Sikorsky 92 incident near Galliano, Louisiana, January 19, 2011
On January 19, 2011 at about 5:34 pm local time, a Sikorsky 92 (helicopter), registered N920AL, suffered minor damage in an incident during approach near Galliano, Louisiana (South Lafourche Airport). It was flown under charter and air-taxi rules (Part 135). No one was hurt; 18 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The misalignment of the retaining washer during routine maintenance, resulting in the subsequent separation of the washer and nut.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 19, 2011 · about 5:34 pm local time
- Place
- Galliano, Louisiana · South Lafourche Airport · map
- Type
- Incident
- Injuries
- No one was hurt; 18 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky 92 A
- Registration
- N920AL · registry record · serial 920088
- Damage
- Minor damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
During the initial approach, as the airspeed decreased through about 70 knots, the helicopter began an uncommanded right yaw of more than 100 degrees, and the yaw could not be stopped by the application of left pedal. The crew diverted to a nearby airport and performed a successful roll-on landing, touching down at 72 knots using differential braking to maintain the runway heading. An after-landing inspection showed that the tail rotor pitch change beam retaining nut, pitch beam retaining washer, and associated screws and washers were missing. The remainder of the tail rotor assembly remained attached and did not depart the helicopter. Recent maintenance had been performed to replace the pitch change beam retaining nut and pitch beam retaining washer. According to maintenance personnel, the maintenance had been performed per the existing maintenance procedures, and the mechanics did not notice anything odd or out of place. Evidence of witness marks along with plastic deformation on the end faces of the pitch change shaft splines is consistent with the retaining washer installed with its indexing spline slightly off, resulting in a cocking condition and incomplete engagement of the spline teeth. Accordingly, there was likely an improper alignment of the components during reassembly, which would have prevented the nut from locking in place. Subsequent tests on an exemplar assembly showed that it was possible for the pitch beam retaining washer to be misaligned with the teeth on the shaft splines, which then showed barely visible evidence of the misalignment.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Aircraft maintenance event during prior to flight
- Aircraft inspection event during prior to flight
- Part(s) separation from AC
- Flight control sys malf/fail during approach defining event
- Flight control sys malf/fail during approach (VFR go-around)
- Off-field or emergency landing during landing
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Tail rotor drive system › Tail rotor drive shaft › Incorrect service/maintenance
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: single-engine land; instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 33,647 hours in all; 624 in this make and model; 70 in the last 90 days; 18 in the last 30 days; 23,485 as pilot in command; 244 on instruments
- Last flight review: July 10, 2010
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
Co-pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 21,677 hours in all; 799 in this make and model; 55 in the last 90 days; 14 in the last 30 days; 14,040 as pilot in command; 16 on instruments
- Last flight review: July 10, 2010
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 1,248 hours
- Last inspection: continuous airworthiness programme, January 17, 2011; 4 hours since
- Maximum gross weight: 26,500 lb
- Seats: 21
- Landing gear: retractable
- Engine 1: Ge CT7-8A (turboshaft); 0 hours total
- Engine 2: Ge CT7-8A (turboshaft); 0 hours total
- Operator: Bristow US LLC
The flight
- Departed from: Gulf Of Mexico LA at 4:30 pm
- Destination: 2LS0 Galliano LA
- Runway 36, 6,502 ft by 100 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 010° at 11 knots, gusting 15
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 59°F (15°C), dew point 46°F (8°C)
- Altimeter: 30.07 inHg
- Observation at 5:40 pm from KGAO
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 3 | |||
| Passengers | 15 |
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number CEN11IA156.