The U.S. aircraft register, updated daily
Approved modifications · supplemental type certificate · current · reissued

SA3-690

Installation of Doyn Kit No. 1400 Swept-Tail Assembly per Doyn Drawing No. 1400, Revision B, dated August 18, 1961. Held by D'Shannon Products LTD., which holds 118 approved modifications in all. Last revised August 16, 2011. System: airframe structure.

What it applies to

Kind of product
Aircraft
Design holder
Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company; Cessna Aircraft Company
Models
172, 172A, 172B, 172C, 172D, 172E, 172F (USAF T-41A), 172G, 172H (USAF T-41A), 172I, 172K, 172L, 172M, 172N, 172P, 172Q, 172R, 172S
Type certificates
3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12, 3A12
On this site
Cessna 172 Skyhawk 20,669 registered
The FAA's record
On the FAA's site

What an approved modification is

A supplemental type certificate is the FAA's approval of a change to a certified design: a new engine or propeller, avionics, an autopilot, floats, a parachute, a larger fuel tank, an ice-protection kit. The company holding it may sell the kit and the paperwork to owners of the listed models; the modification then becomes part of that aircraft's record. The FAA's list says what was approved and for which models, not how many aircraft carry it.

Source: FAA supplemental type certificates (Dynamic Regulatory System). Register counts from the FAA register of October 5, 2026.