A Xiamen Airlines Boeing 787 passenger plane arrives in Jakarta, capital of Indonesia. Photo: courtesy of the Jakarta office of Xiamen Airlines

Xiamen Airlines told the Global Times on Tuesday that it is modifying its Boeing 737 MAX jets after Boeing issued technical guidelines for the carrier, a necessary preparation before the planes return to service.

However, there is no timetable for the planes to return to service yet, and the regulator has the final say.

The comment came after reports circulated online that Xiamen Airlines is preparing to return its 737 MAX fleet to service after years of being grounded.

Xiamen Airlines ordered 30 Boeing 737 MAX planes in March 2018, including 20 737-8 and 10 737-10 aircraft.

Xiamen Airlines has 167 aircraft before the epidemic, making it one of the largest airlines in China. 

All of Xiamen Airlines' 10 737-8 planes are still parked in the western part of the country -- two in Lanzhou, Northwest China's Gansu Province, and eight in Yinchuan, Northwest China's Ningxia Hui Autonomous Region.

China was the first country to ground the Boeing 737 MAX in 2019.

The Civil Aviation Administration of China (CAAC) set three principles for the jet to return to service in China -- design changes need to be certified, pilots need to receive proper training, and effective improvements need to be made to address the specific findings of investigations into two crashes.

Dong Zhiyi, deputy head of the CAAC, said in March that major safety concerns raised by China's civil aviation regulator over the 737 MAX had not been fully addressed, when asked about the timetable for the jet to return to service.