A 1-kg metal part found on a mountain near Narita airport is raising suspicions it’s part of a plane that flew over the area.

On official of the Narita Municipal Government said Monday that a resident found the object Sunday afternoon about 7 km northwest of runway B, and about 30 meters from a residential area.

The trapezoidal object was painted white and was 25 cm wide and 50 cm long. The city and the transport ministry have yet to confirm whether it belongs to an aircraft.

The ministry requires Japanese air carriers to report when aircraft lose parts larger than 100 sq. cm, nonmetal parts weighing 200 grams or more, and metal parts weighing 100 grams or more.

Last September a panel that fell off a KLM Royal Dutch Airlines plane that took off from Kansai International Airport hit a car on a road in Osaka.

Later the same month, an All Nippon Airways aircraft arriving at Narita airport lost a panel twice in two days, one of which was found in Inashiki, Ibaraki Prefecture.