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

SA3887WE

Installation of two Howell H900 solid state exhaust gas temperature indicators. Held by Northwest Airlines, INC., which holds 29 approved modifications in all. Last revised November 14, 1986. System: engine.

What it applies to

Kind of product
Aircraft
Design holder
McDonnell Douglas Corporation
Models
DC-9-30 Series
Type certificate
A6WE
On this site
Mcdonnell Douglas DC-9 93 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 21, 2026.