SAFARI AVIATION, INC.

Operated by Safari Aviation Inc. (per NTSB report)

WHILE CONVERTING AIRCRAFT CONFIGURATION FROM SINGLE PILOT CONTROLS TO DUAL PILOT CONTROLS FOR PILOT TRAINING, MECHANIC FOUND COLLECTIVE CONTROL SPRING, SPRING WASHER, AND COVER LEFT IN COLLECTIVE CONTROL BOX. PREVIOUS MECHANIC HAD CONVERTED AIRCRAFT FROM DUAL PILOT CONTROLS TO SINGLE CONTROLS ON 10/10/21 BY PULLING THE PIT PIN AND FAILED TO RETRIEVE THE SPRING, SPRING WASHER, PLATE. AN OCF WAS PERFORMED BEFORE FLIGHTS ON 10/11/21 WITH NO ISSUES NOTED.

PILOT REPORTED AN ELECTRICAL TYPE BURNING ODOR FOLLOWED BY LIGHT WISPS OF SMOKE FROM UNDER THE INSTRUMENT PANEL HOOD. FLIGHT WAS ABORTED, AND A PRECAUTIONARY LANDING WAS MADE, WHERE THE ACFT WAS SHUTDOWN AND REMOVED FROM SERVICE. UPON FURTHER INSPECTION BY MAINTENANCE IT WAS DETERMINED THE DIRECTIONAL GYRO HAD OVERHEATED. THE AFT COVER OF THE DIRECTIONAL GYRO HAD CRACKED ALLOWING OVERHEATED GREASE TO SEEP FROM THE CASE. IT WAS DETERMINED THAT THE GREASE WAS THE SOURCE OF THE ODOR, AND WAS PRESUMED TO BE THE SOURCE OF THE LIGHT SMOKE. INSPECTION OF ALL THE OTHER INSTRUMENT SYS REVEALED NO OTHER DAMAGE. THE DIRECTIONAL GYRO WAS DISABLED, AND THE ACFT WAS GROUND RUN WITH ALL SYSTEMS RUNNING FOR APPROXIMATELY 15 MINUTES. ALL SYSTEMS FUNCTIONED NORMAL, WITH NO FURTHER INDICATION OF ODOR, OR SMOKE. A SHORT MAINTENANCE FLIGHT WAS CONDUCTED TO RETURN THE ACFT TO BASE. ALL SYSTEMS FUNCTIONED NORMAL, WITH NO PROBLEMS NOTED. A SERVICEABLE DIRECTIONAL GYRO WAS INSTALLED, AND THE ACFT WAS RETURNED TO SERVICE.

DURING PREFLIGHT ENGINE WASH, ENGINE WOULD NOT ROTATE DURING STARTER ENGAGEMENT. FOUND ENGINE COMPRESSOR DIFFICULT TO TURN BY HAND, BUT COULD TURN USING FORCE. SUSPECTED FUEL COKING OF THE FUEL MANIFOLD LABRYNTH SEAL. DISASSEMBLED ENGINE, CONFIRMED COKING OF THE LABRYNTH SEAL. INSTALLED OVERHAULED FUEL MANIFOLD, REASSEMBLED ENGINE. ENGINE FUNCTIONED NORMAL WITH NO FURTHER PROBLEMS. PROBABLE CAUSE UNKNOWN. (K)

PILOT EXPERIENCED HYDRAULIC FAILURE IN FLIGHT. SPLINES BETWEEN HYDRAULIC PUMP AND DRIVING PULLEY FOUND WORN. SPLINES ARE GREASED EVERY 500 HOURS. TT 409.5 HOURS. SPLINE MAY NOT HAVE BEEN GREASED SUFFICIENTLY. WHEN AIRCRAFT WAS ASSEMBLED.

AIRCRAFT WAS ON FINAL APPROACH TO AIRPORT WHEN BATTERY OVER TEMP LIGHT ILLUMINATED. PILOT TURNED OFF GENERATOR SYSTEM AND LANDED. THE BATTERY WAS DISCONNECTED AND ALLOWED TO COOL. BATTERY WAS REPLACED WITH A SERVICEABLE UNIT. INSPECTION OF REMOVED BATTERY INDICATED LOW WATER LEVELS AND ONE DEAD CELL. AIRCRAFT HAD SAT FOR SEVERAL MONTHS WITHOUT BEING OPERATED, THEN RETURNED TO HEAVY, DAILY USAGE. RECOMMEND MORE FREQUENT CONDITION CHECKS OF BATTERIES INSTALLED IN AIRCRAFT.

ROD END WORN TO LIMITS. REPLACED TWO EACH. (X)

INPUT SEAL, MAIN ROTOR GEARBOX, LEAKING POST LIP. (X)

BLOWER MOTOR INOPERATIVE. (X)

TRANSMITTER READING TOO LOW, NOT ACCURATE. (X)

LEFT AND RIGHT MAIN ROTOR SERVO INPUT RODS (LOWER BEARINGS). REPLACED TWO EACH. (X)

BEARING DELAMINATING. (X)

CORRODED PINS AT DIFFERENT CANNON PLUGS AND CORRODED WIRES THROUGHOUT HARNESS. (X)

FUEL CONTROL CABLE ROUGH AND DIFFICULT TO MOVE. (X)

FORE AND AFT SERVO TOP ROD ENDS AND RIGHT LATERAL SERVO LOWER ROD END HAD WORN BEARINGS. (X)

TAIL ROTOR PITCH CHANGE ROD REMOVED DUE TO WEAR ON SPHERICAL BEARING IAW AD 98-4-35. REMOVED 2 EACH. (X)