SA4102SW
Installation of Airstair. Approved for installation on Boeing 707-138B, serial number 18334 ONLY. Held by S & K Engineering, which holds 3 approved modifications in all. Last revised December 1, 1999. System: other and general.
What it applies to
- Kind of product
- Aircraft
- Design holder
- The Boeing Company
- Models
- 707-100 Long Body
- Type certificate
- 4A21
- On this site
- Boeing 707 9 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 5, 2026.