Beech King Air B90, San Jon, N.M., May 14, 2001–The NTSB determined that the probable cause of the accident was the pilot’s failure to maintain aircraft control due to his incapacitation for an undetermined reason. A contributing factor was the subsequent inadvertent stall/spin to the ground.
At 11:22 p.m. MDT King Air N221CH was destroyed when the pilot lost control in cruise flight and the aircraft subsequently spun to the ground near San Jon. The sole-occupant ATP-rated pilot was killed. The airplane was being operated by CMH Investments of Benton, Ark. on a Part 91 positioning flight from Tucson, Ariz., to Springdale, Ark., and was on an IFR flight plan operating in night VMC.
The pilot requested that the airplane be “topped off” before departing Tucson, and the line-service technician pumped 897 pounds of jet-A into the airplane’s tanks. The pilot received a weather briefing and filed an IFR flight plan. Tucson Tower reported that the airplane was airborne at 9:03 p.m.
At 9:39 p.m. Albuquerque Center radioed the pilot to confirm that his altimeter was set at 29.92 because radar returns were showing him at 25,400 feet, 400 feet higher than assigned. The pilot responded, “Affirmative.”
At 10:46 p.m., the pilot was again asked if he would verify that his altimeter was set at 29.92 because radar was showing him to be 300 feet high. The pilot responded, “We might be a little bit high, we’ll correct that.”
Two minutes later Albuquerque Center notified the pilot that radar showed the airplane 500 feet low of the assigned altitude (24,500 feet). The pilot responded, “I just can’t get it right, can I, I’ll get it straight here in a minute.” ARTCC documented, between 11:05 p.m. and 11:11 p.m., the airplane’s altitude readout was 300 feet high, then 400 feet high and then 700 feet high, and that the pilot responded to ARTCC inquiries with “slurred, unclear speech” to standby a minute.
At 11:15 p.m. the airplane reached a maximum altitude of 26,300 feet. For approximately the next two minutes, more than 30 hot-mike transmissions were recorded in which heavy breathing could be heard. At 11:18 p.m., the pilot’s last transmission was “ah, Charlie Hotel, we, we’ve a little bit of a problem here. We’re in a descent, we’ll straighten it out in a minute.” A warning horn could be heard in the background during this last transmission.
Albuquerque Center reported losing radar contact with the airplane at 11:19 p.m.
Several witnesses in the San Jon, area saw the airplane “fall” out of the sky. Another witness said that he saw the airplane’s navigation lights alternating red and green as it rotated down through the sky. One witness said the engines “sounded to him like they were under full power.” Local residents reported that the atmosphere was “very clear” and the visibility was “unlimited” at the time of the accident. The subsequent investigation found no pre-accident engine or airframe problems that might have affected the airplane’s performance.
According to FAA records, the pilot had logged more than 16,800 hours TT, with 3,000 hours in make and model. The pilot had successfully completed a recurrent ground- and flight-training course in the King Air B90 series aircraft approximately six-months before the accident.
The pilot’s wife said that he was in good health and he ran on a treadmill at the local family community center. However, the pilot’s current employer said the pilot didn’t run for exercise, but did walk regularly at the family community center. He also said that the pilot shared several stories with him in which the pilot flew at altitudes of 14,000 to 15,000 feet in non-pressurized aircraft with no apparent physiological effects. On one occasion, while the pilot was transporting a passenger who was a smoker, the passenger complained that she couldn’t breathe. The passenger reported that the pilot smiled and said he would fly at a lower altitude. They were at 16,500 feet.
On the flight from Springdale to Tucson, the owner of the aircraft said that the pilot slept two hours out of the 4.5-hour flight (the owner was a pilot without a current FAA medical). The owner said the pilot was a “very good” pilot, but his sleeping while in the air had worsened over the last couple of years. Several friends reported that the pilot was also observed to “easily doze” off while on the ground, but he did so more regularly and for longer periods while flying. Many people in the Springdale community reported to the investigator about the pilot’s propensity to “take cat naps” while flying. On one occasion, while flying a late-night IFR flight back to Springdale, the pilot flew past his turn point and Center personnel had to call him several times to get him to turn back on course.
The University of New Mexico School of Medicine’s Office of the Medical Investigator performed an autopsy. The doctor identified moderate emphysema in the 61-year-old pilot’s lungs. The autopsy also revealed the presence of fractures of both ankles and of the left forearm, which are consistent with the pilot bracing against the “floor boards” and the flight controls of the aircraft before the crash. The FAA’s Civil Aeromedical Institute in Oklahoma City, Okla., performed toxicology tests for carbon monoxide, cyanide, alcohol and drugs, all with negative results.