# NTSB LAX91LA034: Aerospatiale AS-350-B, N350CB, Kahului, HI, November 16, 1990

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: November 15, 1990, 20:30 local (Nov 16, 1990, 06:30 UTC)
- Place: Kahului, HI
- Coordinates: 20.869192, -156.45079 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=20.8692&lon=-156.4508&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor, 5 uninjured
- Status: Completed, report December 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 27063
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA034
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27063/pdf
- Page: https://openairdocs.org/ntsb/LAX91LA034

## 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.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of control - in flight, taxi - aerial
  - light condition - dark night
  - hydraulic system - inadvertent deactivation, pilot in command (cause)
  - acft/equip,inadequate control location, manufacturer (contributing factor)
  - remedial action - improper, pilot in command (cause)
  - acft/equip,inadequate control shape/size, manufacturer (contributing factor)
- Hard landing, descent - uncontrolled

## Analysis

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.

## Aircraft

- Registration: N350CB (not matched to a registry record)
- Reported make and model: AEROSPATIALE AS-350-B
- Category: Helicopter
- Serial number: 2196
- Engines: TURBOMECA ARRIEL 1B 650 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Executive/Corporate, Part 91
- Operator: Hawaii Helicopters, Inc.
- Destination: HI
- Airport: OGG, Kahului

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; commercial; medical: class 2, valid medical--w/ waivers/lim; flight hours: 9,000 total, 950 in this make and model, 9,000 as pilot in command, 180 in the last 90 days, 60 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 45° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point -0 °F

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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