SP12WP
Installation of greaseless counterweight bearings. (3D 40-225, -277, -231, -235, -267, -271). Held by American Propeller Service, which holds 8 approved modifications in all. Last revised November 20, 1981. System: propeller.
What it applies to
- Kind of product
- Propeller
- Design holder
- Hamilton Standard Division
- Models
- 3D
- Type certificate
- 249
- 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.