# NTSB WPR18TA239: Eurocopter EC130, N11QP, Hilo, HI, August 19, 2018 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Final report - Date: August 19, 2018, 13:20 local (23:20 UTC) - Place: Hilo, HI - Coordinates: 19.643611, -154.984451 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=19.6436&lon=-154.9845&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-descent: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Honolulu Flight Standards District Office - NTSB case key (mKey): 98143 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR18TA239 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98143/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98143 - Page: https://openairdocs.org/ntsb/WPR18TA239 ## Probable cause The separation of the left sliding door in flight after it opened for reasons that could not be determined based on the available evidence, which resulted in damage to the main rotor blades. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Doors: passenger/crew doors](https://openairdocs.org/ntsb-findings/01035210): Aircraft › Aircraft structures · Not specified (probable cause); cases with it: [Eurocopter EC 130 B4, 2 cases](https://openairdocs.org/ntsb-findings/01035210/cases.md?model=8680989), [All aircraft, 86 cases](https://openairdocs.org/ntsb-findings/01035210/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Eurocopter EC 130 B4, 2 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=8680989), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-descent: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Eurocopter EC 130 B4, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=8680989), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis The pilot reported that, before departing, he conducted a walk-around inspection of the helicopter, during which he visually checked to ensure all the doors and cowlings were closed and secured. The pilot departed on the flight with the maintenance apprentice, who was seated in the right front seat. While the flight was en route back to the airport, the left-rear sliding door suddenly slid open, separated from the helicopter, and struck two of the three main rotor blades. The pilot performed a precautionary landing to a field. The helicopter sustained substantial damage to two main rotor blades. The helicopter’s left sliding door tracks and door latch assemblies were normal and unremarkable. The plastic latch on the fuselage which supports the sliding rear door when opened was damaged, and a portion had separated from the fuselage. The sliding door fell into the ocean and was not recovered, thereby preventing examination of the door and its locking components. After the accident, Airbus Helicopters published an alert service bulletin requiring a mandatory spring-scale check on all sliding door-equipped EC-130 B4 helicopters to ensure correct operation of the sliding door locking system. ## Factual narrative On August 19, 2018, about 1320 Hawaiian standard time, a Eurocopter EC-130 B4 helicopter, N11QP, sustained substantial damage when it was involved in an accident near Hilo, Hawaii. The pilot was not injured, and the passenger sustained minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 maintenance flight. The pilot stated that the purpose of the flight, which originated from Hilo International Airport (ITO), Hilo, Hawaii, was for the track and balance of the main rotor blades. He conducted a previous flight in the helicopter that day but returned to ITO early due to issues with the track and balance equipment. Before the accident flight, the pilot conducted a walk-around inspection of the helicopter, during which he visually checked to ensure all the doors, cowlings, and equipment were closed and secured. The pilot and the passenger, a maintenance apprentice who was seated in the right front seat, departed ITO about 1310. The pilot stated that, after completion of the maintenance checks and while en route back to ITO, he lowered the collective to decelerate and began a slow descent. He then heard the left-rear sliding door suddenly slide open. The pilot looked back and saw the door off the helicopter in midair. He stated that he turned his head forward, then heard a loud noise and felt a jolt. The helicopter began to vibrate but remained controllable. The pilot initiated a precautionary landing onto a grass field. He indicated that the door appeared to have struck two main rotor blades and that he thought the door fell into the ocean. The maintenance apprentice stated that on the accident flight, while returning to the airport and after leveling off from a descent, the door suddenly opened and separated from the helicopter. He stated that on the takeoff for the previous flight, a maintenance technician had ensured the doors were closed correctly, but on the takeoff for the accident flight, the maintenance technician did not. The accident helicopter has a sliding rear door on the left side; when opened, it is supported by a plastic latch located on the fuselage of the helicopter at the end of the sliding door track. The helicopter sustained substantial damage to the main rotor blades; two of the three main rotor blades exhibited dents and scratches across their undersides, generally initiating at or near the leading edge and propagating aft along the chord of the blade. Examination of the operator's photographs and reports from the director of maintenance revealed that the helicopter’s left sliding door tracks and door latch assemblies were normal and unremarkable. The plastic latch on the fuselage was damaged, and a portion had separated from the fuselage. The sliding door was not recovered, thereby preventing examination of the door and its locking components. A review of the helicopter's maintenance records revealed no previous door-related issues. On December 10, 2018, Airbus Helicopters publishedAlert Service Bulletin (ASB) ASB EC130-05A031 for operators of EC-130 B4 helicopters with sliding doors, making it mandatory to check for correct operation of the sliding door locking system by measuring the load required to unlock the sliding door. The ASB indicated the check should be conducted with a spring scale and described an in-flight opening and loss of a sliding door as the reason for the bulletin. ## Aircraft - Registration: [N11QP](https://openairdocs.org/aircraft/N11QP), registered now, S/N 4715, built 2009 (OpenAirDocs) - Reported make and model: Eurocopter EC130 (B4) - Registry model: [Eurocopter EC 130 B4](https://openairdocs.org/model/eurocopter-ec-130-b4) (registry code 8680989) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-2B1](https://openairdocs.org/engine/turbomeca-arriel-2b1) (registry code 60056, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 4715 - Year built: 2009 - Airframe hours: 13211.2 - Engines: Safran Arriel 771 horsepower turbo shaft - Damage: Substantial damage - Flight: Other work use, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, August 15, 2018 - Departed: ITO, Hilo, HI - Destination: ITO, Hilo, HI - Flight plan: Company VFR - Airport: ITO, Hilo Intl - Equipment: Electronic primary flight display, Video recording device, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review May 30, 2018; seat: left; restraint: 4-point; flight hours: 10,014 total, 2,122 in this make and model, 9,868 as pilot in command, 73 in the last 90 days, 28 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 110° at 6 knots - Visibility: 8 statute miles - Lowest ceiling: 2,500 ft broken - Temperature: 82 °F, dew point 73 °F - Altimeter: 29.96 inHg - Observed at: PHTO, 6 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20180819023169A](https://openairdocs.org/incident/20180819023169A), Aug 19, 2018: Eurocopter EC 130 B4, Hilo, HI, Substantial damage. Hilo, HI (ito): BL71, N11QP, ec 130 B4, itoinbound from the south after having departed for a maintenance flight; plt rptd rear left door slid off track in… ## Docket (5 files) The files NTSB released with the investigation on June 8, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98143. 10.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 705 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7057092&FileExtension=pdf&FileName=6120_1%20John%20Blau_Redacted-Rel.pdf - Witness statements (item 2, PDF, 2 pages, 130 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7740695&FileExtension=pdf&FileName=Witnesses%20WPR18TA239-Rel.pdf - Alert service bulletin EC130-05A031 (item 3, PDF, 9 pages, 4.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7736212&FileExtension=pdf&FileName=ASB%20EC130-05A031-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 4, PDF, 1 page, 4.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7050061&FileExtension=pdf&FileName=NTSB%20Form%206120_15%20signed_Redacted-Rel.pdf - Photos (item 5, PDF, 6 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7606126&FileExtension=pdf&FileName=Photos%20for%20WPR18TA239-Rel.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.