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

SA8599SW

Installation of left (right) hand forward inboard fuel tank bladder cells, P/N DF060-507 (LH) and 508(RH) as a replacement for original bladders P/N 5630060-507 (508). Held by Floats & Fuel Cells, which holds 17 approved modifications in all. Last revised July 31, 2002. System: fuel system.

What it applies to

Kind of product
Aircraft
Design holder
Twin Commander Aircraft Corporation; Twin Commander Aircraft Corporation; Twin Commander Aircraft Corporation; Twin Commander Aircraft Corporation
Models
690B, 685, 690, 690A
Type certificates
2A4, 2A4, 2A4, 2A4
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.