# NTSB WPR16LA175: Mcdonnell Douglas Helicopter 500N, N5232G, Honolulu, HI, September 2, 2016 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: September 2, 2016, 09:45 local (19:45 UTC) - Place: Honolulu, HI - Coordinates: 21.256111, -157.806945 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=21.2561&lon=-157.8069&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: External load event (Rotorcraft)](https://openairdocs.org/ntsb-events/480) - Highest injury: Serious injuries - Injuries: 1 serious, 3 uninjured - Status: Completed, report September 14, 2020 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 93977 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR16LA175 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93977/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93977 - Page: https://openairdocs.org/ntsb/WPR16LA175 ## 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 NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Object/animal/substance: pole](https://openairdocs.org/ntsb-findings/03022010): Environmental issues › Physical environment · Effect on operation (probable cause); cases with it: [All aircraft, 142 cases](https://openairdocs.org/ntsb-findings/03022010/cases.md) - [Wind: gusts](https://openairdocs.org/ntsb-findings/03034045): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [All aircraft, 1,199 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Other (probable cause); cases with it: [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Initial climb: External load event (Rotorcraft)](https://openairdocs.org/ntsb-events/480) (defining event); cases with it: [All aircraft, 51 cases](https://openairdocs.org/ntsb-events/480/sequence.md) - [Initial climb: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## 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 (not matched to a registry record) - Reported make and model: MCDONNELL DOUGLAS HELICOPTER 500N - Category: Helicopter - Serial number: LN075 - Year built: 1994 - Airframe hours: 9380 - Engines: 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. - Pilot; age 51; injuries: none; 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 files) The files NTSB released with the investigation on July 2, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93977. 5.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - Operator (item 1, .PDF, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485083&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20Operator-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - Pilot (item 2, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485084&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20Pilot-Master.PDF - Record of Email - Meteorology (item 3, .PDF, 698 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485085&FileExtension=.PDF&FileName=Record%20of%20Email%20-%20Meteorology-Master.PDF - Excerpt from the Operator's 'Technical Rescue Standard Operating Guidelines' (item 4, .PDF, 289 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485086&FileExtension=.PDF&FileName=Excerpt%20from%20the%20Operator%27s%20%27Technical%20Rescue%20Standard%20Operating%20Guidelines%27-Master.PDF 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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.