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

SQ00338AT

Unison igniter leads, P/N9048222-101, 102, 103, 104, 105, 106. Held by Unison Industries, which holds 5 approved modifications in all. Last revised September 17, 1993. System: engine.

What it applies to

Kind of product
Engine
Design holder
Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.; Allison Engine Company Inc.
Models
250-B17C, 250-B17B, 250-B17E, 250-B15G, 250-B17, 250-C28B, 250-C28C, 250-C30, 250-C30G, 250-C30M, 250-C30P, 250-C30S, 250-C20, 250-C20F, 250-C20J, 250-C18, 250-C20R, 250-C18A, 250-C18B, 250-C18C, 250-C20R/4, 250-C20R/2, 250-C20R/1, 250-C20B
Type certificates
E10CE, E10CE, E10CE, E10CE, E10CE, E1GL, E1GL, E1GL, E1GL, E1GL, E1GL, E1GL, E4CE, E4CE, E4CE, E4CE, E4CE, E4CE, E4CE, E4CE, E4CE, E4CE, E4CE, E4CE
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 5, 2026.