ST01138DE
Installation of MidContinent MD23 standby altimeter and/or attitude indicators. Held by Butler National Corporation, which holds 18 approved modifications in all. Last revised July 27, 2024. System: instruments and avionics.
What it applies to
- Kind of product
- Aircraft
- Design holder
- Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.; Learjet Inc.
- Models
- 24, 24A, 24B, 24B-A, 24C, 24D, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F, 31, 31A, 35, 35A (C-21A), 36, 36A, 55, 55B, 55C, 60
- Type certificates
- A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE, A10CE
- On this site
- Learjet 24 16 registered
Learjet 25 23 registered
Learjet 31 119 registered
Learjet 35 161 registered
Learjet 55 67 registered
Learjet 60 239 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 13, 2026.