History of the Flight
On August 27, 2018, at approximately 09:59 Japan Standard Time, an Airbus A320-214, registered JA14VA, operated by Vanilla Air Inc., departed from Kansai International Airport as scheduled flight 873 bound for Amami Airport. The aircraft carried 152 people: a pilot in command, five other crew members, and 146 passengers. The pilot in command acted as pilot flying (PF) from the left seat, while the first officer served as pilot monitoring (PM) from the right seat.
Before departure, the pilot in command had briefed the flight attendants that weather conditions along the route were mild, with no significant turbulence expected. During cruise at Flight Level 300 (approximately 9,100 m) over the sea east of Miyazaki Prefecture, the crew observed another aircraft (a Boeing 747-400F, flight CAL5254) crossing their path at FL310, more than 20 nm ahead. The pilot in command judged that wake turbulence would not affect the aircraft due to the distance and left the seat belt sign off.
At 10:33, the other aircraft crossed in front. At 10:34:40, the aircraft suddenly experienced a vertical shaking, described by the pilots as similar to light turbulence. A flight attendant (Flight Attendant A) who was preparing in the aft galley fell, hitting her buttock on the floor. The shaking lasted only momentarily. The pilot in command turned on the seat belt sign and instructed the senior flight attendant to check the cabin. About 10 minutes later, after receiving a report of no apparent problems, the seat belt sign was turned off.
Injuries to Persons
One flight attendant sustained a serious injury: a coccygeal fracture. The injury was diagnosed on September 3, 2018, seven days after the incident, when the flight attendant sought medical attention due to persistent pain.
Damage to Aircraft
No damage to the aircraft was reported.
Personnel Information
The pilot in command, aged 41, held an airline transport pilot certificate and a type rating for the Airbus A320, with a total flight time of 6,787 hours 16 minutes (4,544 hours 56 minutes on type). The first officer, aged 27, held a commercial pilot certificate and an instrument flight certificate, with a total flight time of 1,275 hours 15 minutes (992 hours 57 minutes on type).
Aircraft Information
The aircraft was an Airbus A320-214, serial number 7966, manufactured on December 14, 2017. It had a valid certificate of airworthiness and a total flight time of 1,859 hours 45 minutes at the time of the accident. The estimated weight and center of gravity were within allowable limits.
Meteorological Information
According to Japan Meteorological Agency charts, the airspace near the accident site was under high pressure, with no significant clouds. Winds were weak (5 to 10 kt), and no windshear was observed. No pilot reports of turbulence were filed within one hour before or after the accident.
Additional Information
Radar track records indicated that about one minute 40 seconds before the accident, a Boeing 747-400F (CAL5254) was flying at FL310 from southwest to northeast, crossing the flight path of the aircraft. Quick Access Recorder data showed that the vertical acceleration fluctuated between +0.19 G and +1.39 G at the time of the shaking, with little change in aircraft attitude.