A dark night, western Oklahoma, rocker studs snapped

[byrdflyr]

 

Flying N5808B from Ponca City back to Colorado Springs Friday night, I heard a "miss" and then my #1 Cyl. went cold. I noticed first a 25kt. decrease in airspeed, but not a significant vibration.  When I saw no EGT in my #1, I told ATC about the problem and that I would land at the closest suitable airport.  When I pulled the power back to descend, things got a bit more dicy.  The engine then stumbled and protested more, and I thought it might quit.  I declared an emergency and tried to land at Anthony, Oklahoma (ANY) like ANY airport would be great right now, but the lights would not come on, so I tried another airport just to the north, Harper (8k2), and the lights would not turn on.  So, with the engine on partial power and sounding sick, I turned back toward Ponca City, which would be about 50 miles away.  ATC called in a C-130 from Vance for support (Oiler 57 Heavy) who also flew around trying to turn on the lights at airports in the area, and the FAA called the police in Medford OK, and they (Asst. Chief Shepherd) went out to the airport and turned on the lights there.  Viola, I landed (it was a very good landing BTW, although I'm used to more than 3000 ft. and it was very dark except for the edge lights).  The police chief (asst.) let us borrow crew car and we got to a hotel about midnight. Whew.  I could write a lot more about what I learned from that - being better prepared, and using more of the tools in the panel (e.g., keep synthetic vision on constantly, and especially at night over Oklahoma), but mostly I was working on trying to get the airport lights to come on, not spiral in, and looking for other options. For example, if you don't enter the airport ID in your GPS (IFD 540) as your destination, it will start blaring terrain warnings once you get about 500 ft. agl. because it thinks you're getting too close to terra firma. 

Sunday, a nearby A&P (Ezra Olson, Prairie Wind Aviation, Kingman, KS) pulled off the #1 cover and found the valve rocker studs broken.  This OH Nickel cylinder assembly (J&J Airparts) has about 160 hours on it, and it has not been abused.  The engine oil was at a good level (6-7 on the stick) and only 15 hours old.  So, what would cause these rocker studs to snap?  Have you seen this before?  

Also, with #1 cylinder not making power, #5 had four episodes of cutting out for about 30 seconds, then coming back to life?  By that I mean EGT going from ~1300 to 700 and back to normal temps.  Why would that happen?  It was pretty noticeable loss of power and extra vibration with both cyls were out (did I mention it was very dark outside?).

[carusoam]

You sound calm BF...

Lets invite @M20Doc to see that... (broken rocker studs while flying M20K/262)

I’m going with hardware quality, torque specs, oil distribution, or an unknown to be determined later...

Are all the parts in there free turning? Anything stuck or sticky?

That is one interesting story.

Thanks for sharing it so far on MS.

PP thoughts only, not a mechanic...

Best regards,

-a-

[201Steve]

Nice job handling. How frustrating with the lights...

[Guest]

What a story!  Glad you’re safe.

Only a guess, but I’d suspect overtorque of the studs when they were installed in the head.

Clarence

[byrdflyr]

BTW, the FAA got the airport manager at Anthony Kansas (ANY) to go out to the airport and he confirmed the pilot controlled lighting was indeed inop, a fuse or something, and got the lights back on within an hour.  A bit late to be helpful for my situation, but in any case, maybe helpful for the next soul on board.  Not sure why the lights at Harper (8K2) didn't work either, as the AFD says "Runway edge lights: high intensity APT LGT SKED: ACTVT HIRL AND PAPI RY 17/35 - CTAF" and the C130 couldn't get those on either.  So, come on folks in Harper Kansas, fix your lights before someone gets hurt. 

 

 

[Missile=Awesome]

Super glad that worked out as well as it did.  Cheated death again.  Well played.  So, I heard it was REAL dark that night...

 

[cliffy]

"It was a dark and stormy night" Oh wait that's another story :-)

Good job under stressful conditions

Gazing into my crystal ball is see a top overhaul in the future. Or at least change out all the other studs.

Edited August 4, 2020 by cliffy

[neilpilot]

34 minutes ago, cliffy said:

Gazing into my crystal ball is see a top overhaul in the future. Or at least change out all the other studs.

Maybe....in 1994, due to a mechanic's error, both rocker arm bolts on cyl #2 were left finger tight on my 64E.  About 3 operating hours later they came loose, the push rod left a big dent in the valve cover, and the IO-360-A1A suddenly went from normal performance to high vibration and little power.  I made a successful forced landing, ended up installing a rebuild cylinder, and the engine performed fine thru 2012. 

[Guest]

2 hours ago, neilpilot said:

Maybe....in 1994, due to a mechanic's error, both rocker arm bolts on cyl #2 were left finger tight on my 64E.  About 3 operating hours later they came loose, the push rod left a big dent in the valve cover, and the IO-360-A1A suddenly went from normal performance to high vibration and little power.  I made a successful forced landing, ended up installing a rebuild cylinder, and the engine performed fine thru 2012. 

I’m trying to figure out the bolts you’re referring to?  Do you mean the nuts that hold the rocker shaft cover plate?

Clarence

[N201MKTurbo]

3 hours ago, M20Doc said:

I’m trying to figure out the bolts you’re referring to?  Do you mean the nuts that hold the rocker shaft cover plate?

Clarence

Wrong engine. It’s a 231

[neilpilot]

3 hours ago, M20Doc said:

I’m trying to figure out the bolts you’re referring to?

My mistake.  Not "bolt", but nuts.  IO-360-A1A.

[Guest]

1 hour ago, N201MKTurbo said:

Wrong engine. It’s a 231

Referring to @neilpilot who posted about his A1A in his E model.  The OP is discussing his TSIO360 in his 262.

Clarence

[GeeBee]

Nice job, and thoughtful of you to do your own "after action" assessment. Try not to beat yourself up too much in such assessments, the heat of battle always demands more than we can give. You did everything right in the midst of a giant fubar by the airport managements.

 

 

[N201MKTurbo]

2 hours ago, M20Doc said:

Referring to @neilpilot who posted about his A1A in his E model.  The OP is discussing his TSIO360 in his 262.

Clarence

I see now, sorry about that.

[larryb]

Good job in a difficult situation.

The one statement I zero'd in on is "This OH Nickel cylinder assembly (J&J Airparts) has about 160 hours on it, and it has not been abused." The thing about overhauled cylinders is you have no idea on how many total hours it has and how much prior abuse it suffered. It could have had 5000 hours on 3 engines. My personal standard is only new cylinders, no overhauled units with an unknown pedigree. 

[byrdflyr]

[byrdflyr]

Here are the rocker arm studs that broke.  What I found out -- J&J Airparts has the Work Order history on the three OH cyls I bought in June 2018. One of them required installation of rocker arm studs, the other two - the OH process didn't mess with the rocker arm studs.  My best guess is that either (a) the wrong torque was used to install the studs (there's a Continental SB on rocker arm torque values - but it didn't apply to these cyl part nos.) or (b) there was a defect in one of the studs that was not detected.  Once the rocker arm broke loose, it rattled around, being poked by the pushrod, so we're obviously checking that the pushrod is still straight, and no other damage was done to the rocker arm, the pivot seat (there is some fretting there and we'll need to make sure the rocker arm seat is both smooth and the seating is level).  The OH cylinders have a 12 month warranty, and it's been 25 months since installation.  So, no warranty on this at all.  I'm don't know what the cost difference is between new vs. OH, but for this cylinder, I predict it would have been cheaper to go with a new cylinder, assuming the same thing would not have happened.   BTW, if anyone wants to fly between COS and ICT or Kingman KS, let me know.  I"m going to need a ride to pick up "Mad Eye Mooney" around sometime between the 16-20th of August.

[N201MKTurbo]

21 minutes ago, byrdflyr said:

Here are the rocker arm studs that broke.  What I found out -- J&J Airparts has the Work Order history on the three OH cyls I bought in June 2018. One of them required installation of rocker arm studs, the other two - the OH process didn't mess with the rocker arm studs.  My best guess is that either (a) the wrong torque was used to install the studs (there's a Continental SB on rocker arm torque values - but it didn't apply to these cyl part nos.) or (b) there was a defect in one of the studs that was not detected.  Once the rocker arm broke loose, it rattled around, being poked by the pushrod, so we're obviously checking that the pushrod is still straight, and no other damage was done to the rocker arm, the pivot seat (there is some fretting there and we'll need to make sure the rocker arm seat is both smooth and the seating is level).  The OH cylinders have a 12 month warranty, and it's been 25 months since installation.  So, no warranty on this at all.  I'm don't know what the cost difference is between new vs. OH, but for this cylinder, I predict it would have been cheaper to go with a new cylinder, assuming the same thing would not have happened.   BTW, if anyone wants to fly between COS and ICT or Kingman KS, let me know.  I"m going to need a ride to pick up "Mad Eye Mooney" around sometime between the 16-20th of August.

You can't blame the cylinder for this. The installer would normally remove the rockers to install the cylinder, insert the push rods and then re-install rockers.

[FloridaMan]

FWIW, if you lose your engine or experience rough running, keep it in your mental checklist to work with the mixture and the mags. A clogged injector will often mean the fuel meant for that cylinder is distributed to the remaining cylinders, resulting in excessive richness (also mind that fuel flow for one less cylinder with a blocked injector will be less), and likewise, less air being metered due to one cylinder not taking it in can mean the rest are running excessively lean. I mention this as at the time you lose a jug or engine, unless it comes apart or locks up, you can’t be sure of what’s going on and these things are important to keep in mind. An induction leak with a turbo can also result in excess richness, and a valve failure can do all sorts of things to airflow and mixture as well. And lastly, a mag that has skipped timing or is arcing internally can yield strange results, so when the engine starts acting up, don’t freeze up and only focus on making your landing spot, check your mags and mixture as well as doing so may help you get on the ground safely. 
 

If it comes down to it and you’ve lost your engine, pulling your prop back to minimum RPM will reduce drag, increase glide distance and may help to keep your engine alive longer, though a restart with a full feathering prop may be difficult, as will getting it to feather under 1200 RPM.