Rear Seat Removal

[Farnold]

As spring time promises to come again to New England - hard to believe at the present - I'm thinking of S&F and OSH again.
What is paper work, if any, is needed to remove the rear seat from my '52?
Do I have to file for any FAA paperwork? Or does it just come out and I can save 30 lbs of dead ballast?

[N170BP]

FAR 43.17, sub-part c, item (15) says (paraphrasing) "replacing
seats or seat parts with replacement parts approved for the
aircraft, not involving disassembly of any primary structure
or operating system" is considered "preventative maintenance"
provided it does not involve "complex assembly operations".
Sub-part c is the portion that covers what we, as owners, can do
maintenance-wise with our airplanes (there are currently
32 "Items / tasks" we are allowed to perform).

My line of reasoning is if the FAA says it's OK for me to
remove/replace seats with "approved parts", it's OK for
me to take my back seat out, fly around and put the
"already approved" back seat back in at a later time.
FWIW, I just take mine out and enjoy the lighter weight.

The previous (Canadian) owner noted in his Journey Log
when the seat was removed and also noted the "new" Basic
Empty Weight. Then he made another note when the seat went
back in with the updated (higher) weight. I suppose one could
make the same kind of notations in the aircraft logs....?

Another FWIW, this is done *all* the time by the 180 guys
(can't fill the back end to the roof with camping gear very
well if you leave the back seat in!).

Bela P. Havasreti
'54 C-170B N170BP

[funseventy]

Take it out and enjoy. If you want to make a logbook entry remember that you need to put your certificate number next to your name. This is often times forgotten. Part 91 you are OK; if you were Part 135 you would need to be signed off as having had training by an A&P.

I have a weight and Balance in my glove box that shows basic empty and CG for all the ways I may have it equipped.

26" Tires
8.50 Tires
Bag seat or not
Skis

Then you are covered pretty well. Your weight and balance should be signed by aa A&P so I would attach your calculated W&B to the back of your existing W&B so there is some traceability.

[zero.one.victor]

Don't know exactly what the FAR's say about it,other than what bela quoted,but my position is that it's legal to remove seat & operate without it. Especially if you have a W&B sheet that shows W&B figures with rear seat removed (like mine). For what it's worth,on my ragwing the rear seat removal was worth -32 pounds at station 76",which moved the empty CG forward 0.9".
As Kelly pointed out to me,an A&P must sign your new or revised W&B sheet to make it legal.

Eric

[Bruce Fenstermacher]

Actually this is a good question. Does an A&P have to sign the W&B? Does he sign one everytime you change the CG by fueling up. How about when you load it full of all that important stuff you need to go camping? No he doesn't. You as the pilot does the weight and balance or at least be familiar enough with the loading of your aircraft to insure it's within CG.
I've often asked myself this question and have not come across a FAR that spells it out that I can remember. What's the answer?

[GAHorn]

I believe the answer is related to the FARs, the AFM, and/or operating limitations and Type certificate along with the equipment list.
The airplane is type certificated with a certain number of seats. The equipment list includes that equipment, it's weight, etc.
In order to remove the equipment for flight operations (note: this is different than the preventive maintenance actions of "remove and replace") the aircraft equipment list and the aircraft wt. and balance must be revised and a logbook entry must be made, because the aircraft has not undergone preventive maintenance,...it has undergone modification and/or alteration.
In order to routinely remove for space considerations and later re-install for pax considerations, the aircraft should have a Form 337 submitted showing both configurations and giving the wt/bal for each configuration. Each time the aircraft is so modified, the maintenance records should reflect it, along with the signature and certificate number of the person performing the work. (ALL work, of ANY level, should be recorded in the Maintenance records. The FAA generally holds that unrecorded maintenance is a more serious matter than unauthorized maintenance.)
If you don't like cluttering up your airframe maintenance logbook with this sort of entry, then create a new logbook in accompaniment with the others, to record this particular type of frequent alteration, and make a note of referral in the main airframe logbooks. Keep this supplemental logbook with your other aircraft logbooks.

[Bruce Fenstermacher]

George I follow your reasoning and the 337 is probably the correct way to do this and cover all bases. In any case a log book entry and W&B should always be made.

But..

I just looked over the TCDS and the AFM and didn't see a minimum equipment list required. The TCDS does say there are 4 seats. It also says the airplane was certified for both 4PCLM and 2PCLM. If you fly it as a 2PCLM and make the log entries wouldn't that cover it.

How could you be expected to use the optional tie down rings with out removing the rear seat? If your plane came with the camera provision it looks like in the IPC you didn't even have a rear seat, just a seat pad. George, didn't your plane have this option. Do you have a 337 to install the rear seat?

Besides one front seat and a set of seat belts for a pilot required by FARs do you really need an interior of any kind?

[Joe Moilanen]

Speaking of camera provisions George, I just completed the installation of the camera port that used to be in your plane before you acquired it. My IA just signed it off yesterday ( with all the updated W&B calculations for both applications by the way). I'll send you some pics of the install if you'ld like.

Joe Moilanen

[GAHorn]

Speaking of camera provisions George, I just completed the installation of the camera port that used to be in your plane before you acquired it. My IA just signed it off yesterday ( with all the updated W&B calculations for both applications by the way). I'll send you some pics of the install if you'ld like.

Joe Moilanen

Send me money for my parts! (Seriously, yes I'd love to have the pics. Thanks.)

[GAHorn]

George I follow your reasoning and the 337 is probably the correct way to do this and cover all bases. In any case a log book entry and W&B should always be made.

But..

I just looked over the TCDS and the AFM and didn't see a minimum equipment list required. The TCDS does say there are 4 seats. It also says the airplane was certified for both 4PCLM and 2PCLM. If you fly it as a 2PCLM and make the log entries wouldn't that cover it.

How could you be expected to use the optional tie down rings with out removing the rear seat? If your plane came with the camera provision it looks like in the IPC you didn't even have a rear seat, just a seat pad. George, didn't your plane have this option. Do you have a 337 to install the rear seat?

Besides one front seat and a set of seat belts for a pilot required by FARs do you really need an interior of any kind?

Bruce, FAR's require the equipment list, not the TCDS.
"if you fly it as a 2PCLM..." your data tag should list the aircraft as such. Otherwise I think you'd have to do as I previously posted.
On the other hand, if your datatag shows it as a 2PCLM (as mine does because it left the factory with the camera port), adding the back seat is no problem because it's approved in accordance with the TCDS. A 337, equipment list and wt/bal change is recorded. (Or a new airworthiness conformity inspection and certificate is issued along with the equip. list and wt/bal record.)
"How could you be expected to use the optional tie down rings with out removing the rear seat?" Think of it like this: Floats are approved on the TCDS, but how could you use them without removing the land gear? If your airplane was awarded it's airworthiness certicate as a landplane, you must remove the landing gear to use the floats, and you must document the removal and change. And since your landplane left the factory without the float provisions, (attachments, water-rudder controls, etc.) you must complete a Form 337 even though it's an approved installaton because it's a major alteration.

[Bruce Fenstermacher]

George I follow you completely and see your point and agree.
So following your sample if you remove your rear seat a 337 should be filed and the approval to do this will be the TCDS under the 2PCLM.

As for my comments about the TCDS not having a minimum eguipment list or required equipment this is from my experiance with my J3 Cub and it's TCDS A-699 which says for example that at least one of the many engines listed on the TCDS must be installed.

There is no such requirement for the rear seat to be installed in the 170 by the TCDS.

[wa4jr]

This reminds me of my days at Critical Air Medicine. We routinely changed the configuration of our C-421Cs to suit the mission. Whether it be an infant flight, stretcher patient, or a flight with three medical crew which called for the seventh seat to be installed way in the back. As pilot, I made these changes on a regular basis and no paperwork was ever filled out to my knowledge and no questions were ever asked by the FAA concerning this practice. As long as we flew within the weight and CG limits, we were OK. All I needed to know was the weight and location of each seat and/or stretcher to make last minute changes for a particular mission. This was part 135 flying. I suspect the same methodology could be used with our C-170 aircraft in less stringent part 91 operations. Remove the rear seat and replace as many times as you like as long as you know the proper adjustments to the weight and balance for each configuration. With all due respect, I think some of us are way too concerned and/or preoccupied with the reams of FAA regulations. The old "can't see the forest because the trees are in the way" scenario. RELAX, take a deep breath, take the rear seat out, note the reduction of weight and station location.......and.......go have a nice flight. No need to spend the nice afternoon at your desk buried in stacks of FAA rulebooks

[Bruce Fenstermacher]

John I do agree with you and try to practice what you preach but it sure is fun to discuss and argue about all those FAA regulations.

[dacker]

Just an interesting little side note... Part 43 under Preventive Maintenance says we (holders of a pilot certificate) can replace fuel and oil strainers but it neglects to say that we can replace the fuel or oil. I guess we are all a bunch of outlaws!
Maybe if we just subtract the weight of the seat from the weight and balance that we all religously do before each and every flight we will be OK? In other words REMOVE, fly, then REPLACE.
David

[GAHorn]

This reminds me of my days at Critical Air Medicine. We routinely changed the configuration of our C-421Cs to suit the mission. Whether it be an infant flight, stretcher patient, or a flight with three medical crew which called for the seventh seat to be installed way in the back. As pilot, I made these changes on a regular basis and no paperwork was ever filled out to my knowledge and no questions were ever asked by the FAA concerning this practice. As long as we flew within the weight and CG limits, we were OK. All I needed to know was the weight and location of each seat and/or stretcher to make last minute changes for a particular mission. This was part 135 flying. I suspect the same methodology could be used with our C-170 aircraft in less stringent part 91 operations. Remove the rear seat and replace as many times as you like as long as you know the proper adjustments to the weight and balance for each configuration. With all due respect, I think some of us are way too concerned and/or preoccupied with the reams of FAA regulations. The old "can't see the forest because the trees are in the way" scenario. RELAX, take a deep breath, take the rear seat out, note the reduction of weight and station location.......and.......go have a nice flight. No need to spend the nice afternoon at your desk buried in stacks of FAA rulebooks

John, I'll bet you dollars to doughnuts that unbeknownst to you the airplane's maintenance records had 337's which addressed every possible seating/patient configuration possible for your C-421's and the company operations manual and the company training addressed the crew performing the configuration changes.

All the 170's left the factory with original equipment lists which should have addressed the seating configuration. Any change to that list would have to be documented to stay perfectly legal.
Also, the TCDS item 603 (the camera provision) specifies that the airplane must be operated as a two-place airplane.