Incident Overview
On July 18, 2021, at approximately 11:26 JST, a Piper PA28RT-201T aircraft, registration JA201M, experienced a serious incident during landing at Niigata Airport. The aircraft had departed from Matsumoto Airport at 10:25 under instrument flight rules with the captain and two passengers on board. The landing on Runway 28 was described as smooth with no sideslip or deviation from the centerline. During the landing roll, the captain felt a slow response to rudder steering, similar to a previous experience with a punctured tire. Concluding that the right main landing gear tire had punctured, the captain decided to steer the aircraft off the runway to the grassy area on the north side, believing that deviating from the runway would avoid runway closure and not hinder scheduled flights.
Captain's Actions and Aircraft Behavior
After decelerating to approximately 5 knots, the captain turned the aircraft at almost right angles to the runway and entered the grassy area. The aircraft continued taxiing on the grass, changing course further right, and came to a halt about 41 meters north of the runway centerline, facing east-northeast. The engine was then shut down. The aircraft was disabled and unable to taxi further. The runway was closed from the time of the incident until 18:13, resulting in the cancellation of 18 scheduled flights. The location where the aircraft stopped was inside the runway strip of Runway 28, which, under the applicable guidelines, requires runway closure until the disabled aircraft is removed.
Investigation Findings
The Japan Transport Safety Board (JTSB) investigated the incident. On-site examination revealed that air had leaked from a crack approximately 2 mm in length in the tube of the right main landing gear tire. The tire and tube had been in use for about three years with 216 landings. No other damage to the aircraft or its control systems was found. Runway inspection after the incident found no foreign objects or abnormalities that could have caused the tire damage.
The JTSB analysis concluded that it was highly probable that the steering system operated normally throughout the landing and taxi. The air leakage was gradual, as the crack was small, and the aircraft remained controllable. The deviation from the runway was determined to be an intentional maneuver by the captain. The subsequent inability to taxi was highly probable due to the collapsed and deformed tire and wheel, which prevented rotation.
The JTSB also noted that the captain's belief that deviating from the runway would avoid closure was based on an insufficient understanding of the runway strip extent and associated operational guidelines.
Probable Cause
The JTSB concluded that it is highly probable that the serious incident occurred as a result of the captain’s own steering, prompted by his recognition that the right main landing gear tire had punctured during the landing roll, leading him to deliberately steer the aircraft into the grassy area on the north side of the runway.