Accident Details
Probable Cause and Findings
the pilot's continued flight into adverse weather conditions resulting in a loss of control due to spatial disorientation. Contributing factors were the dark night illumination, the lack of visual cues, the pilot's lack of total instrument time, and the pressure induced by the medical emergency to complete the medical evacuation.
Aircraft Information
Registered Owner (Historical)
Analysis
HISTORY OF FLIGHT
On June 5, 1998, at 0549 central daylight time, a Eurocopter AS350BA medical ambulance helicopter, N911VA, was destroyed upon impact with trees and terrain near La Gloria, Texas. The instrument rated commercial pilot and two medical technicians on board the helicopter were fatally injured. The helicopter was owned by Metro Aviation of Shreveport, Louisiana, and operated by Tex-Air Helicopters of Houston, Texas. Dark night visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 positioning flight for which a company VFR flight plan was filed. The flight departed from a heliport near Harlingen, Texas, at 0514, with a location known as Humble Kelsey, located approximately 8 nautical miles to the northeast of La Gloria along Highway 755, as its intended destination.
The helicopter was dispatched to pick up and transport the driver of an 18-wheeler tanker truck, who had been seriously injured when he lost control of his truck while driving in reduced visibility on Highway 755. The pilot was not provided the coordinates of the truck accident site; however, he was familiar with the town of La Gloria, Texas, which he planned to use as the initial point for locating Highway 755 prior to proceeding northeast bound towards Humble Kelsey to pick up the injured truck driver. The helicopter, operating under the call sign "Air Care One," departed its home base heliport with 1 hour and 55 minutes of fuel on board. At 0529, the pilot reported to his dispatcher that the flight was en route over the Edinburg Airport, estimating arrival at the accident site in 16 minutes. In the last position report to his home base at 0539, the pilot reported that he was "5 minutes out" from his destination and announced that he was "switching to ground."
The helicopter was assigned a mode C transponder code of 5377. Air Traffic Control (ATC) radar tracked the helicopter from 05:19:56 to 05:34:15 flying on a west northwest heading from Harlingen toward La Gloria. During this time period, the helicopter's altitude remained between 700 feet and 1,100 feet MSL. Radar contact was then lost until 05:47:06 when one radar return was recorded which indicated the helicopter was at 1,800 feet, approximately 2 miles southeast of the site where it crashed. Two-way radio communication was not established between the helicopter and any ATC facility in the area. The helicopter failed to arrive at its destination and a search was initiated.
The wreckage of the helicopter was located 30 hours after the accident in a mesquite covered sparsely populated rural area of Starr County, Texas. The accident site was approximately 19.0 nautical miles west of the flight's intended destination, the truck accident location.
There were no reported eyewitnesses to the accident.
PERSONNEL INFORMATION
The 46-year old commercial pilot, who was occupying the right seat of the helicopter, had been employed by the operator since January 1998. He received his commercial pilot certificate on December 13, 1996. According to the operator, the pilot had accumulated a total of 2,950 flight hours, of which 54 hours were in the same make and model as the accident helicopter. The pilot had accumulated a total of 4 hours of actual and 45 hours of simulated instrument flight time. The pilot logged no actual or simulated instrument time in the 90 days preceding the accident. The pilot had accumulated a total of 30 hours of night flight, of which 20 hours were accumulated during the preceding 90 days.
The pilot received a helicopter instrument rating on January 5, 1998, prior to his employment with Tex-Air Helicopters. During his training in preparation for his instrument rating, the pilot received a total of 15.4 hours of ground instrument training and a total of 5.0 hours of instrument flight training prior to taking his instrument check ride. The operator of the training facility that provided the instrument training reported that the pilot failed his first instrument check ride due to deficiencies in basic instrument proficiency and ADF navigation. This check ride was 1.2 hours in duration. The pilot was provided an additional hour of remedial ground school and an additional 1.3 hours of remedial flight training. The pilot was reported to have satisfactory completed the second check ride, which was given two days after the first check ride and lasted 0.9 hours. Including the two check rides, the pilot accumulated a total of 8.4 hours of instrument flight time during this training.
Interviews of the pilot's co-workers revealed that the pilot was very concerned about night flights in the sparsely populated areas north of the Rio Grande Valley in southwest Texas due to the lack of lights on the ground to maintain visual reference. One of the other pilots told the FAA inspector that "at night the area west of the Interstate highway is a big black hole."
AIRCRAFT INFORMATION
The 1981 model helicopter, serial number 1446, had accumulated a total of 4,752.7 flight hours (1,565.0 Hobbs meter hours) at the time of the accident. The helicopter was manufactured in France and re-assembled in Grand Prairie, Texas, on February 25, 1982. The helicopter was being maintained under the manufacturer's maintenance program. The last scheduled maintenance performed on the helicopter was a 100-hour inspection, which was completed on April 17, 1998, at 4,706.2 hours, 46.5 hours prior to the accident. The aircraft logbook was recovered at the accident site. According to the operator, and as confirmed by examination of the aircraft logbook, there were no open deferred maintenance items on the helicopter at the time of the accident.
The 641-horsepower Turbomeca Arriel 1B turboshaft engine, serial number 801, was manufactured in France, on August 24, 1984. The engine had accumulated a total of 4,156.9 hours since new. The last overhaul was completed on June 16, 1994, at 2,997.8 hours. The last engine inspection was completed at 4,062.0 hours, on April 17, 1998.
The basic empty weight of the helicopter was 3,079 pounds, and the maximum gross weight was 4,630 pounds. Weight and balance calculations were performed using figures provided by the operator. The aircraft was found to be within its weight and balance limits at the time of the accident.
The pilot who flew the helicopter prior to the accident flight on the day before the accident was asked by the NTSB investigator-in-charge (IIC) to provide a statement regarding the condition of the aircraft. The pilot stated that "the aircraft flew well and responded normally." The pilot further stated that "no discrepancies were noted during the flight."
The maintenance records for the helicopter were initially reviewed by the FAA inspector who responded to the accident site. The records were later forwarded to the NTSB IIC for further examination. Review of the maintenance records for the helicopter and powerplant did not reveal any evidence of overdue inspections or uncorrected discrepancies that could have contributed to the accident.
The helicopter was equipped for night flights. Besides the on-board medical equipment installed, the following optional equipment was installed in the helicopter: a 3-axis (pitch, roll, yaw) auto pilot system, a strobe light system, a radar altimeter, an EMS lighting system, a GPS with moving map display, and an air conditioner.
METEOROLOGICAL INFORMATION
McAllen, Texas, located 46 nautical miles southeast (132 degrees) of the accident site, was the nearest weather reporting station to the accident site. At 0553, McAllen was reporting a broken ceiling at 1,400 feet, with a visibility of 5 statute miles. The temperature to dew point spread was reported as 1 degree.
A farm worker residing at the Diamond O Ranch, approximately 11 miles southeast of the accident site, reported that visibility on the day of the accident, as well as on the previous day, was "severely restricted by thick smoke from fires in Mexico." The witness stated that a wind mill located approximately 1.25 miles northeast of his house was not visible due to the prevailing smoke. The witness added that a strong wind from the south prevailed on the day of the accident.
The injured truck driver, for whom the flight was intended, was eventually transported to a hospital by ground ambulance. He fully recovered from his injuries. He reported that he was the lead driver of a 30-truck convoy traveling northeast bound on highway 755. He was very familiar with that part of the country. His company required all of the drivers in the convoy to attend a safety briefing prior to their departure. The possibility of encountering fog and restricted visibility was discussed during the safety briefing. Drivers were instructed to slow down and watch their spacing. For the previous 2 months, the area had been affected by ground fog in the early mornings. He added that on the morning of the accident, ground visibility had been restricted due to patchy ground fog and smoke; however, the fog was not as bad as it had been on previous drives. He stated that he had been operating his windshield wipers intermittently to keep the windshield clear and the surface of the highway was "very slick." The driver added that he recalls the paramedics telling him that they could hear the helicopter approaching the accident site, but later stating that it must have been another helicopter, because the one they heard kept on going.
According to the U.S. Naval Observatory, sunrise occurred at 0640 local time. Moonset occurred at 0350 local. The phase of the moon was "waxing gibbous with 82% of the Moon's visible disk illuminated."
WRECKAGE AND IMPACT INFORMATION
The GPS location of the accident site, provided by the pilot of a helicopter that transported the investigation team to the accident site, was reported as 26 degrees 46.23 minutes North latitude, and 98 degr...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# FTW98FA256