Russia’s Sukhoi Civil Aircraft (SCA) has completed repairs on six Sukhoi Superjet 100s (SSJ100s) grounded by Mexican airline Interjet, the only SSJ100 operator in the Americas. The aircraft resumed operations in the first week in January, the manufacturer said in a statement.

“The troubleshooting procedure was agreed with the Russian aviation authorities [Federal Air Transport Agency, Rosaviatsia] and carried out under the control of the Mexican aviation authorities [DGAC],” SCA added.

The manufacturer sent 22 technicians to Mexico for the warranty maintenance work at the end of last year. It is expected all grounded aircraft will be back in service by the middle of January.

Interjet grounded half its 22 SSJ100 fleet at the end of December 2016, after SCA identified a minor fault in the tail stabilizer of one SSJ100 during inspections. “The element [tail stabilizer] has a multi-level redundancy system and was designed with a stability margin far exceeding its service loads.

The element was designed and tested in accordance with the Russian and European airworthiness requirements of the IAC AR [Interstate Aviation Committee Aviation Register] type certificate and its validation by EASA [European Aviation Safety Agency],” SCA said.