Rear Seat Removal

[MontanaBird]

I've removed the rear seat of my '56 170B for an annual, and realized that I might want to keep it out more or less permanently. I fly the back country a lot, and very rarely fly with more then one passenger.

Is it acceptable to keep the rear seat out, and if so, do I need to do anything specific to make it legal? That is, do I need to redo the weight and balance, or something similar?

Also, is there a cargo net and attachment system recommended if I want to carry a few items on teh floor where the seat was?

Thanks!

MontanaBird

[GAHorn]

If you permanently remove the rear seat you should perform a new wt/bal and document the seat removal with a Form 337. (You have altered the airplane's basic design from a 4-place to a 2-place airplane. This is a major alteration, silly as it may seem.)

[voorheesh]

I have a full rear seat and a "fairbanks" style single rear seat (I have never used the single rear seat yet). The installation allows you to alternately use either configuration. The single rear seat installation requires a one time field approval or a 337 citing an STC which should also be written to provide for either single or double seat. If I am not mistaken, I think you can then switch from the double rear seat to the single rear seat by making a recalculation of the weight and balance data and an airframe logbook entry. I believe that a private pilot or greater can perform this function and make the entry provided that the weight and balance data has been certified by a rated mechanic. Could this logic be applied to occasional removal and subsequent reinstallation of the rear seat of a 170?
We should use a cargo restraint system if the rear seat is removed and I believe 91 operators do not need to use "approved" cargo nets because these devices are not permanently installed. Are there any nets for a Cessna 170/172 available commercially? Does the 170type certificate data sheet require that 4 seats be installed? Does CAR 3 or Part 23 have any certification requirements for cargo restraints?

[mod cessna]

by gahorn on Sat Dec 13, 2008 4:11 am

If you permanently remove the rear seat you should perform a new wt/bal and document the seat removal with a Form 337. (You have altered the airplane's basic design from a 4-place to a 2-place airplane. This is a major alteration, silly as it may seem.)

As silly as it may seem? That may be the silliest thing i have ever heard on this forum. In fact i thought i was reading the Onion for a second.

1. You SHOULD do a wt/ bal calculation or just make a new EW/ EW CG sheet if you are going to have the rear seat out for an extended period of time.
2. Permanently removing the rear seat is NOT a major alteration.
3. Permanently removing the rear seat does NOT require a for 337.
4. You CAN romove the Co- pilot seat as well. This is NOT a major alteration.
5. You DO NOT need to be a mechanic to remove or install seats.
6. Update your W&B. Fly the plane. !

[lowNslow]

1. You SHOULD do a wt/ bal calculation or just make a new EW/ EW CG sheet if you are going to have the rear seat out for an extended period of time.
2. Permanently removing the rear seat is NOT a major alteration.
3. Permanently removing the rear seat does NOT require a for 337.
4. You CAN romove the Co- pilot seat as well. This is NOT a major alteration.
5. You DO NOT need to be a mechanic to remove or install seats.
6. Update your W&B. Fly the plane. !

I agree, the rear seat would be considered "standard equipment" not "required equipment" and would be considered a minor alteration. Log book entry and a revised Wt. & Balance is all that is required.

[mit]

George......

Lets not turn this into a Pissing contest and lets not stir the FAA kettel...... I know they are here and reading this but lets just amend the weight and balance so the pilot knows what he has and call it good...... I also do not want it to be; nor consider it a major alteration.........

[GAHorn]

Tim, Karl, and especially, "mod cessna" .... there is no desire on my part to unnecessarily complicate our lives. There is no regulation establishing answers to questions posed in these forums become law and binding upon the readers.

My response was an attempt to give the best answer possible. It makes no difference whatsoever that some of our participants may be employed or retired from the FAA. None of our members/participants will use any information or opinons found here worthy of official action, so everybody relax, take a breath, and enjoy the forums.

As for whether this is a major or a minor alteration, I was merely repeating the most accepted opinion in my region by FAA as well as respected shops. Here is what I believe is the basis of that consensus:
The Type Certificate Data Sheet (TCDS) describes this as a 4 PCLM (Normal Category) and in the textual description that follows is "No. of Seats... 4 (2 at +36), (2 at +70)"
The TCDS considers the seats required equipment, and so indicates that by including it in basic equipment. The statement which adds certain other "required" equipment does not identify that other required equipment to be exclusively required.... that other equipment is required in addition to basic equipment, ... which includes those four seats. In other words, basic equipment is required equipment, and addtional required equipment is also described.

I do not believe it is necessary for a "certificated" mechanic to make wt/bal calculations for the aircraft, except for the fact that Form 337 documenting the alteration of the aircraft is necessary. The official documentation carried within the aircraft can (and should) include the Form 337 whenever the airplane if flown without the installed seat. It should be obvious that the form should include the possibility that the seat may be either installed or removed and therefore the pilot will be covered in either case.

Yes this is a pain in the patootie to obtain the signature of an AP/IA on the Form 337. and it will likely cost some money. But the actual documentation is required regardless and doing so on a Form 337 is the method required/blessed by SAT FSDO. (I know this from personal experience when I flew for the state of Texas and we ferried aircraft to paint/interior shops. Not even the state gov't was let off the hook by the FAA inspector. No fine or penalty was imposed, but the incident was recorded and well-known throughout official-dom within hours.)

That was my personal experience and the basis for my response.

[Showboatsix]

"(I know this from personal experience when I flew for the state of Texas and we ferried aircraft to paint/interior shops. Not even the state gov't was let off the hook by the FAA inspector. No fine or penalty was imposed, but the incident was recorded and well-known throughout official-dom within hours.)

Another "fine" example of how "helpful" the FAA can and IS!

EXAMPLE: No cigar lighter mentioned ealier in another post (FAA ready to ground the plane)

EXAMPLE: Grounding of aircraft due to prop strike by FAA personell (Qtip props)

The FAA has 60,000 employees working for them, of that 85% have never have been in small aircraft much less are pilots, yet we dutifully obey every word they write and everything they say.

EXAMPLE: State of Oregon UAO taxiway repaving plan: Aprroved by the FAA, at the first planning meeting, we bring to the attention of the FAA and the Sate of Oregon engineers that there is NO runup area for the 17 end of the runway, (the what?) the runup area for 17, there is one there now, but in your design, there is not one....why? Answer from them, (we will look into that)

RESULT: FAA dutifully changes active runway FROM 17 to 35 which previously had a runup area constructed, (problem solved)..... Except when winds favor 17 which is ALL WINTER LONG HERE! So again where is the runup area....(FAA we are looking into that!)

So if you happen to come to UAO, and the winds favor 17 and you are about 5th in line, get ready for a big prop blast and sit there while the student and instructor take 10 minutes to complete check list, think to yourself, "THE FAA IS ALL KNOWING, THE FAA IS ALL SEEING, THE FAA IN OUR FRIEND!"

Thank you for flying to Oregon, sorry for the wait, come again the sign says!

N28963 departing runway 17......... finally!

[lowNslow]

George, I agree that any wt & balance change requires the sign off from an A&P (not an AI), where I disagree is that this is considered a "major" alteration. If you look at a typical Cessna 4 PCLM "Comprehensive Equipmnet List" (not to confused with the specific equipment list provided with a particular aircraft) the only "required" seat is the pilot seat, all other seats are listed as "standard" equipment and can be removed with proper documention (logbook and W&B). Obviously if you are hauling passengers you would have to have a seat with belts for each passenger.

I suggest your FAA region and the respected shops in your area read "The Weight and Balance Handbook" (FAA-H-8083-1A). These might be the same guys who were telling you we all needed MMELs.

[lowNslow]

I've
Also, is there a cargo net and attachment system recommended if I want to carry a few items on teh floor where the seat was?
MontanaBird

If you look in the Optional Equipment section of 170 parts manual they do list "Cargo tie down lugs" PN 0541115-3 available from Cessnaparts.com for only $93.60 . You would have to install the AN365-524 nut plates also. There may be a third party solution available.

[GAHorn]

Karl, the only required seat for aircraft operations is the pilot seat. All the others may be removed. Doing so is an alteration to the aircraft's approved design, and is a major alteration.

Showboatsix, you should consult someone who specializes in anger management.
The FAA is not the enemy. The enemy is people in aviation who resist and disregard authority and miss the point of design approvals. Those people will get you hurt.

[Showboatsix]

"G".. I am not angry, I am stating FACT... I have given you (the forum) many examples of FAA incompetence, why is it that you....
1. can not..
2. will not..
realize that these "GODS" you so admire are also humans , and as humans, they can be arrogant, power abusing bureaucrats who impose their own "delusions of grandeur" upon us because they have been appointed to a position of power.

My question is to you "why do you blindly accept their position as the right one", when you yourself have clearly stated an example where they have abused their "power" and in all three of these cases the FAA were CLEARLY WRONG!

I am a very happy person, however I have little patience for bureaucrats who abuse the position to which they have been appointed to!

[lowNslow]

Karl, the only required seat for aircraft operations is the pilot seat. All the others may be removed. Doing so is an alteration to the aircraft's approved design, and is a major alteration.

From the FAAs "Weight and Balance Handbook"

Equipment List
A typical comprehensive equipment list is shown in Figure
2-22 on pages 2-12 and 2-13. The FAA considers addition
or removal of equipment included in this list to be a minor
alteration. The weights and arms are included with the
items in the equipment list, and these minor alterations
can be done and the aircraft approved for return to service
by an appropriately rated aircraft mechanic or repairman.
The only documentation required is an entry in the aircraft
maintenance records and the appropriate change to the
weight and balance record in the POH/AFM.

Here is the the comprehensive equipment list mentioned (item numbers with -R are required -S are standard )

[mit]

My FSDO doesn't think it is a Major... a 207 could have 7 seats or one. It is still TC'd as a 7 plc.............. No matter how may seats are installed...... Remember when the FAA said 135 pilots couldn't remove and install seats cause it was Maint?
They ended up making 135 operators document seat removal and installation training...... Never mind they had been doing it since the TC was approved..... I would just like everyone to advocate for the simplest least amount of hassle way of doing business. More paper does not mean you have a safer product.

If it was a major alteration then in Part 43 Appendix A Par 4 (c) line (15) Where it says "Replacing Seats" It shouldn't be there.......


Yea. yea, I know the lawyer says, it says replacing not removing........sigh Pissing contest here we go round and round where we stop nobody knows.......

[MontanaBird]

Thanks to ALL for the information, very helpful!

I did notice some intense discussion but that just shows that guys care about what they are doing, and a healthy debate is why we live here, right?

So, I will discuss with my A&P/IA and move foward with confidence, and hopefully have plenty of room for more food, beverages, and camping stuff where the rear seat was.

MontanaBird