Human error, faulty sensor behind crash

MOSCOW — Human error may be to blame for the Russian plane crash that killed 71 people, Russian investigators said Tuesday, noting the plane’s pilots failed to turn on the heating unit for its measuring equipment, resulting in flawed speed data.

After studying the An-148’s flight data recorder, the Interstate Aviation Committee said Sunday’s crash near Moscow occurred after the pilots saw conflicting data on the plane’s two air speed indicators.

The flawed readings came because the pilots failed to turn on the heating unit for the plane’s pressure measurement equipment prior to takeoff, the committee said.

The pilots had placed the An-148 on autopilot after taking off from Moscow’s Domodedovo Airport but took its manual controls back when they heard alarm signals warning of conflicting speed data. One indicator showed the plane’s speed at zero, investigators said.

The pilots then performed a series of maneuvers and eventually took the plane into a dive at 30-35 degrees. It plummeted into a snowy field outside of Moscow six minutes after takeoff, killing all 65 passengers and six crew onboard.

The committee said it is continuing to study the data, but noted that “erroneous data on the pilots’ speed indicators may have been a factor that triggered the special flight situation.”

It emphasized the flawed speed data resulted from the “icing of pressure measurement instruments that had their heating systems turned off.”