Friday, 7 September 2018

Microburst - a factor in the Aeromexico Connect E190 crash but Aeromexico still sacks the pilots

The Mexican Investigators charged with looking into the crash of an Embraer E190 of Aeromexico Connect at Durango, Mexico, on 31st July this year have issued a preliminary report which indicates that a microburst wind shear event was a factor in the crash.

The aircraft, an Embraer ERJ-190-100 registration  XA-GAL operated by Aeroméxico Connect was performing Flight AM2431 on 31st July was talking off from Guadalupe Victoria International Airport 's runway 03.  It had reached a height of 30 feet when it suddenly came down and collided with the ground, a fire then ensued, but remarkably all 105 people on the aircraft survived. 

The investigators believe that the aircraft likely encountered a rapidly changing downdraught wind shear event, known as a microburst during the seconds after takeoff which the crew were unable to recover from.

The team, assisted by the US NTSB and plane manufactures Embraer say the aircraft started its take off at around 15:22 from runway 03 and during the journey down the runway, it experienced noticeable changes in wind speed and direction. According to the report, at 15:22:42 the wind at a speed of 33 knots at 47 degrees and the aircraft was rolling at an airspeed of 146 knots. Just 8 seconds later the aircraft was off the ground, at 8 feet and its airspeed was 145 knots yet the wind had changed to a crosswind at 103 degrees at 11 knots.  The report then details the aircraft had managed to climb up to 30 feet, the maximum it ever managed during its short flight, however at 15:22:56 the plane was down to just 19 feet and was hit with a 22 knot tailwind at 30 degrees. The aircraft collided with the ground far off the end of the runway.  The full report into the incidents of 31st July is not due until at least November.

Even before the preliminary report was released Aeromexico has sacked the three air crew in the cockpit of the E190.  The Chief Executive of Aeromexico Andres Conesa told staff in a letter that the three pilots on the flight had already left the company.  “Irrespective of the evidence ... pointing to weather-related factors, the conduct of the three pilots in the cockpit was not carried out in accordance with established protocols,” and violated company procedures he claimed.

Local media has reported that the pilots are being treated as scapegoats for the intense pressure the airline puts on flight staff to keep to schedule, even in bad weather.  Some pilots have complained of being disciplined for not keeping to schedule or allowing flights to be delayed by weather. 

Images from the preliminary report