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

SA2451SW

Installation of Marathon Battery Co. part 85-0050, or 85-0060 six cell magnesium emergency light pack. Held by Marathon Power Tech CO, which holds 11 approved modifications in all. Last revised May 19, 1994. System: electrical power.

What it applies to

Kind of product
Aircraft
Design holder
The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company; The Boeing Company
Models
707-300 Series, 707-300B Series, 707-300C Series, 707-400 Series, 727 Series, DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32 (VC-9C), DC-9-32, DC-9-32F (C-9A), DC-9-32F (C-9B), DC-9-32F, DC-9-33F, DC-9-34, DC-9-34F, DC-9-41, DC-9-51, DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87)
Type certificates
4A26, 4A26, 4A26, 4A26, A3WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE, A6WE
On this site
Boeing 707 9 registered
Boeing 727 37 registered
Douglas DC-9 7 registered
Mcdonnell Douglas DC-9 93 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 20, 2026.