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Block Lesson Three

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 Lesson Three Will Cover: (When you click on an item click on the Table of Contents of CFR page)

Block Lesson Three Video

Inspection Authorization Refresher Training Lesson Three

FAR 23.1 defines the applicability of Part 23, being the historical aircraft certification basis by the FAA, to the production of type-certificated small aircraft prior to August, 2017.  (All FAR 23 links are to the historical Part 23)

In short, just like there are building codes for houses and buildings,  Part 23 is the building code for current type-certificated Small Aircraft. For such an aircraft to continue to be legal and its Airworthiness Certificate to be valid, the aircraft must always meet the requirements of its building code, Part23.   FAR Part 23 replaced the Civil Air Regulations, CAR 3, essentially back in 1958. However, the majority of requirements found in CAR 3 were transferred over into Part 23, granted with some major additions which will be discussed in this program.  Part 23 describes and details all of the regulatory tests and processes that must be accomplished successfully in order to receive an aircraft Type Certificate from the FAA. When anyone desires to alter an aircraft, it is imperative that they determine the Certification Basis, such as CAR 3 or Part 23 for example. 


It’s like replacing the furnace in a house previously built, let’s say about 25 years ago. If you can replace the furnace with one identical to the old one, you can continue to comply with the original building code. However, if such an identical furnace is no longer manufactured, and you need to install one that requires modification to the furnace cabinet, you will have to install it to comply with the current building code, probably much more expensively.

FAR 23.303 is very important, especially when altering an aircraft. It defines the Factor of Safety for all structures.

This safety factor must be calculated at 1.5 times the actual known operating value of any specific structure, such as ribs, spars, and the like, commonly known as Principle Structural Elements or PSE.

FAR 23.561 specifies the structural g-forces that the aircraft structure must withstand under emergency landing conditions.

This is especially important for an IA to know when inspecting and approving Major Repairs or Major Alterations.

FAR 23.603 ensures that all aircraft manufactured conform to Type Design.

FAR 23.603 requires that all materials used to manufacture the aircraft, and all standards of workmanship must be able to produce consistent quality in conformance to the aircraft Type Design.

FAR 23.605 Governs all manufacturing methods to ensure conformity to Type Design.

FAR 23.605 demands that all manufacturing methods, such as riveting, welding, glueing, heat treating, and the like be accomplished using specific FAA-approved process specifications, which can be military or civilian such as AN, MS, NAS, ASTM, SAE, or ANSI to name just a few. Whatever specifications are used however, must be FAA-approved as a part of Type Design approval. Any changes in the specifications require submission to the FAA and further approval before use.

FAR 23.607 requires that all fasteners used in the manufacture of the aircraft be acceptable to the FAA and of specific aircraft quality.

These fasteners would include AN, MS, NAS, SAE, ANSI, and the like. It also prohibits the use of self-locking nuts on any bolt that rotates unless there is a secondary locking device installed.

FAR 23.811 defines the configuration of emergency exits and how they should be identified.

This is important to an IA because inspection of emergency exits is required on Annual and Progressive inspections.

FAR 23.851 is especially important to an IA.

During Annual and Progressive inspections at least one handheld fire extinguisher is required to be available within reach of the pilot during flight.

FAR 23.955 is very important to an IA as well.

For gravity feed aircraft fuel systems such as most Cessna single engine aircraft, the fuel flow under full power at sea level must be 150% that needed. For systems utilizing electric boost pumps, the requirement is only 125%. 


 This would be critical for an IA inspecting and approving an aircraft with ferry tanks or bladders.

FAR 23.959 is critical, not for an IA, but certainly for the aircraft builder and pilot.

This FAR specifies the tests required to determine the unusable amount of fuel in any fuel tank under minimum quantity conditions and specific flight maneuvers.

FAR 23.965 is very important to an IA.

During an Annual or Progressive inspection, if IA discovers that a fuIf there are no documents available attesting to such pressure testing, the tank is unairworthy until it is tested in compliance with this FAR. If there are no documents available attesting to such pressure testing, the tank is unairworthy until it is tested in compliance with this FAR.

FAR 23.1015 is identical to FAR 23.965 for testing fuel tanks except for the required pressure.

If an IA discovers that repairs or alterations have been accomplished on any oil tank vessel, that oil vessel must be appropriately pressure tested to 5 psi to insure its integrity. Such oil vessels would included the kidney tanks on Continental 0-200 engines as well as the external oil tanks on early Bonanzas to name a few.

FAR 23.1191 covers inspection and repair to engine firewalls.

FAR 23.1191 is important to an IA when accomplishing Annual or Progressive inspections, and repairs to engine firewalls. Engine firewalls are required to be fireproof, as are any repairs or alterations to them. This FAR provides specific materials that are FAA approved for use in manufacturing, repairing, or altering firewalls. Further, fittings that penetrate the firewall must be fireproof as well. No aluminum fittings may be used.

End of Block Lesson Three

Now you have finished Block Three, 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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