1972 182P jump door 337 process

averettpilot

averettpilot

Well-Known Member
I posted this over on the diverdriver site as well, but it doesn't seem as well used as it used to be (did get one response though, just trying to branch out). I'm working for an aircraft owner and we are trying to put a jump door on the aircraft. We are operating from a previous 337, have manufactured and engineered the door and installed it. We took it to our A&P to have it signed and ready for FAA inspection. The snag we're running into is the Vne Door Open speed of 80 mph. Our A&P mentioned that the FAA may/will want documentation on how that speed was figured.

Now, I'm no paperwork genius, but I was under the assumption that if this speed was determined previously and we are operating off a previous 337 (STC, not sure the appropriate term here) it is more or less a plug and play type thing.

I'm looking for any and all advice from A&Ps or pilots that have gone through this process or are familiar with it. Our next call would be probably to the FSDO to figure out exactly what they want. Only reason I'm starting here is to see if there are any tricks to the trade to speed this process along. I've heard horror stories of this process taking well over a year to complete.

Thanks in advance!
 
My opinion is consult with the United States Parachute Association. They have several 337s for various skydiving aircraft on file and should be able to help you with the technical specifications.

I was able to find a STC for a 1956 182G jump door, however that took a lot of digging. I hope that helps.
 
I'm very interested in the jump door installation on a 182P. I have a 1973 P model, and I think this mod may be very beneficial. Any help would be greatly appreciated. I'd love to see the photos too...

Mark Hanten
Alpine, CA (San Diego area)
619-818-5611
 
Airworthiness isn't my part of the bureaucratic forest, so I'll begin by saying I "think" I know what I'm talking about, but I won't be surprised if I find out otherwise and my feelings won't be hurt if anyone corrects my statements. Having given that caveat, here is my understanding as it relates to your situation:

An STC and a 337 are two different things.

An STC (Supplemental Type Certificate) is something that is done by a company. They research something that supplements an aircraft type certificate. They provide all of the engineering data to the FAA. Then, if it is approved, they get the rights to the STC. To recoup the expense of the research and certification, they can charge for the sale of the STC.

A good example is an STC for auto gas. A company can research that and show it works fine. They can then sell the right to STC the aircraft for autogas. The only thing that is delivered to the owner is paper and perhaps something like a placard to place by the fuel caps. It doesn't change the aircraft. However, anyone operating on auto gas who hasn't purchased the STC is operating illegally. Reference FAR 21.113 through FAR 21.130.

An FAA Form 337 is a Major Repair and Alteration document. If an aircraft is involved in an accident, it should have an FAA Form 337 in its maintenance records and a copy is suppose to be filed with the FAA. If someone decides to make an alteration to the aircraft, they can present engineering data to the FAA showing that the change will not have a negative effect and the FAA can approve or disapprove the change. Reference FAR 43.9.

If you are purchasing an STC, then you do not need to provide engineering data to the FAA. The person who created the STC has already done that. The mechanics job is to follow the instructions of the STC. If you are doing it as a 337, then you will need to get approval from the FAA, and that can be whatever they require, including data on how the door Vne was determined.

 
Close Houston, hopefully I can help clear the mud a little more though :)

A form 337 is, as you say, a Major Repair or Alteration form. Major and minor repairs are defined fairly specifically in part 43. A 337 form is required for any major repair or any alteration.

If you purchase and install an STC you are altering the aircraft and still must submit a form 337, but the STC documentation, which is approved by the FAA, is referenced as the engineering data.


for example:
Installed left handed widget IAW STC NW999SA per left handed widgets inc. installation document revision D dated December 17th, 1903.


In the old days if you came up with a really good idea and no one else had done it you could submit a form 337 with your idea detailed on it and the FAA would either approve it or not... hopefully you submitted the form and got it approved before you made the mod! Where an STC is good for any of a model listed in the STC, a 337 only applies to that specific serial number. However, other people could make the same mod to the same model airplane by referencing your 337 as approved data.

The FAA cracked down on that a few years ago because, as I understand it, they realized that the people approving the 337's in all probability weren't engineers and many of the mods were approved with little to no engineering review. It's now almost impossible to get a one-off mod approved by 337 unless you're referencing a 337 that was approved previously, or have STC level engineering data in which case you might as well apply for an STC. So, for the OP, if you're referencing a previously approved 337 then you're right in thinking you should be fine.

One other thing that I've seen is someone submitting a 337 for the purpose of adding something that the factory did to later models of the same airplane by referencing the factory drawings. To give an example, my flying club used to have a 172N, in the N model the landing light was in the cowling, but in the later 172's they moved it back to the left wing. They wanted to do this to make the bulbs last longer so they submitted a 337 with a photocopy of the Cessna parts catalog page for the later model as the approved data. It was approved and they ordered the parts and did the mod.
 
Trafficinsight gave a great overview. The FAA takes the 337/major repair and major alteration business very seriously. If you have any doubts at all about the approval basis for your alteration or repair, get with your FSDO and talk things through BEFORE you go cutting sheet metal. You do NOT want to deal with the ramifications of the "do the work first, find approved data for it later" method of maintenance.
 
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