HAMILTON STANDARD 14RF-9–ATA 6120 PROPELLER CONTROLLING SYSTEM–PROPELLER–OVERSPEED. DR 611852398
After take-off, RH propeller observed to be stabilised at 104%. Condition lever retarded, air return to departing base executed. Suspected transient Np limitation exceeded.
MCCAULEY PROPELLERS 4HFR34C778-1–ATA 6112 PROPELLER DE-ICE BOOT SECTION–CLAMP–MISSING. DR 611852404
During pre-flight inspection, TKS hose was found protruding outside the propeller spinner. Moreover, TKS hose clamp was found missing. Tube is straight with a hose clamped to it. Tube softens over time and hose comes off the tube. There is a need to flare the nozzle so that clamp is prevented from coming off. McCauley Propeller tech rep has been advised.
MCCAULEY PROPELLERS D3A34C404/80VA-0–ATA 6122 PROPELLER GOVERNOR–BEARING–DAMAGED. DR 611852409
Governor was disassembled and inspected for bearing condition, it was found that idler gear bearing cage has started to fail on one end. Several similar defects reports—CASA AWB 01-036 Issue 1 published 31/8/18.
DOWTY-ROTOL LIMITED R408/6-123-F/17–ATA 6120 PROPELLER CONTROLLING SYSTEM–PECU–SUSPECT FAULTY. DR 611852413
In flight, no. 2 PEC light illuminated and, shortly after, no. 2 RPM dropped to 320 for approx. 30 seconds and then rose to above 1020 RPM. Condition levers moved to max, autopilot left on, failure identified and confirmed. Trouble shooting identified fault codes 462, 424, 422, 198, 212, 224, 236, 362, 260, 400 and 320 present. Suspect no. 2 propeller electronic control unit (PECU) at fault. PECU replaced, follow-up tests satisfactory. Over speed condition data analysed and nil exceedance beyond AMM 05-11-00. Propeller determined to be serviceable. Strip report requested for removed components.
DOWTY-ROTOL LIMITED R408/6-123-F/17–ATA 6120 PROPELLER CONTROLLING SYSTEM–PCU–UNSERVICEABLE. DR 611852441
After take-off through between 600–1000 feet, crew experienced severe engine surging, power seemed to be going up and down constantly on no.2 engine. No. 2 engine shutdown, safe landing followed. Troubleshooting established propeller control unit (PCU) defective, over speed governor (OSG), PCU replaced, functional checks satisfactory. Strip report has been requested.
HARTZELL PROPELLERS HC-E4A-3A–ATA 6120 PROPELLER CONTROLLING SYSTEM–PROPELLER–Underspeed. DR 611852460
Shortly after setting climb power, LH engine propeller coarsened rapidly without any pilot input. Tq increased to 5000 ft-lbs for approximately 2 (two) seconds, with associated yaw. Normal operation then returned. Crew elected to return to departing base and uneventful approach and landing completed. Root cause: Nut migrated off a stud on the prop thrust bearing housing eventually impinging on the Beta feedback ring, inhibiting aft movement causing the engine to sense a false over-speed condition. Condition corrected itself when nut fell off the stud allowing normal operation. No recent maintenance in the vicinity was carried out. Preventive measures: Action to be added to AMP for one-time run-on torque check of bearing cover retaining nuts.
MCCAULEY PROPELLERS D3A34C404-C–ATA 6111 PROPELLER BLADE SECTION–MAIN ROTOR BLADE–CORRODED. DR 611852486
Propeller was removed after multiple areas of corrosion, including three (3) significant ‘corrosion pits’ were observed on a one blade face. Propeller replaced with serviceable item. Propeller has been sent to an overhaul facility for investigation and report.