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Air Worthy

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basketcase0302

Well-known member
Alright,

Can ya'll please explain to me the defination of an "Air Worthy" aircraft engine? I've heard Jim and Rick and others use the term and would just like to know.

Thanks in advance.

Basketcase
 
Basket it just means that it has no uncertified parts in it, all maintenance has been done by an FAA certified mechanic and it has no measurable wear that would prevent it from being legally flown in an airplane.

In general it means a low time engine taken out of a flying airplane. Storm damaged or crashed plane engines are no longer airworthy until certified by an FAA mechanic again.

Thats the idea without getting into the page numbers and paragraphs and publication numbers. FAA has some evil rules.

Scotty
 
it's a motor that can be put in a plane and meets are the FAA requirements. The logs are up to date. Its as good as its gets.

When they pull a motor out of a plane and replace it. The motor may still be air worthy. They have set overhaul regulation on the hours.

Paper work just about as bad as the PMS log on a Nuc Sub.
 
That's a good question. A lot goes into determining if an engine is air worthy. The FAA certified mechanic with inspection authority makes the final determination after a through inspection. Things that he looks at start with the data plate being the one that is listed in the logs to making sure all airworthiness directives are complied with.

Manufactures like Continental and Lycoming set up a TBO (To Be Overhauled) for each engine they build. The O-235 for example has a 2400 hour TBO and a Continental O-200 has an 1800 TBO. Each engine is different. The manufacures want the engine torn down and inspected at certain stages to ensure a good product. However, you don't have to overhaul the engine at the TBO time to keep it airworthy. As long as all the AD's are complied with and the compression is good, you can fly that engine until something quits. If the aircraft is for hire you have to follow the TBO time.

AD's (Airworthiness directives) come out every now and then when someone finds something potentially bad with an engine. An example is the gaulling on a Lycoming camshaft because of a poor design. The solution was to change oil to one with a Lycoming additive. If not complied with, the engine is no longer airworthy. Change the oil and it's good to go.

If you build an experimental aircraft, you are the inspecting authority and determain if an engine is airworthy. It can be a lawn mower engine or an aircraft engine.

Bottom line, if it's airworthy it meets FAA standards. That doesn't mean it's a good engine or won't fall apart next week. It just means it meets the FAA standards at the time it was inspected and signed off by a certified mechanic with inspection authority.

Sorry to be so windy but I could go on and on.
 
Wow!

Thanks!

So the engine coulda been rebuilt already and as long as the FAA logs were intact it could still be air worthy?

Matter of documentation acuracy?

Basketcase
 
It is a matter that each component part has been inspected and found to be within airworthy standards whether it is new or rebuilt. The assembly and installation has to be performed by qualified people also.

For instance a crankshaft may have an undersized journal where the oil seal rides and not be within airworthy standards. It could make an excellent airboat engine. A case may have been decked too much for aircraft, but be good enough for an airboat.

A new Lycoming crank would probably cost more than a freshly rebuilt airboat engine.

jim
 
Basket, it also doesn't mean that it's an engine that is one bit better than one built by Thurman or Jurnigan. It really only means that the paperwork is in order if you decide to stick it in an airplane.

I've seen some of the work that "licensed" A&P (airframe and powerplant) mechanics have done and it scared the livin crap out of me. :roll: .
When I was still flying I did a lot of my own work and just got somebody with a ticket to sign off on it.

olf
 
Jim, Olf,

Thanks, that does explain it even better yet. Just could never understand why the air worthy engine would be worth so much more for a boat owner. I've seen several of Jr's and JC's engines that were awesome powerplants.

Basketcase
 
Here's and example of a Lycoming Service Bulletin (SB-569).

Lycoming recently issued a service bulletin (SB) calling for crankshaft replacement in engines ranging from the O-360 to the IO-720. The company wants all hammer-forged crankshafts "retired" within three years.

While a service bulletin is not mandatory for Part 91 owners who don't use their aircraft in commercial service, SBs frequently become airworthiness directives (ADs), which are, of course, mandatory for everyone. And Lycoming would very much like the FAA to make this SB an AD, at great expense to aircraft owners.

If the FAA makes this an airworthiness directive, then there will be a lot of crankshafts on the market that have no defects. They can only be used in airboats or experimental aircraft. Of course Lycoming will be selling a huge number of new crankshafts. Makes you think.

Sometimes the fix is worse than the problem.
 
Des, many, many years ago they did a time change on the tail rotor blades on an Army helicopter. Mind you, the ship was flying just fine when they brought it in for replacement ..... the old blades just had too many hours on them.

Well, they put on two new blades, rerigged, and took it for the required test flight. One of the new blades let go during that flight and two fine young airmen died.

"If it ain't broke, don't fix it?" I've often wondered.

olf
 
I wonder about the honesty of manufactures sometimes. American Champion now owns the Type Certificate for the old Aeronca's and Citabria's. They put out a Service Bulletin on the wood spars which later became an airworthiness directive. Everyone had to cut into the fabric and inspect the spars and a lot of people just replaced the wood spars with aluminum spars.

American Champion doesn't sell wood spars. They only make aluminum spars. They made a fortune. Makes you wonder. For the Aeronca's I build and fly, I'm sticking with the wood spars.

Faucet did the same thing with Marvel Schebler carburetors also. They had everyone replace two piece venturi's with single piece ones. After everyone did this, the flying community was up in arms because the one piece venturies were junk and poorly designed and manufactured. The FAA let people go back to the two piece but it was too late. Most had been replaced and now you can't buy a two piece anywhere. Makes you wonder.

Sometimes I wish I could make all my aircraft experimental and then I would be the one to determain if the aircraft is airworthy and not some greedy CEO who doesn't know a rudder from an aileron.
 
I hear you, Sir. Airworthiness should be up to the man who's butt will be at risk if something pops.
The bush pilots in Alaska have basically operated with that guideline for years and you never hear of an incident up there.

Experience, skill, and personal responsibilty should take precedence over blanket directives any day of the week.

olf

BTW, a buddy of mine is about half way through a restoration on a '47 Champ. Nice little airplane.
 
I owned a Super Decathlon during that time period. The issue was legitimate. They need to be inspected periodically in my opinion because of the wood spar and the aluminum ribs. There were problems.

I came away from it thinking that if you have wood spars you should have wood ribs etc.

jim
 
Jim, I don't want to start anything, but in my opinion it was all about profit. There has never been a single failure of the wood spar documented. I've rebuilt both the pre-war (Wood Ribs) and the post war (Aluminum ribs) Aeronca's and one Citabria. The wood ribs were a pain because you had to rib stitch them. Nothing wrong with wood ribs. Just a pain. The aluminum ribs were much better and no one did them better than the Aeronca corporation.

There has never been a failure of the spars in any of the aircraft because they had aluminum ribs. I've got a set of almost 60 year old aluminum ribs on an Aeronca Chief that I'm rebuilding now. They have no effect on the spars. If they did, the aircraft would not be considered airworthy.

In my opinion, aluminum spars are not as trustworthy as wood spars. The ribs do not affect the performance of either.
 
The aerobatic airplanes had failures of the nails that hold the ribs to the spars I believe. They were found laying in the wing on some airplanes. The spar itself was not an issue. I prefer the wood spar because of the way it flew.

Mine had a wood spar and I did not convert it. It was OK, but the airplane had an extensive overhaul a few hours before I bought it.

It was the airplane owned by Steven Spielberg that was used in the movie "Always". It had a rather bizarre paint job in the movie, so the next owner (Screaming Eagle) in Santa Paula, CA decided to do a complete over haul on the airframe and of course a recover. It was still mint when I sold it.

It was not used for dual acro. It is very easy to over gross that airplane when doing dual acro and the airplane can get over stressed in that case.

I never knew the exact cause of the nails coming out but they did and in some severe cases caused the ribs to sort of saw the spar. At least that is what i heard. I never saw one with my own eyes.

jim

jim
 
Des Moine,

Jim,

So an AD such as the crank issue would be good for the airboating industry by creating lots more parts for us. While costly to the everyday "Joe airplane owner"?

With the cost of the engines and parts "Joe airboater" could sure use a few of these SB's or AD's to make available cheaper parts.

Thank ya'll for the info! Trying to get, and do have a little better understanding of the aircraft engines.

Basketcase
 
Jim, you are right about the nails coming out and the metal ribs being distorted and sometimes rubbing the wood spar. In my rebuild of Aeronca wings I've seen lots of the nails loose or missing. The solution was a different nail that is not smooth but has ribs on the side to keep them in place. They are a little longer too. The worst thing about the old cheap nails was distorted ribs that made the fabric look bad as well. The biggest problem was you had to remove all the fabric and rebuild the complete wing to replace the nails. I've never seen any loose ribs that compromised the spars.

Basketcase, you're right about the AD's putting more good aircraft parts on the market for us airboaters. I just hate to see the manufactuers put so many aircraft owners out of business. I think hurricanes and tornados provide enough spar parts to keep us all in business with cheap parts.
 
Basket,

If you want to know the details of how this all works, check with Jr Jurnigan. I believe he deals with both airworthy and airboat parts. He sets aside the parts that are not airworthy to build airboat engines. Some of his airboat parts are airworthy like rods etc. He can tell you the real detailed story. He has been at it for many years.

jim
 
Des Moines Boater,

I guess we were typing at the same time. Many pilots preferred the wood spars because of the "feel" of the maneuvers and their predictable life span. But they did have to be inspected. When you tell a pilot that there is a potential problem with a wing spar he may panic and insist that it be replaced. Someone did need to talk about the nails though.

The strongest fabric wings I have seen are the scratch built redesigned Pitts wings such as the Steve Wolf wings. They are all wood including the leading edge. The wood leading edge is glued in place making the leading edge and front spar a "D" section beam. The ribs are all corner blocked in place and nothing can move.

These wings are as bullet proof as they come, and are the present state of the art Pitts wing.

jim
 
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