The transport ministry may punish personnel involved in an incident this week at Takamatsu Airport in Kagawa Prefecture in which an airplane was unable to communicate with the control tower because of mistakes by the controllers on duty, ministry officials said Thursday.

A Japan Airlines Co. plane could not reach the control tower for about 10 minutes at around 6:30 p.m. Monday and was forced to wait before landing at the airport. This subsequently also delayed the landing of an All Nippon Airways Co. aircraft, the Land, Infrastructure, Transport and Tourism Ministry said.

Regulations require that at least two controllers be on duty. But one controller at Takamatsu, in his 60s, was in another room for about 50 minutes, according to the ministry's investigation. Another controller, in his 40s, meanwhile mishandled the speaker volume in the control tower, the ministry said.