ASN Wikibase Occurrence # 165140
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| Date: | Sunday 30 March 2014 |
| Time: | 11:30 |
| Type: |  Bell 47G-3B-1 Turbo |
| Owner/operator: | Lazy 7 Agricultural Services Llc |
| Registration: | N147WT |
| MSN: | 2920 |
| Year of manufacture: | 1964 |
| Total airframe hrs: | 3280 hours |
| Engine model: | Lycoming TVO-435-B1 |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | West of Moody, near Oglesby, Texas -
 United States of America
|
| Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
| Nature: | Survey |
| Departure airport: | Gatesville, TX (GOP) |
| Gatesville, TX (GOP) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The pilot reported that, during an en route climb in the helicopter, he increased the throttle and noticed a “slight resistance.” Shortly after, the throttle freed up, but it was ineffective; there was no corresponding change in engine power when he moved the throttle control. Both the engine and rotor rpm were indicating in the green, but they began to decrease when he adjusted the collective. When he stopped moving the collective, the engine and rotor rpm increased rapidly and continued to accelerate. The pilot initiated an autorotation and cut off the fuel. The pilot then increased the collective, and the helicopter yawed left, touched down, and rolled over to the right, which resulted in the tailboom separating.
A postaccident examination of the helicopter revealed that the throttle control adapter had disconnected from the serrated shaft on the carburetor. The retention screws on the throttle control adapter were not safety wired to the carburetor idle stop lever as required in the helicopter manufacturer’s maintenance manual. A review of maintenance records revealed that the carburetor was removed and replaced about 1 1/2 years before the accident and that the helicopter’s last annual inspection was conducted about 4 1/4 months before the accident.
Probable Cause: Maintenance personnel’s failure to safety wire the throttle control adapter per maintenance instructions when the carburetor was replaced and to detect that the adapter was not safety wired during the annual inspection, which resulted in the throttle control disconnecting and subsequent loss of engine control.
Accident investigation:
 |
|
Sources:
NTSB
FAA register: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=147WT
History of this aircraft
Other occurrences involving this aircraft
| 11 November 1964 | N1125W | Bauman Helicop | 0 | Santa Ana CA | |
w/o |
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 31-Mar-2014 08:49 | Alexander Wyche | Added |
| 31-Mar-2014 10:21 | Anon. | Updated [Aircraft type] |
| 31-Mar-2014 10:49 | harro | Updated [Aircraft type] |
| 31-Mar-2014 17:51 | Geno | Updated [Aircraft type, Registration, Cn, Location, Source] |
| 03-Apr-2014 15:54 | Geno | Updated [Time, Operator, Phase, Nature, Source] |
| 21-Dec-2016 19:28 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 29-Nov-2017 13:46 | ASN Update Bot | Updated [Operator, Other fatalities, Departure airport, Destination airport, Source, Narrative] |
Corrections or additions? ... Edit this accident description
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