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

SA1787NM

Installation of two Hartzell HC-B3TN-3B/T10178B-10Q propellers on PA-31T PA-31T airplanes equipped with PWC PT6A-28 and PT6A-11 engines. Held by Aero Air INC, which holds 4 approved modifications in all. Last revised February 6, 1986. System: propeller.

What it applies to

Kind of product
Aircraft
Design holder
Piper Aircraft Inc.; Piper Aircraft Inc.
Models
PA-31T, PA-31T1
Type certificates
A8EA, A8EA
On this site
Piper PA-31 Navajo and Chieftain 935 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 22, 2026.