Modification index

Send us your modifications! We're trying to build a database of field approval 337s to attach to the various aircraft types here in the knowledge base. If you're the owner of an aircraft with a valuable backountry-oriented field approval, please scan all sides of the approved form (good high res photos will work) with any additional data and email to knowledge[at] Thank you.

There are few aircraft that leave the factory configured exactly how a backcountry pilot would prefer; that's just the nature of pilots. Everyone has a different idea of what's valuable to the mission, and even missions can change. Many aircraft that have become popular with bush pilots and off-airport work were never intended to be used that way by the design engineers, but the industry has adapted to this specialized form of operation.

Since this is a rabbit hole, we'll ease into it slowly by organizing it into major sections of the airframe and powerplant.

For a list of modifications for a specific aircraft type, start in the List of backcountry aircraft.

Avionics and instrumentation

Self explanatory.

Baggage and seating

Extended baggage, jumps seats, cargo options.


This will include engine upgrades and directory of popular STC's.

Landing gear

This will include tires, wheels, gear legs, suspension, tailwheel and nosewheel mods.


This will include propellers and directory of STC's.


This will include STOL wing cuff, flap, and wing tip/extension mods.

STOL kits

STOL kits usually include a riveted-on leading edge augmentation that changes the camber of the wing for better low speed flying characteristics.

Vortex generators

VG's are small tabs that work like tiny fences to stabilize the air flow over the wing, and help prevent boundary layer detachment at high angles of attack.

Wingtip extensions

Many aircraft are undergunned in the wing area department. Adding inches helps to produce more lift at slower speeds, given adequate power.

Discuss here

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  • Tim, I would ask in the forum if I was you, it's the best place to ask questions of the whole membership here. These comments mainly pertain to this single resource.

  • Thinking about pulling the starter, alt. and battery to lighten up my cessna 120 for better climb performance any thing else I can do? Or maybe I shouldn't, any thoughts?

  • Taildragger, I would post this question in the forum so all of the members have a chance to see it. These comments on this page aren't reviewed frequently.

  • Has anyone put 10x10 wheels and 29x11/10 tires on a Scout ? Good? Bad? Pictures?

  • No one monitors the comments here, this is just a reference page. Use the forum for asking a question.

  • i concur with the guys having problem finding the right place to post. not always the easiest to figure out.
    i dont know where to post it but you wrote a great piece, very good read, of the 170's in AK staring my email buddy big renna.

  • Hi Terry,

    The best place for discussion of all flying topics is in our forum. You can get there in the main menu under "Community." These comments sections appear at the bottom of each article as a means for giving feedback or suggestions relevant to this article alone. Thank you for the compliment, I enjoy making these features.

  • Howdy, awhile back there were some discussions regarding field approval for 26" Goodyears on C180's. In that discussion, a number of pilots volunteered to make their 337's available. I am interested in putting the 26's on my 1955 C180 (which I purchased this last spring) and was wondering if a library of such was developed or of I could get copies of existing 337s. Any help would be greatly appreciated - Paul

  • if you find big renna in this group i bet he would know

  • I recently picked up a first run low time O-320 A3B (150hp wide deck). The engine had been pickled back in the 80's and it looked good, bondidtiout i suspected i might find cam problems in an engine that sat for so long. I took the chance and bought it, after getting it back to my shop and pulling the jugs i found it to be in excellent condition. While I have the cylinders off im thinking of upgrading the pistons to 75089's go from 150hp-160hp. The only problem that i can see is using the steel cylinders, anyone have any experience doing this? This is for a homebuilt (experimental). If anyone has run this set up feedback would be great, thanks in advance.

    from Nova Scotia, Canada

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While this knowledge base is a compilation of information from various sources, some official in nature, it is not a recognized or acredited source of aviation training information, and thus should be considered entertainment. Please consult a FAA-certificated flight instructor or mechanic prior to putting any information found here into practice.