Aviation Accident Summaries

Aviation Accident Summary DEN93FA052

TELLURIDE, CO, USA

Aircraft #1

N5650N

BEECH 58

Analysis

THE AIRLINE TRANSPORT-RATED PILOTS DEPARTED GRAND JUNCTION, CO, AT APPROXIMATELY 0345 MDT EN ROUTE TO FARMINGTON, NM, THEIR HOME BASE. AT 0351, THE FLIGHT LEVELED OFF AT 11,600 FEET ON A GROUND TRACK OF 135 DEGREES, AND MAINTAINED THAT HEADING AND ALTITUDE UNTIL RECORDED RADAR DATA ENDED AT 0407. ABOUT 0415, THE AIRPLANE IMPACTED A 14,246 FOOT MOUNTAIN AT THE 11,600 FOOT LEVEL. NO EVIDENCE OF PREIMPACT AIRFRAME, ENGINE, PROPELLER, OR FLIGHT CONTROL FAILURE OR MALFUNCTION WAS FOUND. AUTOPSY AND TOXICOLOGY PROTOCOLS CONDUCTED ON BOTH PILOTS FAILED TO DISCLOSE ANY PHYSICAL IMPAIRMENT. RECORDS SHOWED THAT BOTH PILOTS HAD BEEN ACTIVE SINCE 0800 THE PREVIOUS MORNING.

Factual Information

HISTORY OF FLIGHT On Thursday, April 29, 1993, at approximately 0415 mountain daylight time, N5650N, a Beech 58, collided with mountainous terrain about 8 miles south of Telluride, Colorado. The airline transport rated pilot (ATP) and the ATP rated passenger were fatally injured and the airplane was destroyed. Visual meteorological conditions prevailed for the business flight. According to Mesa Airlines officials, the pilot in command, a check airman for the Farmington, New Mexico, based airline, and the passenger, a check airman in training from Jacksonville,Florida, based Florida Gulf Airlines (a wholly owned subsidiary of Mesa Airlines), flew to Grand Junction, at some time on April 28. The pilot in command was to administer line checks to two newly hired Mesa Airlines' pilots and observe the actions of the second pilot, who was in training to become a company check airman. After administering the line checks, the two pilots departed Grand Junction in the early morning hours of April 29 to return to Farmington. At 0415, two citizens telephoned the San Juan County Sheriff's Office to report seeing a fireball atop 14,246 foot Mount Wilson, located about eight miles south of the Telluride Regional Airport. The wreckage was located in the Silver Pick Basin of Mt. Wilson at approximately the 11,900 foot level on the morning of April 30. WRECKAGE AND IMPACT INFORMATION The on scene investigation was conducted on May 1. Approximately two inches of snow had fallen since the accident. The airplane impacted 20 foot deep, hard packed snow. The terrain gradually sloped upwards. Both the NTAP plots and wreckage path were aligned on a magnetic heading of approximately 135 degrees. To the right of the wreckage path, the terrain sloped down at an approximate angle of 25 degrees. All major airplane components were recovered and documented. The initial point of impact was marked by a long thin scar in the snow. About 150 feet beyond was a second scar, 42 feet in length. Both propeller assemblies were found at the end of this scar. All three blades remained attached to their respective assemblies but were broken inside the hubs and were bent aft and twisted. Small pieces of fuselage and right wing were scattered for 450 feet. A third scar, measuring 57 feet in length, 10 feet in width, and five feet in depth, was found at the 650 foot mark. Nearby lay the left and right engines. The main wreckage was at the 790 foot mark. The left wing remained attached to the fuselage. Fire had damaged the instrument panel. Burning fuel dripping from the left fuel tank created a hole in the snow, five feet in diameter and about 20 feet deep. The left front seat, determined by part number, was located 12 feet beyond the main wreckage. The right front seat was found to the right of the wreckage. Control continuity was partially established. Measurements of the left and right elevator, rudder trim, and right flap actuators were 31mm (millimeters), 30 mm, 85 mm, and 56 mm. According to the Beech Aircraft Corporation, these measurements equate to 10.9 and 9.1 degrees tab down, 16.1 degrees tab right, and 2.3 degrees flaps down, respectively. The flap actuator was separated from both the flap and its mounting bracket. No permanent or portable oxygen system was found at the accident site. According to Mesa Airlines, the airplane was not equipped with an oxygen system. The airplane was again examined at a storage facility after it had been retrieved from the accident site. Hand rotation of the left and right propeller flanges produced rotation of the magneto drives and vacuum pump drive coupling, respectively. All four magnetos produced spark when rotated by hand. The Janitrol heater was disassembled and examined. No discrepancies were noted. The heater Hobbs meter read 13.9 hours. Fuel was found in the fuel control unit. MEDICAL AND PATHOLOGICAL INFORMATION Toxicological tests failed to disclose the presence of carbon monoxide or other incapacitating substances. Autopsy protocols likewise failed to disclose evidence of any physiological event that could have been causal to the accident. TESTS AND RESEARCH National Track Analysis Program (NTAP) data was retrieved by the Denver Air Route Traffic Control Center (ARTCC). According to this data, a VFR target (transponder code 1200) was observed leaving the Grand Junction area at 0345. As it passed through 7,100 feet MSL (above mean sea level), it steadied on a magnetic heading of 135 degrees and continued climbing to 11,600 feet. The target maintained this altitude from 0351 until radar contact was lost at 0407 at a point 11 miles north of Mount Wilson. The sheriff's office received the first call of a fireball at 0415. ADDITIONAL INFORMATION Mesa Airlines was asked to submit crew rest and duty time records for the two pilots. The following is a 72 hour record of activities for the pilot in command and passenger prior to the accident: Monday, April 26, 1993: 0400 Off duty. 1900 Administered two Beech 1900 first officer initial oral exams. Conducted one Beech 1900 captain recurrency oral exam. 2230 Travel to Durango. 2315 Administered one captain recurrency check ride in Beech 1900. Tuesday, April 27, 1993: 0030 Administered one first officer initial check ride in Beech 1900. 0400 Repositioned aircraft back to Durango. 0415 Return to Farmington. 0415 Off duty. 1500 On duty, travel status. 2230 Administered two recurrency check rides. Wednesday, April 28, 1993: 0200 Off duty. 0800 Pilot in command, on duty, travel status. 1145 Second pilot, on duty, travel status. 2100 Administers two first officer initial oral and flight checks. Administers one check airman oral and flight check. 0345 Travel status, en route to Farmington. Accident occurs.

Probable Cause and Findings

FAILURE OF THE PILOT-IN-COMMAND TO PLAN AND/OR ASSURE SELECTION OF AN ALTITUDE/COURSE COMBINATION THAT WOULD PROVIDE TERRAIN CLEARANCE, AND FAILURE OF THE OTHER (SECOND) PILOT TO ADEQUATELY MONITOR THE SITUATION. DARKNESS, HIGH (MOUNTAINOUS) TERRAIN, AND PILOT/CREW FATIGUE WERE RELATED FACTORS.

 

Source: NTSB Aviation Accident Database

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