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 1,000 feet (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 (23 mph; 37 km/h) 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 knots (169 mph; 272 km/h), the pilot flying the plane rotated the controls to bring the aircraft airborne, and raised the gear when the craft was two feet (0.6 m) above the runway. The plane began its takeoff with a headwind, but the winds quickly shifted to a right crosswind of 11 knots (13 mph; 20 km/h), increasing to 33 knots (38 mph; 61 km/h) as the plane proceeded down the runway. The plane had reached its maximum altitude of about 30 feet (9 m) and a maximum indicated airspeed of 151 knots (174 mph; 280 km/h) when the wind direction suddenly shifted to a 24-knot (28 mph; 44 km/h) 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 1,000 feet (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.
Aircraft
The aircraft was an Embraer 190, registration XA-GAL, msn 19000173. It was first delivered to US Airways in 2008 as N960UW before being sold to Republic Airways Holdings in 2009. Under Republic Airways ownership, the aircraft was re-registered as N167HQ, operating for Midwest Airlines, a former subsidiary of Republic, and later for fellow Republic subsidiary (at the time) Frontier Airlines, until late 2013. After Republic retired its Embraer 190 aircraft from its operations, Republic then leased N167HQ to Aeroméxico Connect in 2014, who registered the aircraft as XA-GAL. At the time of its loss, the aircraft had flown a total of 27,257 hours, and had 18,200 takeoff and landing cycles.
When it was originally manufactured, the aircraft was equipped with a Honeywell WU-880 weather radar. This system can detect storms along the flight path of the aircraft and give pilots a visual indication of the intensity of the storm. The aircraft was also equipped with a wind shear detection and escape guidance system that can detect wind shear conditions and alert the pilots using a combination of visual and audio alarms. The audio alarms are disabled in the event of a higher priority audio alarm, such as the ground proximity sensor alarm.
Crew
The pilot in command of the flight was 38-year-old Carlos Galván Meyran, a resident of Mexico City. He held an airline transport pilot licence and had been working at Aeroméxico since 2010, and as a pilot since 2011. He had a total of 3,700 logged flight hours at the time of the crash. Galván completed his captain training for the Embraer E-Jet series in June 2017 and had logged 1,064 hours in the type. He occupied the left-hand seat in the cockpit during the flight, and suffered serious injuries in the accident, requiring hip and spine surgery which doctors called successful.
The assigned first officer, Daniel Dardon Chávez, held an airline transport pilot licence and had a total of 1,973 logged flight hours, including 460 hours on the Embraer 190 aircraft. He was 25 years old at the time of the accident and was originally from Metepec, State of Mexico. He had become certified to copilot this type of aircraft in February 2018. He received minor injuries in the crash. During the flight, he was occupying the jump seat in the back of the cockpit instead of the right-hand seat normally occupied by the first officer.
Another pilot who flew for the airline, José Ramón Vázquez, was also in the cockpit. He held a commercial pilot license and had a total of 3,296 logged flight hours. He was certified to fly the Beechcraft King Air F90 and Beechcraft Super King Air 200 aircraft. He was in the process of receiving training to fly the E-Jets, but as of the time of the flight, he had only received initial classroom instruction, had completed 64 hours of simulator time, and had not yet received his certification. He had no experience on the Embraer E190 aircraft. At the time of the flight, he occupied the right-hand seat in the cockpit normally occupied by the copilot, and was the pilot flying the plane until the last five seconds before the crash, when Captain Galván took control. Vázquez received minor injuries in the crash.
Two female flight attendants were in the main cabin. The senior flight attendant had been employed by the airline since June 2012 and suffered a fractured lumbar vertebra. The junior flight attendant had been employed by the airline for about a week and received minor injuries in the crash.
Passengers
The plane departed with 99 passengers and 4 crew members. Two of the passengers were airline employees being shuttled between locations, including the student pilot who was in the cockpit. Of the passengers, excluding the student pilot, 31 were Mexican citizens, 65 were United States citizens, 1 was a Spanish citizen, and 1 was a Colombian citizen.
Aftermath
Immediately after the crash, passengers reported seeing smoke and flames as they rushed to escape the plane. Some passengers said that a door had been torn off and that the plane's fuselage had broken in two, allowing them to jump directly out of a gap in the side of the aircraft. The crew was able to open the emergency exit slides and safely evacuate all of the occupants within 90 seconds. About three to four minutes after coming to a stop, and after all passengers had been evacuated, the aircraft exploded and was engulfed in flames.
The air traffic controller attempted to contact the aircraft, and when it received no response he contacted the approach sector controller to see if they were in contact with the aircraft. The controller dispatched an airport service vehicle to inspect the runway. The driver saw the aircraft's engines at the side of the runway and smoke rising from beyond the runway. Airport officials activated the emergency operation center at the airport, and dispatched firefighters to assist with the rescue and to extinguish the fire.
After reports about the crash came in, Aeroméxico sent a team to Durango to provide assistance to affected passengers and their families. The company announced that it would cover all medical, accommodation, transportation, and incidental expenses resulting from the crash. It praised the actions of the crew and said that the crew's quick and efficient evacuation of the plane was instrumental in avoiding additional serious injuries and fatalities. It also said that the pilot's expertise and professionalism had prevented the loss of life in the accident.
Different sources gave conflicting reports about the number of injuries from the incident. The Ministry of Health initially reported that there were 18 passengers injured. The Red Cross said there were 97 injuries. The governor of Durango told media that 49 people had been treated for injuries at hospitals. Two days after the crash, Aeroméxico reported that 17 passengers were still hospitalized, 16 were in the process of being released, and 24 had already been released from medical care. The final official accident report stated that there were 14 serious injuries and 25 minor injuries.
About a month after the crash, Aeroméxico announced that the three pilots who were in the cockpit that day had been fired from the company. It said that while it did not feel that the crash was the fault of the pilots, they had violated company procedures by not following their assigned roles during the flight by allowing the trainee pilot to take control of the aircraft. The labor union representing the pilots protested the termination, saying that the decision was carried out based only on a preliminary accident report, and that a full investigation into the accident was still ongoing. Shortly afterward, Mexico's Directorate General of Civil Aeronautics (DGAC) issued a change in regulations that prohibited airlines from allowing inactive pilots and flight attendants from occupying the cockpit of aircraft during flights. Aeroméxico pilots opposed this change and called for a strike, viewing the sudden removal of a travel benefit as a violation of their collective bargaining agreement between the union and the airline. After negotiations, the union representing the pilots agreed to a change in the agreement, where all non-working flight crews will have reserved seats in the main cabin, and continue to be denied access to the cockpit.
Investigation
Shortly after the crash, the DGAC announced that it had formed a commission to investigate the crash. The commission received assistance from the US National Transportation Safety Board and the US Federal Aviation Administration. Additional assistance was provided by Embraer SA, who had built the aircraft, and General Electric Co., who had built the engines on the aircraft. Investigators quickly located the flight data recorders for the aircraft and found them to be in perfect condition.
On September 5, a little over a month after the accident, José Armando Constantino Tercero, the lead investigator from the DGAC, announced that the final conclusion had not yet been reached, but that the cause of the accident appeared to be sudden wind shear from a microburst. He said that the pilots had not received any notice of the adverse conditions prior to starting the takeoff, and that neither human nor mechanical failure appeared to be to blame for the crash. He also said that analysis of the cockpit voice recorder revealed that an unauthorized pilot training was taking place during the flight, and that the trainee pilot had been occupying the copilot seat and flying the plane until shortly before the crash. This was not in accordance with aviation regulations, and he said that administrative proceedings had been initiated. Nevertheless, he stressed that neither the presence nor the actions of any of the pilots caused the accident. Shortly afterward, the airline announced that it had fired the three pilots who were in the cockpit of the flight.