- Date
- August 26, 1996
- Place
- Guam
- Injuries
- 1 fatal
- Damage
- Destroyed
- Phase of flight
- Enroute
- Aircraft
- N474GABell 47-G4A
- Weather
- Visual (VMC) · Day
- Status
- Completed · report August 25, 1997
- Report
- Approved by Office Director
- FAA report
- 19960826023799A
- Case key
- 29543
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
loss of tail rotor control due to improper maintenance.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The pilot was towing a banner offshore. Witnesses reported everything was normal until the banner fell free from the helicopter. At that point the helicopter started rotating to the right and descended into the bay. During the on-scene investigation, the retaining nut for the universal joint to yoke assembly on the tail rotor drive was found not engaged but retained the safety wire. The safety wire was broken on the last twist prior to entering the universal's affixing hole. The solid drive pin located in the aft universal and through the drive shaft was missing.
Factual narrative
On August 26, 1996, about 1115 hours local Guam standard time, a Bell 47-G4A, N474GA, was destroyed during a banner towing operation at Apra Harbor, Guam. The pilot was fatally injured. Visual meteorological conditions prevailed for the local area flight. The flight originated from a helipad at Tamuning, Guam, at 1030.
According to witnesses, the helicopter was towing a banner about 200 feet msl at 30 to 35 miles per hour. Everything appeared to be normal until the banner fell free from the helicopter. At that point, the helicopter started to rotate to the right and descend. The banner entered the water before the helicopter. The helicopter continued rotating to the right until it impacted the waters of Apra Harbor.
According to an FAA inspector on scene during the recovery, the retaining nut for the universal joint to yoke on the tail rotor drive was not engaged but retained the safety wire. The safety wire was broken on the last twist prior to entering the universal joint's affixing hole. The solid drive pin located in the aft universal joint and through the drive shaft was missing.
Aircraft
- Registration
- N474GA
- Reported as
- Bell 47-G4A
- Category
- Helicopter
- Serial number
- 7580
- Airframe hours
- 2,378
- Engine
- Lycoming VO-540, 305 horsepower, reciprocating
- Damage
- Destroyed
- Flight
- Business · Part 91
- Operator
- Hansen Helicopters Inc., doing business as Fanihi Air Service
- Registered owner
- Fanihi Air Service
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · May 17, 1996 · 10 hours before
- Departed
- NONE · Tamuning, OF
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 33
- Certificate
- Commercial
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Left
- Toxicology
- Performed
- Flight hours
- 2,750 total · 5 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 290° at 6 knots
- Visibility
- 7 statute miles
- Lowest ceiling
- None
- Temperature
- 88 °F, dew point 75 °F
- Altimeter
- 29.00 inHg
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.