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Thread: Skylights data / drawings please help!

  1. #1

    Skylights data / drawings please help!

    Hello, I have a Cessna 150M. I purchased skylights and wondering if anybody has any field approvals, 337s or knows an N number to a plane that were installed not from the factory. Iíve been hunting down trying to find data. I called Cessna and they will not release drawings anymore. Any help would be appreciated

  2. #2

    Join Date
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    These days the FAA does not accept another airplane's 337 approval as the sole input to the Field Approval process. The FAA info on Field Approvals is online. The submittal package needs to include a weight & balance change report, Instructions for Continued Airworthiness, a Regulatory Checklist that lists the Part 23 paragraphs that apply and how your change will not negatively impact the airplane's certification. I will suggest that the 150 Aerobat's inclusion of the windows is a good starting point for your paperwork. Get a Cessna parts manual that shows the Aerobat windows.

    The process is not hard but there are labor hours involved in creating the paperwork and most owners do not want to pay an IA's shop rate to navigate the process. An owner can work with an IA to do it with enough reading, patience, and persistence. You have to have a good relationship with an IA and the IA has to have a sense of humor.

    Best of luck,

    Wes

  3. #3

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    Quote Originally Posted by bmrstunter600 View Post
    Hello, I have a Cessna 150M. I purchased skylights
    When you say "I purchased skylights" does that mean you purchased all the associated hardware for skylight installation from the Cessna 150 IPC fig. 24 or 24A as applicable? (skylight, frame, brackets, channel, etc?)

    Skylights were an option on all 150M's so this is an easy one.

  4. #4
    Yes i purchased Frames, windows, seals. just need data to install them. there was another guy on this form who i messaged who did the same thing as i with field approval. he has been inactive for a couple years so not sure he will get my message. I do believe it will be easy but need something to give the FAA.

  5. #5
    I agree. I have done several field approvals over the years and even with STC data from same model just different year they rejected. claimed data was to "old" so i went DER rout and they approved it.

  6. #6

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    I agree with Mr Mayes that you have one of the easiest Field Approvals to do. You have a factory option in hand. Your cover letter to the FSDO should begin something like "This application is for approval to install in the field the Cessna Model 150M optional skylights using the Cessna factory parts."

    You still have to do the other paperwork that I mentioned in my older post, but you are maintaining the airplane's conformance with its Type Certificate and the Instructions For Continuing Airworthiness, weight and balance change report, etc are as easy as you can get. You just have to dot the i's and cross the t's. All of the info to do the paperwork is on the internet.

    Your only holdup might be first the comfort level of your local IA working with you on this, and then whether the local FSDO in fact has a staff member who has gone to the Field Approval class in Oklahoma City. No inspector will admit that they have not been authorized to approve a Field Approval but if they have not gone to the class they can not. They just drag out the process until someone in the office has been to school. I had a relatively simple Field Approval take 10 months due to that. Patience and persistence are key.

    I will note that STC data owned by someone else will not be accepted as data since it is that other individual's intellectual property. For the FAA to accept your submission of someone else's STC data you must have written permission from the STC owner. After all, they put all of the time, effort, and $$ into creating that data and having it approved and the FAA respects that.

    Best of luck,

    Wes
    Last edited by WLIU; 04-21-2020 at 05:45 PM.

  7. #7

    Join Date
    May 2012
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    118
    No FAA field approval or STC is needed for this installation. Check your airplane's approved equipment list. It should list the skylight windows as a piece of optional equipment. If it's on the list, that is your approval for installation. The engineering has already been performed by Cessna and is a factory (FAA) approved installation. All you need are the genuine Cessna parts, as shown in the C150M parts manual to perform the install. Your molded plastic headliner has already been set up for the optional windows. The headliner can be used to approximate the window locations. I would also recommend measuring a factory installed set on another airplane.

    I performed this install on my C150L. I also installed Aeroflash wing tip strobe lights and fueling steps and handles (AK150-109G) all of which are considered to be MINOR alterations (because they are on the approved equipment list) and require only a logbook entry by an A&P and updating of the W&B and equipment list. Check with your FSDO. I'm sure they will agree.
    Last edited by Eric Brown; 04-24-2020 at 12:10 PM.

  8. #8
    Thank you guys for the help!

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