LAX91LA034 · Aerospatiale AS-350-B
Hawaii Helicopters Aerospatiale AS-350-B · Accident: loss of control in flight while taxiing
From an unrecorded airport to HI
Event
- NTSB case
- LAX91LA034
- 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
- 0
- 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
- General aviation
- 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
Aerospatiale AS-350-B
- Aircraft type
- Aerospatiale AS-350
- 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
- N350CB
- Operator
- Hawaii Helicopters
- Onboard fatalities
- Unknown
- Route
- From not recordedTo HI
- 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 91: General Aviation
- 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
- Taxi · aerial
- 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
- Loss of control in flight
- 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
- Pilot in command › Hydraulic system, inadvertent deactivation
- Pilot in command › Remedial action, improper
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE PURPOSE OF THE PLANNED 5 MIN LONG NIGHT FLIGHT WAS TO REWARD ONE OF THE OPERATOR'S CUSTOMER'S EMPLOYEES FOR THEIR SALES PERFORMANCE RECORD. THE FLT INVOLVED A VIEW OF THE CITY. THE PILOT HAD EARLIER MADE A SIMILAR FLT, & DURING TAKEOFF HE HAD TURNED OFF THE HELICOPTER'S LANDING LIGHT TO 'AMPLIFY THE VISUAL EFFECT' OF THE RUNWAY LIGHTS. THE HELICOPTER'S MANUFACTURER HAD DESIGNED THE LIGHT SWITCH TO BE LOCATED ADJACENT TO THE HYDRAULIC TEST SWITCH. UPON DEPRESSION OF THE LIGHT SWITCH THE HELICOPTER'S LIGHT TURNED OFF. UPON DEPRESSION OF THE HYD TEST SWITCH THE HYD BOOST SYSTEM DEACTIVATED, THE CONTROLS STIFFENED & A WARNING HORN SOUNDED. DURING THE AERIAL TAXI FOR TAKEOFF, BETWEEN 25 & 50 FT AGL, THE PILOT INADVERTNETLY MISTOOK & DEPRESSED THE HYD TEST SWITCH FOR THE LIGHT SWITCH, & THE WARNING HORN ACTIVATED. WHEN THE PILOT RELEASED THE COLLECTIVE CONTROL TO SILENCE THE HORN THE COLLECTIVE LOWERED & THE HELICOPTER DESCENDED UNTIL TOUCHING DOWN HARD ON THE TAXIWAY.
Probable cause
THE PILOT'S INADVERTENT DEACTIVATION OF THE HELICOPTER'S HYDRAULIC BOOST SYSTEM AND HIS IMPROPER REMEDIAL ACTION THEREAFTER TO THE INFLIGHT SITUATIONS WHICH HE CREATED. A CONTRIBUTING FACTOR WAS RELATED TO THE MANUFACTURER'S INADEQUATE LOCATION AND DESIGN (SHAPE) OF THE HYDRAULIC TEST SWITCH.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX91LA034
- Event ID
- 20001212X24639
- Case number
- LAX91LA034
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1990-11-16.
- API snapshot SHA-256: 2f264f6f53cd50ba32d93713683d3f076e6613ca863e3e79ef98ae778625a457; retrieved 2026-09-21T23:42:06.361Z.