The International Cessna 170 Association

Read a lot about belts and harnesses, attempting to narrowing it down, A/C Spruce has $179 ea. retract sets for 170A&B but not 170 . Only difference I see is factory installed nut plate or anchoring point on overhead, perhaps wing spar? Who would faa deem competent to install such an anchoring device on 170 ?? How would the BAS system be anchored? Thank you again, Tim McCoy

The BAS system is a proprietary system approved via their STC.

Your A&P can install the nutplates if they're missing. If you have a model not originally equipped, then you may need the services of an A&P/IA to submit the Form 337.

where do you learn this stuff? so all modification to certificated a/c requires IA approval? If someone goes through the trouble then they have or can apply for stc which they can then sell to all subsequent parties interested in the same type of modification, and benefits to buyer are; inspections are not required, and engineering, planning done and no guess work. I imagine that any redundant IA requests are unwelcome when a stc in place. an IA is not going to be helpful if you submit similar paperwork for a nut plate just to save yourself a thousand dollars or so. I would like a quick read to understand the process, I mean an overview vs. reading codes, and regulations. thank you, tim

The learning process comes from many forms , join the club and attend the fly ins and convention each year and you will make many friends and learn heaps. The members have a very in depth knowledge and heaps of experience with 170,s. I have been in the aviation industry since 1968 and still learning [ yes ,I know I am a slow learner]. The club web site has massive library with great information . There a many books written also. But you have made the right choice in purchasing a 170. It’s very versatile and doesn’t cost a heap of money.

new2cessna wrote:... so all modification to certificated a/c requires IA approval? ...tim

No. Minor alterations do not require IA approval. Minor alterations are defined in the FARs.
Preventive Maintenance does not require A&P/IA approval.

FAR 43 applies. But you have stated you are unwilling to be reading codes and regulations.
As an owner/pilot you are required to be familiar with the FARs which apply to your operations. You are either going to have to read them or learn them via educational classes or experience (perhaps gained thru airplane failure or violation-enforcement.) Sorry to be the bearer of bad news.

Basically, anything other than a "minor alteration" requires an A&P/IA and a "basis of approval" and/or a Form 337 (Major Alteration or Repair) submitted to FAA. Any modification not already having a basis of approval (STC, etc.) will require the FAA Inspector to approve the modification in Block 3 of the Form 337 (a so-called "Field Approval") which is not as simple to obtain as it once was (when FAA Inspectors were usually experienced maintenance types themselves and they did not fear liability issues) unless supporting engineering analysis is provided.