The International Cessna^® 170 Association

gahorn wrote: Is that where you found them?

They're installed in my '54.

voorheesh wrote:I need to provide an additional part of FAA Inspector David Jensen's comments to me last week. David and another inspector at his office believe the rear seat is tied into the type design by virtue of its description in the TCDS. He believes that Cessna would have labeled it optional if they intended for it to be removed. Of course others believe that Cessna would have labeled it required if they intended installation to be mandatory. That is why we are seeking an opinion from FAA engineers. It would be unfair to unilaterally dismiss David's opinion in this question because he based it on his office's guidance and he offered it in a sincere effort to answer an airman's question. He did not say it could not be removed, just that it would be a major alteration. Again, this is but one example of many issues that result in different opinions from various FSDOs and we should be aware that the FAA is seeking to address the problem while respecting the experience and background of its employees.

This is the problem. Today Cessna would label the seat optional but they didn't when our aircraft where made because times where different and the aircraft where certified under different regulations. Younger inspectors such as Jensen probably is don't have the experience to know things were different, they only know what they've learned of the current FARs and of course the current litigious society we live in. At on time you could do anything unless told not to do it, today you can't do anything unless told you can.

If Jensen took the time to study the 170 as many of us have, I'm sure he'd come to the conclusion Cessna intended for the aircraft to be operated without the seats installed. But of course even if he did, by himself, he could not change the mind set of his and other FSDOs.

George, If your alleged very original C-170B does not have those nut plates in the floor like mine had, I choose to believe that Cessna screwed up on the manufacture of your airplane because it was going to some guy down in Central America anyway. They never did give a damn what they sent down there, and it was a way of disposing of a cull that couldn't cut the mustard up north.
I can't even begin to imagine that someone would be so wreckless as to install four to six nutplates in the floor of a Cessna C-170B without a proper log entry, or some kind of paperwork from at least a DER. You somehow must have the idea that the aviation world is full of bootleggers.

gahorn wrote:There are two nutplates installed at the rear of the bag floor (Items 60), and two at the rear spar bulkhead. (Items 34)

Is that where you found them?

Yes. That are where mine are.

That's a solution as from fig 103 in the IPC the 170, it seems cargo constraint was thought out. Thanks all its something new I've learned and a possible solution to the greater issue.

blueldr wrote:George, If your alleged very original C-170B does not have those nut plates in the floor like mine had, I choose to believe that Cessna screwed up on the manufacture of your airplane because it was going to some guy down in Central America anyway. They never did give a damn what they sent down there, and it was a way of disposing of a cull that couldn't cut the mustard up north.
I can't even begin to imagine that someone would be so wreckless as to install four to six nutplates in the floor of a Cessna C-170B without a proper log entry, or some kind of paperwork from at least a DER. You somehow must have the idea that the aviation world is full of bootleggers.

LOL

Actually, the reason I posted the illustrations is to support anyone who finds those nutplates....not because I doubted any were original. (Clearly these four are correct/original...but any others were the ones I'd question.) These four are installed...but not specified as to purpose. One has to wonder what Cessna intended for them, unless the obvious conclusion is drawn, that of cargo-restraints.

(My own airplane actually had additional/optional equipment installed which most others did not, such as "agricultural kit" and factory OEM "camera provision". It was corrosion-proofed as part of the agricultural kit similar to marinizing-treatments given to some naval aircraft. The additional modifications which frequently were factory-installed prior to South American shipments were in order to avoid expensive import-tarrifs associated with foreign-built aircraft. By designating the aircraft for "agricultural" or "photo-mapping" purposes the import tarriffs could be waived.
The photo/camera provisions which came out of my aircraft were installed into another TIC170A-Member's (Joe Moilanen) aircraft, and that modification has been featured here in the forums.)

Here's a view of it:



And a link to the entire article: http://www.cessna170.org/forums/viewtop ... stallation

Well after 16 pages on this thread we know have something interesting and concreate to share with everyone thanks to the effort of our own Harlow Voorhees.

Here is an official FAA memorandum from Kevin Hull, Manager. Los Angeles Aircraft Certification Office, ANM-100L prepared by Mauricio Kutller, Senior Engineer, Cabin Safety Branch, ANM-150L that states removal of the rear seat in a Cessna 170 is not a Major Alteration and considered to be a Minor Alteration.

Now all we have to expect is that all other FSDOs will agree.

If I were running without a back seat, I'd copy and print this letter and carry it in my aircraft.

Thanks Harlow!

Thank you, Harlow!

T. C. Downey wrote:Now all we have to expect is that all other FSDOs will agree.

If I were running without a back seat, I'd copy and print this letter and carry it in my aircraft.

Yes, true, but you will note the opinion doesn't just come from the FSDO but the Aircraft Certification Division and is written by a Senior Engineer of the Aircraft Cabin Safety Branch. AND it is on paper. Your holding a lot of trump cards with this memorandum which would force the other FSDO to find a Senior Senior Engineer of the Cabin Super Safety Branch in their FSDO to put contradicting opinion on paper. Not likely to happen.

Thanks to 170 members involved in getting this data in writing. Question---provided one has the appropriate weight & balance data that would accompany the removal of the rear seat, does removal require a logbook entry upon removal and upon the seat's being installed back into the aircraft? If so, is the pilot/owner permitted to make such an entry?

I realize this letter applies to Cessna 170 aircraft and not necessarily to early model Cessna 172 aircraft, but I will carry a copy of the letter with me and hope to not have to "sell" some inspector on the theory that there is no difference in the late model C-170's and the early model C-172's with regard to the back seat. Might be a tough sell, but better to ask for forgiveness than for permission.

Bruce Fenstermacher wrote:

T. C. Downey wrote:Now all we have to expect is that all other FSDOs will agree.

If I were running without a back seat, I'd copy and print this letter and carry it in my aircraft.

Yes, true, but you will note the opinion doesn't just come from the FSDO but the Aircraft Certification Division and is written by a Senior Engineer of the Aircraft Cabin Safety Branch. AND it is on paper. Your holding a lot of trump cards with this memorandum which would force the other FSDO to find a Senior Senior Engineer of the Cabin Super Safety Branch in their FSDO to put contradicting opinion on paper. Not likely to happen.

What you say is absolutely true, but the point of carrying the letter would be to prove to who ever was concerned that the decision was already made for them. I'd not expect that every CFI or ramp inspector would know the letter exists.

As for W&B why wouldn't the graphs in the Owners manual work. simply enter the proper weight of what is at the rear seat position and compute the moment as we would if there is a seat there.

T. C. Downey wrote:

Bruce Fenstermacher wrote:

T. C. Downey wrote:Now all we have to expect is that all other FSDOs will agree.

If I were running without a back seat, I'd copy and print this letter and carry it in my aircraft.

Yes, true, but you will note the opinion doesn't just come from the FSDO but the Aircraft Certification Division and is written by a Senior Engineer of the Aircraft Cabin Safety Branch. AND it is on paper. Your holding a lot of trump cards with this memorandum which would force the other FSDO to find a Senior Senior Engineer of the Cabin Super Safety Branch in their FSDO to put contradicting opinion on paper. Not likely to happen.

What you say is absolutely true, but the point of carrying the letter would be to prove to who ever was concerned that the decision was already made for them. I'd not expect that every CFI or ramp inspector would know the letter exists.

As for W&B why wouldn't the graphs in the Owners manual work. simply enter the proper weight of what is at the rear seat position and compute the moment as we would if there is a seat there.

Tom, I totally concur. I missed your point the first time.

170C wrote: ...does removal require a logbook entry upon removal and upon the seat's being installed back into the aircraft?

The answer is yes. Anytime work is performed on an aircraft there must be a log of it.

170C wrote:If so, is the pilot/owner permitted to make such an entry?

There is the the $1M question. Under normal circumstance I believe a pilot can remove and reinstall the rear seat under preventive maintenance. However in the strictest sense in this case the seat is being left out and that is a change to the approved configuration and an alteration though minor. A owner operator without a A&P is not authorized to make alterations, they can only perform preventive maintenance. Same is true for reinstalling the seat after it has been appropriately logged as being removed.

I don't like my above opinion but see no way around it unless we can obtain a letter from the FAA stating that removal of the seat is not even a minor alteration but simply a change in configuration.

170C wrote:I realize this letter applies to Cessna 170 aircraft and not necessarily to early model Cessna 172 aircraft, but I will carry a copy of the letter with me and hope to not have to "sell" some inspector on the theory that there is no difference in the late model C-170's and the early model C-172's with regard to the back seat. Might be a tough sell, but better to ask for forgiveness than for permission.

Following my opinion above you would need an A&P to agree and make the log entry. I don't see why one wouldn't if any common sense was used.