What happened
On June 18, 2012, at approximately 14:40 local time, a Cessna 172P, registration JA4135, was performing touch-and-go training maneuvers at Ryugasaki Airfield in Ibaraki Prefecture, Japan. The aircraft, operated by IBEX Aviation Co., Ltd., was occupied by an instructor and a student pilot. Following the third takeoff of the session, the aircraft was climbing at an altitude of roughly 200 feet with an airspeed of 75 knots when two birds suddenly emerged from beneath the aircraft.
While the first bird passed safely below the plane, the second bird ascended into the aircraft's flight path, striking the leading edge of the left wing. Following the impact, the instructor maintained control of the aircraft to prevent any sudden movements by the student pilot. The crew reported the incident to the Ryugasaki Flight Service and entered a holding pattern to assess the situation. After confirming that engine performance and flight controls remained normal, and receiving confirmation that no debris had fallen onto the runway, the instructor elected to continue the flight to Chofu Airfield, where the aircraft landed safely at 15:16.
The investigation
The Japan Transport Safety Board (JTSB) conducted an investigation into the incident, with participation from a representative of the United States as the state of design and manufacture. The investigation focused on the flight history, the physical condition of the aircraft, and the identification of the bird involved. Investigators examined the damage to the wing structure and reviewed meteorological and airfield information provided by the flight service and the airfield administrator.
Findings
- The collision resulted in substantial damage to the Cessman 172P, specifically involving a large dent on the underside of the left wing leading edge, measuring 63 cm in width and 2 cm in depth, which caused the deformation of two primary structural ribs.
- The bird involved was identified as a gray heron, a species weighing approximately 1.4 kg and measuring 80 cm in length, which is common to the local paddy fields and waterfronts.
- The bird strike occurred during a critical phase of flight—the post-takeoff climb—where the aircraft had insufficient altitude and airspeed to perform abrupt maneuvers to avoid the sudden emergence of the birds.