Saturday, August 10, 2019

Low Altitude Operation / Event: Hughes 369D, N138WH; fatal accident occurred November 07, 2017 in Sulphur, Louisiana

Nicholas Gamalski

Travis Chiokai

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Baton Rouge, Louisiana

Aviation Accident Factual Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:

Location: Sulphur, LA
Accident Number: CEN18LA026
Date & Time: 11/07/2017, 0934 CST
Registration: N138WH
Aircraft: HUGHES 369D
Aircraft Damage: None
Defining Event: Low altitude operation/event
Injuries: 2 Fatal, 1 None
Flight Conducted Under: Part 133: Rotorcraft Ext. Load 

On November 7, 2017, at 0934 central standard time, a Hughes 369D helicopter, N138WH, was not damaged when its external cargo long line severed after contacting a shield wire suspended between power transmission towers near Sulphur, Louisiana. The two linemen being hoisted on the long line were fatally injured when they fell about 100 ft to the ground. The helicopter was registered to and operated by Winco, Inc. as a Title 14 Code of Federal Regulations (CFR) Part 133 external load flight. Day visual meteorological conditions prevailed and no flight plan was filed for the local flight, which departed at 0932 from a temporary landing zone near the accident site.

According to the power company, the purpose of the flight was to install guard ropes between the deenergized 500-kilovolt power transmission lines before the existing braided steel shield wire from the nearby transmission tower was replaced. The east/west power transmission lines, with three sets of bundled conductors (northern, center, and southern), crossed perpendicular over a road. The pilot reported that, following a preflight safety briefing, he and one of the linemen discussed the expected work tasks. The pilot stated that, following their discussion, he brought the helicopter into a hover to allow the linemen to hook onto the external cargo long line. He then repositioned the helicopter to allow the linemen to work on the center conductor bundle.

The pilot reported that, after the linemen had tied off the guard rope to the center conductor bundle, he repositioned the helicopter to allow work on the northern conductor bundle. The pilot reported that he saw the long line contact the braided steel shield wire as one of the linemen held onto the northern conductor. The long line severed as the pilot turned the helicopter into the wind and attempted to move the linemen away from the northern conductor. The pilot reported that, immediately before the long line severed, he observed one of the linemen tugging at the conductor to reposition the guard rope perpendicular to the conductors. After the long line severed, the pilot returned to the landing zone and made an uneventful landing. The pilot did not report any malfunction or failures with the helicopter that would have precluded normal operation. According to postaccident measurements made by local law enforcement and witness video footage of the flight, the 60-ft long line separated about midspan while it was in contact with the braided steel shield wire suspended between power transmission towers. 

Pilot Information

Certificate: Flight Instructor; Commercial
Age: 71, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): Helicopter
Restraint Used:
Instrument Rating(s): Airplane; Helicopter
Second Pilot Present: No
Instructor Rating(s): Helicopter
Toxicology Performed: No
Medical Certification: Class 2 Without Waivers/Limitations
Last FAA Medical Exam: 06/19/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 08/29/2016
Flight Time:  (Estimated) 25090 hours (Total, all aircraft), 11286 hours (Total, this make and model), 21063 hours (Pilot In Command, all aircraft), 26 hours (Last 90 days, all aircraft), 17 hours (Last 30 days, all aircraft), 1 hours (Last 24 hours, all aircraft)

According to Federal Aviation Administration (FAA) records, the 71-year-old pilot held a commercial pilot certificate with ratings for airplane single-engine land, rotorcraft-helicopter, and instrument airplane and helicopter. His most recent FAA second-class medical certificate was issued on June 19, 2017, with no limitations.

The pilot had accumulated 25,090 total hours of flight experience, of which 21,063 hours were logged as pilot-in-command and 11,286 hours were flown in Hughes 369 helicopters. The pilot flew 26 hours and 17 hours during the 90 days and 30 days before the accident, respectively. The pilot had flown less than 1 hour on the day of the accident. His most recent flight review, as required by Title 14 CFR 61.56, was completed on August 29, 2016, in a Hughes 369D helicopter. 

Aircraft and Owner/Operator Information

Aircraft Make: HUGHES
Registration: N138WH
Model/Series: 369D D
Aircraft Category: Helicopter
Year of Manufacture: 1981
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 911027D
Landing Gear Type: Skid
Seats: 2
Date/Type of Last Inspection: 10/29/2017, 100 Hour
Certified Max Gross Wt.: 3000 lbs
Time Since Last Inspection: 42 Hours
Engines: 1 Turbo Shaft
Airframe Total Time: 9595.1 Hours at time of accident
Engine Manufacturer: Rolls Royce
ELT: C126 installed, not activated
Engine Model/Series: 250-C20R/2
Registered Owner: Winco, Inc.
Rated Power: 450 hp
Operator: Winco, Inc.
Operating Certificate(s) Held: Rotorcraft External Load (133) 

The helicopter, serial number 911027D, was manufactured in 1981 and was powered by a 450-horsepower Rolls-Royce 250-C20R/2 turboshaft engine, serial number CAE-295387. The helicopter had a maximum gross weight of 3,000 pounds and was equipped for external load operations. The FAA issued the helicopter a standard airworthiness certificate on December 29, 1981. The helicopter had accumulated 9,595.1 hours at the time of the accident. The last recorded maintenance was a 100-hour inspection completed on October 29, 2017, at 9,552.7 total airframe hours. 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: UXL, 10 ft msl
Distance from Accident Site: 9 Nautical Miles
Observation Time: 0935 CST
Direction from Accident Site: 177°
Lowest Cloud Condition:
Visibility:  10 Miles
Lowest Ceiling: Broken / 1400 ft agl
Visibility (RVR):
Wind Speed/Gusts: 8 knots /
Turbulence Type Forecast/Actual: / None
Wind Direction: 210°
Turbulence Severity Forecast/Actual: / N/A
Altimeter Setting: 30.11 inches Hg
Temperature/Dew Point: 27°C / 23°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Sulphur, LA
Type of Flight Plan Filed: None
Destination: Sulphur, LA
Type of Clearance: None
Departure Time: 0932 CST
Type of Airspace: Class G 

A postaccident review of available meteorological data established that day visual meteorological conditions prevailed at the accident site. The nearest aviation weather reporting station was located at Southland Field Airport (UXL), Sulphur, Louisiana, about 9 miles south of the accident site. At 0935, about 1 minute after the accident, the UXL automated surface observing system reported wind from 210° at 8 knots, 10 miles surface visibility, broken ceilings at 1,400 ft above ground level (agl), 2,400 ft agl, and 3,000 ft agl, temperature 27°C, dew point 23°C, and an altimeter setting of 30.11 inches of mercury.

Wreckage and Impact Information

Crew Injuries: 2 Fatal, 1 None
Aircraft Damage: None
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 Fatal, 1 None
Latitude, Longitude: 30.281944, -93.384444 

Additional Information

Local law enforcement reported that the 60 ft long synthetic long line severed about midspan. The long line was not equipped with an abrasion-resistant cover. A 100-ft synthetic long line equipped with an abrasion-resistant cover was found on the ground at the temporary landing zone near the operator's support vehicle.

The operator reported that the helicopter was operating under Part 133 Class B during the flight, and that linemen were considered crewmembers (not passengers) during powerline construction operations. The FAA had approved the helicopter's hook installation; however, because the flight was conducted under Part 133 Class B, the FAA did not regulate, specify, or approve the long line or the harnesses that was used to hoist the two linemen.

The operator reported that the long line was a 7/16 inch Amsteel Blue synthetic rope made of Dyneema SK-75 synthetic fiber that had a break strength of 21,500 lbs. The operator reported that the use of Amsteel Blue synthetic rope had been an industry standard for at least 15-20 years, and that the use of synthetic rope is advantageous for powerline work because it is non-conductive and has a higher break strength than a similarly sized braided steel cable. The operator stated that the use of an abrasion-resistant cover was typically used to protect a long line from incidental contact with sharp edges on tower structures. Additionally, the operator stated that the use of an abrasion-resistant cover would not offer much protection if the long line had prolonged lateral contact with a braided steel cable. The operator noted that the use of a braided steel long line is not practical when working on powerlines due to the potential for electrocution. The operator reported that the pilot selects the length of the long line for a specific mission after he/she considers the required length to position the lineman at the specified workstation and to keep the helicopter above any wires, structures, or obstacles. The pilot chooses the shortest long line available that ensures obstacle clearance, which increases positive control of the cargo/linemen during the flight.

1 comment:

  1. How many 71 year olds do you know can park a car straight at Luby's let alone fly a precision maneuver with a chopper? We need BFRs that address aging pilots. The stats prove it.