TYPE CERTIFICATES, GROUP 2, AND THE APPROVAL PROCESS
The Department of Commerce Aeronautics Branch, established in May 1926, had issued the first Air Commerce Regulations on 31 Dec 1926 which detailed how a manufacturer obtained a type certificate. The federal government than issued the first Approved Type Certificate (ATC) on 19 March 1927.
Although the rules seemed fairly basic and straightforward, obtaining a type certificate proved somewhat difficult. In 1927, the Aeronautics Branch suffered from limited resources in terms of budgets and staff. To simplify and expedite approvals of type certificates, in October 1927, the Branch required aircraft manufacturers to meet minimum engineering standards set forth in detail in a new handbook. However, manufacturers still had to send blueprints and engineering data to the Branch for examination by its engineering section. If the data conformed to the standards, a Branch inspector went to the factory to determine if the manufacturer adhered to the approved design and specification. If the inspector found no issues, one aircraft of the type being manufactured underwent flight tests – first by a company pilot and then by a federal inspector. If the aircraft passed the flight tests, the Department of Commerce issued a type certificate.
There were two different approval paths a manufacturer could pursue. The Approved Type Certificate was issued when the manufacturer intended to produce a large number of essentially the same airplane. The second was the Group 2 Approval (or as known back then, “the -2’s”) which was a type certificate issued for a limited number of airplanes, for example a weight increase to only a few individual airplanes. The approval process is essentially the same as that of an aircraft built under the type certificate process except that a more rigid inspection of the airplane is conducted when the factory facilities have not previously been approved.