ST53CH
Replacement of McD PN 4642526 compressor check valve flapper assembly with ABX Air, PN A04574. Held by Abx Air Incorporated, which holds 64 approved modifications in all. Last revised April 17, 2013. System: engine.
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; McDonnell Douglas Corporation
- Models
- DC-8-63F, DC-8-63, DC-8-62F, DC-8-62, DC-8-61F, DC-8-61
- Type certificates
- 4A25, 4A25, 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 8, 2026.