Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Lahaina, Hawaii 96761
Thursday, January 5, 2006 9:45 HST
NTSB Narrative Summary Released at Completion of Accident
The pilot reported that he heard the main rotor low speed warning horn, and saw that the rotor speed was decreasing. He entered into an autorotation to make a forced landing and tried to regain engine torque and rotor speed, but was unsuccessful and the low rotor horn sounded again. He lowered the collective and flared for landing. The helicopter came down in trees, with the main rotor blades contacting the treetops.
The helicopter was equipped with an on board video recording system that also recorded audio channels. Sound spectrum analysis of the audio recording confirmed the main rotor system speed decay consistent with the pilot's report. The power plant mechanical components: Hydro-Mechanical Unit (HMU), Digital Engine Control Unit (DECU), Engine Back-up Control Ancillary Unit (EBCAU), and Anticipator System Collective Potentiometer (XPC) were tested individually and no abnormalities were found within any component. Visual inspection of the DECU-XPC wiring harness showed very little external damage. Further examination and testing of the wiring harness revealed a loss of internal shielding continuity and shorts between a wire and the shielding.
No evidence of lightning strike damage was found in any of the wiring. Faults in the manufacturing assembly of one of the XPC harness backshells were also discovered. Further examination and testing revealed the insulation breakdown was a result of wire damage due to a tight bend in the harness, located about 80 and 90 cm from the rear of the connector (potentiometer side).
It was discovered that the AS350B3 and EC130B4 XPC cables (a part of the aircraft wire harness) had been manufactured with extra length to accommodate multiple installation configurations. The length of the accident helicopter's harness was longer than necessary, and it had been bent in a tight radius during aircraft production to accommodate the extra length in during installation. The wiring faults resulted in a gradual, intermittent decay of the XPC signal to the DECU. A review of the DECU design with the manufacturer confirmed that the DECU logic would not detect the XPC signal shift error, such as occurred in this event, which would cause an uncommanded and undetected loss of rotor speed. The aircraft flight manual only contains emergency procedures for a decrease in main rotor speed below 360 rpm when it corresponds with an engine failure. The aircraft flight manual does not address an intermittent XPC signal failure.
As a result of the investigation, on March 13, 2009, Eurocopter issued Alert Service Bulletin No. 76.00.18, which called for a modification to eliminate the potential for NR drop in flight - Slow drift in the XPC anticipator (collective pitch signal) on AS350B3 and EC130B4 helicopters.
NTSB Probable Cause Narrative
An intermittent electrical continuity failure and short of the DECU-XPC wiring harness, which resulted in an uncommanded and an initially undetected engine deceleration and a resulting loss of main rotor rpm. Also causal was the manufacturer's inadequate installation of the wiring harness at the time of manufacture.
Event Information
| Type of Event | Accident |
| Event Date | 1/5/2006 |
| Event Day of the Week | Thursday |
| Time of Event | 945 |
| Event Time Zone | Hawaii Standard Time |
| Event City | Lahaina |
| Event State | HAWAII |
| Event Country | -- |
| Zipcode of the event site | 96761 |
| Event Date Year | 2006 |
| Event Date Month | 1 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 205726N |
| Event Location Longitude | 1563513W |
| Event Location Airport | -- |
| Event Location Nearest Airport ID | -- |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 10 |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 854 Hawaii Standard Time |
| Direction of event from weather observation facility (degrees) | 285 |
| Weather Observation Facility ID | PHOG |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | 10 |
| Time Zone of the weather observation | HST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 1000 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 15 |
| Air Temperature at event time (in degrees celsius) | 23 |
| Dew Point at event time (in degress fahrenheit) | 16 |
| Wind Direction (degrees magnetic) | 20 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 15 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.17 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 6 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 25866 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Jan 5 2006 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Sep 30 2009 11:46AM |
| User who most recently changed record | lema |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | WP-HNL-FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N11QD |
| NTSB Number | LAX06FA080 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 135: Air Taxi & Commuter |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | Yes |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | EUROCOPTER |
| Aircraft Model | EC 130B4 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 3363 |
| Certified Max Gross Weight | 5350 |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 7 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | 100 Hour |
| Date of Last Inspection | Dec 1 2005 12:00AM |
| Airframe hours since last inspection | 38 |
| Airframe Hours | 4836 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Nevada Helicopter Leasing LLC |
| Aircraft Owner Street Address | 1349 Galleria Dr. Suite 200 |
| Aircraft Owner City | Henderson |
| Aircraft Owner State | NV |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 89014 |
| Operator is an individual? | No |
| Operator Name | Helicopter Consultants of Maui, Inc. |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | Kahului |
| Operator State | HI |
| Operator Country | USA |
| Operator Zip code | 96732 |
| Operator Code | HOMA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Non-scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | OGG |
| Departure City | Kahului |
| Departure State | HI |
| Departure Country | USA |
| Departure Time | 930 |
| Departure Time Zone | HST |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | OGG |
| Destination City | -- |
| Destination State | -- |
| Destination Country | USA |
| Specific Phase of Flight | Cruise - normal |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Aug 18 2009 11:47AM |
| User who most recently changed record | coos |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | Yes |
| Air Medical Flight | No |
| Medical Flight | -- |