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Would this require an STC

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addicted2climbing

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Hello All,

I have a quick question that I figured someone on here would know. Lets say I wanted to remove the front seat on a Cessna 172, 175, 182 and use the seat rails as mounting points for something far lighter than the seat and the human that would sit in it and thus those rails would be under much less load. I might also need to remove the rear seat as well to accommodate the item I am thinking. I could ensure and prove ( with engineering calc) if needed that my method of clamping does not damage the rail and will never let the item shift in flight.

Thoughts?
 

Dana

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It may depend on the aircraft's original TC, you may need an STC just to remove the seat. Some allow removal of the rear seat, others do not. And of course the W&B will change...

As I understand it, anything that's bolted to the aircraft requiring tools to remove becomes part of the aircraft and thus requires an STC or a field approval, though I suspect that's an interpretation and not an actual regulation. There's been a lot of discussion lately about the legality of cameras mounted to airplanes. And I heard about a case awhile ago where a FAA inspector hassled a pilot because he (the pilot) had attached a battery charger with a bolt and nut because the charger's original alligator clip was making a bad connection and sparking.
 

narfi

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Cessna seats are removable for configuration changes without an stc. (You must ensure baggage is restrained and will not interfere with the peddles or yoke)

Mounting something else may depend on what or how. Just tying down baggage to the rails however also does not require an stc.
 

Victor Bravo

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Removal of the seats is in the original Cessna operator manuals with a drawing and a caption. Within the existing CG range, there is nothing to worry about with that by itself.

It would be very inexpensive for you to have a weight and balance done with your proposed cargo on board. Having this weight and balance handy to show any FAA inspector who walks by will 99% resolve any and all problems before they happen.

If you buy a damaged Cessna lower seat frame from a junkyard, and mount your device onto that, and that seat mounts NORMALLY onto the seat rails, then nobody could ever raise a question about it damaging the seat rails or imposing any unacceptable loads on the rails/floor. So that would eliminate 99% of the few complaints or questions remaining (after the first 99%).

Also be prepared to demonstrate that whatever is on that mount cannot interfere with controls, equipment, ingress/egress, etc. Make up a bunch of drawings with dimensions and measurements, and that should address 99% of what's left after the first and second 99%.
 

Pops

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My work C-172 had one seat, large camera hole in the floor between the right seat rails forward of the gear box, quick release pins for removal of both doors, Large camera fold down camera doors in the rear windows. Harness attachment at shoulder harness attach point and or rear seat attach bolts. No paint except for N number. Strong C-0300-A engine for the low vibration level and used a 1959 straight tail for the extra rudder effectiveness for getting a harder side slip for getting the wing out of the way compared to the swept tail C-172. IFR with autopilot for long trips around the U.S. for work. All in the Restricted Category and all mods approved by Cessna engineers. If I had everything closed up and cover panels installed, it could be flown in the Normal Cat with all the paper work for each and the "restricted" sign removed from the airplane. I traveled in Normal and worked in Restricted.
Took about 4 months working with the FAA and Cessna engineers to get it ready for work. They all were very good and had no problems.
 
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proppastie

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Took about 4 months working with the FAA and Cessna engineers to get it ready for work. They all were very good and had no problems.
I wonder how long ago that was and weather Cessna or the FAA today would be as nice.......I can see Cessna saying "not interested" (liability) and FAA saying hire a DER .....of course only way to find out is to ask
 

Pops

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I wonder how long ago that was and weather Cessna or the FAA today would be as nice.......I can see Cessna saying "not interested" (liability) and FAA saying hire a DER .....of course only way to find out is to ask
Flying Fed Gov contracts opens lots of doors.
 

TFF

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I have seen some crazy 172/182 camera planes. One, the back window looked more like a tail gunner. The plastic could come out to get the pictures. The bottom had 3’x3’ of the skin removed for a big format camera. Lots of floor holes in others. Some legal; some not.

I got a one time STC for a camera mount external to one of our helicopters mostly infrared. How much you want to use it is relative too. It took 4 years to get ours legal; there might have been some mock up tests waiting. A different helicopter had a removable front seat and we had a gyro camera mount that would hook into seat tracks. We just mounted and went. We went with the do it and if we were wrong interpreting the rules we would say sorry. The FAA never had an issue. The big thing the FAA wanted was a paper trail in the log books. Actually we had another camera mount that would lay on the floor and hold a 35mm and they wanted it logged in and out in the logs. That way to them you are not hiding or trying to fool.
 

Pops

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My rear windows was a squared off as big as possible and cut out. Then a 1/4" Lexan door made with the edges routed where the outside surface was flat. A small piano hinge on the bottom and a latch on the front side and rear side. When opened the door layed down against the inside wall with the arm rest removed. Both right and left windows. One problem was with large cameras was the rear top of the camera was up against the headliner if needed to be tilted down a lot. ( large movie cameras) Would be nice if I could lowered the bottom of the window about a foot.
The camera hole in the floor was as close to the seat rails as possible in width and a lot longer fore and aft. The brake line on the right side in the floor has to be moved more to the right side. Same size opening on the lower skin. Had solid skin bolted in the lower skin when not in use and other skins with difference size openings for difference camera lens OD's.
Don't remember the EW for sure but I know it was quite a bit lower than when new.
 

Richard Roller

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Hello All,

I have a quick question that I figured someone on here would know. Lets say I wanted to remove the front seat on a Cessna 172, 175, 182 and use the seat rails as mounting points for something far lighter than the seat and the human that would sit in it and thus those rails would be under much less load. I might also need to remove the rear seat as well to accommodate the item I am thinking. I could ensure and prove ( with engineering calc) if needed that my method of clamping does not damage the rail and will never let the item shift in flight.

Thoughts?
When I was still working on light a/c we would routinely remove seats for special cargo/baggage situations with just a log book entry. Example: Cessna 206, the aircraft has cargo doors, we would remove all seats aft of the flight deck for large bulky cargo with just a log entry for removal and reinstallation.
 

glencessna

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When I was still working on light a/c we would routinely remove seats for special cargo/baggage situations with just a log book entry. Example: Cessna 206, the aircraft has cargo doors, we would remove all seats aft of the flight deck for large bulky cargo with just a log entry for removal and reinstallation.

And in case of a ramp check etc. you will need a matching W&B reflecting the missing seat and CG change. I add and remove the rear seat all the time, and I know of folks who fly rescue animals around who also remove the pax seat to give additional crate room.
 

addicted2climbing

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Hello All,

So yes this will be a camera platform of sorts. I can make it all attach without tools using over center levers on the clamps like on a bicycle skewer if needed. Operator would sit in the back seat. Door would be removed with a possible wind deflector. Deflector does require an STC though. No other interaction with the airframe. Plane would be a C182p so its a pretty smooth platform. Considered a few jump door equipped aircraft for this, but **** they were all on their last legs.

I figured using the seat rails as existing mounting points might get around the STC since they are already in the plane and carrying a much larger payload on a larger lever arm (highback chair). I could ensure it would not come loose and could even make a provision for the seatbelt to thread through it as a redundancy. I would get a new empty W&B sorted out for that configuration with the platform minus the camera system as it could vary and just add in the camera system weight as a variable like a person.

Thoughts?
 

Dana

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The answer might be in the wording of any FAA opinion on external camera mounts... the interpretation seems to be that if it clamps to a strut or tiedown ring it doesn't require an STC, I think I heard about the FAA issuing an opinion about that but I could be mistaken. Whether or not tools are required to install and remove it might be a determining factor. Or ask your FSDO?
 

Victor Bravo

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There is a world class DAR about 1000 feet from your hangar. And a world class DER in my phone contact list. Even if it did require that kind of involvement, it will be a no-brainer and no- biggie.

If you need a deflector at the front of the door, don't forget to put a round lip at the back to prevent the edge of the door frame from causing a big separation.

Just making a new door with a hole and fairing is easy. Junkyard door, cut a hole, glass and foam fairing to smooth the airflow, etc.
 

addicted2climbing

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The answer might be in the wording of any FAA opinion on external camera mounts... the interpretation seems to be that if it clamps to a strut or tiedown ring it doesn't require an STC, I think I heard about the FAA issuing an opinion about that but I could be mistaken. Whether or not tools are required to install and remove it might be a determining factor. Or ask your FSDO?
When I designed my gopro camera mount that I sell I designed to meet the no tool FAR At thd time and Spoke with the FSDO in Alaska since they have more Lenient rules as well as thd FSDO in Los Angeles . In alaska they have written in how to externally carry Rifles, snow shoes snd even antlers. On wingstruts I used this with the LA FSDO to plead my case and they agreed my mount would be legal per current regs and cause far less aerodynsmic impedance to thd flying qualities than any of the items listed above. Then after all that work a few years later the FAA Legslizes all mounts and puts the liability on the user. Reason for the change was both gopros on aircraft and drones arrived about the same time and ther FAA did a quick evaluation on the Gopro issue so it could then focus on thd bigger problem of drones.
 

Pops

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When I was flying my C-172 in the Restricted Cat with the doors off, paper work said I had to keep below V/a speed ( Maneuvering Speed ). You will probably get the same.
Its not a great difference in the wind coming in the cabin as you might think. I enjoyed it.
By the width of the door opening the defector is going to have to be large. I don't think its worth the trouble.

In the mid 1990's I started designing an airplane as a photo platform. Maybe a little of a long shot to get to work an experimental, but the Gov can fly anything they want, so using solely in a Gov contract, judging from other experiences, I think it would be do-able with the FAA.
The design was a 48" wide steel tube fuselage with flip-up (Sea plane) front doors, 3' square sliding doors ( like a Dodge Mini-van) on each side behind the front left seat in the rear seat and cargo area to slide open in flight. Large photo hole in the floor . Also a TV camera under the fuselage pointing down and forward to help keep the airplane on target as it go's under the nose. Using Cessna 175 wings ( Long range fuel tanks) with a STOL kit installed and C-175 tail surfaces. Powered by a Lyc-360. Also using the C-175 main and nose gear.
I had C-175 fuselage for the dimensions , tail surfaces and LG and was getting ready to start construction of the fuselage. About that time the Gov wanted us to re-locate to south TX on the southern border and my wife sold the business to another company.
Sold all the parts except for the main gear.
 
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Riggerrob

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How much load can those Cessna seat-rails hold?
I am thinking of using seat-rails as alternate tie-downs for cargo or seat-belts.
 

Pops

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How much load can those Cessna seat-rails hold?
I am thinking of using seat-rails as alternate tie-downs for cargo or seat-belts.
I made cargo brackets that slid on the rear of the seat rails of my C-172. Block of aluminum , milled to slide on the rail and drilled and taped for an eye bolt. Tighten the eye bolt. Worked good for many years.
 
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