NTSB Factual Report

On February 2, 2006, at 0143 eastern standard time (est), a Bell 206L-1 helicopter, N593AE, operated by Petroleum Helicopters, Inc., based in Lafayette, Louisiana, was destroyed during impact with trees, wires, and residential structures while maneuvering near Chesterfield, Indiana. The emergency medical service (EMS) flight was dispatched to pickup a patient at the St. Joseph Hospital, Kokomo, Indiana, and was operating under the provisions of 14 Code of Federal Regulations Part 91 when the accident occurred. Instrument meteorological conditions prevailed during the flight. The pilot, flight nurse, and paramedic were seriously injured. The flight departed Anderson Municipal Airport (AID), Anderson, Indiana, at 0139.

During an interview with a Federal Aviation Administration (FAA) Operations Inspector, the pilot reported that they received the dispatch call at 0131. He went outside to assess the current weather conditions, which he described as being a "little hazy." The pilot then checked the local weather radar depiction and the surface conditions at the departure airport and Kokomo Municipal Airport (OKK). He indicated that the weather conditions at AID and OKK were suitable for visual flight rules (VFR) operations. The pilot reported that he did not listen to the airport's automated weather observing system (AWOS) broadcast before departure.

The pilot stated that he departed to the north and almost immediately entered instrument meteorological conditions. He radioed dispatch advising that he was aborting the flight and returning to the base. He started a right turn back toward the airport. The pilot stated that he had difficultly maintaining level flight and felt that the helicopter was climbing slightly during the turn. He thought the attitude indicator was giving a false indication because it was not moving and was "cocked off center about 30 degrees." The pilot verified that the circuit breaker for the attitude indicator was not tripped. He saw some ground lighting to the left of the helicopter and started a left turn toward the lights. The pilot remembered seeing two houses before impact and attempted to steer the helicopter between them.

According to company dispatch records, the flight departed at 0139:30 (hhmm:ss) and shortly after departure the pilot reported that he was aborting the flight due to poor weather conditions. The helicopter's position (latitude, longitude, altitude) was transmitted to a dispatch center every 30 seconds. The global positioning system (GPS) data was recovered from the dispatch monitoring system. The plotted data showed the helicopter departing to the north, and then it made a climbing right turn, followed by a climbing left turn. The helicopter's maximum recorded altitude during the left turn was 1,952 feet mean sea level (msl), or about 1,035 feet above ground level (agl). At 0142:30, the final GPS position showed the helicopter near the intersection of Linden Lane and 10th Street at an altitude of 1,528 feet msl (610 feet agl).

The helicopter initially impacted two pine trees located on the southwest corner of SR-32 (Main Street) and Shepard Drive. The helicopter then contacted utility lines that were running parallel to and located on the south side of Main Street. The helicopter then proceeded northeast across Main Street impacting a residential structure, a tree, and a garage. The helicopter traveled about 325 feet from the initial contact with the two pine trees to its final position.

The closest weather reporting facility to the accident site was at the departure airport. The airport was equipped with an automated weather observing system (AWOS). The local weather conditions were continually broadcast and accessible using a telephone or radio. The following weather conditions were reported by the AID AWOS:

At 0045 est: Calm winds; visibility 3 statute miles (sm) with mist; sky overcast at 400 feet agl; temperature 2 degrees Celsius; dew point 2 degrees Celsius; altimeter setting 29.78 inches of mercury.

At 0145 est: Calm winds; visibility 2 1/2 sm; sky overcast at 400 feet agl; temperature 2 degrees Celsius; dew point 2 degrees Celsius; altimeter setting 29.78 inches of mercury.

The departure airport was classified as Class-D airspace when the control tower was operational (0600 to 2200 est). At the time of the accident, the departure airport was classified as Class-G (uncontrolled) airspace. At night, the minimum visibility to operate under visual flight rules (VFR) in Class-G airspace is 3 sm. In addition to the minimum visibility, an aircraft must also maintain a minimum distance of 500-feet below, 1,000-feet above, and 2,000-feet horizontal from any cloud formation.

The accident helicopter was not certified for flight in instrument meteorological conditions (IMC). The pilot held a commercial pilot certificate with an instrument rating for helicopters. According to company documentation, the pilot had logged 26 hours of instrument experience since being hired in 1989. He had flown 13 hours during the prior 90 days, none of which were in IMC.

The attitude indicator (p/n 504-0017-901-5, s/n 10432B) was manufactured by Jet Electronics & Technology, Inc. The electronic attitude indicator was removed from the wreckage and sent to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) for testing. The attitude indicator was tested in the presence of the NTSB IIC on December 27, 2006. The attitude indicator was mounted on an oscillating test apparatus commonly used during maintenance. Electrical power was applied to the attitude indicator and it displayed a level attitude within the approved time specifications. The attitude indicator displayed values within test specifications when the device was placed in several static pitch and roll positions. The attitude indicator displayed the correct orientation while it was oscillated in both roll and pitch axis for a period of 5 minutes. The attitude indicator displayed values within test specifications when it was rechecked using several static pitch and roll positions. Electrical power was disconnected from the instrument and its gyro spun-down completely. The attitude indicator was then powered-up again and it displayed a level attitude within the approved time specification.

NTSB Probable Cause

The pilot's failure to maintain aircraft control after becoming spatially disorientated shortly after departure. Contributing to the accident was the pilot's inadequate preflight weather evaluation, his inadvertent flight into night instrument meteorological conditions, and the ground objects that the helicopter impacted during the descent.