SE03498AT
Conversion of Lycoming IO-540-D4B5 to Alamo Aerospace Model IO-540-D4B5-AA that has the same performance ratings and limitations as Lycoming Model IO-540-D4B5. Held by Air Plains Services Corporation, which holds 35 approved modifications in all. Last revised August 14, 2018. System: engine.
What it applies to
- Kind of product
- Engine
- Design holder
- Lycoming Engines
- Models
- IO-540-D4B5
- Type certificate
- 1E4
- 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 8, 2026.