20090906019909A

Accident · Destroyed

FAA accident report · Bolkms BO-105S · Thibodaux, LA · September 6, 2009

Date: September 6, 2009 · 14:02 local
Place: Thibodaux, LA
Airport: Transco Schriever
Phase of flight: Hovering
Operating rules: General operating rules (Part 91)
Operator: UOGA
Damage: Destroyed
Aircraft: N131EH
NTSB investigation: NTSBCEN09LA571
Reported as: Bolkms BO105S
People aboard: 1
Fatal injuries: 0
Other injuries: 0
Pilot’s flight hours: 10,033 total1,969 in this make and model0 in the last 90 days

N131EHRegistration cancelled Mar 22, 2012 · Messerschmitt-Boelkow-Blohm BO-105SS/N S-595 · Built 1982 Airframe modelMesserschmitt-Boelkow-Blohm BO-105S Engine modelAllison 250-C20 seriesTurbo-prop

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 pilot reported that the helicopter entered and un-commanded right bank and right drift during hover. The pilot was unable to arrest the bank with full left input to the cyclic control. The skids impacted the ground and the helicopter rolled on to its right side. The purpose of the flight was to perform an operational check for maintenance performed on the cyclic control system. A mechanic had removed and replaced the lower lateral and longitudinal control tubes for the cyclic control system prior to this flight. It is suspected that mechanic had installed the control tubes in the wrong position during reinstallation (I.e. lateral in the longitudinal position). The control tubes are indentical; however, the rigging adjustments are different. It is suspected that the reversal of the control tubes created an out of righ condition, resulting in the helicopter being uncontrollable.

As the FAA filed it

THE PILOT REPORTED THAT THE HELICOPTER ENTERED AND UN-COMMANDED RIGHT BANK AND RIGHT DRIFT DURING HOVER. THE PILOT WAS UNABLE TO ARREST THE BANK WITH FULL LEFT INPUT TO THE CYCLIC CONTROL. THE SKIDS IMPACTED THE GROUND AND THE HELICOPTER ROLLED ON TO ITS RIGHT SIDE. THE PURPOSE OF THE FLIGHT WAS TO PERFORM AN OPERATIONAL CHECK FOR MAINTENANCE PERFORMED ON THE CYCLIC CONTROL SYSTEM. A MECHANIC HAD REMOVED AND REPLACED THE LOWER LATERAL AND LONGITUDINAL CONTROL TUBES FOR THE CYCLIC CONTROL SYSTEM PRIOR TO THIS FLIGHT. IT IS SUSPECTED THAT MECHANIC HAD INSTALLED THE CONTROL TUBES IN THE WRONG POSITION DURING REINSTALLATION (I.E. LATERAL IN THE LONGITUDINAL POSITION). THE CONTROL TUBES ARE INDENTICAL; HOWEVER, THE RIGGING ADJUSTMENTS ARE DIFFERENT. IT IS SUSPECTED THAT THE REVERSAL OF THE CONTROL TUBES CREATED AN OUT OF RIGH CONDITION, RESULTING IN THE HELICOPTER BEING UNCONTROLLABLE.

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 CEN09LA571Accident · Minor injuriesLimited investigationFinal reportThibodaux, LAThe pilot's inability to maintain control due to the mechanic's inadvertent switching of two cyclic control tubes of different lengths during maintenance.Sep 6, 2009 · Substantial damage