An A&P-IS's best insurance.

Tom-D

Tom-D

Taxi to Parking
Joined
Feb 23, 2005
Messages
34,740
Display Name
Display name:
Tom-D
Today I talked to my friend who suffered thru the 150 accident.
He holds no animosity, and does not plan on any Litigation.
Good GOD fearing people who treat others as they would like to be treated.
The A&P's best customers.
 
God fearing.

Always found that a rather funny saying
 
You almost killed him. You should really rethink what you do with airplanes, because engine overhauls obviously aren't your forté.
 
Tom-D said:
It seems to represent a way of life unknown to but a few.
Click to expand...

What a miserable way of life, must be like living under isis or the nazis, demanding worship while still invoking fear from their underlings.

I'd think with how many of these creation myths are written, God should normally be loved, looked up to, enjoyed, many things, but any god that you should fear, that sounds more like a devil or the antagonist of the creation story.

Best way to look at it, you don't need to worship anything or anyone, just live a honest life, be nice, leave it a little better than you found it, and any God worth worshipping, or that you'd even want to spend eternity with, would be glad to have you.

Still it's like a bonus round in a video game, live your life expecting to die, bloat, pop, and breakdown for critters to eat, cut to black. Now if by chance you end up being greeted by some long haired bearded hippy looking dude, or the flying spaghetti monester, or whatever, cool, bonus. IMO life's too short to life your life expecting such outlandish things.

But to each their own, but I feel much pity for the poor souls who spend their lives worshipping...and sadly fearing, their god.
 
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



"...treat others as they would like to be treated"
Really Tom?

I'd would have expected to be drawn and quartered


The best insurance a AP could have would be to double, and triple check his work, or hire someone who will.
 
Last edited:
James331 said:
What a miserable way of life, must be like living under isis or the nazis, demanding worship while still invoking fear from their underlings.

I'd think with how many of these creation myths are written, God should normally be loved, looked up to, enjoyed, many things, but any god that you should fear, that sounds more like a devil or the antagonist of the creation story.

Best way to look at it, you don't need to worship anything or anyone, just live a honest life, be nice, leave it a little better than you found it, and any God worth worshipping, or that you'd even want to spend eternity with, would be glad to have you.

Still it's like a bonus round in a video game, live your life expecting to die, bloat, pop, and breakdown for critters to eat, cut to black. Now if by chance you end up being greeted by some long haired bearded hippy looking dude, or the flying spaghetti monester, or whatever, cool, bonus. IMO life's too short to life your life expecting such outlandish things.

But to each their own, but I feel much pity for the poor souls who spend their lives worshipping...and sadly fearing, their god.
Click to expand...

I'll pray for you.
 
I believe it is possible that the bolts could fail in a failure sequence that starts with properly-tightened bolts.

I know I was not present when the mechanic in question installed the gear.

I have seen NTSB reports reaching clearly-flawed conclusions. And, I have personally witnessed premature failure of properly-installed bolts on an engine, in such a manner that examination strongly suggested improper installation.

Looking carefully at my palms, I see no nail holes, and believe I (as do we all) live in a glass house.
 
James331 said:
SThe best insurance a AP could have would be to double, and triple check his work, or hire someone who will.
Click to expand...
How would you do it any better?
NEW bolts, Snapon Torque wrench calibrated less than 2 months prior and Properly safetied.

Tell us how you would have done it better.
 
Tom-D said:
How would you do it any better?
NEW bolts, Snapon Torque wrench calibrated less than 2 months prior and Properly safetied.

Tell us how you would have done it better.
Click to expand...

Don't think the issue was with the tool or the bolts Tom.


What is your opinion on the microscopic analysis?

What about the black sealer found on the screen which was still installed even though you had a remote filter mounted?
 
James331 said:
Don't think the issue was with the tool or the bolts Tom.


What is your opinion on the microscopic analysis?

What about the black sealer found on the screen which was still installed even though you had a remote filter mounted?
Click to expand...
the screen was left in for the break in period, the bolts were sheered as shown, these bolts are black parkerized finished, If they were loose why don't they show wear?
Simple, quick stoppage.
when next you can, shear a 7/16th" tool steel rod, see if it doesn't look exactly like the dowl. plus why doesn't the dowl show wear or the crank show elongation of the hole?
and you should know the that the NTSB investigator (tom Little) is neither a mechanic or a engineer of any kind, he is a retired airline pilot. He made several misquotes in that report.
 
Tom-D said:
Simple, quick stoppage.
Click to expand...

What stopped the engine if the prop looks as undamaged as it did ?

when next you can, shear a 7/16th" tool steel rod, see if it doesn't look exactly like the dowl.
Click to expand...

Just on the unaided picture, the dowel shows start and stop sites along the fracture surface. That was also confirmed on the stereo microscopy and is a sign of fatigue cracking of steel.

and you should know the that the NTSB investigator (tom Little) is neither a mechanic or a engineer of any kind, he is a retired airline pilot. He made several misquotes in that report.
Click to expand...

How does that negate the findings of the materials lab ?
 
Tom-D said:
the screen was left in for the break in period, the bolts were sheered as shown, these bolts are black parkerized finished, If they were loose why don't they show wear?
Simple, quick stoppage.
when next you can, shear a 7/16th" tool steel rod, see if it doesn't look exactly like the dowl. plus why doesn't the dowl show wear or the crank show elongation of the hole?
and you should know the that the NTSB investigator (tom Little) is neither a mechanic or a engineer of any kind, he is a retired airline pilot. He made several misquotes in that report.
Click to expand...

Tom, I dig that you love aviation, I'm sure everyone here gets it, no doubt, but have you ever thought maybe it's time to hang it up?

I mean these folks nearly died, at their age this type of trauma is likley to be life changing for them.

Everyone makes mistakes, some mistakes are ones you can do a "I'm sorry" and fix, others require a little more, and others are not forgivable. In this case, you haven't even said sorry, haven't even admitted you MIGHT have screwed up... Even with a laboratory report, even with industry experts, not even a "maybe" out of you.

As far as not taking you to court, probably has zero to do with God, or your fault in the matter, probably has much more to do with what they could, or rather couldn't, recoup from you vs. the time and expense of court, and right now they probably have many more important things to worry about and spend what time they have on.

Hang out at the airport, get into ultralights, wrench on your own stuff, whatever, but as far as turning wrenches on other folks airplanes, hang it up brother.
 
did your friends insurance pay for any damage to aircraft or other property,or passenger?
 
hotprops said:
did your friends insurance pay for any damage to aircraft or other property,or passenger?
Click to expand...

Exactly. It doesn't matter if the injured customer bears any ill will or not. If their insurance company paid a claim, it is up to them whether or not they will sue.
 
I really don't have a dog in this fight.

I used to race cars. Short dirt tracks. I built my own engines and had fair amount of success doing that.

When I moved up to paved tracks, my engines were not competitive. So I bought an engine from a reputable engine builder. Lotsa $$$.

About 1/4 of the way into the race, 1 1/2 mile paved track, the engine let go. I mean it sounded and looked like a bomb went off inside it. We found pieces of pistons in the radiator. I found a piece of the cylinder head on the track that had a spark plug in it.

So of course I contacted the engine builder, and one of the techs came to my shop to look at it.

Looking at the rod bolts, one had a manufacturing flaw in it. It was within limits on the stretch test, it was torqued and retorqued and tested at least 7 times during assembly. But it sure enough failed. Sometimes stuff just happens.

The builder made good on the engine. I wish I could say that I went on to win many races and championships, but no. Being a great driver just isn't good enough.
 
Fearless Tower said:
Exactly. It doesn't matter if the injured customer bears any ill will or not. If their insurance company paid a claim, it is up to them whether or not they will sue.
Click to expand...

This was a 150, maybe 25k damage including the golf course cleanup. In the world of insurance that is small potatoes and I doubt the aircraft insurer would go after a 1 man overhaul shop. The health insurer otoh may look to recoup a million $$ payout (victim was 69, probably no health insurer to worry about if he was on medicare).
 
tom ask the mods to make this and its sister thread disappear. asap
 
hotprops said:
tom ask the mods to make this and its sister thread disappear. asap
Click to expand...

So censor two threads about a person, in this community, who is offering services to pilots/aircraft owners, which according to the NTSB nearly cost two people their lives.

Yes let's sweep that under the rug o_O
 
I agree with hotprops, too much at stake here, torpedo it and call a lawyer for advice.
 
PaulS said:
I agree with hotprops, too much at stake here, torpedo it and call a lawyer for advice.
Click to expand...

Much at stake, yes, people lives.

Besides:

Tom started this thread himself

The facts are the facts, the prelim and factual NTSB reports have been linked to, and are available for anyone to read.

The NTSB clearly placed the blame on Tom, not POA, not me, not the admin, the NTSB.


or.... maybe he could get the NTSB to erase those reports off their website too.


The facts are the facts, don't fear them, fear those who wish to hide them.
 
NTSB can be fantastically spot-on, especially on high profile events. And can also be full of crap, often enough, on lower profile events - varying from wildly illogical to simply publishing SWAGS as facts. Probably only so much time and resources to go around, limited qualified people, and 150 wreck may not get you the "A" team, and the time and attention.
 
Sundancer said:
NTSB can be fantastically spot-on, especially on high profile events. And can also be full of crap, often enough, on lower profile events - varying from wildly illogical to simply publishing SWAGS as facts. Probably only so much time and resources to go around, limited qualified people, and 150 wreck may not get you the "A" team, and the time and attention.
Click to expand...

What is your interpretation of the witness marks and microscopy in the report ?
 
weilke said:
What is your interpretation of the witness marks and microscopy in the report ?
Click to expand...
Did you know plastic deformation occurs on all mild steel when sheared ? why would this be any different?
 
Tom-D said:
Did you know plastic deformation occurs on all mild steel when sheared ? why would this be any different?
Click to expand...

Those linear features along the face of the dowel are the crack arrest marks that indicate a fatigue fracture (magnified detail from Fig27 in engine report).

Fig27_detail.JPG

I didn't see how they treated the piece (etched or magnetic particles), but this is the dowel on the microscope picture (Fig 5 materials lab report).
Figure5.JPG

I noted a discrepancy between the Materials lab report and the final report. The full narrative states:

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 materials lab report does not include pictures of the bolts and doesn't comment on overload vs. stress fractures.

Just based on the unmagnified Fig27 in the engine report, they just look like overload fractures to me.
 
Fatigue fractures look very different from sudden overload fractures, and any competent metallurgist can easily tell the difference. That's the "ratcheting" failure mentioned in the report.

Dry vs wet torque... fatigue failures of fasteners generally result from undertorqued fasteners. Standard is dry; if torqued wet they'd be over, not undertorqued.

Probably way too late, but rechecking the calibration on that torque wrench would be a good idea...
 
weilke said:
What is your interpretation of the witness marks and microscopy in the report ?
Click to expand...
Beats me - I didn't see them, and I'm not an ME anyway - I was making a general statement about NTSB findings; sometimes they are the result of superb applied science, in-depth experience coupled with attention to precedence, and hard, hard work. And sometimes they are dreck; cursory, light weight, even a bit nonsensical.
 
So the fatigue marks are concerning, but it is important to realize that this engine was probably spinning 2,700 rpm which means once those bolts stopped holding they and the pin were being whacked 45 times a second. Things can happen very fast and each of those striations could represent 9 or 10 successive hits that occurred in a quarter of a second.
 
You must log in or register to reply here.
Back
Top