Worst possible news

rtk11 said:
Ah crud - this is rough. I wonder if it is bolt fatigue and failure due to not being in spec (as someone earlier suggested).

Tom D - glad to read your friends are recovering. Sorry to read of the preliminary finding. I wonder if there's a way for you to get a hold of one (if not all) of the crankshaft bolts and send them for metallurgical testing?
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that's is what NTSB did.
Steve and his wife are mending well after over a year of medical treatments and more to go. they are doing better than expected, but life will never be the same.
 
gismo said:
So sorry to hear about your friends, wishing for a complete and speedy recovery.

There's was an AD several years ago for counterfeit con-rod bolts that were sold through one or more reputable distributors and accompanied with legitimate looking paperwork. Turned out to be totally bogus with a fraction of the required tensile strength. The first documented engine failure was an IO360 in a C-177RG I used to fly (but wasn't flying at the time). Perhaps something similar here?
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The bolts in question were not rod bolts, they 1/4X28X3/4" crank shaft to gear attachment bolts, they came as owner applied from Aircraft Specialities in Tulsa OK, they are a required replacement item. and no service bulletin or AD exists on them.
the Dowl pin came in the new crank from TCM. as owner supplied part, all parts had proper documentation.
 
Are there any pictures of the parts in question from the accident? A picture is worth a thousand words. Also, many times the manufacturer is involved in these analyses. It would be interesting to see the bolts, the crank, the dowel and the gear. Tom, sorry for this news, but I would want more proof were I you.
 
PaulS said:
Are there any pictures of the parts in question from the accident? A picture is worth a thousand words. Also, many times the manufacturer is involved in these analyses. It would be interesting to see the bolts, the crank, the dowel and the gear. Tom, sorry for this news, but I would want more proof were I you.
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I would much rather not have any more action on this, but If I do hear of anything happening MY next move will be to use the FOIA to obtain the NTSB photos. The investigator could not give them to me during a on going investigation.
And I hope I never need them.
 
Rough all around. From the map, they made a golf course but couldn't make the fairway. One big takeaway: Get shoulder harnesses.Golf.jpg
 
F01LA said:
Rough all around. From the map, they made a golf course but couldn't make the fairway. One big takeaway: Get shoulder harnesses.View attachment 48976
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Notice the little grass field just NNW of the scene?
That's where he was headed, just couldn't make it.
 
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F01LA said:
One big takeaway: Get shoulder harnesses.
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I noticed that too. That's a huge and relatively cheap safety enhancement for most airplanes. I've seen too many accidents that should have resulted in minor injuries but were instead serious or fatal.
 
Tom-D said:
Notice the little grass field just NNW of the scene?
That's where he was headed, just couldn't make it.
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I can't imagine the stress and rapid decision making required for a low level engine failure landing. I read this and can easily see me seeing that field and trying to make it.

I do get a tinge of fear thinking about a forced landing in airplanes without shoulder harnesses. Whenever I buy a plane I will install them if it doesn't already have them.
 
Figure 28-29... looks like the bolts sheared, one or two while the assembly was still rotating.
 
Why doesn't that gear have more damage? That engine would have been developing a lot of horsepower that suddenly would be absorbed by that gear as it lost alignment.
 
Somedudeintn said:
I do get a tinge of fear thinking about a forced landing in airplanes without shoulder harnesses. Whenever I buy a plane I will install them if it doesn't already have them.
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Yeah, so true. Maybe if one person reading this thread takes the initiative and fits the belts, some good can come out of this unfortunate situation. So glad that 5-point harnesses are the norm for my aircraft.
 
Checkout_my_Six said:
What year?...my C-150 had factory shoulder harnesses.
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There's shoulder harnesses and shoulder harnesses.

Non inertia reel is almost pointless, it's ether too tight to work in most planes, or too lose to help.

FTW
http://basinc-aeromod.com/cessna.php


So.. I didn't read the whole NTSB thing till just now...

"The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
  • The loss of engine power due to the mechanic's inadequate tightening of the crankshaft gear retaining bolts during an engine overhaul, which resulted in fatigue failure of the bolts and the crankshaft gear dowel pin that allowed the crankshaft gear to separate from the crankshaft."

http://www.ntsb.gov/investigations/_layouts/ntsb.aviation/brief.aspx?ev_id=20150928X72825&key=1




From the factual

"The four crankshaft gear bolts all exhibited overstress fractures in their threaded portion. Two of
the four bolts, referred to as bolts #1 and #2, exhibited gross plastic deformation in the shank
portion. Bolt #1 had broken free of the safety wire, and bolt #2 had a portion of safety wire still
attached. Both of these two bolts exhibited fractures consistent with overstress. The remaining two
bolts, referred to as bolts #3 and #4, remained safety wired to each other, and did not exhibit gross
plastic deformation. These two bolts exhibited flat fractures and crack arrest marks consistent with
fatigue fractures.
The bolt holes in the crankshaft gear had become elongated. This effect was less pronounced on the
face of the gear that would have mated to the crankshaft, and more pronounced on the opposing face.
The crankshaft gear teeth appeared to be well formed, and did not exhibit any irregularities or uneven
wear.
The crankshaft gear dowel pin was fractured, and partially missing. The portion that was submitted to
the laboratory contained a flat fracture surface. Examination of the fracture surface using a stereo
microscope revealed crack arrest marks and ratchet marks consistent with a fatigue fracture. There
were three prominent ratchet marks indicating a fatigue fracture with multiple origins. Examination of
the body of the dowel pin revealed wear marks on one side. (Refer to the NTSB Materials Laboratory Report, No. 16-024"
http://www.ntsb.gov/investigations/_layouts/ntsb.aviation/GeneratePDF.aspx?id=WPR15FA268&rpt=fa
 
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James331 said:
There's shoulder harnesses and shoulder harnesses.

Non inertia reel is almost pointless, it's ether too tight to work in most planes, or too lose to help.
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never mind.....mine were prolly worthless....:lol:
 
Checkout_my_Six said:
never mind.....mine were prolly worthless....:lol:
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Some are more worthless compared to others based on the aircraft.

If you have Johnson bar flaps, and cowl flaps and retracts other stuff on the floor you need to manipliate during critical phases of flight, seatbelt needed stuff is more likely to happen, reels are a very important upgrade.
 
James331 said:
There's shoulder harnesses and shoulder harnesses.

Non inertia reel is almost pointless, it's ether too tight to work in most planes, or too lose to help.
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Not familiar with the design, but can most GA shoulder belts be **easily** cinched up tight in an engine-out, given enough time and altitude? I know it's uncomfortable for many to have them snug all the time.

With the 5-points, I've got the shoulder straps snug all the time, but I really crank them down in turbulence, and also would if anticipating an off-airport landing.
 
SoCal RV Flyer said:
Not familiar with the design, but can most GA shoulder belts be **easily** cinched up tight in an engine-out, given enough time and altitude? I know it's uncomfortable for many to have them snug all the time.

With the 5-points, I've got the shoulder straps snug all the time, but I really crank them down in turbulence, and also would if anticipating an off-airport landing.
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yes.....IIRC...they did tighten when needed.
 
SoCal RV Flyer said:
Not familiar with the design, but can most GA shoulder belts be **easily** cinched up tight in an engine-out, given enough time and altitude? I know it's uncomfortable for many to have them snug all the time.

With the 5-points, I've got the shoulder straps snug all the time, but I really crank them down in turbulence, and also would if anticipating an off-airport landing.
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Depends on when the issue occurs.

For takeoff and landing in some plane, like mine, where you need to bend down and grab flap bars, cowl flaps, water rudders, and if something happens on takeoff or landing, you ain't going to have time to mess with the harness, hence the reels, most float planes, super cubs, etc end up with reels for that reason.

Example of a landing where reels come in handy if you hit something, comming into land, end up closing the cowl flaps, come in nice and low, flaps to 30, power out, hand off the power and on the flaps to adjust as I get nice and low, almost like pulling collective on a chopper ;)

Touch down, flaps up, cowl flaps open, water rudders down.

Try that with a tight harness, nope

Or do it with a loose harness and hit a deadhead, you're getting little from that harness.
 
Geez....we're talking about a 150...nothing low to reach for there at the last minute...cept to pop the door.
 
Checkout_my_Six said:
Geez....we're talking about a 150...nothing low to reach for there at the last minute...cept to pop the door.
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Indeed, I was more talking in general.

Actually, some 150s have Johnson bars, and being able to have one hand on the flaps and the other on the yoke can make a good difference in a precision landing.
 
Checkout_my_Six said:
Geez....we're talking about a 150...nothing low to reach for there at the last minute...cept to pop the door.
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Yeah, I can have the 5-point squeezing the breath out of me and still reach everything I need...one of the advantages of designing the panel yourself.
 
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