The International Cessna^® 170 Association

In a follow-up to the chewing gum foil .... that little trick was part of an in-house challenge between two aircraft welders I knew. One of them had welded a piece of .024 sheet to an aluminum block and challenged anyone in the shop to beat him. My buddy welded the foil to the angle and won the bet.
To his horror, as he was showing off his handiwork the shop owner walked in and saw the device and asked, "Did YOU do this on MY time using MY shop materials and welding equipment?"... to which my buddy replied in the affirmative, fairly certain he was in deep trouble...

The shop owner said, "Well you just got a $2-hour raise. I can't afford to lose someone who can weld that good! Now you guys all get back to work!"

Well, i've been gone a couple days flying and see now that I have stirred up a bit of a debate. I never intended to hide the engines history, which is pretty much unknown. As a relative newbe to the aircraft ownership thing I was just curious as to what can be done with such an engine, if anything. Lots of good points to consider. Thanks all for your input.

A few years back, OK - more than a few, when the Coast Guard sent me to MK (Machinery Technician) school - we came to about week 14 and spent the next two weeks in the teardown shop. One half of the class went to the GM shop, the other half Cummins. So you did a complete teardown and rebuild on either a GM 6V53 or the Cummins VT903's.

Point being that those engines had some very young wrench turners stripping them to the very last part, and then building them pack up to the point of a full power test They ran for years, with bearings, rings and other assorted parts replaced each week and other "on conditional inspection" (as we called it) parts replaced as needed.

So I would agree that full disclosure is important, and then as George mentioned the inspector can utilize whatever method he needs to ensure airworthiness.

Sounds like it might be quite a find...

By the way, Training Center Yorktown is still up and running, but just to show you how much has changed - they don't have two weeks of welding and machine shop, no training on boilers etc. We are starting to become a group of warranty exercisers, parts changers and overall less diagnosticly inclined techs... And the Chiefs I learned from are all starting to retire. hey thats me in another 6

Stay dry... raining like crazy on the lower Cape

Kyle

Kyle,
I agree with your statement in regards to the engine tear down and rebuild 100%. MK "A" school, wow! brings back some good memories. Went through in 91, then off to Station Merrimac River as an FNMK. Changed rates in 93 and been in food service ever since. Like they say, sometimes we don't choose our careers, our careers choose us, no regrets. Mike

I think some of the parts could be used subject to an inspection to determine a parts condition for non certified aircraft. Big stuff subjected to high stress should be chucked. That doesn't leave you with much left. Most shops now cut a chunk of material out of a part so a us part does not become a bogus part in the future.

Just to claify...I certainly never expected that anyone in present company would deliberately do anything dishonest.
My only intent was to demonstrate that if an unairworthy item is being considered for return to service, that full disclosure would be especially important in order to insure that appropriate methods of inspection are utilized.
I've personally seen an old 172 with a prop that was bought on e-bait and installed and flown. Subsequent annual inspection revealed a deliberately machined/polished eradication of "unairworthy" stamped* upon the hub. A follow-up exposed that the prop had been severely bent, heated and straightened (in violation of acceptable practices) and then sold for "wall hanger" to a local...who removed the unairworthy notation and sold it via internet to someone unknowlegeable who installed it on his airplane.

*Stampings that have been ground off can sometimes be revealed by chemical treatment and special lighting. Law enforcement uses the method to identify stolen property. The stamping deeply compresses the underlying metal and even if ground off...the stamping can usually be made legible again. But only if you know what to look for. The subject prop even included a "logbook" that made it look credible.
Be careful where and from whom you acquire your airplane parts.

Mike - thats neat, small world our CG. I went in 84. Seems long ago, and like you went to my first unit as an FNMK. It was and 82, the Point Brown out of Oregon Inlet on the outer banks. Now I'm still in the reserves with 6 years left, primarily teaching leadership courses.

I will hate the day I have to face the fact that the watch will pass to someone else - except that we have some really great people coming along and it's only right that they have a shot...

gonna respond to two things hyear. the welding story doant hav no truth lessen tat weller use the chew gum to stik it on. yeh iva heerd thuy story way fore gum rapper foil wuzn't part of thu paper. i axe u to try to seprate shiniy frum paper!!!!!!! I did wunce have a weller axe me ifn he cud well threads inna hole an I laf at him reel good. we bet, then he burn a hole ina peec of airn an skrew a nut on a bolt an wel the nut in thu hoel then unscrew the bolt an there them dam threds wuz!. I hadda by him beer for tree days!

BTW son there ain't no welder can weld different material into a steel forging an leave no trace. I know for a fact that any weld modification to a forging shows a difference in the deposited "weld" metal that reacts differently to inspection than the parent metal. An acid etch is the best way to identify that modification. And BTW it isn't always illegal!

Now the Canadian aircraft rules are lots different than FAA rules which btw may change too often to keep up with. Some research in their records may shed some light on the history of the engine.

What can be done or not done legally often is modified by common sense or unadulterated greed. I know of an incident where a prop shop refused to "fix" a prop, bent, they said, beyond tolerance, but not etched as scrap in an un-removable way. This hayseed flyer (crop-duster type) took the prop home, ran it over with his truck till it didn't show the full extent of the former damage, then took it to another shop for them to repair. They did the repair, yellow tagged it and he took it home and put it on his Maule! Never heard since what bad things might or might not have happened to him as a result of that foolish (or maybe not) act.

Yes...if one is looking for a weld repair in a forging, then the appropriate method of inspection will reveal it. But one has to know to use that method. I don't believe an "acid etch" is commonly performed to inspect crankshafts.

In any case, my reference to my friend the welder's abilities was only an anecdote to illustrate the point that in order to properly inspect suspicious parts.... the inspector must be aware they are suspect.... not merely "run out" to be looked at for return to service using ordinary methods.

The biggest "nut" around here with stripped threads is well-known to have atrocious spelling, a weird synapse system that frequently mis-fires, and a taste for dynamited catfish and other people's St. Pauli Girl beer!