SA133AL
Installation of flap actuated landing gear aural warning device. Held by Reeve Aleutian Airways INC, which holds 2 approved modifications in all. Last revised January 1, 1960. System: landing gear.
What it applies to
- Kind of product
- Aircraft
- Design holder
- McDonnell Douglas Corporation; McDonnell Douglas Corporation; McDonnell Douglas Corporation; McDonnell Douglas Corporation; McDonnell Douglas Corporation
- Models
- DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-S4C4G
- Type certificates
- A-669, A-669, A-669, A-669, A-669
- On this site
- Douglas DC-3 155 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.