SR00135LA
Installation of Yehnert Tail Rotor Blades YH-278 as replacements for Hiller Tail Rotor Blades 55073. Held by Yehnert Helicopters, INC, which holds 4 approved modifications in all. Last revised December 15, 1995. System: rotorcraft systems.
What it applies to
- Kind of product
- Aircraft
- Design holder
- Hiller Aviation; Rogerson Hiller Corporation; Rogerson Hiller Corporation
- Models
- UH-12D (Army UH-23D), UH-12E-L, UH-12E
- Type certificates
- 4H10, 4H11, 4H11
- On this site
- Hiller UH-12 217 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.