Think about some of the performance numbers you use to operate your aircraft—climb or descent rates, airspeeds, and so on. In a jet, most of those numbers normally increase, significantly. In a Cessna 172, a descent rate of 3,100 fpm would be frightening to anyone on board, not to mention the nose down angle required for that rate would probably rip parts from the fuselage. But in a jet, a descent rate of 3,100 fpm would be quick, but not all that unusual if the PIC received an “increase your rate of descent” request from ATC. Now, imagine an unplanned descent rate of 31,000 fpm, a 10-fold increase. The airplane’s nose would be pointed nearly straight down, but not for long before this jet would also begin shedding parts.
That 31,000-fpm descent rate is one of the last pieces of usable radar data the Nashville TRACON’s radar recorded from N66BK, a Cessna Citation 501, before it crashed into Lake Percy Priest about 3 nm northeast of the Smyrna, Tennessee, airport (KMQY) on May 29, 2021. What facts are known were released last week in the NTSB’s preliminary report of the accident. The aircraft left KMQY on an IFR flight plan headed to West Palm Beach, Florida, and crashed less than three minutes after departure, claiming the lives of the pilot and all six passengers aboard. While legal to pilot the jet, the pilot had minimal experience with the airplane and apparently with flying in the IFR system.
“The airplane departed at 1053:06 and made a climbing right turn to the east,” according to the NTSB report. “The pilot was instructed to contact Nashville departure control. At 1054:27, when the airplane was about 3 miles north of the airport, a departure controller contacted the airplane and asked if they were ‘on frequency.’ The pilot responded with, ‘N66BK with you.’ The controller instructed the pilot to turn right to a heading 130 degrees; however, the pilot did not acknowledge. At 1054:46, the controller asked the pilot if he ‘copied’ the heading instruction. The pilot responded about four seconds later and said, ’130…Bravo Kilo.’ At 1055:11, the controller instructed the pilot to climb and maintain 15,000 ft but there was no response.” The controller then made multiple unsuccessful attempts to re-establish communications with the airplane.
“A review of radar data revealed that after the pilot established contact with departure control the airplane made a series of heading changes along with several climbs and descents before it entered a steep, descending left turn. The last radar return, at 1055:05, indicated the airplane was at an altitude of about 700 ft msl, descending about 31,000 [fpm], on a heading of 090.”
A nearby witness fishing in the lake heard what he thought was a low flying military jet before he saw the Citation impact the lake in a “straight down” nose-first attitude. He did not see any evidence of fire or an explosion. The airplane impacted a shallow section of the lake about 2 to 8 ft deep. After approximately two thirds of the aircraft wreckage was recovered, investigators were able to confirm there was no evidence of an in-flight fire prior to impact.
The Citation was not required to carry a flight data or a cockpit voice recorder, so little in-flight data exists to aid investigators. The NTSB said the commercial multi-engine pilot had logged nearly 1,700 hours and was type rated for the Citation, but had logged only 83 total hours in the accident aircraft. One item out of line was that his second-class medical was expired. Since that automatically reverts to a third class medical certificate, the pilot was legal to operate the jet under Part 91, though he could not exercise any of the privileges of his commercial pilot certificate. It is unknown how much of the pilot’s 83 hours were gained flying in actual IFR conditions.
The final NTSB report will include post-autopsy information about the pilot which may offer some insights into a probable cause. That final report will most likely not be available until 2023.