SA303GL
Install Cleveland conversion kit No. 199-74 on models which use MIL-H-5606 brake fluid (red oil) or install conversion kit No. 199-74A on models which use Skydrol brake fluid (nonpetroleum base). Held by Parker Hannifin CORP, which holds 44 approved modifications in all. Last revised October 28, 1980. System: landing gear.
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; Twin Commander Aircraft Corporation; Twin Commander Aircraft Corporation; Twin Commander Aircraft Corporation
- Models
- 500-S, 500, 500-A, 500-U, 560-A, 560-E, 500-B
- Type certificates
- 6A1, 6A1, 6A1, 6A1, 6A1, 6A1, 6A1
- 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 8, 2026.