56-17-03: Valve Tube
FAA order 56-17-03 is an airworthiness directive. The FAA's subject line: Valve Tube. System: engine.
What it applies to as the FAA lists it
- Kind of product
- Engine
- Makes
- Hartzell Propeller, Inc.
- Models
- HC-12X20-1, HC-12X20-2, HC-12X20-3, HC-12X20-4, HC-12X20-5, HC-12X20-6, HC-12X20-7, HC-12X20-8, HC-12X20-9
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 (1,080 characters)
56-17-03 HARTZELL: Applies to All Model HC-12X20 Reversing Propellers Installed on Downer (Republic) RC-3 Aircraft Having B-55 Valve Assembly.
Compliance required as soon as possible but not later than next 25 hours of operation and each 100 hours flight time thereafter.
There have been two reported instances of broken valve tube A-57. These failures were due to vibration of the valve assembly and the weakening effect of the valve porthole. Failure of this part will allow the propeller to go into reverse under certain conditions, forcing the airplane to land. In view of the possible serious consequences resulting from inadvertent reversal of the propeller, disassemble the valve and inspect the A-57 valve tube around the valve port with a magnifying glass or with magnetic inspection equipment. If no cracks are found, the sharp edges at the sides of the porthole should be rounded slightly, using a fine round file.
This inspection is not required for valve assembly B-299.
(Hartzell Service Bulletin No. 38 dated June 16, 1956, covers the 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/56-17-03.json · aircraft systems.