Five additional pilots of Skynet Asia Airways Co failed to report histories of illness at the time of medical checkups, sources close to the matter said on June 2.

In a bid to strengthen surveillance on the Miyazaki City-based airline, Japan's Ministry of Land, Infrastructure, Transport and Tourism is planning to carry out another inspection this month, the sources said.

Another round of coverups came to light when the ministry inspected the company's head office on May 29-30 on its compliance with law after the revelation that the airline submitted false medical records to aviation authorities on some of its pilots in violation of the aviation law.

In the latest case, the company failed to instruct the five pilots - two pilots of foreign nationality and three Japanese copilots - appropriately to report on their treatment records on such illnesses as eye, shoulder or ear ailments, as well as intestinal cancer or gastric ulcers.