Experts decode possible cause behind An-148 jet crash
The crash of the passenger plane near Moscow could have been caused by the incorrect data on the flight’s speed as a result of the sensors icing up, the Interst
"A preliminary analysis of the recorded information, and also the analysis of similar cases that occurred in the past suggest that a distinct situation could have developed in mid-air due to incorrect data on the flight’s speed on the pilots’ displays. This in turn, could have been linked to the ice-up of the total pressure probes since their heating systems were switched off," the Interstate Aviation Committee said.
"During all the other flights registered on the flight recorder [15 more flights], the heating of the total pressure probes was switched on before takeoff in its line-up position," the Interstate Aviation Committee said in its report.
An emergency situation developed aboard the crashed An-148 passenger plane about 2.5 minutes after takeoff, the Interstate Aviation Committee also said.
"A special situation began to develop about 2 minutes and 30 seconds after the takeoff at an altitude of around 1,300 meters and the indicator speed of 465-470 km/h," the Interstate Aviation Committee said.
At that moment, the passenger plane’s flight recorders recorded divergences between the readings of the speed sensors, it said.
Thirty seconds after that, the divergences in the speed sensors reached about 30 km/h, after which the one-off command for the crew appeared: "The Instrument Panel - Compare!" This command was repeated at an altitude of about 2,000 meters and this time the difference between the speed sensors’ readings grew even bigger.
After the second command: "The Instrument Panel - Compare!" the crew turned off the autopilot and the subsequent flight proceeded in manual mode. The speed indications of the plane’s air parameter modules strongly differed from each other: one showed a speed of 0 km/h and the other 540-560 km/h. Then the speed indications of the latter sensor started to fall intensively (to 200 km/h and lower) and the plane was switched into intensive descent with angular movement for a dive at 30-35 degrees.
Before the plane hit the ground, one of the sensors continued to show a speed of 0 km/h while the other showed a speed of 800 km/h.
"Four-five seconds before hitting the ground, the plane developed a right-side roll of 25 degrees," the Interstate Aviation Committee said, adding that it continued to analyze the information obtained.
Radio contact with the An-148 passenger plane of the Saratov Airlines, which took off from Domodedovo airport at 14:24 Moscow time on Sunday, was lost four minutes after taking off.
Fragments of the plane were found near the village of Stepanovskoye in the Moscow Region’s Ramensky district. There were 65 passengers and six crew members on board. According to the latest data, no one has survived.
A criminal case on charges of violations of flight safety and aircraft operation rules entailing the death of two or more people through negligence has been opened.