right below where the water pump drive gear is located. It is in a chamber that has engine oil to lube the drive gear, so of course oil started dribbling out of this small hole. Apparently it was a slow enough leak that it gave me time to fly about 15 miles to Wasco airport and still maintain oil pressure and normal oil temperature. However, the water pump must have quit operating because of the broken drive gear so no water was circulating even though the coolant system remained full, causing my overheated cylinder heads. The moment the water pump drive gear broke must have mechanically jammed the engine, causing it to suddenly stop. When I activated the starter about 10 seconds later it must have pushed the broken piece thru the housing and cleared the jam, allowing the engine to restart and continue running, even though oil was running out the hole. The ignition housing and water pump drive needed to be replaced, possibly the overheated cylinder heads, and inspected for other damage.


This was a very unusual occurrence, but was related to some work I had done a year ago (4/29/2020 at 850 hours) by Aircore Aviation (Jim Scott, A&P/IA), in Arlington, WA, an authorized Rotax Repair Center. He replaced the ignition housing the first time due to a crack in the top of the original housing. The replacement housing was remanufactured unit purchased from South Mississippi Light Aircraft which already had a water pump and drive assembly installed by SMLA. Aircore Aviation is no longer in business and the owner has retired. So I shipped the engine to SMLA to evaluate damage and repair. Findings were: the Arlington shop mechanic had carelessly let a starter idler gear thrust washer slip out of position when installing the new ignition housing/starter assembly and it dropped down into the bottom of the case unknown to anyone; after I flew it for about 50 hours the washer finally worked its way into the water pump drive gear assembly and caused the sudden engine stoppage in the canyon; broken gear teeth and other pieces then ruined the camshaft drive gear and bearings, scarred up bearing journals in the crankcase, and damaged some pistons and bores. The engine was trash; would have cost more to repair than it was worth as a half TBO (952 hrs) engine.

The good news is that Jim Scott, the retired mechanic, stood behind his mistake when I contacted him and sent me $8000 as an insurance payment, and I got $2000 from SMLA for core value for my trashed engine. That gave me $10,000, half the cost of a new engine, so I purchased a brand new 912uls and installed it. I have been flying it now for 30 hours and everything is working fine. My 8 year old, 1000 hr, Kitfox SS7 is like brand new, and I didn't crash or get a scratch. I thank God that old engine was able to clear the jammed gears and restart and get me to an airport.

I don't blame Rotax at all; that old engine ran sweetly and perfectly for nearly 1000 hours, until human error caused its demise. Still lovin the Rotax 912.