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

ST753SO

Installation of main cabin equipment to provide accommodations for 137 passengers (12 first class and 125 tourist class). (727-225). Held by Eastern Airlines, INC, which holds 42 approved modifications in all. Last revised August 4, 1976. System: cabin, seats and restraints.

What it applies to

Kind of product
Aircraft
Design holder
The Boeing Company
Models
727
Type certificate
A3WE
On this site
Boeing 727 37 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.