Aeroméxico Connect Flight 2431

Aeroméxico Connect Flight 2431 was a Mexican domestic scheduled passenger flight bound for Mexico City that crashed on takeoff from Durango International Airport on July 31, 2018. Shortly after becoming airborne, the plane encountered sudden wind shear caused by a microburst. The plane rapidly lost speed and altitude and impacted the runway, detaching the engines and skidding to a halt about 300 m beyond the runway. The plane caught fire and was destroyed. All 103 people on board survived, but 39 passengers and crew members were injured.

A final report on the crash was released on February 23, 2019. Investigators found that the primary cause of the accident was adverse weather conditions encountered by the flight, and contributing factors included crew error, air traffic controller error, and the lack of equipment that could detect wind shear conditions at airports. Investigators determined that the flight crew was distracted by an unauthorized student in the cockpit who was flying the plane, which led to a loss of situational awareness. The crew failed to react to dangerous weather conditions that were developing, and did not notice irregularities in the airspeed indicators that could have alerted them to potential hazards. The sole air traffic controller on duty at the airport at the time also failed to notify the aircraft of rapidly deteriorating weather conditions.

The accident and the subsequent investigation led to changes in Mexican aviation regulations to prevent non-working airline employees from being present in the cockpit of an aircraft at any time during a flight. Investigators also made several recommendations for changes in flight crew and air traffic controller training, and to improve the capabilities of weather detection equipment in place at airports to improve overall aviation safety.

Accident

The flight, number 2431, was operated by Aeroméxico Connect and was a regularly scheduled flight from Durango International Airport to Mexico City International Airport. Originally scheduled to leave at 2:56 p.m. Central Time (UTC−06:00), the departure was slightly delayed when the first officer observed a fuel leak from the number one engine and asked maintenance crews to investigate. Crews eventually concluded that the rate of leakage was within safe limits and cleared the plane for flight. The aircraft left the gate at 3:14 p.m. and headed toward the end of runway 03. As the plane taxied, rain started to fall with increasing intensity, accompanied by strong gusts of wind. At 3:18, the air traffic controller reported 20 knot winds from 90 degrees. The flight information service for the airport published an updated weather report at 3:18 indicating the presence of thunderstorms and rain, reduced visibility, and the presence of cumulonimbus clouds. The air traffic controller did not see this update because he was working alone and was attending to Flight 2431. The rain became so heavy that the controller in the tower could not see the runway. Even though the controller was in the best position to see the deteriorating weather conditions, he did not notify the aircraft about any of his observations. The flight was cleared for takeoff at 3:21. Severe wind gusts uprooted several trees at the airport, knocking out power and communication lines. A special weather update was sent out by the flight information service at 3:22, warning of thunderstorms, 0 feet of visibility and a decrease in the ceiling to 0 feet, but this report was never received by the tower controller due to the power outage.

The aircraft proceeded down the runway. After it reached a speed of 147 knot, the pilot flying the plane rotated the controls to bring the aircraft airborne, and raised the gear when the craft was 2 ft above the runway. The plane began its takeoff with a headwind, but the winds quickly shifted to a right crosswind of 11 knot, increasing to 33 knot as the plane proceeded down the runway. The plane had reached its maximum altitude of about 30 ft and a maximum indicated airspeed of 151 knot when the wind direction suddenly shifted to a 24 knot tailwind. The plane rapidly lost airspeed and altitude, and an audible alarm of "DON'T SINK" sounded in the cockpit. Five seconds later, the left wing struck the runway, and both engines broke away from the wings. The plane skidded off the runway and came to rest about 300 m beyond the end of the runway. All 103 people on board the plane were able to evacuate and survived the crash before a fire broke out that destroyed the aircraft.