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

SA1033SO

Replace existing nickel-cadmium batteries with Teledyne Gill BB638/T series lead-acid batteries. Held by Teledyne Battery Products, which holds 56 approved modifications in all. Last revised August 25, 1992. System: electrical power.

What it applies to

Kind of product
Aircraft
Design holder
Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.
Models
Learjet 28, Learjet 35 Series, Learjet 29, Learjet 24 Series, Learjet 25 Series, Learjet 36 Series, Learjet 23
Type certificates
A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A5CE
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.