Maintaining a Production Airplane

Sport Aviation  - June, 1998
by Ron Alexander

What about those of us who own a production airplane with a standard airworthiness certificate? Can we legally maintain that airplane? If so, what does the FAA allow us to do? Can we document it in the aircraft logbook? Where can we find more information concerning what can be done and how to do it? These are all valid questions for an aircraft owner. Several of us not only own an experimental aircraft, but we also own a production aircraft. I know that I can maintain my experimental airplane because FAR Part 43 that pertains to maintenance on a production airplane does not apply to aircraft operating with a special airworthiness certificate under the experimental category. I can even perform my own annual inspection ( condition inspection ) on my experimental and then sign it off in the logbook if I have a repairman’s certificate.

Not so with an airplane certificated with a standard airworthiness certificate. A whole new set of rules applies and they are found under FAR Part 43. The maintenance performed on my production airplane must be done by a properly certified mechanic or under their supervision. Also, a certified mechanic holding an Inspectors Authorization must sign off the annual inspection.

It is reasonable to assume that a pilot of any aircraft is capable of a safer operation if they know the mechanical workings of their airplane. The more I know about the aircraft and its related systems the better. When mechanical problems arise I will be much more capable of safely handling the situation. An interesting regulation also exists in FAR part 91. It is FAR 91.403 (a) and it states "The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition, including compliance with Part 39 of this chapter." Part 39 pertains to AD ( airworthiness directive ) notes. I also know that it is expensive to hire a mechanic to do routine maintenance. The cost of owning an airplane is high enough without hiring someone to change oil in my flying machine. The enhanced safety of operation and the cost of maintenance are two factors that create an interest in doing my own preventive maintenance.

Often pilots are reluctant to do any preventive maintenance at all simply because of the complexity of an airplane along with potential problems with their local FAA inspector. Most do not understand that there are a number of maintenance items that can be legally performed by the pilot who owns or operates the airplane. There are regulations that specifically detail those items and who may perform them. These items are not difficult to do provided instructions found in the aircraft service manual are closely followed. With these facts in mind, lets examine what the regulations really do say about pilot preventive maintenance and other types of maintenance that we can legally perform.

Before we consider preventive maintenance lets look at another common question. What if I want to restore an antique, classic, or warbird? What about doing the work myself—is it legal? We are always discussing the possibility of doing our own fabric covering, sheet metal work, etc., how do we do that without holding a valid mechanic’s license? FAR Part 43.3 defines persons authorized to perform maintenance, preventive maintenance, rebuilding, and alteration. FAR 43.3 (d) reads "A person working under the supervision of a holder of a mechanic or repairman certificate may perform the maintenance, preventive maintenance, and alterations that his supervisor is authorized to perform, if the supervisor personally observes the work being done to the extent necessary to ensure that it is being done properly, and if the supervisor is readily available, in person, for consultation." It goes on to say that inspections are not included. So, this means that the FAA allows me to do work on my airplane without holding a mechanic’s certificate. I simply must do it under the direct supervision of the holder of a mechanic’s certificate. This is subject to a certain degree of interpretation, however, it is generally understood that the licensed mechanic does not have to be present during all of the work.

You can, as an example, place fabric on an aircraft wing as long as the mechanic has inspected the wing prior to covering and ensures that you are using proper covering techniques. Remember, the mechanic is going to make an entry in the aircraft logbook stating that the work in question has been done properly. You, as the restorer, do not make logbook entries without holding a mechanic’s certificate.

Most aircraft mechanics will take the necessary steps to make sure you do the work properly because their ticket is on the line. They become the guest speaker at any hearing. So, in summary, I can restore my airplane if I do it under the supervision of a certificated mechanic.

Now lets return to the discussion on routine maintenance—the primary topic. FAR 43.3 (g) states "The holder of a pilot certificate issued under Part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under FAR Part 121, 127, 129, or 135." A pilot certificate means Private Pilot or higher. The next question—what is considered preventive maintenance? FAR Part 1 definition is "Preventive maintenance means simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations." FAR Part 43 Appendix A goes even further to specifically list 32 items that may be performed by a certificated pilot. Of these 32 items, 29 actually pertain to standard aircraft. The remainder applies to balloons and primary category aircraft. I will discuss only the 29 pertinent to the majority of airplanes.

If during the performance of any of these 29 items further work is required meaning it becomes complex or requires a major operation or replacement of parts involving complex assembly operations, then the item becomes a "maintenance" function and must be performed by certificated maintenance personnel. In more simple terms, if you are performing a routine preventive maintenance item and discover a problem, you will have to have a certified mechanic either do the work or supervise the work.

FAR’s also prescribe two additional requirements for preventive maintenance. We must use proper practices and we must document the logbook. FAR 43.13 (a) states "Each person performing maintenance, alteration, or PREVENTIVE MAINTENANCE on aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer’s maintenance manual…..He shall use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices."

Therefore, a copy of Advisory Circular 43.13-1A should be used as a guide for proper practices along with reference to the aircraft service manual. FAA Advisory Circular 43-12A pertains specifically to preventive maintenance. Obtaining and referring to a copy of this circular is also helpful. A note in 43-12A states " It is absolutely essential to have the appropriate manuals and data when performing preventive maintenance."

The second requirement is to correctly document the aircraft logbook. It is very important to maintain accurate records on your aircraft. FAR 43.9 (a) pertains to maintenance record entries. It states " Except as provided in paragraphs (b) and (c) of this section, each person who maintains, performs PREVENTIVE MAINTENANCE, rebuilds, or alters an aircraft, airframe, aircraft engine, propeller, appliance, or component part shall make an entry in the maintenance record of that equipment containing the following information:

• A description of work performed.
• The date of completion of the work performed.
• The name of the person performing the work.
• If the work performed on the aircraft, airframe, aircraft engine, propeller, appliance, or component part has been performed satisfactorily, the signature, certificate number, and kind of certificate held by the person approving the work, the signature constitutes the approval for return to service only for the work performed.

SAMPLE PREVENTIVE MAINTENANCE ENTRY

(Date) Total Time_______hours. Left main gear tire removed in accordance with (manufacturers maintenance manual) and replaced with ________type tire.

Pilot’s signature________________ and certificate number__________________.

To summarize, as a pilot and aircraft owner of a production airplane, we are allowed to do certain preventive maintenance items as long as they are done properly and in accordance with accepted practices. They then must be properly documented in the logbook.

Prior to beginning our discussion of the specific items that are considered preventive maintenance, let talk about pre-flighting your airplane. All preventive maintenance begins with a good preflight inspection. A few suggestions on pre-flight inspections:

1. Use your checklist and recommended pre-flight procedure as outlined in the aircraft manual.

2. Use the same procedure each time.

3. Do Not be in a hurry. This can be a major obstacle to a safe flight. be in a hurry. This can be a major obstacle to a safe flight.

4. Listen to your airplane. Write down maintenance items that need attention when you detect them.

5. Always do a post-flight inspection.

In this and subsequent articles, I will present the 29 preventive maintenance items pertaining to the majority of production aircraft. I will discuss in detail the ones that you will more likely encounter on your airplane.

Prior to actually beginning the maintenance process on any of these items you should review the following steps:

• Be physically and mentally alert

• Have the proper tools

• Work in a clean, well lit place

• Do your homework—have the parts you will need

• Use the aircraft service manual and AC43-13 as a reference

• Complete what you start

• Ask for assistance if you need it

• Do not fix things that don’t need fixing

• Check your work, or better, have someone else check it

• Do an operational check

• Make the appropriate logbook entry

PREVENTIVE MAINTENANCE ITEMS

Item number 1—"removal, installation, and repair of landing gear tires."
This preventive maintenance item usually will be outlined in your service manual. Here are a few general suggestions. The primary concern is proper jacking of the aircraft. This is found in your manual. Wheel pants and brake lines should be properly removed and noted for reinstallation. After removal of the wheel, completely deflate the tires before dismounting. Always use caution when removing valve cores. Break the beads of the tire before loosening the wheel bolts using a bead breaker. Do not use a pry bar, tire iron, or any other sharp tool to loosen tire beads.

Prior to mounting the tire, dust the deflated tube with talc and insert it into the tire. Then inflate it until the tube is just rounded out. Install the valve core, line up the tube and tire balance marks. Inflate, deflate, and then reinflate to the recommended pressure. If you are unsure as to how freely the wheel should rotate when reinstalled, have a mechanic show you. Do not use old cotter pins. NOTE: These items and procedures will vary considerably depending upon your type of aircraft.

Item number 2—"replacing elastic shock absorber cords on landing gear."
The bottom line with this procedure involves having the right tool. If you do not have the proper tool to do this job hire someone else to do it. It appears simple but can be very complex.

Item number 3—"servicing landing gear struts by adding oil, air, or both."
Again, follow the instructions in the aircraft manual for proper strut inflation. Be sure you wipe down the bottom of shock struts with a rag and MIL-H-5606 (hydraulic fluid) to keep them clean. Use the right kind of oil. A number of struts use nitrogen instead of air for inflation. The use of nitrogen prevents corrosion. Usually your FBO will have a nitrogen bottle you can borrow or rent. Be cautious when placing the air or nitrogen fitting onto the strut fitting—make sure your hands are out of the way in case the strut totally deflates.

Item number 4—"servicing landing gear wheel bearings, such as cleaning and greasing."
You must first thoroughly clean the bearing using Varsol or a similar type cleaner. Inspect the bearing for corrosion and wear. Keep track of which bearing goes with which wheel side and keep them together. Use a quality wheel bearing grease. Then place the grease in the palm of your hand and force the grease into one side of the bearing until it comes out on the other side. A tool is also available that will accomplish this task.

Item number 5—"replacing defective safety wiring or cotter keys."
Always use aircraft quality safety wire of the size specified. That will usually be .032 or .041 in diameter. Ensure that placement of the safety wire will cause the item to be tightened. A good pair of safety wire pliers is a must for proper safetying. Cotter pins should be of proper size and after placement in the castle nut they should be bent over so they lock in place.

Item number 6—"Lubrication not requiring disassembly other than removal of nonstructural items such as cover plates, cowlings, and fairings."
Your aircraft manual should contain a lubrication chart outlining points and types of lubrication. Note that you may only lubricate areas not requiring disassembly of structural items.

This particular preventive maintenance item also allows the pilot or aircraft owner to change engine oil. This is, of course, one of the most important tasks you can perform. It is usually very simple to do and is usually accomplished in conjunction with item number 23 that allows changing of the oil filter. I will specifically address that later. Occasionally, you will encounter an Airworthiness Directive that may apply to changing your oil. Check that out before beginning. Change the oil and replace the filter, or check the oil screen, at time intervals recommended by the manufacturer. Always ensure that the oil is replaced and that the proper type and weight of oil is used. Do not forget to safety the drain plug. After you have completed the oil and filter change, wash down the engine and the run it to check for oil leaks. Anytime you have your engine cowling removed check for all types of leaks and problems. In particular, check the fuel system, oil system, exhaust system, cooling air, induction air, and electrical. A thorough inspection of all areas should be accomplished.

If you desire you can send an oil sample for an analysis. In order to be effective, this should be done on a regular basis. A history must be established by taking a sample from the same area at a regular time interval. An occasional analysis will tell you very little.

Item number 7—"making simple fabric patches not requiring rib stitching or the removal of structural parts or control surfaces."
To do this item, you must first determine what type of fabric covering system was initially used. You should repair the surface using the same type of system and the repair procedures outlined in that manual. A simple repair means a small repair. The covering manual should specifically address repairs and how to make them. If you are unable to find any information the Poly-Fiber System manual has a good presentation on fabric repairs. AC43-13 also talks about making fabric repairs.

You are not allowed to remove a control surface or repair in any area requiring rib lacing without a mechanic’s supervision. Remember, however, that it is perfectly acceptable for you to perform such a maintenance item under the direct supervision of a certificated mechanic.

Item number 8—"replenishing hydraulic fluid in the hydraulic reservoir."
The most important consideration for item number 8 is the use of the proper fluid. MIL-H-5606 is by far the most common type of hydraulic fluid used in smaller aircraft. It is used in the brake systems and hydraulic systems. Use of any other type of fluid will cause a lot of problems with seals, O-rings, etc.. Follow instructions in your service manual.

In the next issue I will list and discuss the remaining preventive maintenance items that can be accomplished without a mechanic’s license. As a review, FAR 43.3 (g) states "The holder of a pilot certificate issued under Part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under FAR Part 121, 127, 129, or 135." This applies to production aircraft operated with a standard airworthiness certificate. Aircraft certificated under a special airworthiness category such as "experimental" fall under a different set of rules that we have previously discussed in earlier issues of Sport Aviation.

You also may legally restore, rebuild, or maintain your production airplane under FAR 43.3 (d). This regulation allows an individual, not holding a valid mechanic’s certificate, to perform the rebuilding tasks under the supervision of a certificated mechanic.

Always have the proper manuals and tools available to perform the maintenance. Document the performed maintenance in the aircraft logbook. Proper maintenance begins with a very thorough pre-flight inspection of your airplane. Perform this inspection as outlined in your aircraft service manual.