Civil Air Regulations (CAR)
Prior to 1926, access to flying was uncontrolled. No licensing or certification was required. By the middle of the 1920s, it became obvious that unregulated private and commercial flying was dangerous. There was a growing awareness and acceptance that regulation could improve safety and encourage growth in aviation. Therefore in 1926, the aviation industry requested Congress to enact federal legislation to regulate civil aviation. Thus, the Air Commerce Act of 1926 provided for the:
- Establishment of airways
- Development of aviation aids
- Investigation of aviation accidents
- Licensing of pilots
- Certification of aircraft
The Civil Air Regulations (CARs) were part of the original certification basis for aircraft first certified in the 1940s, 1950s, and 1960s by the Civil Aviation Authority (CAA). Therefore, the CARs may still be needed as a reference for these older aircraft or as a standard for minor changes to older aircraft designs. [Figure 2-11]
CAR 3—Airplane Airworthiness—Normal, Utility, Aerobatic, and Restricted Purpose Categories
As the name implies, this specific regulation is the basis for the current 14 CFR part 23 regulation [Figure 2-1]. It has the following subpart categories:
- A—Airworthiness Requirements
- B—Flight Requirements—General
- C—Strength Requirements—General
- D—Design and Construction—General
- E—Powerplant Installations—Reciprocating Engines
- F—Equipment
Some examples of CAR 3 aircraft are Piper PA 22, PA 28, PA 32, and Cessna 182, 195, and 310.

NOTE: The “CAR” acronym actually has two interpretations: Civil Air Regulations and Canadian Aviation Regulations. The technician must clearly understand the difference and recognize when one or the other is appropriate.
CAR 4a—Airplane Airworthiness
This regulation was originated in 1936 and last amended on December 15, 1952. The subparts included in this regulation are:
- A—Airworthiness Requirements
- B—Definitions
- C—Structural Loading Conditions, General Structural Requirements
- D—Proof of Structure
- E—Detail Design and Construction
- F—Equipment
- G—Powerplant Installation
- H—Performance
- I—Miscellaneous Requirements
Initially, this regulation was the basis for establishing the design requirements for virtually all produced aircraft in the 1930s, 1940s, and 1950s. Eventually CAR 3 evolved as the regulatory material specific to small aircraft,and CAR4a and b focused on regulatory requirements for large aircraft.
It is very important to review the TCDS for each aircraft. For example, The Cessna 140 was certified as a landplane under CAR 3, but under CAR 4a as a ski-plane or seaplane. Another example of a more current and larger aircraft is the Gulfstream 1159 and 1159A. The former is certified under CAR 4b, but the latter is certified to 14 CFR part 25.
Suspected Unapproved Parts (SUP)
There are four types of aircraft parts:
- Good parts with good paperwork
- Good parts with bad paperwork
- Bad parts with “good” (bogus) paperwork
- Bad parts with bad paperwork
The first of those listed represents properly authorized parts that, when properly installed, are approved parts, and the aircraft can be returned to service. The last of those listed represent unauthorized and unapproved parts. The technician should be alert for these and must never install them on an aircraft.
The center two categories of parts represent suspected unapproved parts. If either the physical part or the paperwork associated with the part is questionable, it is best to contact the shop foreman, shift supervisor, or the assigned quality individual to discuss your concerns. Suspected unapproved parts (SUPs) should be segregated and quarantined until proper disposition can be determined. Contacting the manufacturer of the product is a good way to start gathering the facts concerning the product in question. Refer to the current version of AC 21-29, Detecting and Reporting Suspected Unapproved Parts, for additional information. Current contact information for submitting a SUP Notification can be found at www.faa.gov.
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