Mexican investigators have disclosed that an unqualified pilot had been sitting in the first officer’s seat of an Embraer 190, flying the aircraft, moments before it crashed on take-off during poor weather at Durango.
All 103 occupants survived the crash, on 31 July last year, although the Aeromexico Connect aircraft (XA-GAL) was destroyed.
The commission probing the accident found that a crew member travelling in the cabin had been allowed into the cockpit, but took the place of the first officer before the departure.
It points out that the crew member held a multi-engine licence to command Beechcraft King Air turboprops, and was an “aspiring” to become an E-Jet first officer, having started initial theoretical training in May 2018 and completing 64h of simulator activity.
While he had logged nearly 3,300h on other aircraft, he had zero flight experience on E-Jets, and had not completed the simulator evaluations required before route training.
But investigators state that the crew member had been sitting in the first officer’s seat while the first officer had been assigned to carry out external pre-flight inspection of the E190.
Not only was the crew member not authorised to operate the aircraft, the captain was effectively acting as his instructor – a task for which he was also unqualified. The actual first officer sat in the observer’s seat in the cockpit.
Prior to the departure from runway 03 an adverse weather system, with thunderstorm activity and rain, had moved into the vicinity of Durango airport from the north-west. Cockpit-voice recorder information revealed that the windscreen wipers were active as engine thrust increased for the take-off roll.
As the aircraft accelerated – with the crew member in control – differences in airspeed indications between the captain’s and first officer’s instruments between apparent at 80kt, indicative of windshear.
The crew member rotated the aircraft at 148kt, according to his instruments, and 152kt according to the captain’s, pitching the jet nose-up at just over 10°.
Barely had the aircraft lifted off when a “gear up” command was recorded, with the aircraft little more than 2ft above the runway. The inquiry says this “contradicts” standard operating procedures in windshear, which require the undercarriage and flap configuration to remain unchanged until reaching 1,500ft.
Flight-data recorder information shows the gear-up command came at a height of 2.1ft and a ground speed of 144kt.
The E190 had reached a height of only 11ft, with airspeed indications starting to decline, when the captain declared that he was taking over control of the aircraft. It continued to climb, reaching a maximum height of 30ft with the captain’s airspeed indicator showing 130kt.
While the crew testified to hearing windshear alarms, none was heard on the cockpit-voice recorder. The inquiry found that a “don’t sink” alert – which takes priority over windshear alarms – started sounding at about 20ft.
The jet lost height and struck the runway surface, to the left of the centreline, some 2,150m from the threshold and close to taxiway B. Both engines broke away from the aircraft which slid along the ground, almost parallel to the runway, coming to a halt 400m beyond the threshold of the opposite-direction runway 21.
Investigators state that the unauthorised crew member was “performing the functions of the flying pilot” up to a point 8s before the impact with the ground, according to evidence retrieved from interviews and the cockpit-voice recorder.
Among its concerns, the inquiry notes that, during the crew member’s briefing to the captain, an incorrect pressure setting was used to calculate take-off configuration and performance.
No evidence of engine failure, technical problem or system malfunction was found and the aircraft was within weight and balance limits, even after the introduction of a last-minute cargo shipment.
Investigators have concluded that the E190 encountered windshear at low altitude during a critical phase of take-off. As the aircraft accelerated, increased rainfall obscured the external view, reducing visibility to “practically zero”, says the inquiry, while the wind intensified suddenly and the aircraft lost speed.
But while it primarily attributes the crash to windshear, it highlights the decision to allow an unauthorised pilot to take control of the aircraft, pointing out that the crew experienced decreased situational awareness and failed to adhere to sterile cockpit procedures.