An ATR 42-600 (although identified by the JTSB as an ATR 42-500) was scheduled to operate a six-sector scheduled passenger service between regional airports in Japan on this day in aviation history, the 8th of January 2020. After completing the first two sectors the crew prepared the aircraft for the third sector of the day at Kikai Airport (Amani Island, Japan). The destination for the next flight was Amani Airport (Amani Island, Japan). A very short, 13 nautical miles, flight across the East Cina Sea.
The aircraft in the grass on the side of the runway (Source & © JTSB)
At 09:53 lt (local time) the aircraft took off from Kikai airport and set course for Armani airport at an altitude of 2000 feet. The captain was operating as PF (Pilot Flying), and the co-pilot as PM (Pilot Monitoring). An approach to runway 03 with the flaps at 35º and a Vref (Reference Approach Speed) of 105 knots was briefed, during the briefing, no mention was made of the existing crosswind conditions.
The wind was reported at 320º at 28 knots, with gusts of 40 knots when the aircraft was on the right base leg. At 1400 feet the autopilot was disconnected and the landing checklist was completed and the approach was deemed as stabilised. Fluctuations of the airspeed of -5 to +10 knots at 1000 feet made the PM callout 'AIRSPEED", as per AOM (Aircraft Operating Manual) procedures. The PF decided to continue the approach. At 300 feet the copilot again called out 'AIRSPEED", when the aircraft's speed fluctuated again and also noticed the aircraft deviated to the left of the Final Approach Course.
Estimated flight path (Source & © JTSB)
At 250 feet a correction of the flight path was initiated and at ~50 feet the aircraft passed over the threshold with a left bank of 4º and slightly of the Final Approach Course at a heading of 023º. At 20 feet de aircraft was flared followed by a touchdown with the left main landing gear on the runway centerline. The roll was reduced to 2.6º and 1 second later all gears were sensing Weight on Wheels after which reverse pitch on the propellors was selected. Several control inputs were made on the rudder, control wheel, nose wheel steering and wheel brakes in order to maintain directional control and keep the aircraft on the runway. These inputs were made and/or backed up by both crewmembers, with a transfer of control occurring after the touchdown. These inputs were not enough to keep the aircraft on the paved surface of the runway and enter the grass on the left side of the runway (~680 meters from the threshold), coming to a stop and being unable to taxi (790 meters from the threshold) at 10.01 lt, 8 minutes after take-off.
The aircraft was shut down and passengers disembarked, there were no injuries.
e serious incident was reported to the JTSB (Japan Transport Safety Board), who launched an investigation. No abnormalities were found in the operational examination of the braking system, rudders, and nosewheel steering system on the Aircraft during the on-site investigation.
FDR readout from the incident flight (Source & © JTSB) After completing the investigation the JTSB concluded that the probable cause of this serious incident was the delay in correcting the deviation to the left immediately after the touchdown at landing in a crosswind from the left, which resulted in the Aircraft running off the side of the runway, halting in the grass area. Several safety actions were taken as a result of this incident by the airline as well as the aircraft manufacturer. These safety actions can be found in the investigation report (which served as the source for this blog) accessible by clicking on the .pdf file below;