This could have ruined my day and then some!

[Guest]

After installation of the cylinders the engine overhauler would have to check and possibly adjust the rocker arm clearance.  Once this was finished the rocker shaft gasket and cover plate would be installed and torqued.

Clarence

[Yetti]

So the valve push rods have to have clearances checked.  There are different sized rods.   You have to remove the cover and pull the rocker arm to switch out the rods.  so whoever put the cylinders on is the responsible party for the loose nuts. 

[Joe Larussa]

Just now, Yetti said:

So the valve push rods have to have clearances checked.  There are different sized rods.   You have to remove the cover and pull the rocker arm to switch out the rods.  so whoever put the cylinders on is the responsible party for the loose nuts. 

There's going to be some interesting phone calls tomorrow morning!

[Yetti]

More than likely there is an apprentice involved....   they were given the easy tasks of buttoning up...  or there was a phone call answered in the middle.

I bought a four wheeler one time... I am sure the high school student was given the task of putting the wheels on...   got all the nuts on.... forgot to tighten up one of the wheels.  We found it when one of the nuts went away and the wheel became wobbly....

Once I rotated the tires.  Got all the nuts on, forgot to tighten up one tire.

twice I have forgotten to reset the trim before take off.

Check and recheck

[MB65E]

Take the high road you'll be better off. 

-Matt

[Guest]

11 minutes ago, Yetti said:

So the valve push rods have to have clearances checked.  There are different sized rods.   You have to remove the cover and pull the rocker arm to switch out the rods.  so whoever put the cylinders on is the responsible party for the loose nuts. 

We don't know that for sure, maybe during the annual the boss told the apprentice to take out the fuel injector and the apprentice cracked the wrong nuts.  In any event the guy who just signed out the annual and presumably the fuel line AD was the last guy there and bears most of the responsibility.

If it were a loose nut inside the engine I would agree and buy the engine overhauler being responsible.

Clarence

[Joe Larussa]

Ironically enough the week before I had the bolt that holds the cowl flap rod on depart the plane. Found the flap hanging there after landing. 37.00 for the damn bushing! Should that been caught as well?

[Piloto]

This looks like a mechanic shift during the engine assembly. First mechanic hand tighten the nuts to later have them torque. But at the lunch shift the second mechanic thought the nuts were tight and continued with the rest of the assembly. That is why the assembler has to complete the task list before the shift.

José   

[Yetti]

1 hour ago, Joe Larussa said:

Ironically enough the week before I had the bolt that holds the cowl flap rod on depart the plane. Found the flap hanging there after landing. 37.00 for the damn bushing! Should that been caught as well?

If you have the quick release ball and joint then probably not an Annual.  If you don't have a quick release then they probably unbolted it to get to things.   Many times it is easier to reach through the cowl flap hole.   or if they took the lower cowl off...

[N201MKTurbo]

I assume you found the rocker spacer when you took off the valve cover?

 

[DaV8or]

15 hours ago, M20Doc said:

We don't know that for sure, maybe during the annual the boss told the apprentice to take out the fuel injector and the apprentice cracked the wrong nuts.  In any event the guy who just signed out the annual and presumably the fuel line AD was the last guy there and bears most of the responsibility.

If it were a loose nut inside the engine I would agree and buy the engine overhauler being responsible.

Clarence

I'm not sure why you say this with such conviction. The annual was three weeks ago. How many hours was put on in those three weeks? I can conceive of how those nuts, washers and plate could have been all there and looking quite normal, but with one or both nuts just finger tight. In the following weeks one of those nuts could have come loose and once one nut is loose, the whole thing will fall apart in no time.

I think it over reaching to toss the annual IA under the bus. The real fault is with whoever installed the plate. What the condition looked like at annual is unverifiable and unknown. Like you said, there is no requirement to check the torque on those nuts at annual.

[Ron McBride]

Who did the Annual Inspection?

Ron

[DaV8or]

To the OP-

I hope this experience causes you to consider those routes over the Sierras even more. I don't know what route you were planning, but far too many pilots just choose to go direct over some pretty nasty terrain. We should always be thinking- "When my engine quits..." rather then "If my engine quits...". Same goes for ocean crossings, night time, hard IFR, urban areas, forests, etc.

As you have experienced, a "well maintained" engine is not always enough. Far too many people subscribe to the concept of "The engine doesn't know the difference", but as you can tell from internet forum surfing over the years, these engines quit on us far more than the optimists will have us believe. Fortunately, most are like you and catch it before disaster, or are able to easily set it down.

Just stuff for everybody to think about during the flight planning phase.

[DaV8or]

Also, this is good reminder that the owner/pilot has a responsibility to pull the cowl once in awhile and inspect the engine too. Something more frequent than oil changes and annuals. I'm not faulting the OP here, but just a comment. Don't be afraid to pop those screws and have a look around every now and again. Before going on a trip over the mountains might be a good time. I too am guilty of complacency.

[Joe Larussa]

45 minutes ago, DaV8or said:

Also, this is good reminder that the owner/pilot has a responsibility to pull the cowl once in awhile and inspect the engine too. Something more frequent than oil changes and annuals. I'm not faulting the OP here, but just a comment. Don't be afraid to pop those screws and have a look around every now and again. Before going on a trip over the mountains might be a good time. I too am guilty of complacency.

I completely agree. I helped rebuild this plane from tip to tail a year ago when I bought it. 

[Joe Larussa]

51 minutes ago, DaV8or said:

To the OP-

I hope this experience causes you to consider those routes over the Sierras even more. I don't know what route you were planning, but far too many pilots just choose to go direct over some pretty nasty terrain. We should always be thinking- "When my engine quits..." rather then "If my engine quits...". Same goes for ocean crossings, night time, hard IFR, urban areas, forests, etc.

As you have experienced, a "well maintained" engine is not always enough. Far too many people subscribe to the concept of "The engine doesn't know the difference", but as you can tell from internet forum surfing over the years, these engines quit on us far more than the optimists will have us believe. Fortunately, most are like you and catch it before disaster, or are able to easily set it down.

Just stuff for everybody to think about during the flight planning phase.

You got that right! I always choose a route that has the most possible landing sights. If it takes me more time so be it.

I do however think it's time for more emergency type training.

[Joe Larussa]

So the engine builder is going to supply the replacement parts and mechanic is going to 

do the repairs no charge. Should all work out in the end. We are all only human and stuff

happens. When I started flying 15 years ago my pilot friend said flying is about as safe

as walking across the street to buy a can of green beans. Managed risk !

[Yetti]

Learning moment with a good outcome

[Guest]

7 hours ago, DaV8or said:

I'm not sure why you say this with such conviction. The annual was three weeks ago. How many hours was put on in those three weeks? I can conceive of how those nuts, washers and plate could have been all there and looking quite normal, but with one or both nuts just finger tight. In the following weeks one of those nuts could have come loose and once one nut is loose, the whole thing will fall apart in no time.

I think it over reaching to toss the annual IA under the bus. The real fault is with whoever installed the plate. What the condition looked like at annual is unverifiable and unknown. Like you said, there is no requirement to check the torque on those nuts at annual.

What I said with conviction was "we don't know....maybe......Presumabley the fuel line AD was complied with, maybe not. 

If it were complied with his eyes, hands, a mirror, a flash light and a magnifying glass were all in the spot right beside the cover.  If the engine shop left it loose, its amazing that it took 180 hours and a year to fall off.

There is more to the story to be discovered

Clarence

[jetdriven]

I wonder if that pressure on the rocker at an angle is enough to tweak and crack the boss that is still holding the rocker shaft on. May be the camera angle but that rocker shaft looks a little cocked from straight. 

Edited September 27, 2016 by jetdriven

[Guest]

11 hours ago, N201MKTurbo said:

I assume you found the rocker spacer when you took off the valve cover?

 

It appears to be hanging between the rocker arm and the centre boss.  You can see it in the second picture.

Clarence 

[DaV8or]

5 hours ago, M20Doc said:

What I said with conviction was "we don't know....maybe......Presumabley the fuel line AD was complied with, maybe not. 

If it were complied with his eyes, hands, a mirror, a flash light and a magnifying glass were all in the spot right beside the cover.  If the engine shop left it loose, its amazing that it took 180 hours and a year to fall off.

There is more to the story to be discovered

Clarence

You could be right. The IA might have called this one in. However in my mind it is completely possible that it just coincidentally fell apart when it did just after annual. Likely we will never know, but it sounds like the engine builders are stepping up, so I think they kinda know...

[N201MKTurbo]

3 hours ago, M20Doc said:

It appears to be hanging between the rocker arm and the centre boss.  You can see it in the second picture.

Clarence 

Yep, there it is stuck on the rocker.

[MB65E]

4 hours ago, jetdriven said:

I wonder if that pressure on the rocker at an angle is enough to tweak and crack the boss that is still holding the rocker shaft on. May be the camera angle but that rocker shaft looks a little cocked from straight. 

I've see 2 cracked bosses. Both on angle valve engines where the weldment on the valve cover broke due to "G" loading on the tab. Then the rocker pin fell in, arm was cocked and the boss failed. This caused the rocker arm to drop and causes an in flight shut down. Both were on new production factory chromed valve covers. The tabs broke at radius of the welded tab. I'd highly recommend old valve covers that have not been chromed. This all happened at 2850 rpm. 

I would recommend a serious inspection on the boss. Dye-penetrant what ever you need for a warm and fuzzy to prove its not cracked. Hopefully since it happened at idle, no damage occurred. I'd make sure the pushrod didn't bend or obtain a smiley face from the rocker. 

Hopefully everything shakes out nicely.

-Matt

 

[Yetti]

I started studying for the General Mechanics test.   What is interesting is I am seeing the functional part, but not the work practices part.    So an inspection port.   I would start all the screws by hand.  then go around a circle getting them snug enough to to stay in place if I get a call, then go for final torque.  Then one more time around checking for torque.     Not sure where I learned this, being a plane owner for just  a year....   But this is how you make sure it is done properly.   Still have not seen this in the testing material, maybe it will show up.

Engines and such require a tactile feel to make sure everything is snug and where it is supposed to be and won't rattle loose or fall off or get up against a hot surface