DFW07GA119

NTSB accident investigation · Eurocopter AS 350 B3 · San Elizario, TX · May 22, 2007

Accident · FatalFinal report
Date
May 22, 2007, 08:38 local (14:38 UTC)
Place
San Elizario, TX
Injuries
1 fatal, 1 serious
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N851BPEurocopter AS 350 B3
Weather
Visual (VMC) · Day
Status
Completed · report December 28, 2008
Report
Approved by Office Director
Parties
CBP Air, Turbomeca, FAA, American Eurocopter
FAA report
20070522011779A
Case key
65826

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The NTSB’s determination of the probable cause, and any contributing factors.

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

The factual narrative1,268 words

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

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of control - in flightHover - out of ground effect
Vortex ring state - encounteredPilot in commandCause
Aircraft control - not possiblePilot in commandCause
In flight collision with objectDescent - uncontrolled
Object - vehicle

Aircraft

Registration
N851BP
Reported as
Eurocopter AS 350 B3
Category
Helicopter
Serial number
3588
Airframe hours
3,819
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
46
Injuries
Fatal
Certificates
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

Docket · 37

The files NTSB released with the investigation on December 23, 2008, on NTSB’s docket system: statements, records, photos and specialists’ reports. 37.5 MB in all.

Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1Item 1 · .PDF · 671 KBMaterials Laboratory 15 - Factual Report 07-079Item 2 · .PDF · 1.3 MBWitness Statements - Interviews by CBPItem 3 · .PDF · 1.3 MBWitness Statement CBP StatementItem 4 · .PDF · 8 KBMap of Accident AreaItem 5 · .PDF · 135 KBSatellite Maps of Crash siteItem 6 · .PDF · 133 KBGPS track of flightItem 7 · .PDF · 3.6 MBWeather Reports and RecordsItem 8 · .PDF · 2.0 MBPhoto 1 Overview topItem 9 · .PDF · 6.7 MBPhoto 2 Overview top 2Item 10 · .PDF · 934 KBPhoto 3 main rotor and engine compartmentItem 11 · .PDF · 948 KBPhoto 4 Tailboom and truck damageItem 12 · .PDF · 957 KBPhoto 5 Tailboom and tailrotorItem 13 · .PDF · 975 KBPhoto 6 Rear viewItem 14 · .PDF · 996 KBPhoto 7 Rear view 2Item 15 · .PDF · 963 KBPhoto 8 Tail rotorItem 16 · .PDF · 1.0 MBPhoto 9 Tail rotor hubItem 17 · .PDF · 987 KBPhoto 10 Helicopter bottom viewItem 18 · .PDF · 993 KBPhoto 11 Helicopter cabinItem 19 · .PDF · 933 KBPhoto 12 Instrument PanelItem 20 · .PDF · 836 KBReports from Federal Agencies - FBI witness unterviewsItem 21 · .PDF · 572 KBReports from Parties to the Investigation - Turbomeca Engine ReportItem 22 · .PDF · 731 KBReports from Parties to the Investigation - Turbomecas DECU ReportItem 23 · .PDF · 40 KBReports from Federal Agencies - BEA France VEMD ReportItem 24 · .PDF · 99 KBReports from Parties to the Investigation - EU France VEMD ReportItem 25 · .PDF · 150 KBReports from Parties to the Investigation - EU France Wiring Harness examItem 26 · .PDF · 521 KBReports from Parties to the Investigation - Turbomeca HMU examItem 27 · .PDF · 939 KBOther Pertinent Forms and Reports - Hawker Pacific Servo examItem 28 · .PDF · 1.5 MBOther Pertinent Forms and Reports - Goodrich Servo ReportItem 29 · .PDF · 143 KBOther Pertinent Forms and Reports - Goodrich Servo Report 2Item 30 · .PDF · 2.4 MBOther Pertinent Forms and Reports - Maintenance Records ExtractItem 31 · .PDF · 1.3 MBOther Pertinent Forms and Reports -Hydrauluc fluid test resultsItem 32 · .PDF · 256 KBOther Pertinent Forms and Reports - Weight and BalanceItem 33 · .PDF · 1.4 MBOther Pertinent Forms and Reports - AS350B3 Flight manual Performance chapter ExtractItem 34 · .PDF · 715 KBOther Pertinent Forms and Reports - Height Velocity DiagramItem 35 · .PDF · 100 KBOther Pertinent Forms and Reports - Rotorcraft Flying Handbook Extract Chapter 11Item 36 · .PDF · 148 KBStatement of Party Representatives to NTSB InvestigationItem 37 · .PDF · 129 KB

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.