SA237SO

Modification of the control wheel. Held by Riley Aircraft CORP, which holds 31 approved modifications in all. Last revised November 29, 1984. System: landing gear.

What it applies to

Kind of product: Aircraft
Design holder: The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company; The Cessna Aircraft Company
Models: 310D, 310G, 310E (USAF U-3B), 310C, 310B, 310A (USAF U-3A), 310, 310F, 320-1, 320
Type certificates: 3A10, 3A10, 3A10, 3A10, 3A10, 3A10, 3A10, 3A10, 3A25, 3A25
On this site: Cessna 310 1,410 registered
Cessna 320 137 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.