Damage records

[busav8or]

Hi All,

My search for the "perfect" 170 continues and I have a question about what records to expect regarding past damage to an airplane. One of the aircraft I am considering suffered an encounter with a fence on a rejected takeoff in the early '70's. It did not fly again until 2008 when it was purchased and had a set of C-175 wings installed. I have the 337 documenting the wing installation and the log page documenting the replacement of some fuselage skins. What other records, if any, should I expect to find? The reason I'm asking is that I have a couple of buddies, both A/P and IA's, that think the records should more complete. Also, the engine has not had a major overhaul since the early '70's, but the current owner has had it topped and is currently flying it. Any thoughts on that? Thanks in advance for the forthcoming advice!

Joe

[GAHorn]

Form 337 should be completed whenever any MAJOR alteration or repair is made to the aircraft. If your wing replacement and your fuselage repairs are adequately described in the form and t he forms are included in the aircraft records...then that is all that is required.
Would it be nice to have more documentation? Perhaps. <gentle sarcasm ON> Some Pictures would be nice. A video would even better. <sarcasm OFF>
Seriously...your friends who are A&P/IA certificated are your advisors and t his is a subjective matter when it comes to how completely the repairs are described. Hopefully they are well-described. But even if they are not, the aircraft itself should provide ample evidence of whether or not the repairs are good or not. Take a look at it. Have your friends look at it.
If it looks good....then it probably IS good. (And the 337 meets the rule requiring recordation of the repairs.)
So what is the problem? (Hint: 90% of all airplanes 50-60 years old have major repairs. Taildraggers have a 98% record of major repairs. The "perfect" airplane is the one that meets YOUR requirements. It's unlikely you will find or be able to afford one that has never been anywhere but a museum-hangar since the assemblyline.)

According to the mfr'r and most folks,.....engines should be flown regularly until they reach TBO (or are 10-12 years old) and then they should be completely overhauled. According to actual practice....this almost never is the case. I trust MY engine explicitly (as much as engines can be trusted)....yet it was "overhauled" ** in 1983 and preserved, and not put into service until 1996 when it was actually installed in the airframe. According to TCM that engine should have been completely overhauled again at that point, before it was even started.
Since 1996 it's had less than 900 hrs put on it, the last 10 years having averaging 65 hours per year. Most folks (following conventional wisdom) would be very suspicious of it. But anyone who knows me and knows how I care for my airplane would know that it would be very wasteful to tear that engine down and re-build it when it likely has another 900 hours to go, (perhaps even longer according to some folks.)
The question regarding engines that sit is... how much rust and/or corrosion exists in that engine? And the only way to know that is to tear it down...in which case it's probably wise to go ahead and "overhaul" or rebuild it. However, most prudent owners/mechanics will boroscope it, compression-test it, run it, test-fly it, and then (if all seems good) go ahead and re-introduce it to service for the remainder of it's originally-planned TBO.

You are correct to carefully scrutinize a potential purchase. But keep in mind the reality of matters: There is no "average bluebook" airplane, and there is no way to guarantee that, even if a "perfect" airplane is found, that it's engine will make TBO.
If you find an airplane that will pass a proper and thorough annual inspection, and is otherwise equipped and in/near the condition you want for your airplane, and if a test-flight shows it to fly straight...then make your best bargain and buy it. I'll bet that within a month of ownership, you too will have the same viewpoint as the seller.... the engine is just fine for "continued time in service" and the "damage history" is no longer relevant to your operations.

** The definition of "overhaul" is widely misused/misunderstood. What most folks actually mean when they say "overhaul".... is a "REPAIR"....not a true overhaul. Visit with your friends and ask them the difference between an "overhaul", a "rebuild" and a "repair" as those terms apply to aircraft engines and components.
The description you provide of your potential airplane purchase seems to indicate that the seller found a wreck and repaired it for resale. Chances are that he was concerned about how a potential purchaser such as yourself might view an engine that had sat for so long without being flown, so he did a "top" ..."overhaul"...(which is really a repair/replacement of the cylinder assemblies that probably included piston, ring, and valve work) .... which allowed him to also take a "look" down into the bowels of the engine to perform a cursory inspection (largely of no particular value other than to clean it up a bit and look for rust/corrosion.) But that "top overhaul" basically addresses the areas of a stored, part-life engine that is most likely to need repair. If that work was performed well, then the engine should be as good as any other part-life engine...in theory, it is even better than a part-life engine which has not received any upper-end work at all.

Hope this helps.

[Bruce Fenstermacher]

What George says is very true. Don't overlook a word he said.

But as an owner of an airplane with ghost paperwork I've found it's a lot easier to buy an airplane with little paperwork than it is to keep and eventually sell an airplane with skimpy paperwork. I'm also way to honest when it comes to these things so that doesn't help me to sell something that's just not right to the next guy.

I would be curious for example was the 337 for the 175 wings approved by the Feds or just signed by the mechanic. If approved by the FAA it would be much harder for someone to say the wings don't belong there. Does this plane have the larger 175 fuel tanks? If so is that documented. How was it approved? Has the AFM been updated to reflect the arm of the fuel in those larger tanks and what exactly is the usable fuel for that configuration?

You didn't mention if this was a B model but it probably is. Because if it was an A model there are about 200 other parts that need to be swapped to use the 175 wings. Are they documented? If it is a B model use of the 175 wings is a pretty straight forward swap.

BTW lots of folks would love to have the 175 wings and larger fuel capacity.

As for an engine with an old overhaul I'd look at the last two years. If the engine had been run 100 hours or so in that time, if the engine had any rust from before that it would likely have shown itself by now in the form of low compression or low oil pressure. On the other hand if the engine was run early in life but has only a hand full of hours in the last few that it sat at a tie down to rust, then your first 100 hours will be the experiment.

[busav8or]

As always, thanks for the great advice. I know I'm not going to find a "perfect" 55-60 year old airplane, heck, if I can find one in as good a shape as MY 55 year old "fuselage" (read: body) I'll be happy (and there are definitely some issues there!) It does appear that the local inspector signed off on the wing replacement. At least there is a signature in block 3 of the 337; is that the same thing? It does have the larger capacity fuel tanks and it is a B model. The airplane appears to be in great shape to me, but I haven't had a complete inspection done as it is about 1000 miles away and I've seen it only once. You guys have answered my questions regarding the paperwork. It appears to meet the requirement of the law and what else can you ask for? Well, I guess you can ASK for a lot more, but that doesn't mean you'll get it, right!? I guess the next step is a trip back "up north" with my A/P buddies and let them have a look. Regarding the engine, the present owner did tell me that he had the cylinders pulled to check for corrosion, found none, put it back together and has since put a few hours on it, but not 100 yet.

I don't want to seem too picky with all this, but I don't want to make a mistake, for obvious reasons, either! Thanks again for all your patience and words of wisdom.

Joe

[GAHorn]

Those 175 fuel tanks, if included in the 337, (check it out..!).. are a nice attraction, in my view. Do they have the electric gauges? or are they converted to mechanical...?

[busav8or]

Panel mounted electrical gauges. I agree, the extra range would certainly be nice.

[Blue4]

My 170 had 175 wings installed by a one-time STC (previous owner). Would a 337 have been sufficient?

The "extra" fuel is almost a requirement with an O-360 engine.

[Bruce Fenstermacher]

The signature from the local FSDO guy carries a lot of weight. Look into the details of the tanks. If they are not covered on the 337 it will be a sleeping dog you may choose to let lye. In other words you can take the position that the wings were approved and they have larger tanks and so by default the tanks were approved as well. And of course the 175 wings had electric fuel quantity gauges so the approval extends to them as well. The sleeping dog is the devil in the details. Not everyone will agree the larger tanks and gauges were approved. Most likely no one will know but you (and us now) and most likely no one will care until you go to sell and the next buyer has the same questions.

I'm simply playing devil's advocate here based on my first hand experience.

[Bruce Fenstermacher]

Blue4 what you have IS a 337. All major repairs OR alterations are approved on a form 337. There is no real difference between an alteration that is approved for one aircraft and a one time STC (Supplement to the Type Certificate) except for perhaps the procedure to get the approval and maybe the final intent.

A major difference could be the wording of a 337 and or the one time STC. For example it sounds like this aircraft was REPAIRED to meet the TCDS with the use of 175 wings. Your plane might have been intentionally modified with the 175 wings to get the extra fuel and maybe even the electric gauges (if that is what you have).

So a repaired 337 might simply say damaged wings repaired by replacement with equivalent wings from a 175. The question of the fuel tanks is not addressed and it could be presumed the intent was to use the original tanks and gauge system. This was a repair remenber.

Your one time STC might address the tanks because that might have been the intent of the modification. The previous owner might have even applied for a multiple STC but was denied we won't know.

Either way 175 wings are approved and they have the capability to hold larger tanks. The devil is in the details? Are the tanks and gauges approved or not.

[Zreyn]

Blue4,I have the O 360 Lyc. & the Jav.18 gal aux. tank that I hardly ever use since I stopped going back & forth to Honduras.I get two hrs. & twenty min on each wing tank till the eng. quits. (I only know that because of the aux tank of course) I really like having the extra fuel but would hardly think of it as anything other than a convenience unless I was going from Key West to Coz Mel direct or operating in Alaska naturally. That being said I have never operated an airplane with the O 300 so I don,t know the comparison. what IS the fuel burn on an O 300?

[hilltop170]

It does appear that the local inspector signed off on the wing replacement. At least there is a signature in block 3 of the 337; is that the same thing? Joe

Joe-
A 337 with the block 3 signature from an FAA inspector is a "Field Approval" which is the same as a one-time approval. The field approval makes those 175 wings legal on that one airplane only.

If block 3 is not signed off, it is just a 337 major alteration form with some other basis of approval required, such as an STC, signed-off by an IA as installed and fit for return to service.

Do not buy the plane without flying it to make sure it flies straight, preferrably on a calm day so you can trim it out in cruise and let go of the controls. If it does not fly straight and has already been adjusted to the maximum extent of it's travel with the wing rear spar eccentric bushings, be prepared to hold control input continuously from now on or be prepared for a very expensive repair to straighten out the problem. Either way, it's NOT desirable.

[GAHorn]

.... what IS the fuel burn on an O 300?

As I was taught (when first hired as a simulator instructor)...the most-correct answer to such client questions is: "It depends."

The performanc charts show anything from 13.3 to 5.1 gph... but the actual LEANED average is 8 gph. (I usually cruise mine at 2450 RPM, at 55K to 75K leaned and find it to burn about 7.8 gph .... so I flight-plan 8.0 gph and find that pretty accurate.

C0145/O-300 Fuel consumption chart

fuel consumption chart.JPG (21.74 KiB) Viewed 4878 times

[hilltop170]

............I usually cruise mine at 2450 RPM, at 55K to 75K...............

George-
You da man! I could not get mine to climb above 17,500' !!!!!!!!!!!!

[GAHorn]

............I usually cruise mine at 2450 RPM, at 55K to 75K...............

George-
You da man! I could not get mine to climb above 17,500' !!!!!!!!!!!!

HA! I must be slipping into delirium!

(Last week I wrote a pay-check...fortunately to an employee who is also a good friend... and for unimaginable reason the year-date I placed on the check was 2013 I have no idea what I was thinking when I wrote it and no one noticed until the bank refused to accept it from him. So he called me...
So I personally handed him another check. This time he made a big deal about checking the date and giving me a hard time.
Two days later he called.... I had dated it correct... BUT... the amount was $1448.66.... however I had hand-written "One thousand forty eight and 66/100 Dollars." Again...the bank refused it.

I think I'll give him cash!)

[170C]

Geeze George, you must be a tough guy to work for Let's see, how old are you now