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About tgardnerh

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  1. I think I watched that webinar maybe 3 weeks before this incident. When I saw the crazy-high CHT I more or less heard Mike Busch on my shoulder telling me "pull the power to idle NOW." Probably saved the engine, and maybe even avoided a serious accident.
  2. To close this out: The cylinder came off, and the verdict was that the valve guides and valves were bad, the cylinder barrel was polished smooth, and the piston was scored on the sides (presumably from contacting the cylinder, and also badly pitted (I presume whatever was going on in there eroded that aluminum pretty fast). Since then, I also had an event that has been tentatively diagnosed as a stuck carb float, but manifested as partial power loss over mountains. I put the airplane down on the nearest airfield, and found blue staining all over the nose-wheel. All this, combined with the fact that every new mechanic who looks under the cowling says something to the effect of "ehh, i guess it's airworthy," means that if anybody is in the market for a 1/6th share of a Cessna 152 based at KSQL, I've got one for sale. Thank you everybody for helping me navigate this adventure!
  3. I couldn't agree more about the "oh crap" reaction. I had an event a few weeks ago where I had to abruptly pull power to idle 3 minutes after takeoff, and it was 100% my glider rope-break training that got me home safe. There's really no time to make any decisions, just time to execute the decisions you've already made. A bit of tape on the ASI is a healthy reminder that you decided long ago to keep the speed up even if that means landing short.
  4. @carusoam, I did see those notes, though the time for conservative management has past (in the sense that the cylinder is currently sitting on a workbench, which sort of precludes the "gather more info first" strategy). As of now, the #3 cylinder is either getting OH'd or replaced. The plan is to also check the other 3 cylinder head covers for the oil sludge we found on #3, and check all 4 compressions, and check the timing (spark plugs have already been checked for fouling). Once the airplane is whole again, I'll set the JPI to record on a 2 second interval (quickest possible), and upload proper Savvy profile recordings for the first flight, and another flight once the cylinder is broken in. If the mag checks then look off, I'll check plug resistance. Is there anything else you'd do in my shoes? To everybody who has chimed in, thank you! The collective response here has been incredibly helpful. This is a side of aviation that PPL training just doesn't cover, and I couldn't ask for a better crowd to help out with the "Oh shit, now what?" questions.
  5. Huh. My (geico) umbrella policy pre-dates my pilot's license, so I didn't think too much about aviation when it was written, and never checked. Glad I have stand-alone liability insurance for the airplane!
  6. The incident flight is on a 6 second interval, so 10/minute. On the actual monitor the alarm is set at 450--it was the bright red flashing light that got me to pull the power to idle!
  7. That's exactly how I generated the link!
  8. I went back through since April, looking for anything amiss. It looks like there's plenty of hard use, but no classic saw-toothed pattern or anything else that looks bad to me. If you want to take a look, I'm curious what you think!
  9. @carusoam Thanks for the thoughts! Since I'm not the only decision maker on this plane (downside of a six person partnership), longer-term members and the A&P have ended up driving the bus on this one. At this point, the #3 cylinder has been pulled, the shop's IA says it shows no visible damage, the cylinder is going to a specialist to check it over and see if it's all in spec, and I suspect we'll reinstall, check the timing, and move on. Other plugs looked fine, and since the EGT only gets weird at 9:42 (when I pulled the power to idle), I suspect the plug is secondary to whatever caused the thermal runaway. I will probably see if the other 5 members can be sold on a Savvy maintenance subscription--if it turns out the cylinder didn't need to come off, that means the subscription would have paid for itself right there! (never mind the downtime and risk associated with it)
  10. Alright, I suppose I can do that at least--let some of the water out but also have the airplane squared away before the next person flies.
  11. I don't, tbh with six guys sharing a plane, I suspect that's not likely to happen/I'd be too concerned that the next guy flying would forget to screw it back in. On the flip side, the airplane flies regularly on flights long enough to get the oil good and hot. (And yes, there was quite a bit of condensation in that oil sludge, maybe 10ml total)
  12. doubt it--i dont have it on the JPI, but since only one cylinder was hot, and only for ~2 minutes, i suspect the oil only cooked locally. The oil on the dip stick looks good, with no change from before. Not at all, first and only indication was the high cht. mag check was perfect 3 minutes before the episode.
  13. This is a question about my O-235 in a Cessna 152, so forgive me since it's not a mooney, but y'all are the best collection of technical aviation judgment and knowledge I've encountered: tl:dr is that I think I had preignition, scoped the engine, mechanic wants to pull and likely replace the cylinder, and I want more opinions on the whole thing. Here is the flight in question: Mag-check from 3-6 minutes, takeoff at 6 minutes, and at 9:40 I noticed CHT #3 was reading 588, so I pulled to idle and landed promptly. A runup on the ground showed the #3 bottom plug entirely non-functional (3:18 here), and so the mechanic gave me a new plug and his blessing to fly away. Plug removed from #3. Cracked Porcelain not visible here However, a compression test ~2 flight hours later showed 60/80 with mist coming out of the oil fill cap, and the attached boroscope images. Additionally, the valve cover was coated in something that looked like a bad egg dish. What say y'all about what happened (was it preignition, and if so what could have caused it?), and if there are any next steps beyond pulling the cylinder. Valve: Piston: Valve Cover:
  14. Hell, I'm a negative net worth pilot (student loans...) and I carry an umbrella policy. I pay less for $1M in coverage than I do for netflix.