Flight-data traces reveal how Azerbaijan crew kept crippled E190 airborne

Flight-data recorder traces from the Azerbaijan Airlines Embraer 190 illustrate the extent of damage with which the crew had to cope after the twinjet was crippled by an explosion in Russian airspace. The E190 sustained multiple penetrative impacts – many of them rectangular in shape – from fragments which damaged its hydraulic circuit tubes and reservoirs, its stabiliser pitch-trim electric drive, and the empennage including its fin, elevators and rudder. Similar damage affected its left wing and left-hand GE Aerospace CF34 engine. The crew of the aircraft – operating a Baku-Grozny service on 25 December – had abandoned attempts to land at the Chechen capital, after losing GPS navigation capability and encountering difficult weather conditions including haze, reduced visibility, and overcast cloud at about 240-420m (790-1,380ft). After the pilots opted to return to Baku, the aircraft was climbing through 3,500ft when, at 08:13:31 local time, its cockpit-voice recorder captured a “sonic boom” noise, says the Kazakhstan air accident investigation commission. Flight-data recorder traces reveal that the autopilot disengaged and, over the next 23s, all hydraulic pressure bled away before another bang was heard. The data provided in the commission’s preliminary findings show that routine variations in both inboard and outboard elevators immediately ceased, with the elevators’ traces flatlining at slightly different positions. Cabin altitude instantly began to rise, coinciding with the E190’s actual altitude after about 20s, indicating depressurisation. The aircraft, which had been cleared to 15,000ft, continued to climb to about 8,000ft, before briefly sinking back to around 6,000ft, and then climbing again to 10,000ft.<br/>