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

SA113SO

Replacement brake linings on Grumman G-29 main landing gear brake shoes. Held by Miami Brake & Clutch Svc. Last revised January 16, 1967. System: landing gear.

What it applies to

Kind of product
Aircraft
Design holder
Grumman American Aviation Corporation; Grumman American Aviation Corporation; Grumman American Aviation Corporation
Models
G-21, G-21A (Army OA-9), G-21A
Type certificates
654, 654, 654
On this site
Grumman G-21 35 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 20, 2026.