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

ST01331AT

Installation of the AlliedSignal Enhanced Ground Proximity Warning System. (757-200 S/N 22918, 22919, 25013, 25035). Held by Delta Airlines INC, which holds 209 approved modifications in all. Last revised April 2, 1997. System: other and general.

What it applies to

Kind of product
Aircraft
Design holder
The Boeing Company
Models
757-200
Type certificate
A2NM
On this site
Boeing 757 440 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.