47-21-20: Oil Pressure Gage Line Restrictor
FAA order 47-21-20 is an airworthiness directive. The FAA's subject line: Oil Pressure Gage Line Restrictor. System: other and general.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- Sky Enterprises, Inc.
- Models
- RC-3
Dates and paperwork
- Docket
- Unknown
- Status
- Current
- The FAA's document
- Read the order on the FAA's site
The order itself the regulatory text, as published
Show the full text (580 characters)
47-21-20 REPUBLIC: (Was Mandatory Note 10 of AD-769-2.) Applies to Model RC-3 Aircraft Serial Numbers 426 Through 484, Except 446, 447, 452, 455, 460, 468, 471, 473, 475, 480, 481 and 483.
Compliance required not later than the next 25 hours of operation subsequent to July 1, 1947, and in any case not later than September 1, 1947.
In order to prevent excessive loss of oil through oil pressure gage line in case of its failure, install a restrictor fitting at the engine end of that line.
(Seabee Service Bulletin No. 13, dated March 17, 1947, covers this same subject.)
Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of November 6, 2026. Connections as data: /graph/directive/47-21-20.json · aircraft systems.