Caravan PT6A-114/-114A Engine-Control Rigging
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.
PT6A-114/-114A cambox, FCU pickup and cutoff
Follow the earlier Caravan power, condition and propeller paths to the fuel control unit (FCU). Ng means gas-generator speed. Then predict what a supplied correction can establish before comparing its actual work record. A cockpit position, a felt pickup point, a physical stop and a running speed answer different questions.
Earlier Caravan command and response paths — select a component to inspect its purpose
Green outlines identify components named in the selected exercise record; they do not indicate a healthy component.
Named connections and what each arrow means
- Power lever → Cable and cambox track pointPhysical relationship: Power cable transmits lever motion
- Cable and cambox track point → FCU arm and interconnect rodPhysical relationship: Cambox actuating lever and interconnect rod
- Condition lever and cutoff cable → FCU fuel scheduling and propeller loadPhysical relationship: Separate FCU idle/cutoff linkage input
- Cable and cambox track point → Beta linkage and feedback ringPhysical relationship: Reversing cam and beta cable branch
- FCU arm and interconnect rod → FCU fuel scheduling and propeller loadInformation / signal: FCU demand influences fuel scheduling
- Beta linkage and feedback ring → FCU fuel scheduling and propeller loadPhysical relationship: Blade-angle control changes propeller load
Power lever
Select forward power and the beta/reverse command.
How it works with the rest
The cockpit lever transmits motion through the power cable to the cambox. Its visible position does not establish the engine-end datum, freedom throughout the cable range or FCU stop contact.
What the evidence must show
Compare cockpit movement with actual cambox return and engine-end movement.
Selected: Power lever
Follow the change through the system.
Fictional record C47-1: a PT6A-114A Caravan has had power-cable work. The engine is stopped. The disconnected cockpit cable moves freely from IDLE to MAX and back. When connected in the as-found arrangement, the cambox follower does not return to its track point. No FCU internal stop is adjusted. The supplied action establishes the source-defined cambox/cable reference and repeats the permitted sweep.
Before the recorded change
Cable freedom: satisfactory. Connected track-point return: unsatisfactory. FCU pickup clearances and MAX endpoint proof: not yet recorded.
Next observation
Choose your prediction before revealing the supplied result.
Reference: Cessna D2078 Rev.42: 76-10-03 pp.507–513, Jan 1/2018 (source PDF 3795–3801).
Course applicability and study references
Earlier Cessna Model 208/208B with an identified PT6A-114 or PT6A-114A. This formative supplement uses original simplified concept diagrams and fictional supplied work records. Diagram positions are not installed geometry; observations are supplied, not calculated from rod turns. Grand Caravan EX/PT6A-140 and conversions require their own instructions. Physical work uses current applicable aircraft and referenced engine instructions.
- Earlier Caravan control architecture
Supplied Cessna D2078 Revision 42, June 1, 2024; 76-10-00 pp.1–2, Dec 3/2001. Power/cambox/FCU, condition/cutoff and beta-feedback relationships. Individual task dates and installed-engine applicability remain separate.
- Mechanical reference, pickup and endpoint tasks
Cessna 76-10-03 pp.507–518, Jan 1/2018. Actual task text supports the named setup, two different measuring interfaces, fresh endpoint checks and cutoff hard-stop/cushion proof. Original concept drawing does not reproduce installation geometry.
- Named running adjustment context
Cessna 76-10-02 pp.506–509, Jul 1/2016. Loaded LOW-IDLE and separate HIGH-IDLE adjustment contexts. The fictional records supply observations; no RPM-per-turn behavior is invented.
Original learning diagrams and supplied training records explain the stated relationships. Current aircraft-effective instructions and authorization govern actual maintenance.