SA421NW
Removal of passenger configuration interior items and installation of a cargo door. (DC-8-51 SN 45648 only) (DC-8-21 SNs 45422-45427, 45429-45431, 45433-45437 only). Held by Plattner, LLC, which holds 3 approved modifications in all. Last revised June 9, 1999. System: cabin, seats and restraints.
What it applies to
- Kind of product
- Aircraft
- Design holder
- McDonnell Douglas Corporation; McDonnell Douglas Corporation; McDonnell Douglas Corporation; McDonnell Douglas Corporation
- Models
- DC-8-51, DC-8-32, DC-8-21, DC-8-33
- Type certificates
- 4A25, 4A25, 4A25, 4A25
- On this site
- Douglas DC-8 6 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.