Facts
On October 10, 2012, a serious incident occurred over Nagoya City, Aichi Prefecture, Japan, involving two aircraft: a Bell 206B helicopter (registration JA9745) operated by Nakanihon Air Service Co., Ltd., and a Mitsubishi MU-300 fixed-wing aircraft (registration JA30DA) operated by Diamond Air Service, Inc. The Bell 206B had three persons on board (a pilot-in-command and two trainees), while the Mitsubishi MU-300 carried seven (a pilot-in-command, first officer, and five other crewmembers). No injuries were reported, and neither aircraft sustained damage.
Flight History
The Bell 206B departed Nagoya Airfield at 10:13 JST under Visual Flight Rules (VFR) and was flying west-southwest at an altitude of 2,000 ft toward the civil training/testing area CK1-3 east of the Suzuka Mountains. The Mitsubishi MU-300 had departed from the same airfield earlier, at 09:39 JST, and was returning under VFR at 2,000 ft after completing training in the Japan Air Self-Defence Force area K south of the Atsumi Peninsula.
At approximately 11:22 JST, an air traffic controller at the Nagoya airdrome control tower instructed the MU-300 to hold over Mamba Bridge, located 7.3 nm southwest of the airfield. While executing a counter-clockwise turn above the bridge, the MU-300 approached the Bell 206B from the left rear and overtook it on the left side.
Traffic Information
During the flight, traffic information was provided to the MU-300 crew. At 11:20:22, Nagoya TCA informed the MU-300 of traffic at 2,100 ft and 7 nm north, to which the crew responded they were looking. At 11:21:03, they received updated traffic information of traffic at 2,000 ft and 4 nm north. At 11:21:49, the tower warned of an aircraft at 2,000 ft and 2 nm north, and the crew responded that they had no visual contact.
Probable Cause
The Japan Transport Safety Board determined that it is highly probable that even though information on the azimuth and flight altitude of JA9745 was provided, JA30DA could not recognize it and continued the flight; accordingly, both aircraft approached into close proximity.