# NTSB CEN19FA109: Aerospatiale AS350, N818MC, Montgomery, TX, March 27, 2019 - Type: NTSB accident investigation - Classification: Accident · Fatal · Class 3 · Field · Final report - Date: March 27, 2019, 14:10 local (19:10 UTC) - Place: Montgomery, TX - Coordinates: 30.510278, -95.770835 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.5103&lon=-95.7708&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Fatal - Injuries: 1 fatal, 2 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Mountain Air Helicopters, FAA FSDO, SafranHE, Airbus Helicopters, FAA Rotorcraft Directorate - NTSB case key (mKey): 99185 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN19FA109 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99185/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99185 - Page: https://openairdocs.org/ntsb/CEN19FA109 ## Probable cause Maintenance personnel's failure to properly re-install and secure a fuel line, which resulted in a total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Eurocopter AS 350 B3, 1 case](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=8680954), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md) - [Fuel system: fuel distribution](https://openairdocs.org/ntsb-findings/01022820): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Eurocopter AS 350 B3, 1 case](https://openairdocs.org/ntsb-findings/01022820/cases.md?model=8680954), [All aircraft, 141 cases](https://openairdocs.org/ntsb-findings/01022820/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Eurocopter AS 350 B3, 3 cases](https://openairdocs.org/ntsb-events/040/sequence.md?model=8680954), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Eurocopter AS 350 B3, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=8680954), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Autorotation: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Eurocopter AS 350 B3, 10 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=8680954), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis While conducting controlled fire operations, the helicopter was maneuvering over trees, when the engine lost power. The pilot performed an autorotation and the helicopter impacted trees and then terrain, and came to rest on its side. The fuselage and empennage sustained substantial damage. One crewmember was fatally injured. Examination revealed that a fuel line between the engine firewall and hydro-mechanical unit (HMU) was loose and not secured with safety wire as required. About 25 flight hours before the accident, that fuel line was disconnected to defuel of the helicopter in order to perform a weight and balance check. No other maintenance was performed in that area. The mechanic who returned the helicopter to service stated that he was confident that he torqued and secured the line. No other anomalies were detected with the helicopter which would have precluded normal flight. The circumstances of the accident are consistent with a loss of engine power due to the loose fuel line. ## Factual narrative Review of Mountain Air Fleet Following the accident, Mountain Air inspected their other helicopters, and all helicopters had the fuel lines properly secured. On March 27, 2019, about 1410 central daylight time, an Airbus AS350B3 helicopter, N818MC, was substantially damaged when it was involved in an accident near Montgomery, Texas. The pilot was seriously injured, one crew member was fatally injured, and another crew member sustained minor injuries. The helicopter was operated as a public flight. The helicopter and United States Forest Service (USFS) crew were conducting plastic sphere dispenser (PSD) applications in support of a controlled fire operation in an area of the Sam Houston National Forest. The pilot and surviving crew member reported that, after completing the application, they began flying back to the staging area when the engine lost total power. The helicopter descended into trees and subsequently impacted terrain, coming to rest on its right side. The surviving crew member and pilot were able to exit the helicopter; however, the second crew member was partially ejected from the helicopter and sustained fatal injuries. The helicopter came to rest in a wooded area of the Sam Houston National Forest, at an elevation of 328 ft mean sea level on a 108° magnetic heading. All major components of the helicopter were located at the accident scene. Trees surrounding the accident site were about 70 ft tall and displayed damage consistent with a helicopter descent vector of about 40-50°. There was no post impact fire. The fuel line between the firewall and hydro-mechanical unit (HMU) was loose and the required safety wire was not installed. All other connections were found to be secure. Examination of the airframe and engine did not reveal any additional discrepancies. Federal Aviation Administration inspectors from the Houston Flight Standards District Office interviewed Mountain Air’s Director of Maintenance, who stated that on February 14, 2019, the USFS requested to validate the helicopter’s weight and balance. The helicopter was defueled, which involved disconnecting the main fuel line. After the weight and balance were verified, the main fuel line was reconnected. The director of maintenance asked another mechanic to verify that the fuel lines were reconnected, which was reportedly accomplished. The mechanic that accomplished the work informed the operator that he “was confident” that he torqued and secured the line. There was no other maintenance work which involved opening the fuel line after that day. On February 23, 2019, the helicopter’s engine would not light, and the engine’s igniters and/or igniter box was replaced. A maintenance records review found that the helicopter flew about 24.9 hours after the weight and balance was conducted on February 14, 2019. On March 25, 2019, the pilot reported to management that the fuel pressure light had “flickered” during a flight “a few days before;” the pilot turned on the fuel boost pump,turned it off, and the light never reappeared. The pilot was informed to monitor the situation and report if it occurred again. Following the accident, the digital engine control unit (DECU) was removed and sent to the manufacturer for data download. On April 11, 2019, the DECU was downloaded under the auspices of the FAA. The last recorded fault was a “P3 drift or engine flame out.” ## Aircraft - Registration: [N818MC](https://openairdocs.org/deregistered/N818MC-2021-12-04), registration cancelled 2021-12-04, S/N 4755, built 2009 (OpenAirDocs) - Reported make and model: Aerospatiale AS350 (B3) - Registry model: [Eurocopter AS 350 B3](https://openairdocs.org/model/eurocopter-as-350-b3) (registry code 8680954) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-2B1](https://openairdocs.org/engine/turbomeca-arriel-2b1) (registry code 60056, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 4755 - Year built: 2009 - Airframe hours: 5027.3 - Engines: Safran Arriel 2B1 871 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft - federal, Public use - Operator: Mountain Air Helicopters Inc - Registered owner: Mountain Air Helicopters Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, February 4, 2019, 72.4 hours before - Destination: Same as departure - Flight plan: Company VFR - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: serious; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review March 29, 2018; seat: right; restraint: 4-point; flight hours: 8,760 total, 3,886 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 7 knots - Lowest ceiling: none - Temperature: 73 °F, dew point 45 °F - Altimeter: 30.25 inHg - Observed at: KCXO, 21 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 20190327002069A](https://openairdocs.org/incident/20190327002069A), Mar 27, 2019: Eurocopter AS 350 B3, Montogomery, TX, Destroyed, 1 fatal. N818MC flight with 01 pilot and 02 forestry service passengers onboard originated from huntsville municipal airport (kuts), huntsville, TX, with a destination… ## Docket (6 files) The files NTSB released with the investigation on December 17, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99185. 5.9 MB in all. - Case notes (item 1, PDF, 5 pages, 855 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12136901&FileExtension=pdf&FileName=Case%20Notes%20CEN19FA109-Rel.pdf - Photos (item 2, PDF, 3 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12137428&FileExtension=pdf&FileName=CEN19FA109%20Docket%20Photos-Rel.pdf - Accreditation letter from bea (item 3, PDF, 1 page, 163 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12137438&FileExtension=pdf&FileName=2019-03-27_AIM_4912_Accreditation-letter_N818MC_USA_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 4, PDF, 1 page, 288 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12137545&FileExtension=pdf&FileName=Mountain%20Air%20Party%20Form_Redacted-Rel.pdf - Email with maintenance statement (item 5, PDF, 1 page, 135 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12136847&FileExtension=pdf&FileName=Email%20with%20maintainance%20statement_Redacted-Rel.pdf - Ppe documentation (item 6, PDF, 11 pages, 18 photos, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12137261&FileExtension=pdf&FileName=Survivability%20Notes%20CEN19FA109-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.