DXB

My checklist has that but my rollers are not nearly as slick - I couldn't detect the problem until I leaned right to close the cabin door when I was #1 for takeoff and the seat leaned in unison with me - it was not on the left rail. I had to tell tower at that point that I need to go back to the ramp. I might have never noticed had it been the right rail that wasn't engaged.

Also, if your avionics shop or someone else removes and reinstalls a seat, add it to your post maintenance checklist to make sure the seat is securely on BOTH rails, not just one. Failure to do so can lead to an untimely surprise. Ask me how I know .

Thanks for the interesting details on metallurgical considerations - I'm also curious how they apply to our spars. However, the circumstances of this crash are radically different from that Arrow accident that led to the Piper wing AD, and I suspect it will not inspire nearly as much regulatory scrutiny from an airframe perspective. I also think the center section of spar that failed is relatively easy to examine and no fleet-wide issues have been noted regarding corrosion susceptibility of that area to date? What worries me more are the portions of the wing structure that are covered with tank sealant - I think someone here stripped a tank for reseal at some point, only to learn that his plane was totaled due to corrosion. Then there are planes like mine, where someone put in bladders when the leaks became intractable. In that case, not only does the sealant not get stripped (possibly underlying corrosion that was contributing to the leak), but a portion of the wing structure is made permanently inaccessible for visual inspection.

nice job not flipping despite the fixed gear

So this is basically like a factory new mag that I have right? I feel a little weird swapping it after <200 hrs….

Thanks - My left Surefly is definitely set up and timed correctly, and its associated harness is new, and plugs are in good shape - so I'll take its 150 rpm drop as the gold standard on my particular engine when just running just on it at mag check. The overhaul exchange R mag was put on 200 hours ago by a trusted shop that permanently lost my trust over unrelated serious issues I had with that annual. My CHTs went up some with the new mag, and so I had a reputable shop look over the timing on it and they adjusted it (not sure what direction). with no discernable effect on CHTs. Then 12 months later, the next A&P to do my annual found the right mag timing to be more than 10 degrees too retarded (which is massive as you note) - but his correcting changed the rpm drop on that side from 150 to 100 and seemed to leave me with even worse CHT problems (for the first time becoming a serious issue in cruise) and so I was suspicious that it was over-advanced. But checking the timing hands-on myself while working with another A&P a couple months later seemed to indicate the timing was about right, but we had quite a bit of difficulty figuring out exactly where the points open. In the end, I think there is something wonky internal to this right mag - a 10 degree shift in timing makes no sense to me based on the E-gap changing. You've convinced me to pull the right mag and replace with an overhaul exchange from a reputable place (maybe that one in Montana).

I used this stuff https://www.aircraftspruce.com/catalog/appages/windlacedoorwelt.php

Been using my Clarity Aloft since I was a student pilot 8 years ago and love it mostly - but recently the mic boom has become won't hold its position and sags down, so I constantly have to hold the mic up to my lips. Anyone else have this issue? I wonder if their customer service can do something to make it less...um...flaccid? Like some kinda headset Viagra?

bottom left of front cowl - hmmm interesting point - I wonder if a winterization plate in the winter would reduce the difference between sides of the engine….

I don't know squat about aircraft loans, but I wish I'd had the balls to get into flying and aircraft ownership at your stage in life (back when I was a broke surgical resident). I didn't come from money and simply couldn't visualize what a favorable financial trajectory might look like and the life options it could offer me. My financial fears were ridiculous in retrospect - the demands on time are still substantial, but with discipline and commitment there is enough that can be carved out in the latter part of ones training. Don't let anyone here discourage you.

Plugs are 250 hr old Tempest UREM37BY, and I clean/gap/resistance test/rotate regularly, replace at around 500hrs. Harness for the Bendix mag is 20 years old and harness for Surefly is new. However, running on the Bendix mag gives the LESSER rpm drop full rich (100rpm) vs. 150rpm on the Surefly, so it does not seem to be an ignition problem on that side, leading to hypothesis that timing was overadvanced. 150 RPM is the standard drop I'd always gotten on conventional mags as long as I've owned the plane, so the fact that the overhauled Bendix gave less of a drop (even relative to the correctly timed Surefly, which has a longer spark duration) was striking to me.

great question, haven't been able to figure out what source the shop used - and that was such a bad service experience overall I don't plan to use them again

<200 hrs on an overhaul, and yes I’d read about the backlash issue and was carefully supervised by an experienced person while moving the prop so I don’t think that was contributing

I've been chasing a CHT issue predominantly on the leanest cylinder (#4), that was there before my last annual but got worse after annual in both climb and cruise - I've discussed several other CHT factors in another thread but wanted a separate one focused on magneto timing. I have a Surefly on the left and a Bendix mag on the right of my O-360-A1D. Per my A&P at annual, the timing on the right mag was way off, and he advanced it to about 10 degrees to 25 before TDC. Since my overheat issues got worse after that annual, I've scrutinized mag timing carefully. Before annual, I'd get symmetric mag drop at runup (150 on each side) but after annual the right mag drop changed to only 100, making me think the right side was over-advanced (I'd actually think the Surefly should give you the smaller drop, all other things being equal, due to the longer duration of its spark). So I had my annual-performing A&P recheck timing on both, and he didn't find anything to be off. Then I personally rechecked timing on both after watching a Mike Busch webinar on mags and some youtube videos (under direct supervision of a different A&P). The left Surefly looked perfectly timed (at TDC on #1). The right Bendix mag looked good - somewhere around 24 degrees before TDC on #1. HOWEVER, there was there was some inconsistency on the right regarding where the points opened when moving the prop back and forth. Sometimes the box would buzz initially, stop briefly, and then continue while moving the prop - my supervising second A&P said it was very odd and she'd never seen that before. We retimed it based on the very earliest moment the buzz started, but that made zero difference in the asymmetric mag drop or in flight cooling of the engine. I also recalled my first A&P mentioning similar weirdness when he checked the timing of the Bendix mag, with variability in timing light behavior on different cylinders. My question - does this Bendix mag have an internal issue contributing to misfiring and potential CHT issues? It is an overhaul exchange mag with <200 hours on it. The engine runs very smooth. To put this issue to rest, I'm thinking of swapping that mag with a different overhaul exchange mag. Or is that just blindly throwing money at the problem without a clear idea what is going on?

A partially clogged injector would explain the rapid rise in #5 CHT and running rough - but how could that happen without an effect on EGT?

Interpreting the engine monitor : (1) Some kind of #5 cylinder malfunction causes rough running engine and anomalous rapid rise in CHT but no clear effect on EGT one hypotheses: A glowing carbon deposit causing intermittent pre-ignition? I'm having a hard time figuring out what could raise CHT so dramatically but have no effect on EGT. (2) upon reducing power to land, #5 CHT plummets and EGT flatlines, meaning zero combustion in that cylinder - makes no sense to me in context of my hypothesis to explain #1. (3) There is clearly something wrong with the #5 EGT sensing upon landing - Combustion seems to recover around 00:22. On the ground, CHT trace for #5 acts like all the rest, but #5 EGT trace remains flatline. Did whatever temporarily killed combustion in malfunctioning #5 cylinder somehow also permanently kill the EGT probe?? Interesting case....

I dunno why AA batteries drain, but I've noted the same issue with nearly the identical handheld (Yaesu FT550). Since I can't be bothered to check the batteries on a regular basis, I carry a second AA battery holder to snap into it so I can revive it easily in an emergency.

I suppose high EGT/low CHT can happen if you have a sticking or poorly seating valve reducing compression, but it's hard to for me to imagine how increases in leakage past the rings during the compression or power stroke increase EGT? When my #1 got replaced a few years ago, I was struck by how much hotter its EGT was and how its CHT ran substantially cooler. I was pretty worried about a sticking exhaust valve or poor exhaust valve seal, although it was a brand new cylinder and the engine ran smooth. It's run that way now for a few hundred hours though with no signs of burning when I borescope. I kinda wish my other cylinders acted the same way! Yeah that is an interesting point that I haven't considered in a while - if accurate, that's a tough one to fix without total redesign of the inlet and baffle I'd think. It's surprising then that most other C owners don't see the same pattern and mainly complain about #3 being hottest - and it seems the factory felt the same way because that's where they put the factory probe.

BTW If this is a carb'd plane, it needs aggressive leaning on the ground right after startup to keep from fouling. I learned the hard way when I first got my C - which also didn't have an engine monitor at the time so I got some practice finding the fouled plug quickly by intuition . It's more often a bottom plug, so that narrows down to four plugs to check first. The routing of the harness from that mag should be to top on one side and bottom on the other, so that gives you two plugs to check first. And in my experience it's the same offending bottom plug over and over - on the richest and/or oiliest of the bottom cylinders. An idle mixture that's too rich may also contribute to the issue, so it's worth looking at that.

It's the air pressure gradient from above each cylinder to below that cools the fins - I've hypothesized that the left side of the doghouse creates less of a gradient to cool 2 and 4 for reasons I just can't grasp. There may be a point of air flow stagnation on the left but a favorable gradient on the right. It may take an engineer brain like yours to solve - I'm clearly not up to the task.

All are <1300 at WOT on takeoff from sea level. Oddly #1 EGT is always the hottest though it runs rich relative to 2 and 4 and always has the lowest CHTs by far. It may be just probe placement variation.

I can say this for sure after a lot of time looking at my engine monitor data: 4 is the leanest, usually followed by 3. 1 and 2 are richer than either - but since I can't run those two to peak EGT without roughness, I don't know which is richest. I can cool 4 in cruise by running it LOP, but then CHT on 2 skyrockets, so I try to find a compromise mixture where 2 rises to the low 400s and 4 falls to the low 400s - it's a PITA. The extra power from the Powerflow exhaust really seems to have exacerbated the problem for 4, less so for 2. But because 2 and 4 have always the hottest regardless of mixture setting, climb, cruise, airspeed, or power setting, timing advance, or exhaust type, I do think that airflow over 1 and 2 is much worse for some structural reason I just can't seem to nail down.

Thanks - I've heard this partial carb heat technique does improve mixture distribution for some folks - unfortunately I've messed with it ad nauseam in cruise without significant effects - it does change the distribution slightly but I think somehow #2 and #4 get much worse cooling airflow on my setup so that is the overarching effect. I have noticed some benefit of very slightly cocking the throttle plate in helping my #4 run cooler in initial takeoff climb, presumably by improving mixture distribution, but the effect seems inconsistent.

I imagine a stop could be placed on your mixture cable, either at the panel side (ideally an easily removable one) or a change in how it attaches to the carb, that would give you a very slight decrease in fuel flow at the full rich setting? It doesn't seem worth the time, expense, hassle of pulling your carb again. Also this is very interesting information for me - my 17-18gph leaves my #2 and particularly #4 running hotin , but on the O-360 it sounds like enriching to 18-19gph under many conditions causes other problems. It makes me less inclined to pull my carb.

Though no autopilot would be helpful once there is full loss of control and rapid descent, this is still a pretty nuanced issue. If he was hand flying, the LVL button on the GFC500 would have been very helpful if he was primed to use it at the first sensation of disorientation. Even if he didn't use it, the ESP would also have kicked in to prevent extreme attitudes and speeds and gone to wings level automatically if lack of further inputs indicated pilot incapacitation. But more likely, he was not hand flying but rather using an older autopilot, and an avionics failure precipitated loss of control. If he had a digital AI controlling a GFC500, that type of failure would have been less likely to happen. But if that modern autopilot did indeed suffer loss of attitude info, loss of ship's power, or an internal failure, then he would have been in the exact same pickle. Since most of us fly in IMC and on approaches much of the time using he autopilot , the greatest benefit of modern hardware seems to be increased overall reliability, not necessarily automated envelope protections and LVL buttons (even my lowly STEC-30 has a form of the latter). If modern hardware does fail for any reason, the need to identify reliable attitude info and hand fly accurately while still in the normal flight envelope remains just as pressing.