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

SE956GL

Superseded by STC SE01943CH. Add approved fuel: unleaded automotive gasoline, 87 minimum antiknock index. Held by Eaa Aviation Foundation, which holds 71 approved modifications in all. Last revised March 5, 2004. System: engine.

What it applies to

Kind of product
Engine
Design holder
Textron Lycoming AVCO Corporation; Textron Lycoming AVCO Corporation; Textron Lycoming AVCO Corporation; Textron Lycoming AVCO Corporation; Textron Lycoming AVCO Corporation; Textron Lycoming AVCO Corporation; Textron Lycoming AVCO Corporation; Textron Lycoming AVCO Corporation
Models
O-540-B2C5, O-540-B4A5, O-540-B4B5, O-540-B1A5, O-540-B1D5, O-540-B2A5, O-540-B2B5, O-540-B1B5
Type certificates
E-295, E-295, E-295, E-295, E-295, E-295, E-295, E-295
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.