What it approves
Vacuum system 121 and 121A. (Eligible only on engines with dampened crankshafts).
ADs that name this STC · 0
An AD can apply because an STC is installed, or mention one in its text.
No AD in this release names this STC
Supplemental type certificate · Marlin and Myron Harms
- Holder
- Marlin and Myron Harms · United States
- Status
- Current · Issued
- Status date
- January 1, 1960
- Product
- Aircraft · Single-Engine
- Certification basis
- Part 21
From FAA DRS. DRS record last changed December 6, 2025.