Pilferage of cables of runway visual range (RVR) equipment at Netaji Subhash Chandra Bose International Airport is the reason behind frequent snags in the system, airport authorities said on Thursday.
We had suspected that the cables of the RVR equipment were being stolen resulting in glitches in the equipment, an official said.
The thieves escaped detection by cutting small lengths of the cables. The authorities thought the damage was caused by the gadgets used for construction or repair works.
Emboldened, the thieves tried to sneak out larger lengths and were caught on Tuesday.
On Tuesday, four contract labourers Sristi Sardar, Ajay Sarkar, Gopal Mondal and Ranjit Oraon were arrested for stealing about 30 metres of cables of the RVR equipment, worth Rs 10,000.
According to Airports Authority of India officials, the accused evaded detection with the help of a section of drivers engaged by the contractor.
The drivers helped them ferry the stolen cables for a share of the booty.
Labourers are checked by CISF personnel when they enter or leave the airport premises. Tokens are issued to each labourer on the basis of a written statement, which contains details including the address.
The details are checked by the CISF personnel before the workers are allowed on the premises.