20110119002029I

Incident · Minor damage

FAA incident report · Sikorsky S-92A · Galliano, LA · January 19, 2011

Date: January 19, 2011 · 11:40 local
Place: Galliano, LA
Airport: South Lafourche
Phase of flight: Landing: Approach
Operating rules: Air taxi and commuter (Part 135)
Operator: ALGA
Damage: Minor damage
Aircraft: N920AL
NTSB investigation: NTSBCEN11IA156
Reported as: Sikorsky S-92A
Reported engine: GE CT7-8A
People aboard: 18
Fatal injuries: 0
Other injuries: 0
Pilot’s flight hours: 0 total0 in this make and model0 in the last 90 days

N920ALRegistration cancelled Apr 8, 2011 · Sikorsky S-92AS/N 920088 · Built 2008 Airframe modelSikorsky S-92A Engine modelGE CT7-8ATurbo-shaft

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.

The tail rotor pitch change shaft was replaced 4.6 hours prior to this incident. It was determined that the pitch change beam retaining nut and lock washer were improperly installed at that time. During flight the pitch change beam retaining nut and washer lost torque and separated from the tail rotor assembly. The pitch change beam could no longer move with the pitch change shaft to apply pitch changes to the tail rotor blades causing a loss of tail rotor authority.

As the FAA filed it

THE TAIL ROTOR PITCH CHANGE SHAFT WAS REPLACED 4.6 HOURS PRIOR TO THIS INCIDENT. IT WAS DETERMINED THAT THE PITCH CHANGE BEAM RETAINING NUT AND LOCK WASHER WERE IMPROPERLY INSTALLED AT THAT TIME. DURING FLIGHT THE PITCH CHANGE BEAM RETAINING NUT AND WASHER LOST TORQUE AND SEPARATED FROM THE TAIL ROTOR ASSEMBLY. THE PITCH CHANGE BEAM COULD NO LONGER MOVE WITH THE PITCH CHANGE SHAFT TO APPLY PITCH CHANGES TO THE TAIL ROTOR BLADES CAUSING A LOSS OF TAIL ROTOR AUTHORITY.

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 CEN11IA156Incident · No injuriesIncident investigationFinal reportGalliano, LAThe misalignment of the retaining washer during routine maintenance, resulting in the subsequent separation of the washer and nut.Jan 19, 2011 · Minor damage