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

SA420SW

Install Dual Collins FD-108 flight director system replacing Collins ID -105 Flight Director System having dual instrumentation with single steering computer. Held by Braniff Airways INC, which holds 7 approved modifications in all. Last revised June 26, 1969. System: other and general.

What it applies to

Kind of product
Aircraft
Design holder
The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company
Models
707-100B Long Body, 707-100B Short Body, 707-200, 720 Series
Type certificates
4A21, 4A21, 4A21, 4A28
On this site
Boeing 707 9 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 8, 2026.