WPR16LA175

NTSB accident investigation · Mcdonnell Douglas Helicopter 500N · Honolulu, HI · September 2, 2016

Accident · Serious injuriesLimited investigationFinal report
Date
September 2, 2016, 09:45 local (19:45 UTC)
Place
Honolulu, HI
Injuries
1 serious, 3 uninjured
Damage
No damage
Phase of flight
Initial climb
Aircraft
N5232GMcdonnell Douglas Helicopter 500N
Defining event
Initial climb: External load event (Rotorcraft)
Weather
Visual (VMC) · Day
Status
Completed · report September 14, 2020
Report
Approved by Office Director
NTSB office
Western Pacific Region
Parties
Federal Aviation Administration
Case key
93977

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The pilot's failure to maintain helicopter control in gusting wind conditions, which resulted in the helicopter rescue net’s contact with a utility pole and serious injury to an occupant who fell from the rescue net. Contributing to the accident was the pilot’s and rescue personnel’s decision to continue the extraction in proximity to the pole.

Findings · 5

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Use of equip/info: aircraft controlPersonnel issues › Task performance · PilotAll aircraft: 9,295 casesProbable cause
Object/animal/substance: poleEnvironmental issues › Physical environment · Effect on operationAll aircraft: 142 casesProbable cause
Wind: gustsEnvironmental issues › Conditions/weather/phenomena · Effect on operationAll aircraft: 1,199 casesProbable cause
Info processing/decision: decision making/judgmentPersonnel issues › Action/decision · PilotAll aircraft: 3,098 casesProbable cause
Info processing/decision: decision making/judgmentPersonnel issues › Action/decision · OtherAll aircraft: 3,098 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The helicopter pilot reported that, during a rescue operation to extract a hiker in distress, he flew to a hiking trail lookout where fire department personnel were already present. He observed a utility pole on the east side of the lookout and estimated the wind was about 10-20 kts from the east. The pilot landed the helicopter in a nearby landing zone and prepared the helicopter for a rescue net extraction. The pilot then took off and lowered the rescue net from the 75-100-ft-long line to the injured hiker and firefighter. After they both climbed into the net, the helicopter started to ascend; a strong gust of wind unexpectedly caused the helicopter to ascend too quickly and move laterally toward the utility pole. The pilot attempted to stop the swing of the long line, but the net impacted the utility pole. The firefighter was electrocuted and fell from the net about 20 ft to the ground, which resulted in serious injury. At the time of the accident, the Hawaiian Islands were under the influence of tropical easterly winds, and a hurricane watch had been issued. The surface observations indicated northeast winds of 14-20 kts with peak gusts of 28 kts during the time surrounding the accident. It is likely that the northeast winds produced unfavorable wind conditions over the terrain at the lookout. The operator's "Technical Rescue Standard Operating Guidelines" states, in part, that "[t]eam members and the pilot shall agree that the area they are being inserted into is safe and free of obstructions…"

Factual narrative

On September 2, 2016, about 0945 Hawaii-Aleutian standard time, a McDonnell Douglas 500N helicopter, N5232G, was involved in an accident near Honolulu, Hawaii. The pilot, one crewmember and a passenger were not injured. One crewmember was seriously injured. The helicopter was not damaged. The helicopter was being operated as a public aircraft. The pilot reported that, after being dispatched to a hiker in distress, he took off from the airport and flew towards the hiking trail lookout where fire department personnel were already present. He flew over the lookout and surveyed the area, observing a utility pole on the east side of the lookout. In addition, he estimated the wind was about 10-20 knots from the east. The pilot landed the helicopter in a nearby landing zone and prepared the helicopter for a rescue net extraction. The pilot then took off and after flying to the injured hiker, the long line was extended to about 75-100 ft and the injured hiker and a firefighter climbed into the net. The pilot reported that as the helicopter started to ascend, a strong gust of wind unexpectedly caused the helicopter to ascend too quickly and move laterally toward the utility pole. The pilot attempted to stop the swing of the long line, but the net impacted the utility pole. The firefighter was electrocuted and fell from the net about 20 ft to the ground. At the time of the accident, the Hawaiian Islands were under the influence of the tropical easterly winds and under a Hurricane Watch. The surface observations indicated northeast winds of 14-20 knots with peak gusts of 28 knots during the time surrounding the accident. The northeast winds would produce downslope conditions and unfavorable conditions in the Diamond Head area. The National Weather Service had an AIRMET for moderate turbulence below 10,000 ft to the lee of higher terrain due to the stronger winds. The closest upper air sounding taken in the hour indicated little change in wind direction with height and wind speeds of 30 knots immediately above the surface. In the operator's "Technical Rescue Standard Operating Guidelines" it states "Team members and the pilot shall agree that the area they are being inserted into is safe and free of obstructions…"

Aircraft

Registration
N5232G
Reported as
Mcdonnell Douglas Helicopter 500N
Category
Helicopter
Serial number
LN075
Built
1994
Airframe hours
9,380
Engine
Rolls Royce C20R, 450 horsepower, turbo shaft
Damage
No damage
Flight
Public aircraft - local · Public use
Operator
City And County Of Honolulu
Registered owner
City And County Of Honolulu
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · June 30, 2016 · 73 hours before
Departed
HNL · Honolulu, HI
Destination
HNL · Honolulu, HI

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
51
Injuries
None
Certificates
Commercial, Flight instructor
Instrument ratings
Helicopter
Medical
Class 2, With waivers/limitations
Last flight review
July 23, 2015
Seat
Left
Restraint
4-point
Flight hours
3,582 total · 2,282 in this make and model · 2,882 as pilot in command · 28 in the last 90 days · 13 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
50° at 15 knots
Visibility
10 statute miles
Lowest ceiling
4,800 ft broken
Temperature
84 °F, dew point 66 °F
Altimeter
30.02 inHg
Observed at
HNL, 8 nm away

Docket · 4

The files NTSB released with the investigation on July 2, 2020, on NTSB’s docket system: statements, records, photos and specialists’ reports. 5.7 MB in all.