What happened
On January 19, 2024, a Cessna 208B, registration N1983X, was operating a scheduled domestic passenger flight from Washington Dulles International Airport (IAD) to Lancaster Airport (LNS). The flight, operated by Southern Airways Express, included two commercial pilots and five passengers.
During the initial climb, approximately 400 feet above the ground, the flight crew experienced engine vibrations described as feeling "like a flat tire," accompanied by a loss of engine power. The pilot-in-ability began a turn to return to IAD and declared an emergency. Realizing the aircraft could not reach the runway, the crew elected to land on a highway in front of them. During the landing roll-out, the aircraft contacted a right guard rail, causing minor damage to the airplane. There were no injuries to the seven people on board.
At the time of the incident, the weather at IAD included light snow and temperatures below freezing, with a visibility of 1 mile and winds from 330 degrees at 10 knots.
The investigation
Investigators examined the aircraft's turboprop engine and found no evidence of mechanical failure or internal damage that would have prevented normal operation. A test cell run confirmed the engine met performance specifications. The propeller blades showed damage consistent with significant rotational energy at the time of impact.
Review of the aircraft's Pilot Operating Handbook (POH) indicated that a tactile check of the wing is required when the outside air temperature is below 10°C (5D°F). Surveillance video showed that the flight crew did not perform a tactile inspection of the lift-generating surfaces. While the crew performed a visual check of the wings before takeoff and noted they were "just wet," post-incident photographs by first responders showed contamination buildup on the wings and horizontal and vertical stabilizers.
Findings
- The pilot-in-command's approach to the critical angle of attack during the initial climb caused vibrations that the crew misidentified as an engine issue.
- The aircraft's groundspeed decreased below the stall speeds listed in the POH during the climb.
- The pilot-in-command decided not to deice the aircraft and did not perform a tactile check of the wings.
- The operator provided inadequate and contradictory guidance regarding when flight crews should perform tactile versus visual contamination checks in winter conditions.
- Ice had accumulated on the airframe prior to takeoff.