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

SA1-14

Relocation of airspeed pitot head. Held by Reading Avn Svc INC, which holds 15 approved modifications in all. System: instruments and avionics.

What it applies to

Kind of product
Aircraft
Design holder
McDonnell Douglas Corporation
Models
Super DC-3
Type certificate
6A2
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 7, 2026.