FTW93FA103

The airplane was in cruise flight along an airway, with a minimum en route altitude of 13,300 feet, when it impacted terrain at an elevation of 10,600 feet. Impact occurred on a snow covered mountain cresting at 11,301 feet. Dark night conditions existed and the pilot had just activated a VFR flight plan. Cargo included cobalt 60, a radioactive material. Supplemental oxygen was not available for the pilot or the passengers. Recorded radar data indicated that the airplane ground track was consistent with the measured ground scar heading of approximately 272 degrees. Tree/terrain impact occurred in a level flight attitude. Weight at the time of the accident was estimated to be 5,718 pounds; maximum gross weight was 5,400 pounds.

History of flight

On March 14, 1993, at approximately 2234 mountain standard time, a Beech 58, N4320W, was destroyed upon impact with terrain while in cruise flight near Grants, New Mexico. The airline transport pilot and his three passengers were fatally injured. Visual meteorological conditions prevailed for the 14 CFR Part 135 on demand air taxi flight from Houston, Texas, to Oakland, California. The airplane was owned and operated by Guinn Flying Service of Houston, Texas.

According to the Albuquerque Flight Service Station, the airplane landed at Albuquerque to refuel. The pilot filed a VFR flight plan at 2150 MST, with a planned altitude of 8,500 feet. At 2215 MST, the airplane made a VFR departure from Albuquerque. The pilot requested VFR flight following, was assigned a transponder code and identified as the airplane proceeded westbound along V291 at 10,500 feet (minimum en route altitude for the route is 13,300 feet). The pilot left the assigned frequency to open the VFR flight plan at 2231, and never returned to the assigned center frequency. Radar contact was lost approximately 60 miles west of Albuquerque.

Personnel information

The pilot in command was the owner of the Part 135 air taxi service. The flight was chartered by ICI Tracerco of Houston, Texas, to transport two of their technologists along with a cargo of radioactive material and related equipment to Oakland, California, for a working assignment in nearby Benicia.

According to the operator, their plan was to return to Houston as soon as the two passengers and their cargo were unloaded at Oakland. The third passenger aboard the airplane was a certificated commercial pilot on non paid status, along for the flight to assist the pilot in command on the return flight back to Houston. The cabin seating arrangement is enclosed in this report.

Aircraft information

The airplane was topped off with 121 gallons of 100LL AVGAS during their stop at Albuquerque. An estimate of the airplane's gross weight at the time of departure from Albuquerque and at the time of the accident was made based on the known weight of all the occupants, the known fuel status, and the actual weight of all the cargo and personal gear located with the wreckage. It was estimated that the weight of the airplane at the time of departure from Albuquerque was 5,798 pounds. The estimated weight at the time of the accident was 5,718 pounds. The certificated maximum takeoff weight for the airplane is 5,400 pounds.

Meteorological information

Official sunset on the night of the accident was at 1817 and the moon did not rise until 0116 the next morning. The pilot obtained a briefing prior to his departure and also received a weather update from flight service station during his stop at Albuquerque.

Communications

The airplane was tracked by radar from the point of departure, until radar contact was lost at 2233:10. The enclosed radar plot tracks the flight path of the airplane at 10,500 feet. The transcripts from all pertinent communications between the airplane and the air Traffic Control facilities are enclosed in this report.

Wreckage and impact information

The wreckage was located by a United States Air Force search and rescue helicopter at approximately 1235 the next afternoon. The airplane impacted trees and terrain on the east side of snow covered Mount Taylor, in the Cibola National Forest, at the 10,600 foot level (crest is at 11,301 feet).

Radioactive material (Cobalt 60) was on board the airplane at the time of the accident. The radioactive source was located, recovered, and removed on March 22, 1993. There was no reported environmental contamination or leakage.

The damage path through trees was on a measured heading of 272 degrees, which was consistent with the ground track of recorded radar data. The fuselage came to rest on a measured heading of 327 degrees. Tree strikes were found at consistent elevations.

The horizontal distance from the main wreckage to the initial tree strike was 92 feet. Terrain slope angle at the main wreckage was measured as 48 degrees sloping down to the east. A total of 19 aspen trees were either severed, uprooted, of severely damaged. Snow depth at the accident site was estimated to be between seven and nine feet.

Medical and pathological information

Autopsies and toxicological tests were ordered and performed on the pilot. The autopsy was performed by the Office of the State Medical Investigator, at the University of New Mexico in Albuquerque, New Mexico, on March 16, 1993.

Four prescriptions bearing the pilot's name were found among the personal effects for the passengers and crew. The prescriptions were shipped to the FAA Civil Aeromedical Institute for evaluation. Their evaluation report is enclosed in this report.

Survival aspects

The airplane was not equipped with shoulder harnesses. Supplemental oxygen was not available for the pilot nor the passengers. The installed emergency locator transmitter (ELT) failed to function during the impact sequence.

Test and research

The wreckage was recovered from the site and transported to Albuquerque, New Mexico, on June 24, 1993, where a complete wreckage layout and detailed examination was accomplished on June 25, 1993. The cargo was segregated from the baggage and personal belongings, and weighed. Both engines were examined on August 31 and September 1, 1993. The propellers were examined on October 16, 1993. The results of their examination are enclosed in this report.

Additional data

The wreckage was released to the owner's representative on September 13, 1993, upon completion of the investigation.