I know this topic has been beaten to death here, but after looking through all of the threads I wasn't able to find a straight answer for some of the questions I had, so here they are:

Can I do all the work myself after getting the kit from Maule?

Does a mechanic need to sign the work off?

Do I even need to buy the kit from Maule or can I just use the plans?

I've seen full glass doors but Maule said they don't know anything about them, are they legal? Do I need a 337?

I'd love to put on some full glass doors if I can but if they're not legal then I'll settle for the door kits but the kits from Maule are something like $400 a side is what I heard which seems ridiculous. Any help would be greatly appreciated, thanks!

My understanding is that the doors are effectively open season for anything. They are not considered structural. That said you always have to have the doors in place on at least one side during flight so that might throw a kink in there somewhere.

I will likely go full “glass” myself but am torn on not being able to open a window if I wanted. That said I’m thinking the little round window vents might be more efficient at getting air into the cabin anyways. The full “glass” is simply a piece of plexiglass or Lexan or what ever you prefer that is cut to shape and riveted to the original frame in place of the skins. So I would just get cutting a drilling personally. I would say this is a minor and no structural modification so a signature from and A&P might be debatable.

That’s just my 2¢

Depending on the FAA inspector, doors might be considered part of the fuselage, thus modifications to them that deviate from manufacturer-approved drawings would qualify as major alterations, thus requiring a field approval. Since Maule does not do full-glass doors, those would be interpreted as falling into that category.

Even if the doors are not considered part of the fuselage, thus not a “Major Modification” the work would require the sign-off of an A&P. This is true even if doing them per the Maule drawing.

As far as doing the work yourself, you must be under the supervision of an A&P unless that work is listed in Part 43 Appendix A(c), which is the Preventive Maintenance task list.

Nothing prevents you from manufacturing the parts yourself, as long as they comply with the Maule drawing. You would need to get the drawing to work from in doing this. Fabricating the vertical aluminum pieces requires having access to a shrinker, to from the curve in the angle aluminum. The rest of the aluminum can be done with a shear and a bending break.

All the above should not be interpreted to imply a judgement on my part as to what you should or shouldn’t do, or what you might get away with. It’s simply an answer to the questions regarding what you are allowed to do according to the regs.

I will say that for something as visible and obvious as a door, a curious inspector who happened to see them might be likely to do a quick search of the database in Oklahoma City to see if there is a 337 on file for that work. No one would bat an eye here in Alaska, but in the lower 48, all-glass doors would be more likely to catch someone’s attention.

Some of the owners on this forum have fabricated their own observer doors and there are several threads such as this one: http://www.maulepilots.org/Hangartalk/v ... rver+doors. Do a search on "observer doors" or "patroller doors" with the forum's search tool.

Besides having good metal cutting and welding skills, you would either need to be an A&P or work under one's supervision and have them sign off on your work. I would think that most A&Ps would consider this a major modification and require a 337. Maule doors are individually fitted to the airframe because each airplane has it's own unique curvature on the sides. Even if you buy a kit, there's a lot of cutting, welding and drilling involved. I would say that unless you are skilled and experienced in this area, it would be better to have an experienced A&P or Maule Flight do it. Otherwise, you could end up with poorly fitted doors that leak air or lack structural strength.