SA4974NM
Installation of Jacobs Model R-755-9, -A2 or B2 engine with Hamilton Std 2B20/6135-15 propellers. Held by Radial Engines LTD, which holds 5 approved modifications in all. Last revised May 1, 2008. System: propeller.
What it applies to
- Kind of product
- Aircraft
- Design holder
- Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division; Boeing Airplane Company Wichita Division
- Models
- 75 (Army PT-13), A75 (Army PT-13A; -13B; -13C), A75J1 (Army PT-18), A75L3, A75N1 (Army PT-17; -17A; Navy N2S-1; -4), B75 (Navy N2S-5), B75N1 (Navy N2S-3), D75N1 (Army PT-27), E75 (Army PT-13D; Navy N2S-5; PT-13D/N2S-5)
- Type certificates
- A-743, A-743, A-743, A-743, A-743, A-743, A-743, A-743, A-743
- On this site
- Boeing 75 18 registered
Boeing A75 Stearman Kaydet 979 registered
Boeing B75 Stearman Kaydet 257 registered
Boeing D75 35 registered
Boeing E75 Stearman Kaydet 343 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.