In Wake Of Superjet Crash, Yakovlev Issues Instructions On AOA Sensors

The manufacturer of Russia’s Superjet 100 regional jet, Yakovlev, has issued instructions to the type’s operators regarding the replacement of angle of attack (AOA) sensors.

The warning came days after a Gazpromavia SSJ100 crashed near Moscow during a ferry flight from a maintenance facility.

According to state newswire TASS, which cited the instructions July 16, the manufacturer has asked maintenance technicians to pay special attention to aligning the holes and marks on the sensor’s overlay with the markings on the fuselage skin and reinstalling the overlay only in the same position from which it was removed.

Yakovlev also advised that quality control for the procedure should be doubled and that a single technician should not be allowed to replace two or more sensors per aircraft.

The type’s largest operator, Aeroflot Group subsidiary Rossiya, confirmed receipt of the instructions and said the information had been passed on to its MRO providers.

Russian media have suggested that the incorrect installation of the sensor could be a reason for the SSJ100 crash on July 12. The 10-year-old aircraft operated by Gazpromavia was returning to Moscow Vnukovo International after a maintenance check at a facility in Lukhovitsy which belongs to Yakovlev’s parent United Aircraft Corporation.

According to sources cited by state newspaper Izvestiya, a technician at Lukhovitsy may have installed two out of the four angle of attack sensors with a deviation of approximately five degrees. Wrong data from the sensors could activate the electronic stall protection system, which in turn may have directed the aircraft toward the ground.

Neither Yakovlev nor UAC have commented on the investigation so far.

The maintenance center at Lukhovitsy was launched in 2020 and has performed maintenance checks for 25 SSJ100s operated by various Russian airlines to date.