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Block Lesson Seven

Course Instructions

We have found people learn in different ways. Some learn better by reading the material themselves, others by watching a video. Throughout our Blocks we have the course set up in two different ways; 

  • The first is a video you can watch with text to speech. The video is an MP4 which is not interactive. There is no capability to link anything. That being said, any part that requires you to interact with, you will need to find the link in the text, or watch another video further down the page.
  • The second part is set up with text you can read with all FARs and documents linked to the FAA’s website. Everything is interactive. When it is time to interact with the FAA’s website, or watch another video the capability is there for you.

You can choose which way you would like to precede. 

NOTE:  Each block covers specific FAR information in chronological order, and it is recommended that you work through them in that order. However, you are free to work through them in any order you wish. These Block Lessons are FREE to anyone to read, and work through as often as you would like, all year round. The course can also be used as a TRAINING TOOL so that everyone in your organization is following the same processes.

If you would like to use this course to meet the 8 hours of learning required by FAR 65.93, you are required to complete ALL 8 blocks of Learning, and then take the Final Quiz. About 65% of the questions on the Quiz can be found in these block lessons, the rest you should know. Some of the questions on the quiz can only be answered by going through the course. The Quiz consists of 96 questions and you will need 70% to pass. If you don’t pass the quiz the first time, you will be able to take the Quiz again at any time. Once you start the Quiz you can pause it at any time, in order to search for information on the FAAs website, or review one of our Block Lessons. Once you have completed the Quiz and received at least 70% correct, you will be able to print a certificate to then submit to the FAA.

Block Seven Will Cover:

Block Lesson Seven Video

Inspection Authorization Refresher Training

FAA  AC 43-9C Advisory Circular

FAA AC 43-9C Advisory Circular is very important to an IA because it details exactly what maintenance records are required, definitions of specific terms, and other important information about maintenance records such as maintaining them by the owner or operator. This AC provides both IA and the owner or operator a common ground for determining what records the owner must provide an IA when IA is accomplishing any required inspection.


FAR 43.11 It details how an IA must certify to the  airworthiness, or non-airworthiness of a product undergoing an Annual, or Progressive inspection.

This FAR, together  with Far43.15 are the two most important FARs to an IA and the two main FARs under which IAs are violated.

It is recommended that an IA. when signing inspection entries, utilize the exact wording for the entry provided in the FAR. 

FAR 43.11 also requires an IA to record the TOTAL TIME for each aircraft, eack installed engine and propeller, all based upon legal Time-in-Service in FAR 43.1.I

FAR 43.13 mainly pertains to persons other than IAs, but is also important to an IA because it details the maintenance performance requirements. It requires persons performing maintenance to accomplish it in accordance with the product manufacturer’s manuals and data, and assure that, when the maintenance is completed, it results in the product being at least equal to the original or properly altered in accordance with applicable FARs. This FAR describes the maintenance rules to be used by an IA as the inspection audit trail for reviewing the maintenance records. This FAR is the one most widely used by the FAA for processing maintenance violations.

FAA AC 43.13-1B Advisory Circular

FAA AC 43.13-1B Advisory Circular defines the Acceptable Methods, Techniques, and Practices referenced in FAR 43.13 when there are no product manufacturer manuals published for specific work being required. 

A good example might be structural repairs required on a Piper Cherokee aircraft. In the Piper Service Manual it specifically dictates that structural repairs should be accomplished using AC 43.13-1B. If an engine mount needs repair, it is an absolute that it is a Major Repair. You will find specific engine mount repairs in AC 43.13-1B. Since any repair to an engine mount is a Major Repair, you must use FAA approved data, not just acceptable data. In this case AC 43.13-1B may be considered FAA approved as long as the repair to the mount complies with the repair published in the AC. 

In short, the Piper Service Manual sent the mechanic to AC 43.13-1B. The mechanic found a suitable mount repair in the AC, and accomplished the repair in compliance. The mechanic made a logbook entry and then executed Form 337 and requested an IA inspect and approve it. All perfectly legal. 

Another good example would be the repair to a Cessna 172 aluminum fuel tank that leaked at a weld. The mechanic removed the tank in accordance with the Cessna Service Manual, prepared it for the weld repair, welded it in accordance with an AC 43.13-1B fuel tank weld repair scheme, pressure tested the tank in accordance with FAR 23.965, reinstalled the tank back into the aircraft, made an appropriate logbook entry in accordance with FAR 43.9C, executed a Form 337 for a Major Repair in accordance with FAR 43, Appendix B and AC 43-9-1G, and requested an IA to inspect and approve it. Again, perfectly legal.

FAR 43.15 is perhaps the most important FAR for an IA.

It details the exact performance rules for an IA to accomplish Annual and Progressive inspections. It is under this FAR that the majority of IA violation enforcements occur. Each requirement in FAR 43.15 begins with the imperative word SHALL, meaning legally, this is the way you MUST do it otherwise you are in violation. Each violation can cost an IA a minimum of $1100. The initial violation is found in the very first paragraph where it requires an IA to perform an Annual or Progressive inspection to the extent that it is determined that the product meets all applicable airworthiness requirements. These requirements include the Type Certificate Data Sheet, Equipment List, Weight and Balance Report, Airworthiness Directives, Certification Basis requirements found in FAR 23 and CAR 3 as applicable, and all items detailed in FAR 43, Appendix D. The most important item is the requirement that an IA MUST use a checklist while performing Annual and Progressive inspections, and it MUST comply with all requirements of FAR 43, Appendix D. Further, it demands certain tests be performed prior to an IA approving the product for return to service such as performing engine runs checking specifically for proper oil pressure and temperature, cylinder head temperature, and fuel pressure. It also describes the procedures for an IA to accept Progressive inspections when the aircraft for which he is legally responsible is away from its home base. Any violation of any single requirement in FAR 43.15 can subject an IA to a fine of $1100.

You can download our Annual Airworthiness Checklist

FAR 43, Appendix D is vital to an IA, especially as each requirement begins with the word SHALL.

FAR 43, Appendix D is the minimum inspection requirement for an IA to use when performing Annual or Progressive inspections. It should be copied, just like the Type Certificate Data Sheet, and remain on the clipboard of an IA throughout the entire inspection process. Airworthiness depends upon two elements as previously discussed condition for safe operation and in compliance with Type Design. FAR 43, Appendix D is the document that relates to condition for safe operation. 

There are inspection requirements that are critical both to assure air safety, and to assure that an IA can’t be violated by the FAA or impeached in any aviation litigation where they are called to witness for their work. The very first paragraph of FAR 43, Appendix D is most widely violated. It specifically mandates that, prior to any inspection, the aircraft MUST be thoroughly cleaned and all inspection access covers, including cowling, be either opened or removed as necessary. Many IAs fail to clean engines because they believe they won’t be able to see any oil leaks. This is a complete fallacy if you follow FAR 43.15, paragraph C2. This is the requirement to do engine runs after an inspection. If the engine is completely clean, then the mandatory engine run will expose any leaks. That is its specific purpose. Don’t ever get caught by the FAA performing an Annual or Progressive inspection on a dirty aircraft. 

One item on FAR 43, Appendix D of critical importance is found in paragraph D2. This mandates the inspection of proper torquing of the studs and nuts on a engine, especially related to the case attaching hardware and the hardware securing the cylinders to the case. An IA MUST, since the paragraph states SHALL, use a calibrated torque wrench to assure that all studs and nuts meet the torque required by the engine service instructions. Lastly, the inspection requirements mandated by FAR 43, Appendix D also require that an IA have available all applicable inspection and test equipment, properly calibrated.

The Annual Inspection Flowchart can be useful to an IA to determine the varying courses of action to be taken depending upon the results of the Annual or Progressive inspection.

Feel free to print it out and keep it with your toolbox.

Like the Airworthiness 

Flowchart it can make your life easier while keeping you out of trouble with the FAA.

Print the Airworthiness  Flowchart AW-Flowchart Back  

Annual Inspection Checklist

FAR 43.17 is an interesting FAR with which an IA should be familiar should he discover that an aircraft, engine, or propeller has been maintained in Canada.

In short, a US registered aircraft or product may be maintained in Canada except for accomplishing an Annual Inspection, which MUST be performed by FAA certificated persons. Further, a US aircraft may have major repairs or major alterations accomplished by appropriately rated Canadian persons, but the repair or alteration data used MUST be FAA approved. Approvals by Canadian persons for use on US aircraft are not legal.

FAR 43, Appendix A is very important to an IA

FAR 43, Appendix A is very important to an IA, especially when inspecting an aircraft or other product on Annual or Progressive inspections, or when inspecting Major Repairs or Major Alterations related to approving FAA Form 337. FAR 43, Appendix A provides a listing of those specific aircraft elements, and specific methods of maintenance to those elements, that constitute either Major Repairs or Major Alterations requiring FAA approved instructions. 

Appendix A is divided into two separate lists. 

  • The first is for Major Alterations, 
  • The second is for Major Repairs. 


A repair is defined as restoring to an original condition. It may occur that a repair morphs into an alteration due to how it is accomplished. If a repair actually alters Type Design, then it becomes a Major Alteration. 


Most Major Alterations involve common sense. Any alteration, for example, of wings, spars, engine mounts, primary control systems, landing gear, and the like would be Major Alterations just using common sense. 

AN IA should be careful to note in the propeller records whether or not the hub has been altered to accommodate dyed grease under an Airworthiness Directive. If it has, there should be a Form 337 for the hub alteration. Many propeller Repair Stations neglect to execute a Form 337, which is violation of FAR 43, Appendix B, and FAR 43.9. The Airworthiness Directive is merely the FAA approved data to alter the hub. Form 337 is certainly required as is revising the Weight and Balance Report as some four pounds of red dye grease is being added to the propeller hub at the most forward CG. A good rule-of-thumb might be, if the alteration is not done correctly and it could kill someone, it is certainly a Major Alteration. 

The Major Repair list is critical as well. It not only covers repairs to specific parts, but also covers methods of repair such as welding, riveting, and the like as a part of a repair if they are to be used. FAA approved data is always necessary for Major Repairs. 

As a good example, an IA will frequently discover stainless steel screws securing the fuel tanks on Piper Cherokee aircraft. Any owner of such aircraft can relate the high cost of having someone spend hours drilling out the alloy steel structural screws that have rusted themselves to the nutplates. Once out, the owner opts to install stainless steel screws, which are completely illegal. As FAR 43, Appendix A dictates, any substitution of material becomes a Major Repair requiring FAA approval. Because the wing fuel tanks on a Piper Cherokee are specifically structural becoming an integral part of the wing, the FAA will never approve the use of stainless steel non-structural screws replacing the required high tensile strength alloy steel screws. AN IA will have to write up the use of the wrong screws as an inspection discrepancy to be corrected. 

Another item an IA should look for are aircraft engines whose cases have been powder coated. While it makes the case look artistic, it is not only illegal to apply any coating to an aircraft engine case not specified in the engine manufacturer’s service or overhaul instructions, but it prevents the case from its heat exchanging properties during operation. It also prevents an IA from determining the source of any oil leaks, which is specifically required by FAR 43, Appendix D. As previously discussed, an IA should be particularly concerned in reviewing logbook records whether or not a fuel tank or oil tank has been repaired. Any repair to either is a Major Repair requiring FAA approved data and pressure testing.

FAA  AC 43-13-2B has recently been completely revised, and is very important now to an IA inspecting Major Alterations.

FAA AC 43-13-2B has recently been completely revised, and is very important now to an IA inspecting Major Alterations. This AC is now in concert with the FAA data approval elements of AC 43-13-1B. It may now be used as FAA approved data for Major Alterations under the same conditions, but only in the case of non-pressurized aircraft. Otherwise, the elements and condition of use for Minor Alterations remain the same. One major change is that now any addition to an aircraft electrical system is a Major Alteration.

AC 20-94A details the processes and procedures that may be required to install digital clocks in older aircraft.

AC 20-94 is important to an IA because it details the processes and procedures that may be required to install digital clocks in older aircraft, especially if they are wired into the Master Switch or directly to the battery so they remain energized.

AC 21-25B is very important to an IA.

AC 21-25B is very important to an IA. It details processes and procedures for altering aircraft compartment seats such as replacing foam cushioning and seat covers. Seats in any type certificated aircraft MUST be FAA approved. In older CAR 3 aircraft most seats were manufactured by the type certificate holder, and then certificated for the aircraft during the FAA approval process. This is the case with most Beech Bonanza seats. On later built aircraft, when the TSO system went into effect, it was far easier for an aircraft manufacturer to simply specify a TSO seat, already FAA approved. All that was required then was to certify the foam and fabric. All foam and seat covers MUST be FAA approved. This requires compliance with FAR 23.853, including appropriate burn certifications first on the raw fabrics and foam, then again when they are actually installed on the seat. Further, as an example, imagine replacing the foam and fabric on a simple passenger seat in a small aircraft. The seat is TSO, and the foam and fabric was installed by the type certificate holder. Reviewing the aircraft Equipment List you find the part number of the TSO seat, but not the foam and fabric. You then review the aircraft Illustrated Parts Catalog and find part numbers for the installation of the foam and fabric. You would now be altering the type design of the seat assembly, which would be a Major Alteration unless you obtained the replacement foam and fabric from the holder of the type design. If you did it would be a MINOR alteration with only a log entry. If not, it is a Major Alteration.


FAA Order 8900.1 volume 4, chapter 14, section 12 is part of the Airworthiness Inspector’s Handbook.

FAA Order 8900.1 volume 4, chapter 14, section 12 is part of the Airworthiness Inspector’s Handbook. However, its elements are current and applicable. It details items that are considered Powerplant Major Repairs requiring FAA approval. Some of these repairs are in daily use such as welding of cases halves, remachining after weld repairs, and the like. If complex machining operations are necessary, it becomes a Major Repair. When an IA reviews logbooks and discovers powerplant repairs like those mentioned, there should be Form 337 in the aircraft records or a signed workorder as detailed in FAR 43, Appendix B if the repairs were accomplished by an appropriately rated Repair Station.

AC 20-37E is important to an IA relative to propeller maintenance.

In some cases it contradicts information provided in FAR 1.1 defining Major Repair, as well as FAR 43, Appendix A for propeller alteration and repair. 

In short, it is recommended that IAs who discover that propellers have had maintenance performed on them such as the filing out of nicks and dents and the like, recommend that the owner or operator have an appropriately rated propeller Repair Station inspect the propeller. There is no terror like losing a propeller blade in flight and having to shit down the engine to prevent it from tearing itself loose from the engine mount.


FAR 45.15 requires aircraft materials be identified such as PMA and TSO parts, and critical parts. 

FAR 45.15 is important for an IA. Certain aircraft materials are required to be identified such as PMA and TSO parts, and critical parts. This FAR details the appropriate marking requirements.


FAR 45.25 details the precise marking requirements on fixed-wing aircraft.

FAR 45.25 is important to an IA. It details the precise marking requirements on fixed-wing aircraft. While the mis-marking is not an IA inspection item discrepancy, it would be good customer relations to advise the own or operator of the discrepant condition.

FAR 45.29 is another non-inspection discrepancy item for an IA. 

FAR 45.29 this FAR details the size of the registration marks on the aircraft. If the registration numbers have been changed or repainted, they now must be 12 inches high. FAR 45.29 is another non-inspection discrepancy item for an IA. But again, it would be good customer relations to advise the own or operator of the discrepant condition.

End of Block Lesson Seven

Now you have finished Block Seven, and may review the remaining blocks in any order you would like. After reviewing all 8 blocks of learning, you are ready to take the quiz. I hope you have enjoyed this lesson and have learned something that will help you and keep you out of trouble with the FAA.

Thank you for taking our Online Inspection Authorization Refresher Training Seminar!

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