Helicopter Consultants of Maui Eurocopter EC 130B4 accident
Eurocopter EC 130B4 · Accident: airframe, component or system failure en route
From Kahului International Airport (OGG) to Kahului International Airport (OGG)
Event
- NTSB case
- LAX06FA080
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Charter & commuter
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Eurocopter EC 130B4
- Aircraft type
- Eurocopter EC-130
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N11QD
- Operator
- Helicopter Consultants of Maui
- Onboard fatalities
- Unknown
- Route
- From Kahului International Airport (OGG), Kahului, HITo Kahului International Airport (OGG)
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 135: Air Taxi & Commuter
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Electrical system, electric wiring › Chafed
- Manufacturer › Maintenance, installation, improper
- Rotor RPM › Diminished
- Turboshaft engine › Output low
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
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.
Probable cause
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX06FA080
- Event ID
- 20060111X00057
- Case number
- LAX06FA080
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 436971a96ae4b95e424586cf15895a3b64f9466a160f2364823fe501846b7531; retrieved 2026-09-18T14:56:11.950Z.