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

SA157SO

Air-oil type main landing gear shock absorber. Held by Piper Aircraft CORP, which holds 11 approved modifications in all. Last revised January 1, 1960. System: landing gear.

What it applies to

Kind of product
Aircraft
Design holder
The New Piper Aircraft Inc.; The New Piper Aircraft Inc.
Models
PA-25 Series (Restricted Cat.), PA-25 Series (Normal Cat.)
Type certificates
2A10, 2A8
On this site
Piper PA-25 Pawnee 455 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 7, 2026.