India’s largest association of pilots asked the country’s regulator to ground all Air India Boeing 787s and inspect them for electrical issues after one of the planes unexpectedly deployed an emergency power system over the weekend.

The device, known as the ram air turbine, drops from the fuselage when a plane loses power or hydraulic pressure, and helps power critical systems like flight controls and navigation instruments. In this case, Flight 117 landed safely in Birmingham, England, on Saturday. Air India said in a statement that an initial inspection found “all electrical and hydraulic parameters” were normal.

Boeing and Air India did not immediately respond to a request for comment. Air India operates 34 Boeing 787s, according to a document on its website from April.

“I have never heard of the R.A.T. being deployed automatically without any hydraulic loss, power loss or failures,” Capt. Charanvir Randhawa, president of the Federation of Indian Pilots, which represents more than 6,000 pilots across the country, said in an interview. He said all of the Boeing 787s in the nation must go through an electrical inspection after Saturday’s incident.

Saturday’s incident was the second time since June that a ram air turbine was deployed on an Air India Boeing 787. On June 12, Air India Flight 171 also used the turbine on a flight headed to London.

The plane crashed 30 seconds after takeoff from Sardar Vallabhbhai Patel International Airport in the western Indian city of Ahmedabad, killing 241 of the 242 people on board, and 19 others on the ground.

A preliminary report confirmed that the device activated on Flight 171 when power was lost, but crash investigators are still working to determine whether the turbine was a symptom or a cause of the aircraft’s loss of power.