Bottom Cowl on BC12D

[freightpilot27]

Re: Bottom Cowl on BC12D

owners (assuming they are pilots) without an A&P should not be doing any maintenance on certified aircraft except what the FAA specifically allows a pilot to do. (and even some of those are beyond the ability of some pilots)
If you want to work on an airplane, go to school and get your A&P.

And Hank- YES, substituting MS hardware for MS hardware is a minor alteration. the replacement hardware must be of at least equivalent strength for the intended use. A&P's know this.

BTW, i am an A&P AND IA (16 active years)
ATP with 7k hours and type ratings too

[Hank Jarrett]

Re: Bottom Cowl on BC12D

One reason I like these discussions here is I don't want to have them grave side. I am afraid a lot of what is said here could be taken by someone who doesn't know better as allowing them to do things that could get them hurt. It isn't the A&P and above we have to worry about (although there is one A&P at the field I fly from I wouldn't allow to SIT in my plane, much less work on it) it is the un-informed owner who "thinks" it is OK for him to make a "simple" change.


I think Bob hit the nail on the head, those without the proper credentials have NO BUSINESS modifying their planes without the proper supervision. I worked on military planes for over 20 years and am a structural engineer with an Aerospace engineering degree. There is NO work done on my plane without a properly recognized aircraft mechanic checking what is done. IF the work is on the list of things the FAA allows me to do, I do it (but I usually get my local A&P or IA to look at it just to be sure). If it is NOT on the list of things I am allowed to do, I get with my mechanic first and he either tells me I can do it (usually with stops for him to check things before they are covered up) or tells me HE needs to do it, but I can watch/help (sometimes my "help" costs me extra). ;-)


Even a "minor alteration" is not supposed to be done by an owner, unless he has the right "paper" in his pocket. I am approaching a major hold on the 41 right now because the person I use is in Afghanistan and I am rapidly running out of things I can do without covering up something he has to look at. If she has to sit, SHE SITS! Happily a couple of friends helped me hang the wings and I have a whole slew of new things I can work on that aren't hidden when I finish, but the "inspect" list is getting really long.

I figure it will take some time to get the wing to fuselage covers cut to satisfy me for fit and finish as well as the new strut fairings that were on her when new and have been gone for years. Good thing is they all come off easy for inspection of the fuel, pitot line and control hookups.


Bottom line is, if you think you can do it, that doesn't mean you are allowed to. When my A&P signs off my plane, he is saying HE takes responsibility for all the work. I know him, he isn't signing till he KNOWS it is right. That is the way I want it. I may have the degrees, but I do not have the A&P/IA (yet). Until then, I can't sign off squat.
Hank

It IS nice to know what the mechanic is doing when he works on my plane. Even a professional mechanic can make a mistake and all the good ones I have known want owner involvement, especially at annual time. We REALLY need to start having Annual parties again around here. We used to get together and open up our planes for annual as a group and most times WE found all the gripes before the mechanic started to look. We always tried to have EVERY gripe written down before he started. If we missed one, it was always a disappointment. We also went back to OUR planes and looked for every fault we found on the annual bird. Scary how often we found the same problem on other planes!

[astjp2]

Re: Bottom Cowl on BC12D

(a) Major alterations —(1) Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:

(i) Wings.

(ii) Tail surfaces.

(iii) Fuselage.

(iv) Engine mounts.

(v) Control system.

(vi) Landing gear.

(vii) Hull or floats.

(viii) Elements of an airframe including spars, ribs, fittings, shock absorbers, bracing, cowling, fairings, and balance weights.

(ix) Hydraulic and electrical actuating system of components.

(x) Rotor blades.

(xi) Changes to the empty weight or empty balance which result in an increase in the maximum certificated weight or center of gravity limits of the aircraft.

(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.

(xiii) Changes to the wing or to fixed or movable control surfaces which affect flutter and vibration characteristics.

(2) Powerplant major alterations. The following alterations of a powerplant when not listed in the engine specifications issued by the FAA, are powerplant major alterations.

(i) Conversion of an aircraft engine from one approved model to another, involving any changes in compression ratio, propeller reduction gear, impeller gear ratios or the substitution of major engine parts which requires extensive rework and testing of the engine.

(ii) Changes to the engine by replacing aircraft engine structural parts with parts not supplied by the original manufacturer or parts not specifically approved by the Administrator.

(iii) Installation of an accessory which is not approved for the engine.

(iv) Removal of accessories that are listed as required equipment on the aircraft or engine specification.

(v) Installation of structural parts other than the type of parts approved for the installation.

(vi) Conversions of any sort for the purpose of using fuel of a rating or grade other than that listed in the engine specifications.

(3) Propeller major alterations. The following alterations of a propeller when not authorized in the propeller specifications issued by the FAA are propeller major alterations:

(i) Changes in blade design.

(ii) Changes in hub design.

(iii) Changes in the governor or control design.

(iv) Installation of a propeller governor or feathering system.

(v) Installation of propeller de-icing system.

(vi) Installation of parts not approved for the propeller.

(4) Appliance major alterations. Alterations of the basic design not made in accordance with recommendations of the appliance manufacturer or in accordance with an FAA Airworthiness Directive are appliance major alterations. In addition, changes in the basic design of radio communication and navigation equipment approved under type certification or a Technical Standard Order that have an effect on frequency stability, noise level, sensitivity, selectivity, distortion, spurious radiation, AVC characteristics, or ability to meet environmental test conditions and other changes that have an effect on the performance of the equipment are also major alterations.

(b) Major repairs —(1) Airframe major repairs. Repairs to the following parts of an airframe and repairs of the following types, involving the strengthening, reinforcing, splicing, and manufacturing of primary structural members or their replacement, when replacement is by fabrication such as riveting or welding, are airframe major repairs.

(i) Box beams.

(ii) Monocoque or semimonocoque wings or control surfaces.

(iii) Wing stringers or chord members.

(iv) Spars.

(v) Spar flanges.

(vi) Members of truss-type beams.

(vii) Thin sheet webs of beams.

(viii) Keel and chine members of boat hulls or floats.

(ix) Corrugated sheet compression members which act as flange material of wings or tail surfaces.

(x) Wing main ribs and compression members.

(xi) Wing or tail surface brace struts.

(xii) Engine mounts.

(xiii) Fuselage longerons.

(xiv) Members of the side truss, horizontal truss, or bulkheads.

(xv) Main seat support braces and brackets.

(xvi) Landing gear brace struts.

(xvii) Axles.

(xviii) Wheels.

(xix) Skis, and ski pedestals.

(xx) Parts of the control system such as control columns, pedals, shafts, brackets, or horns.

(xxi) Repairs involving the substitution of material.

(xxii) The repair of damaged areas in metal or plywood stressed covering exceeding six inches in any direction.

(xxiii) The repair of portions of skin sheets by making additional seams.

(xxiv) The splicing of skin sheets.

(xxv) The repair of three or more adjacent wing or control surface ribs or the leading edge of wings and control surfaces, between such adjacent ribs.

(xxvi) Repair of fabric covering involving an area greater than that required to repair two adjacent ribs.

(xxvii) Replacement of fabric on fabric covered parts such as wings, fuselages, stabilizers, and control surfaces.

(xxviii) Repairing, including rebottoming, of removable or integral fuel tanks and oil tanks.

(2) Powerplant major repairs. Repairs of the following parts of an engine and repairs of the following types, are powerplant major repairs:

(i) Separation or disassembly of a crankcase or crankshaft of a reciprocating engine equipped with an integral supercharger.

(ii) Separation or disassembly of a crankcase or crankshaft of a reciprocating engine equipped with other than spur-type propeller reduction gearing.

(iii) Special repairs to structural engine parts by welding, plating, metalizing, or other methods.

(3) Propeller major repairs. Repairs of the following types to a propeller are propeller major repairs:

(i) Any repairs to, or straightening of steel blades.

(ii) Repairing or machining of steel hubs.

(iii) Shortening of blades.

(iv) Retipping of wood propellers.

(v) Replacement of outer laminations on fixed pitch wood propellers.

(vi) Repairing elongated bolt holes in the hub of fixed pitch wood propellers.

(vii) Inlay work on wood blades.

(viii) Repairs to composition blades.

(ix) Replacement of tip fabric.

(x) Replacement of plastic covering.

(xi) Repair of propeller governors.

(xii) Overhaul of controllable pitch propellers.

(xiii) Repairs to deep dents, cuts, scars, nicks, etc., and straightening of aluminum blades.

(xiv) The repair or replacement of internal elements of blades.

(4) Appliance major repairs. Repairs of the following types to appliances are appliance major repairs:

(i) Calibration and repair of instruments.

(ii) Calibration of radio equipment.

(iii) Rewinding the field coil of an electrical accessory.

(iv) Complete disassembly of complex hydraulic power valves.

(v) Overhaul of pressure type carburetors, and pressure type fuel, oil and hydraulic pumps.

(c) Preventive maintenance. Preventive maintenance is limited to the following work, provided it does not involve complex assembly operations:

(1) Removal, installation, and repair of landing gear tires.

(2) Replacing elastic shock absorber cords on landing gear.

(3) Servicing landing gear shock struts by adding oil, air, or both.

(4) Servicing landing gear wheel bearings, such as cleaning and greasing.

(5) Replacing defective safety wiring or cotter keys.

(6) Lubrication not requiring disassembly other than removal of nonstructural items such as cover plates, cowlings, and fairings.

(7) Making simple fabric patches not requiring rib stitching or the removal of structural parts or control surfaces. In the case of balloons, the making of small fabric repairs to envelopes (as defined in, and in accordance with, the balloon manufacturers' instructions) not requiring load tape repair or replacement.

(8) Replenishing hydraulic fluid in the hydraulic reservoir.

(9) Refinishing decorative coating of fuselage, balloon baskets, wings tail group surfaces (excluding balanced control surfaces), fairings, cowlings, landing gear, cabin, or cockpit interior when removal or disassembly of any primary structure or operating system is not required.

(10) Applying preservative or protective material to components where no disassembly of any primary structure or operating system is involved and where such coating is not prohibited or is not contrary to good practices.

(11) Repairing upholstery and decorative furnishings of the cabin, cockpit, or balloon basket interior when the repairing does not require disassembly of any primary structure or operating system or interfere with an operating system or affect the primary structure of the aircraft.

(12) Making small simple repairs to fairings, nonstructural cover plates, cowlings, and small patches and reinforcements not changing the contour so as to interfere with proper air flow.

(13) Replacing side windows where that work does not interfere with the structure or any operating system such as controls, electrical equipment, etc.

(14) Replacing safety belts.

(15) Replacing seats or seat parts with replacement parts approved for the aircraft, not involving disassembly of any primary structure or operating system.

(16) Trouble shooting and repairing broken circuits in landing light wiring circuits.

(17) Replacing bulbs, reflectors, and lenses of position and landing lights.

(18) Replacing wheels and skis where no weight and balance computation is involved.

(19) Replacing any cowling not requiring removal of the propeller or disconnection of flight controls.

(20) Replacing or cleaning spark plugs and setting of spark plug gap clearance.

(21) Replacing any hose connection except hydraulic connections.

(22) Replacing prefabricated fuel lines.

(23) Cleaning or replacing fuel and oil strainers or filter elements.

(24) Replacing and servicing batteries.

(25) Cleaning of balloon burner pilot and main nozzles in accordance with the balloon manufacturer's instructions.

(26) Replacement or adjustment of nonstructural standard fasteners incidental to operations.

(27) The interchange of balloon baskets and burners on envelopes when the basket or burner is designated as interchangeable in the balloon type certificate data and the baskets and burners are specifically designed for quick removal and installation.

(28) The installations of anti-misfueling devices to reduce the diameter of fuel tank filler openings provided the specific device has been made a part of the aircraft type certificiate data by the aircraft manufacturer, the aircraft manufacturer has provided FAA-approved instructions for installation of the specific device, and installation does not involve the disassembly of the existing tank filler opening.

(29) Removing, checking, and replacing magnetic chip detectors.

(30) The inspection and maintenance tasks prescribed and specifically identified as preventive maintenance in a primary category aircraft type certificate or supplemental type certificate holder's approved special inspection and preventive maintenance program when accomplished on a primary category aircraft provided:

(i) They are performed by the holder of at least a private pilot certificate issued under part 61 who is the registered owner (including co-owners) of the affected aircraft and who holds a certificate of competency for the affected aircraft (1) issued by a school approved under §147.21(e) of this chapter; (2) issued by the holder of the production certificate for that primary category aircraft that has a special training program approved under §21.24 of this subchapter; or (3) issued by another entity that has a course approved by the Administrator; and

(ii) The inspections and maintenance tasks are performed in accordance with instructions contained by the special inspection and preventive maintenance program approved as part of the aircraft's type design or supplemental type design.

(31) Removing and replacing self-contained, front instrument panel-mounted navigation and communication devices that employ tray-mounted connectors that connect the unit when the unit is installed into the instrument panel, (excluding automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)). The approved unit must be designed to be readily and repeatedly removed and replaced, and pertinent instructions must be provided. Prior to the unit's intended use, and operational check must be performed in accordance with the applicable sections of part 91 of this chapter.

(32) Updating self-contained, front instrument panel-mounted Air Traffic Control (ATC) navigational software data bases (excluding those of automatic flight control systems, transponders, and microwave frequency distance measuring equipment (DME)) provided no disassembly of the unit is required and pertinent instructions are provided. Prior to the unit's intended use, an operational check must be performed in accordance with applicable sections of part 91 of this chapter.

[astjp2]

Re: Bottom Cowl on BC12D

Unless its specifically included in Appendix A of FAR 43, its minor, PERIOD. Its the mechanics responsibility to interpret, determine applicapplibility, and document to the scrutiny of the FAA. The owner is not to determine what is applicabile, its there responsibility to find a MECHANIC they feel comfortable with that will ensure compliance and conformity. The FAA does have some guidance that they recommend IA's use when working with owners. Its a good read and give an owner an understanding of the IA/A&P's responsibilities to the owner and the regulations.

On a side note, if your mechanic is not requiring the owner to perform necessary maintenance when it is needed, they are doing a disservice to other mechanics and to the owners they provide services to. Things like 500 hour inspections are not regulatory, but they are necessary to prevent mag failure. I know owners that expect to run mags to failure then just repair what is broke. Then that same owner will say what a piece of junk the mags are. If their mechanic had forced them to perform the 500 hr service, they may have never had a failure.

Tim

[lfries]

Re: Bottom Cowl on BC12D

Do you need the end piece. I'm fairly certain that I have one.

[Larry Lyons]

Re: Bottom Cowl on BC12D

Having nothing we are working from scratch. We did a mock up with plywood at each end cut out to match the existing boot and nose bowl. We then lofted them in to place and made them very rigid. Then we cut cardboard patterns. We found that cutting the notch for the intake allows the bottom to form a "sort of" compound curve with out any wheeling need. Again we are not in to restoration as much as good looking, safe flying craft. We are just starting to hang the aluminum on the bird. I would have to guess at the grade of metal, (CRS) so will get back here after checking. We plan on using a piano hinge and bumps will be mandatory as the left plug is sticking out about an inch right now. L

I am going to need to make new top cowls for the 41 (I HATE those cowl bumps for the long plugs). What are you using to make yours? Do you have drawings or are you just using the old ones as a sample? My old ones are pretty bad. They fit terrible and have a couple of piano hinge in the middle. I have managed to make a nice set of front and rear hinge ends and a nice set of the inter-curled hinges (there MUST be a name for those "wound into each other" hinges), but I need to start thinking about making the flat sheet metal parts and the stiffeners.

For anyone interested, DO NOT think about trying to make those goofy hinges! They were a RIDICULOUS amount of work and I am lucky to still have ten fingers. If you don't get them PERFECTLY straight and shaped "just right" they jam and tear apart. Another of those little things that are JUST NOT WORTH trying to do yourself. There HAS to be someone with the tool to make them somewhere. Whatever they want to make them, PAY IT!

We all need to post some pictures of what we make to help each other get them right.

Hank

By the way, there is more than just the short and long lower cowls. Some of the early short ones were NOT made from flat sheet. They were worked on an English Wheel or draw formed with a distinct "bowl" shape to the bottom. The shaped ones looked really nice.

[Robert G. Hamm]

Re: Bottom Cowl on BC12D

Sorry for the firestorm! I do know the rules and am not doing the work. But when I see something that looks wrong, I will find out if it is correct before paying for the work. The louvers are backwards and go inwards instead of outwards when looking at many other airplanes. It was hard to tell from the Barnstormers pictures what was correct. Thanks to Rob I know what is correct for the BC12D. As the owner/pilot of this BC12D I will continue to ask to make sure I am flying a safe and legal aircraft. Have a IA to do the work so virtually anything that needs to be done can be done.

Bob

[M Towsley]

Re: Bottom Cowl on BC12D

Robert,

No firestorm, this is how we share and learn things. Keep the questions coming, we all learn from them.

[Robert Lees]

Re: Bottom Cowl on BC12D

Thanks to Rob I know what is correct for the BC12D.
Bob

I'm sure I said " ..and to be honest, I don't (my bold) know what is the "correct" version".

YMMV

[Hank Jarrett]

Re: Bottom Cowl on BC12D

Understand we are like family here (surprise! You are a member and you have a whole lunatic new side to your family!). We get into some discussions that may seem like we are upset with each other, but it is more like brothers and sisters talking. We are not mad or fighting, we just don't hold back, especially if there is safety or "legalities" involved. All of us just want to get it right.
Speak your minds, EVERYBODY. If you see or find something that you aren't sure of, speak up. It could save a family member.
Hank

[waltermrich]

Re: Bottom Cowl on BC12D

Hank sent you a PM