19960919029369A

Accident · Substantial damage

FAA accident report · Bell 47G-4A · Belmont, MS · September 19, 1996

Date: September 19, 1996 · 12:45 local
Place: Belmont, MS
Phase of flight: Low Level Operations
Operating rules: Agricultural (Part 137)
Operator: ZMPG
Damage: Substantial damage
Aircraft: N23PH
NTSB investigation: NTSBATL96LA129
Reported as: Bell 47G4A
Reported engine: Allison 250C20B
Fatal injuries: 0
Pilot’s flight hours: 2,550 total924 in this make and model164 in the last 90 days

N23PHRegistration cancelled Aug 8, 2000 · Bell 47G-4AS/N 7506 Airframe modelBell 47G-4A

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry by N-number and event date, checked against the reported make and model; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

Aircraft lost control and crashed into trees. (.4)during an aerial application operation, the pilot was making east and west swath runs. He reported that he had dispensed about half of his load, when he noted a vibration in the tail rotor pedals during a turn-around maneuver. He conducted three more swath runs with the vibration becoming progressively worse during each turn-around. Subsequently, during the fourth turn-around, the tail rotor drive was lost when the tail rotor drive shaft aft universal joint failed. Examination of the universal joint revealed a lack of lubricant, and the tail rotor drive shaft was discolored blue. There was no log book entry to indicate that the universal joint had been lubricated in the 150 plus hours of operation since the last inspection. The manufacturer's recommended maintenance practices included lubrication of the universal joint after each 50 hours of operation.

As the FAA filed it

AIRCRAFT LOST CONTROL AND CRASHED INTO TREES. (.4)DURING AN AERIAL APPLICATION OPERATION, THE PILOT WAS MAKING EAST AND WEST SWATH RUNS. HE REPORTED THAT HE HAD DISPENSED ABOUT HALF OF HIS LOAD, WHEN HE NOTED A VIBRATION IN THE TAIL ROTOR PEDALS DURING A TURN-AROUND MANEUVER. HE CONDUCTED THREE MORE SWATH RUNS WITH THE VIBRATION BECOMING PROGRESSIVELY WORSE DURING EACH TURN-AROUND. SUBSEQUENTLY, DURING THE FOURTH TURN-AROUND, THE TAIL ROTOR DRIVE WAS LOST WHEN THE TAIL ROTOR DRIVE SHAFT AFT UNIVERSAL JOINT FAILED. EXAMINATION OF THE UNIVERSAL JOINT REVEALED A LACK OF LUBRICANT, AND THE TAIL ROTOR DRIVE SHAFT WAS DISCOLORED BLUE. THERE WAS NO LOG BOOK ENTRY TO INDICATE THAT THE UNIVERSAL JOINT HAD BEEN LUBRICATED IN THE 150 PLUS HOURS OF OPERATION SINCE THE LAST INSPECTION. THE MANUFACTURER'S RECOMMENDED MAINTENANCE PRACTICES INCLUDED LUBRICATION OF THE UNIVERSAL JOINT AFTER EACH 50 HOURS OF OPERATION.

NTSB investigation

The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.

NTSB ATL96LA129Accident · Minor injuriesLimited investigationFinal reportBelmont, MSfailure of the aft universal joint of the tail rotor drive shaft, due to inadequate lubrication by company maintenance personnel. A factor relating to the accident was the pilot's delay in discontinuing the flight after noting a progressively worse tail rotor…Sep 19, 1996 · Substantial damage