top of page

Block Lesson Two

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 Two Will Cover

  • FAR 21.41, Type Certificate.
  • FAR 21.93, Changes to Type Design.
  • FAR 21.175, Classification of Airworthiness Certificates.
  • FAR 21.181, Duration of Airworthiness Certificates.
  • FAR 21.183, Issuance of Standard Airworthiness Certificates.
  • FAR 21.9, Approval of Parts.
  • AC 20-62E, Acceptability of Parts.
  • FAR 21.9, PMA and Replacement Parts.
  • FAR 21.5O2, Approval of Foreign Parts.
  • FAR 21.601 TSO Parts.

Block Lesson Two Video

Inspection Authorization Refresher Training Lesson Two

What is FAR 21.41, Type Certificate? 

As the FAR states, each type certificate, is considered to include; the type design, the operating limitations, the certificate data sheet, the applicable regulations, and any other conditions or limitations prescribed for the product in this subchapter.

The actual Type Certificate is in fact, a document certifying by the FAA that all of the required tests in the FARs have been successfully completed. To actually manufacture the product, the FAA must issue a Production Certificate to the certificate holder, having found their production quality system in compliance with the FARs.

What does FAR 21.93 do?

It defines how changes can be made to, Type Design.

In addition, changes in type design are classified as minor and major.

A “minor change” is one that has no appreciable effect on

  • The weight
  • Balance
  • Structural strength
  • Reliability
  • Operational characteristics
  • or other characteristics affecting the airworthiness of the product.

All other changes are usually “major changes”.

Why is FAR 21.175 important?

FAR 21.175 defines the classification of FAA-issued Airworthiness Certificates. Standard airworthiness certificates are airworthiness certificates issued for aircraft type certificated in the normal, utility, acrobatic, commuter, or transport category, and for manned free balloons, and for aircraft designated as special classes of aircraft. 

Special airworthiness certificates are primary, restricted, limited, light-sport, and provisional airworthiness certificates, special flight permits, and experimental certificates. This FAR is important because an IA is not allowed privileges on aircraft with Special Airworthiness certificates such as any aircraft in the experimental category.

Standard Airworthiness Certificate

Block five defines the basis upon which the FAA has issued the certificate. It states, AUTHORITY AND BASIS FOR ISSUENCE. That is, it is in a condition for safe operation and complies with its Type Design.

Block 6 it states "TERMS AND CONDITIONS".

Why is FAR 21.181 important?

This FAR describes the validity and duration of an Airworthiness Certificate. If you refer to blocks five and six of the Standard Airworthiness Certificate you will discover two requirements:

  • First, block five defines the basis upon which the FAA has issued the certificate. It states AUTHORITY AND BASIS FOR ISSUENCE. That is, it is in a condition for safe operation and complies with its Type Design.

  • Second, in Block 6 it states "TERMS AND CONDITIONS".

With no expiration date for the certificate, provided the operation and maintenance are accomplished in compliance with relevant FARs. In other words, the aircraft is Airworthy by definition. If either element disappears, either through illegal alteration of the Type Design, or by failing to comply with relevant maintenance requirements, the certificate becomes invalid. If the owner or operator has insured the aircraft, every insurance policy has an exclusion clause in it that states the insurance is null-and-void, if the aircraft, at the time of a claim, was unairworthy. The Airworthiness Certificate must be maintained in a valid state at all times for the insurance to be in force. You can see the importance and responsibility on the part of an IA to accomplish inspections with integrity.

Why is FAR 21.183 important?

This FAR legally defines the elements that must be present in a brand new aircraft to be eligible for an Airworthiness Certificate. 

In short, it is the Birth Certificate of the Aircraft. For a new aircraft to be eligible it must conform to the FAA-approved Type Design, and be in condition for safe operation. You can see that this language right in this FAR defines the legal elements of the terms airworthy and airworthiness. This is where the entire process begins.

Cobalt issues "design-centric" small aircraft

Beechcraft 35 Bonanza 

Why is FAR 21.9 important?

This FAR lists the only four ways that the FAA uses to approve parts, when those parts require FAA approval under the FARs. Such parts requiring FAA approval can be found in the FARs that define the Certification Basis of the product such as, Car 3 or FAR 23Parts that do not specifically require FAA approval are only required to be acceptable to the FAA. These would include items such as common hardware and any other materials listed in a Type Certificate Holder’s maintenance instructions.

There are only four way's to approve a part when required:

  • One is through the Type Certificate Holder,
  • Two is through the TSO process,
  • Three is the Parts Manufacturer Approval process, or
  • Four by any other means acceptable to the FAA.

For example, all seats in a Type Certificated Aircraft must be FAA approved.

Most are FAA approved by TSO today, but many, such as the Bonanza for example, are FAA approved by the initial certification process.

PS Engineering PM 500EX 4 Place Mono Panel Mount Intercom  NON-TSO for Experimental Aircraft

FAA  AC20-62E is very important to an IA.

It defines, and provides examples of aircraft parts and materials found acceptable by the FAA for use on type certificated aircraft.

It lists the usual documentation that should be included by a supplier. It also provides examples of acceptable electrical materials that can be purchased commercially, like from Radio Shack, and used for minor aircraft repairs and alterations. These would include such items as transistors, diodes, and other standard electrical parts. As long as these parts are equal to the original and provide the same operational characteristics, they are acceptable for use. Also, the AC defines the potential installation of owner or operator produced electronic components such as kit audio panels. Since there are no TSO requirements in FAR 91.2O5 for TSO radio equipment for IFR, home-built audio panel kits would be acceptable for installation as long as all other structural and operational requirements are met.

Amateur-built Aircraft

PMA is not needed for Standard parts such as AN, MS, NAS, or SAE.

Piper Aluminum Engine Baffle

FAR 21.9 is very important to an IA for PMA parts

This is the FAR, that details the requirements for aircraft parts to meet when manufactured by other than the original "certificated" manufacturer.

Generally, anyone who manufactures a part for sale, for installation on a type-certificated aircraft must obtain an FAA Parts Manufacturer Approval, or PMA to do it legally. The keys here are that the producer must be offering the part for sale, and he must be specifically producing the part to install on a type certificated product. 

If the producer is selling parts made strictly for Experimental aircraft, such as Amateur built, there is no violation and PMA would not be required. 

However, there are several exceptions to the PMA rule such as:

  1. ) The Type Certificate or Production Approval holder, can produce any spare part under their FAA approval without needing a PMA.
  2. ) Parts manufactured to a TSO approval.
  3. ) Anyone producing standard parts, such as AN, MS, NAS, or SAE, does not require a PMA because these parts are the subject of published standards.
  4. ) Most parts that are produced by an owner, or operator for repairing, or altering any aircraft owned, or operated by them do not require PMA, provided the producer has, and uses all necessary current production data obtained from the type-certificate holder.

In other words, parts produced by an owner, or operator must be airworthy, meaning they meet the appropriate type design and are in condition for safe operation.

As an example, an owner can’t fabricate, and a mechanic can’t install a piece of new aluminum engine baffle, if it was fabricated without having the current production drawing from the type certificate holder. Without knowing what material and processes were used to make the original, the producer can’t possibly certify to its airworthiness, therefore rendering it illegal to install.

Note: Whenever mechanics install an owner-produced part, they should always make sure they indicate in the aircraft log or maintenance record that it was such a part.

FAR 21.502 is very important to an IA.

This FAR defines the requirements for introducing foreign made parts into the aviation industry in the United States.

Most developed countries with aviation industries, such as England, France, Germany, Canada, and Brazil, have Bi-Lateral Airworthiness Agreements with America. These agreements are in effect to accept each other’s fabricated aircraft products and parts. These products include complete aircraft, spare parts for aircraft, engines, and propellers.

One such example would be the Pratt and Whitney PT6 engine. This engine, in wide use in the United States, is produced in Canada. All of the parts on it are produced in Canada. One ongoing problem with the engine surrounds the fuel nozzles. They must be inspected, overhauled and flow-tested at certain frequencies. Each of these nozzles has a discreet serial number impressed on themHowever, many operators, in the interest of time, agree to exchange their nozzles for pre-maintained nozzles at repair stations. The problem is that you really are not assured that you are receiving legitimate Pratt and Whitney produced nozzles in the exchange. There have been reports of counterfeit nozzles available.

In conclusion, every foreign produced aircraft product is required to have the country of manufacture’s Certificate of Export shipped with the original part. Without a copy of this certificate, you have no guarantee that the part is legal.

Pratt & Whitney PT6 Engine

Pratt & Whitney Canada and the PT6 Engine - Hartzell Propeller 

BERLIN, GERMANY – MAY 21, 2014: Turboprop engine Pratt & Whitney Canada PT6A-

KX-170-B, TSO radio

Exchange King KX170B 

Air-path C-2200 compass, All compasses in the C-2200 series meet FAA TSO-C7c requirements

2 1/4" Panel Mount Magnetic Compass, non-TSO

FAR 21.9, TSO, as an exception to PMA.

FAR 21.9, is also very important, as it mentions Technical Standard Order approvals, TSO, as an exception to PMA. Further, FAR 45.15 requires holders of Technical Standard Order approvals, as well as PMA holders, to identify their approved parts.

If it is not identified as TSO, it isn’t TSO.

Also, there are big differences between TSO parts, and non-TSO parts.

For example, the King KX-170 non-TSO radio, and the KX-170-B, TSO radio are very different.

The KX-170-B, TSO radio, while having both communication and navigation functions, utilizes a separate crystal for each function. The KX-170, non-TSO radio, while having both communication and navigation functions, utilizes a single crystal for both functions. With the KX-170, non-TSO radio, if you lose the crystal, you lose both functions! Naturally the TSO radio is more expensive.

Another example are fluid compasses made by Air-path.

These are the most widely used non-stabilized compasses used in general aviation. Air-path produces both TSO compasses and non-TSO compasses. Each TSO compass bears the TSO identification and a serial number on the compass frame under the housing. TSO compasses are made to higher standards, especially the final testing, and are therefore more expensive. The non-TSO compasses are about two-thirds the price, but they appear identical. The compass is a minimum Day-VFR piece of gear required by FAR 91.205. 

If there is anything rendering the compass inoperative, the aircraft must be grounded. 

If your aircraft requires, for example, an Air-path C-2200 compass, it must be TSO.

However, there are plentiful non-TSO compasses being maintained and sold by instrument repair stations who neglect to inspect the compasses for the TSO identification, required by FAR 45.15.

These compasses are illegal for installation in type certificated aircraft.

End of Block Lesson Two

Now you have finished Block Two, 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!

bottom of page