Date: 201508
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 50
Light: Daylight
Aircraft: Skylane 182/RG Turbo Skylane/RG
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Descent
Airspace: Class E ZZZ
Aircraft component: Engine
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Private; Flight Crew Instrument
Human factors: Time Pressure; Troubleshooting; Confusion; Distraction; Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; Flight Crew Inflight Shutdown; General Maintenance Action
Contributing factors: Aircraft; Human Factors; Procedure
Primary problem: Aircraft

Narrative: The flight was mostly uneventful up to about 10 miles before landing. It was challenging to keep engine temps at 380 and below 400F CHT without throwing a lot of fuel at it; but I worked on that most of the flight (cowl flaps opened). I had 82 gallons of fuel; enough for a return flight as long as I was burning closer to 15 gallons than 20 gallons per hour (there was virtually no headwind). I checked that I had 8qt of oil before takeoff. During the flight; the fuel totalizer failed; so I didn't know what my fuel flow was and I tried to use fuel based on CHT temperatures only without knowing what the flow was. This was a known fault with this plane that was going to be fixed eventually.When I got over the mountains; we got smoke in the cockpit. Strangely it felt like it came from the back of the plane and because I was carrying a lot of batteries (lipo and lithium); I had my passenger look in the back to make sure none were on fire (they were in a fire proof lipo safe bag; but still; I wanted to be sure). He looked through all the luggage and couldn't find anything. By then; the smoke had stopped things were back to normal and I figured it was probably one battery I was carrying that shorted and things were back to normal. I was busy with the approach since I had to follow a specific route and altitude; and unfortunately at the time; I didn't think about looking at the alternator; but I got no low voltage warnings. It's possible the alternator did die and that I was running on batteries. I made the mistake of not checking electrical systems or oil pressure/temperature; mostly because after I felt confident that I didn't have an active fire in the plane; and no more smoke; I was close enough to my destination that I had to concentrate on the approach.At the time; I didn't think/know anything was wrong with the airplane (clearly; I made a mistake there); but soon I could tell the engine sounded a bit differently; something like a pinging sound when I was a lowered throttle (maybe 20'). I saw CHT go to 410F and added more fuel (more than needed); and unfortunately I was too busy worrying about not busting airspace and being over the right places to approach landing to think about looking at oil pressure and temperature when I heard the pinging; but I'm guessing they were bad.The pinging soon (maybe within 2 minutes at most; I didn't time it) changed to what felt like a cylinder that failed and very heavy shaking. I feathered the prop and just shut off the engine because of how bad the vibrations were. I believe the prop stopped on its own. On the ground; it was not possible to turn the prop by hand. I was able to make a perfect glide to the runway numbers and land smoothly at the airport. Because of the location I likely could have landed safely anywhere else; but given the choice of gliding to a hard runway; I went for that).I had enough speed to turn on a taxiway before the plane stopped entirely; and it then had to get towed. I had a bit of oil on the windscreen (not a lot thankfully); and after landing took this picture which was my first strong hint that the smoke did come from the cockpit and likely the alternator that shorted; or some other wires that went loose and shorted. I don't know if this in turn caused a failure that messed with oil delivery and killed the engine; hard to say; but it would be a possible outcome. It is also possible that I had a failure with the oil system that caused a leak that caused an electrical short and the smoke we got. Clearly; I got so concerned about lipo batteries being in fire that I totally forgot to check those systems unfortunately.I'm happy that I did remember to put the gear down and that I had enough electrical power for it to go down because I don't think I could have pumped it fast enough. I was able to coast off the runway and was later towed to the airport parking. There we no injuries; the landing was perfect; but the plane likely has an engine that isdestroyed. I hope that I didn't cause it to die by not keeping it cool enough (I've been told under 400F CHT is ok; but maybe that was too close to the limit; or the engine had other issues that caused it to be marginal and more likely to be damaged by any temperatures above 380F).




Synopsis: After crossing a high mountain range; a C182RG had an apparent engine failure. The pilot saw smoke in the cockpit earlier and felt vibrations severe enough that they shut the engine down before landing.