Nagpur: As technicians working for Air India Engineering Services Limited (AIESL) aircraft maintenance, repair and overhaul (MRO) depots in Nagpur and five other cities have shunned work, at least seven aircraft are held up at the hangars. These planes were supposed to take off this week after completion of the checks, said sources among the technicians. AIESL has MROs in Nagpur, Delhi, Mumbai, Hyderabad, Kolkata and Trivandrum, where around 20 aircraft have been taken in for overhaul jobs. The engineering arm of erstwhile Air India, now taken over by Tatas, AIESL remains a PSU. A source in the workers' union shared details of the flights with their call signs. These were due to be released after the maintenance. Out of these there are two aircraft at the Nagpur MRO, out of which one was due for release this week, a source said. Among the other planes two are chartered aircraft, the source said.The protest began a week ago after 180 technicians who resigned were allegedly not relieved from the respective MROs. Four of them are from Nagpur MRO. Deputy chief labour commissioner (Central) has sought a response from the management at AIESL Nagpur. The letter says that the four technicians who have resigned have placed their case over the terms of agreement with the employer. "It is evident that four of the technicians who have completed two months since tendering resignation are being denied relief, not only violating the terms of agreement but also the provisions of Code of Wages 2019. The situation could have been handled better," the letter says.