Caravan Propeller Control & Diagnostics
Explore the named components, make a prediction, then connect the supplied result to the system. This workshop adds coached practice alongside the course handbook and assessed lab.
Caravan Hartzell propeller: governor, piston and beta feedback
The propeller lever selects a governed speed. The governor uses boosted engine oil to move the servo and blades toward lower pitch; springs and rotating counterweights act in the opposite direction as oil is released. Follow those forces and the separate mechanical beta feedback in a named Caravan installation. Propeller speed is expressed in revolutions per minute (RPM).
Oil force, opposing mechanical force and position feedback — simplified relationships
Recorded state: before the supplied change
Green outlines identify components named in the selected exercise record; they do not indicate a healthy component.
Named connections and what each arrow means
- Propeller lever and speed linkage → Primary governor and oil meteringPhysical relationship: Cable/linkage changes selected governor setting
- Engine oil and governor gear pump → Primary governor and oil meteringElectrical power: Governor pump supplies boosted engine oil
- Primary governor and oil metering → Servo piston, links and bladesElectrical power: Metered oil through transfer path: admit, block or release
- Feathering springs and counterweights → Servo piston, links and bladesPhysical relationship: Springs and rotating counterweights oppose servo oil
- Servo piston, links and blades → Beta ring, carbon block and reversing leverPhysical relationship: Servo movement carries rods and feedback ring
- Beta ring, carbon block and reversing lever → Primary governor and oil meteringPhysical relationship: Carbon block and reversing lever return beta position
Propeller lever and speed linkage
Transmit the selected propeller-speed setting to the primary governor.
Supplied record: Initial speed selected
How it works with the rest
The cockpit propeller lever changes the governor setting through its cable and linkage. It selects the speed the governing loop will seek within the available power and blade-angle range; it does not mechanically drive the hub piston. Beta/reverse coordination uses additional control and feedback relationships.
What the evidence must show
Compare the changed selected setting with actual governor oil direction, blade movement and speed response.
Selected: Propeller lever and speed linkage
Follow the change through the system.
Fictional record CP41-1 identifies the stated late Hartzell installation. The propeller is rotating steadily in normal governing, clear of blade-angle stops and operating restrictions. Engine power and external conditions remain steady; adequate power, boosted oil, transfer, mechanical freedom and intact linkage are supplied. Beta and feather are not selected. The recorded action moves the propeller lever toward a higher governed-speed setting. Predict the response before revealing the already supplied result.
Before the recorded change
The initial selected speed and actual speed agree. The new higher setting has not yet been applied in the displayed record; oil and mechanism prerequisites are supplied.
Next observation
Choose your prediction before revealing the supplied result.
Reference: Cessna D2078 Rev 42: 61-10-00 p.1, Dec 1/2012; 61-20-00 p.201, Sep 1/2014. Stated HC-B3TN-3AFX/T10890CNB branch and fictional normal-governing conditions only.
Course applicability and study references
Supplemental practice for the Cessna 208B5000-and-on Hartzell HC-B3TN-3AFX/T10890CNB aluminum installation described in supplied D2078 Revision 42. Actual fitted parts and modifications still select the applicable instructions. The early Hartzell composite and McCauley installations have their own component and inspection branches. These are fictional supplied records and original concept diagrams, not a geometry-accurate simulator, engine-run procedure or aircraft-work authorization. Existing graded work and saved records remain separate.
- Oil, servo and opposing forces
Supplied Cessna Model 208 MM D2078 Revision 42, Chapter 61 LEP May 1/2024: Hartzell 61-10-00 p.1, Dec 1/2012, and McCauley 61-11-00 p.1, Dec 1/2015. The scenes select the late Hartzell aluminum installation rather than transferring component-specific inspection limits between propellers.
- Governor and mechanical beta feedback
Hartzell 61-10-00 p.1 and 61-20-00 p.201, Sep 1/2014. Oil/force direction, three-rod ring/carbon-block/reversing-lever feedback and distinct primary/beta/overspeed purposes. The normal oil-control and beta-feedback roles remain distinct from the separate overspeed unit.
- Existing accepted course
TM-041 Rev B architecture, eight component-purpose cards, six prediction/Apply exercises and guided mechanical cases remain the baseline. These additional scenes supply qualitative conditions and observations for the named installation.
Original learning diagrams and supplied training records explain the stated relationships. Current aircraft-effective instructions and authorization govern actual maintenance.