Incident Overview
On 23 September 2020, a Cessna C208B Super Cargomaster (registration N967FE) was operating a commercial cargo flight from San Juan International Airport, Puerto Rico, to Terrance B. Lettsome International Airport on Beef Island, Tortola, British Virgin Islands. The pilot discontinued the first approach due to poor weather. During the subsequent approach, the aircraft touched down 795 m beyond the threshold of the 1,206 m runway. The right tyre burst on landing, and the under-fuselage baggage pod contacted the runway. During the landing roll, the aircraft veered to the right onto grass, coming to rest approximately 18 m north of the runway. The pilot was not injured.
Flight History
The pilot departed San Juan at 1619 UTC, routing northeast and climbing to 7,000 ft. At 1642 UTC, he began a descent toward the western edge of Tortola. He contacted Beef Island Air Traffic Control (ATC) for a visual approach to Runway 25. ATC advised of wind from 180° at 12 kt and showers approaching the field. The pilot initially reported joining a right downwind, but at 1659 UTC he was 10 nm west-southwest of the airport. Unable to see the airport, he requested a diversion to San Juan. While routing northwest, the aircraft passed overhead Beef Island Airport at about 5,000 ft. The pilot saw the runway and decided to attempt a visual approach. ATC cleared him for a visual approach to Runway 25.
During the descent on a wide right base, the pilot entered a rain shower and lost visual contact with the runway, executing a go-around. He reported applying full power and pitching up, but the aircraft did not climb. He felt like it was experiencing strong windshear. Two witnesses observed the aircraft at approximately 200 ft, too high and fast to land, and noted it was swaying side to side before the nose turned down and it descended. Air traffic controllers also saw the aircraft fly along the runway before a sudden descent.
Recorded Data
The aircraft was not equipped with a Flight Data Recorder or Cockpit Voice Recorder, but the engine had a Pratt & Whitney Canada ADAS+ engine monitoring system. The data for the approach showed the aircraft descended at 155–160 kt with an average rate of descent of 1,400 ft/min until 350 ft above aerodrome level. Approximately 30 seconds from landing, engine power substantially reduced, as indicated by decreases in gas generator speed and torque. The airspeed decreased to about 95 kt, and the aircraft flew level at 250 ft for 10 seconds. However, the gas generator speed continued to fall below the expected high idle value of 62%, and propeller rpm decayed. A high rate of descent approaching 2,000 ft/min developed as the aircraft passed through 150 ft. The Emergency Power Lever, which could directly modulate fuel flow, was not used. The data showed no significant short-term airspeed changes indicative of windshear.
Flight tracking data from Flightradar24 and CCTV footage from the airfield corroborated the flight path and the landing sequence, showing the aircraft banked to the right at touchdown.
Examination and Findings
Examination and testing of the engine found no evidence of anomalies. It was not possible to determine why the engine operated below the normal idle speed while in flight. The approach did not meet the operator’s stable approach criteria. It is likely that the pilot was experiencing high workload due to the unstable approach and poor weather, which may have limited his ability to manage the situation. The operator intends to update its operations manual to specify the altitude by which stable approach criteria must be achieved for all approaches.