# NTSB DFW07GA119: Eurocopter AS 350 B3, N851BP, San Elizario, TX, May 22, 2007 - Type: NTSB accident investigation - Classification: Accident · Fatal · Final report - Date: May 22, 2007, 08:38 local (14:38 UTC) - Place: San Elizario, TX - Coordinates: 31.579166, -106.284446 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.5792&lon=-106.2844&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal, 1 serious - Status: Completed, report December 28, 2008 - Report: Approved by Office Director - Parties: CBP Air, Turbomeca, FAA, American Eurocopter - NTSB case key (mKey): 65826 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW07GA119 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65826/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=65826 - Page: https://openairdocs.org/ntsb/DFW07GA119 ## Probable cause The pilot's encounter with a vortex ring state and his inability to maintain control of the helicopter. ## Analysis The helicopter was reported to have been maneuvering at a low airspeed at an altitude of approximately 150 feet above the ground while on a patrol flight near an international border. Local authorities reported that the helicopter impacted a parked pickup truck in a nose-low attitude while in a right turn, coming to rest on its right side. Witnesses said that the helicopter "appeared to dip the nose-down and enter a spin to the right nearly straight down. One witness added that the helicopter appeared to have recovered from the spin and initiated a climb before it began to spin to the right again, impacting the ground in a near-vertical attitude. Other witnesses added that the engine appeared to be "screaming." A witness, who reported having experience as a helicopter mechanic, added that the engine was screaming, but that the rotor system sounded as though it was slowing down. One witness stated it sounded like it was sucking or chopping air. The recorded weather near the accident site was reported as winds from 260 degrees at 12 knots, visibility 10 statute miles, clear skies, temperature 23 degrees Celsius, dew point 1 degree Celsius, and a barometric pressure of 29.94 inches of Mercury. Density Altitude was computed to be 5,433 feet MSL, No discrepancies or pre-existing anomalies were found with the helicopter or the engine that could have precluded normal flight. A performance study was conducted to determine the controllability and maneuvering capabilities while operating in the flight environment during the assigned observation mission. The study concluded that at the approximate altitude of 150 feet AGL and an airspeed of 20-30 knots, may not have allowed sufficient time or altitude for the pilot to recover after the helicopter entered a vortex ring state, A fully developed vortex ring state is characterized by an unstable condition where the helicopter experiences uncommanded pitch and roll oscillations, has little or no cyclic authority, and achieves a descent rate which, if allowed to develop, may approach 6000 feet per minute. A vortex ring state may be entered during any maneuver that places the main rotor in a condition of high upflow and low forward airspeed ## Factual narrative History of Flight On May 22, 2007 at 0838 mountain daylight time, a single-engine Eurocopter, AS350-B3 turbo-shaft helicopter, N851BP, registered to and operated by the U.S. Customs and Border Protection (CBP) Air Operations, was destroyed when it impacted terrain following a loss of control while maneuvering at approximately 150- above ground level and an airspeed between 20 to 30 knots on a routine border patrol mission near San Elizario, Texas, approximately 15 miles southeast of the El Paso International Airport. The accident occurred 1.8 hours in to the flight. The commercial pilot sustained fatal injuries and his non-rated observer was seriously injured. Visual meteorological conditions prevailed, and a company visual flight rules flight plan was filed for the local flight conducted as a Public Use Flight under 14 Code of Federal Regulations Part 91. The flight departed El Paso International Airport (KELP), near El Paso, Texas, at approximately 0655. Local authorities reported that the helicopter impacted a parked pickup truck in a nose-low attitude while in a right turn, coming to rest on its right side in a residential area. There were no reported injuries to anyone on the ground. Emergency medical services personnel removed the pilot and observer from the cockpit and transported them to a local hospital. Following the documentation of the wreckage, the helicopter was recovered to a secured facility at Biggs Army Airfield, near El Paso, Texas, for a detailed examination. The engine, transmission, and flight control hydraulic servos were removed and shipped to laboratory facilities for testing and/or teardown examination along with other drive train components. Damage to Aircraft Several witnesses were interviewed during the field portion of the investigation. Most witnesses concluded that the helicopter "appeared to dip the nose-down and enter a spin to the right nearly straight down. One witness stated that the helicopter appeared to have recovered from the spin and initiated a climb before it began to spin to the right again and impacted the ground in a near-vertical attitude. Other witnesses added that the engine appeared to be "screaming." Another witness, who reported having experience as a helicopter mechanic, added that the engine was screaming, but that the rotor system sounded as though it was slowing down. One witness stated it sounded like it was sucking or chopping air. Injuries to Persons The air transport rated pilot was killed. The observer sustained critical injuries. Other Damage A 1978 GMC pickup truck that was parked at the rear of the residence was destroyed. As the aircraft impacted the vehicle, the right skid of the helicopter struck the cab roof causing the top to collapse across the width of the body. The truck bed showed collision damage on both the forward end of the driver’s side and aft end of the passenger’s side. The tail gate was cut along its width when the helicopter’s main rotor struck the vehicle, and it was found hanging from the vehicle’s frame. Personnel Information The pilot held an Airline Transport Pilot certificate with single engine airplane, multi-engine airplane, helicopter, and instrument ratings. He joined the U.S. Customs and Border Patrol (CBP) Air and Marine in 1991 where he was assigned to the New York Air Unit and the Puerto Rico Air Operations Branch before transferring to the El Paso Air Branch in the summer of 1996. While at the El Paso Air Branch, the pilot received training in, and was eventually endorsed to fly the AS350-B3 aircraft as Pilot-In-Command. The pilot had accumulated a total of 3919 flight hours, of which 173 hours was in CBP AS350 aircraft. Initial AS350 training for the pilot was conducted at the University of North Dakota, UND Aerospace, Grand Forks, North Dakota and completed on July 31, 1998. During that year, the pilot logged 19.7 hours of which 1.5 hours were as PIC. From 1999 until late 2003, the pilot accumulated an additional 11.2 hours in the AS350 with 4 hours as PIC. From 2003-2004, no records were discovered indicating the pilot had flown any additional AS350 hours. The next indication of flight time was in 2005 when he logged 22.6 hours as Second-In-Command. From January 01, 2006 to the accident in May 2007, the pilot amassed an additional 121 hours of which 62.7 hours were as PIC. On December 19, 2006, the pilot started AS350-B3 initial transition training at HeliStream located in southern California. On January 5, 2007 in El Paso, the AIA started CBP AS350-B3 transition training and completed said training on February 6, 2007. On February 28, 2007, the pilot was designated as a pilot in command and maintenance test pilot. All training and check rides were completed with satisfactory marks with no derogatory comments. CBP initial training and check ride were completed by the same instructor. The Border Patrol Agent Observer joined CBP on February 23, 2003 and upon completing his academy training was assigned to the El Paso Sector in August 2003. In 2007, the agent volunteered as an observer with the Air and Marine program and was assigned flight duties as a Qualified Observer in May 2007. The Observer held a private pilot certificate for single engine land airplanes. Aircraft Information N851BP, serial number 3588, was purchased by U.S. Customs and Border Protection in April 2003 from American Eurocopter, Grand Prairie, TX. According to records, the aircraft was maintained in accordance with the manufacturer’s recommended procedures. Documentation indicated that the last major maintenance was performed May 18, 2007 by El Paso Aero, Inc., a licensed, FAA-certified repair facility. The maintenance was a 100-hour airframe inspection in accordance with the US CBP Inspection Program and AS350-B3 Master Service Recommendations. Maintenance procedures were completed with no discrepancies noted. N851BP had a Turbomeca Arriel 2B1 engine producing 848 horsepower that was installed on the aircraft 941.9 hours prior to the accident. The engine had 941.9 total hours and the airframe had 3843.8 hours. Work cards for the aircraft showed that there were no major discrepancies outstanding on the airframe prior to departure and that all major Airworthiness Directives had been complied with. Weight and balance calculations confirmed that the aircraft was within maximum weight allowances and within center of gravity limits at the time of departure. The aircraft was fueled with approximately 100 gallons of Jet A making the aircraft weight approximately 4357 pounds at time of takeoff. After flying for 1.8 hours, at the estimated time of impact, the aircraft would have weighed 3709.9 pounds and the Center of Gravity would have been 130.7 inches aft of datum. Meteorological Information At 0851 MDT, the weather reporting facility at the El Paso International Airport (KELP) reported wind from 260 degrees at 12 knots, visibility 10 statute miles, clear skies, temperature 23 degrees Celsius, dew point 1 degree Celsius, and a barometric pressure of 29.94 inches of Mercury. Density Altitude was computed to be 5433 feet MSL, Pressure Altitude 3941 feet based on these conditions and a terrain level of 3645 feet MSL at the accident site. Flight Recorders No flight recorders were installed on this helicopter. Wreckage and Impact Information The fuselage came to rest on its right side in the back yard of a residence, adjacent to a parked truck. A large portion of the tailboom had separated and came to rest on the bed of the truck. Rotational damage consistent with the size and dimensions of the tail rotor strike tabs was observed on the left side of the truck. A detailed examination of the wreckage was conducted at Biggs Army Airfield, El Paso, Texas. Impact damage to cabin and fuselage, deformation of the transmission deck and displacement of the main transmiss ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, hover - out of ground effect - vortex ring state - encountered, pilot in command (cause) - aircraft control - not possible, pilot in command (cause) - In flight collision with object, descent - uncontrolled - object - vehicle ## Aircraft - Registration: [N851BP](https://openairdocs.org/deregistered/N851BP-2009-02-20), registration cancelled 2009-02-20, S/N 3588, built 2002 (OpenAirDocs) - Reported make and model: EUROCOPTER AS 350 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: 3588 - Airframe hours: 3819 - Engines: TURBOMECA ARRIEL 2B1 747 horsepower turbo shaft - Damage: Destroyed - Flight: Public aircraft - federal, Public use - Operator: US Border Patrol Air Operations, doing business as US Border Patrol Air Operations - Registered owner: US Border Patrol Air Operations - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 1, 2007, 42 hours before - Departed: KELP, El Paso, TX - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; injuries: fatal; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane, helicopter; medical: class 1, without waivers/limitations; last flight review February 6, 2007; seat: right; flight hours: 5,526 total, 173 in this make and model, 3,947 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 12 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 73 °F, dew point 34 °F - Altimeter: 29.94 inHg - Observed at: KELP, 15 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 20070522011779A](https://openairdocs.org/incident/20070522011779A), May 22, 2007: Snias AS350B3, San Elizario, TX, Destroyed, 1 fatal. (-23) On may 22, 2007 at 0838 MDT, a Eurocopter as 350 B3, N851BP, registered to us border patrol air operations, collided with terrain while performing… ## Docket (37 files) The files NTSB released with the investigation on December 23, 2008, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=65826. 37.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 671 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305396&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Materials Laboratory 15 - Factual Report 07-079 (item 2, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40278783&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2007-079-Master.PDF - Witness Statements - Interviews by CBP (item 3, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397750&FileExtension=.PDF&FileName=Witness%20Statements%20-%20Interviews%20by%20CBP-Redacted.PDF - Witness Statement CBP Statement (item 4, .PDF, 8 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305431&FileExtension=.PDF&FileName=Witness%20Statement%20CBP%20Statement-Redacted.PDF - Map of Accident Area (item 5, .PDF, 135 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305411&FileExtension=.PDF&FileName=Map%20of%20Accident%20Area-Master.PDF - Satellite Maps of Crash site (item 6, .PDF, 133 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305412&FileExtension=.PDF&FileName=Satellite%20Maps%20of%20Crash%20site-Master.PDF - GPS track of flight (item 7, .PDF, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305413&FileExtension=.PDF&FileName=GPS%20track%20of%20flight-Master.PDF - Weather Reports and Records (item 8, .PDF, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305414&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF - Photo 1 Overview top (item 9, .PDF, 6.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40317226&FileExtension=.PDF&FileName=Photo%201%20Overview%20top-Master.PDF - Photo 2 Overview top 2 (item 10, .PDF, 934 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305418&FileExtension=.PDF&FileName=Photo%20%202%20Overview%20top%202-Master.PDF - Photo 3 main rotor and engine compartment (item 11, .PDF, 948 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305419&FileExtension=.PDF&FileName=Photo%203%20main%20rotor%20and%20engine%20compartment-Master.PDF - Photo 4 Tailboom and truck damage (item 12, .PDF, 957 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305420&FileExtension=.PDF&FileName=Photo%204%20Tailboom%20and%20truck%20damage-Master.PDF - Photo 5 Tailboom and tailrotor (item 13, .PDF, 975 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305421&FileExtension=.PDF&FileName=Photo%205%20Tailboom%20and%20tailrotor-Master.PDF - Photo 6 Rear view (item 14, .PDF, 996 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305422&FileExtension=.PDF&FileName=Photo%206%20Rear%20view-Master.PDF - Photo 7 Rear view 2 (item 15, .PDF, 963 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305424&FileExtension=.PDF&FileName=Photo%207%20Rear%20view%202-Master.PDF - Photo 8 Tail rotor (item 16, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305426&FileExtension=.PDF&FileName=Photo%208%20Tail%20rotor-Master.PDF - Photo 9 Tail rotor hub (item 17, .PDF, 987 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305427&FileExtension=.PDF&FileName=Photo%209%20Tail%20rotor%20hub-Master.PDF - Photo 10 Helicopter bottom view (item 18, .PDF, 993 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305428&FileExtension=.PDF&FileName=Photo%2010%20Helicopter%20bottom%20view-Master.PDF - Photo 11 Helicopter cabin (item 19, .PDF, 933 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305429&FileExtension=.PDF&FileName=Photo%2011%20Helicopter%20cabin-Master.PDF - Photo 12 Instrument Panel (item 20, .PDF, 836 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305430&FileExtension=.PDF&FileName=Photo%2012%20Instrument%20Panel-Master.PDF - Reports from Federal Agencies - FBI witness unterviews (item 21, .PDF, 572 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305437&FileExtension=.PDF&FileName=Reports%20from%20Federal%20Agencies%20-%20FBI%20witness%20unterviews-Redacted.PDF - Reports from Parties to the Investigation - Turbomeca Engine Report (item 22, .PDF, 731 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305439&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20-%20Turbomeca%20Engine%20Report-Master.PDF - Reports from Parties to the Investigation - Turbomecas DECU Report (item 23, .PDF, 40 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397734&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20-%20Turbomecas%20DECU%20Report-Redacted.PDF - Reports from Federal Agencies - BEA France VEMD Report (item 24, .PDF, 99 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305444&FileExtension=.PDF&FileName=Reports%20from%20Federal%20Agencies%20-%20BEA%20France%20VEMD%20Report-Master.PDF - Reports from Parties to the Investigation - EU France VEMD Report (item 25, .PDF, 150 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397735&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20-%20EU%20France%20VEMD%20Report-Redacted.PDF - Reports from Parties to the Investigation - EU France Wiring Harness exam (item 26, .PDF, 521 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305446&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20-%20EU%20France%20Wiring%20Harness%20exam-Master.PDF - Reports from Parties to the Investigation - Turbomeca HMU exam (item 27, .PDF, 939 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305447&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20-%20Turbomeca%20HMU%20exam-Master.PDF - Other Pertinent Forms and Reports - Hawker Pacific Servo exam (item 28, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305450&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Hawker%20Pacific%20Servo%20exam-Master.PDF - Other Pertinent Forms and Reports - Goodrich Servo Report (item 29, .PDF, 143 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397736&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Goodrich%20Servo%20Report-Redacted.PDF - Other Pertinent Forms and Reports - Goodrich Servo Report 2 (item 30, .PDF, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397737&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Goodrich%20Servo%20Report%202-Redacted.PDF - Other Pertinent Forms and Reports - Maintenance Records Extract (item 31, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40397738&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Maintenance%20Records%20Extract-Redacted.PDF - Other Pertinent Forms and Reports -Hydrauluc fluid test results (item 32, .PDF, 256 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305452&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-Hydrauluc%20fluid%20test%20results-Master.PDF - Other Pertinent Forms and Reports - Weight and Balance (item 33, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305457&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Weight%20and%20Balance-Master.PDF - Other Pertinent Forms and Reports - AS350B3 Flight manual Performance chapter Extract (item 34, .PDF, 715 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305461&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20AS350B3%20Flight%20manual%20Performance%20chapter%20Extract-Master.PDF - Other Pertinent Forms and Reports - Height Velocity Diagram (item 35, .PDF, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305454&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Height%20Velocity%20Diagram-Master.PDF - Other Pertinent Forms and Reports - Rotorcraft Flying Handbook Extract Chapter 11 (item 36, .PDF, 148 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305463&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports%20-%20Rotorcraft%20Flying%20Handbook%20Extract%20Chapter%2011-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 37, .PDF, 129 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40305467&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF From the NTSB's public API. 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