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

SE2004NM

A three planetary impeller drive, inconel exhaust valves, and other changes to improve engine reliability. Held by Tulare Aircraft Service, which holds 5 approved modifications in all. Last revised August 29, 1983. System: engine.

What it applies to

Kind of product
Engine
Design holder
Curtiss-Wright/Marquette Inc.
Models
Double Row Turbo Cyclone 972TC18DA1 (R-3350-34; -91)
Type certificate
E-272
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.