ST01395CH-D
Installation of an AlliedSignal CAS-66A Traffic Alert and Collision Avoidance System (TCAS I). Held by Electrosonics, which holds 76 approved modifications in all. Last revised August 4, 2003. System: instruments and avionics.
What it applies to
- Kind of product
- Aircraft
- Design holder
- McDonnell Douglas Corporation; McDonnell Douglas Corporation; McDonnell Douglas Corporation; McDonnell Douglas Corporation
- Models
- DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G
- Type certificates
- 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.