Incident Overview
On May 8, 2005, a Boeing 747-400, registration JA8072, operated by Japan Airlines International Co., Ltd. as scheduled Flight 47, experienced a cabin pressure drop while cruising at approximately 36,000 ft. The aircraft was en route from John F. Kennedy International Airport to Narita International Airport. The incident occurred around 11:41 Japan Standard Time, approximately 370 km southeast of New Chitose Airport. Of the 374 people on board—19 crew and 355 passengers—no injuries were reported.
Flight Timeline
The aircraft had departed New York at 23:14 on May 7. At 11:41:08, the cabin altitude began increasing from 5,548 ft. By 11:41:19, it reached 10,046 ft, triggering the "CABIN ALTITUDE" message. The cabin altitude peaked at 10,795 ft at 11:41:31. The crew initiated an emergency descent at 11:42:01, deploying speed brakes at 11:41:56. Passenger oxygen masks were released at 11:42:54. The aircraft leveled off at 10,143 ft at 11:48:32. It then proceeded to New Chitose Airport, beginning descent for landing at 12:18:34 and touching down at approximately 12:51.
Crew Response
Upon noticing a slight ear popping sensation, the flight crew observed on the engine indication and crew alerting system (EICAS) that the cabin altitude was rising. The environmental control system page showed the right outflow valve in manual mode and indicated "OUTFLOW VLV R" in yellow. The crew donned oxygen masks, deployed passenger oxygen masks, declared an emergency, and set the transponder to 7700. After the emergency descent to 10,000 ft, they confirmed the outflow valve positions: the left valve was fully open on auto, the right fully closed on manual. The captain decided to divert to New Chitose Airport, the closest suitable airport at approximately 280 nm away, with an estimated flight time of 40 minutes. The aircraft landed uneventfully.
Cabin Events
Cabin attendants reported feeling ear popping, cold airflow, and hearing a hissing sound from aft. A panel near seat row 66 opened, and a blanket and plastic bag were slowly sucked in. Passengers described a sudden hissing noise, cold air, and a sensation of air blowing from above or below the window. One passenger reported a small bag containing a passport being sucked away. Oxygen masks dropped automatically, followed by pre-recorded announcements. The cabin remained calm, and passengers assisted each other. After the crew announced it was safe to remove masks, conditions were checked and reported normal.
Investigation
The Aircraft and Railway Accidents Investigation Commission (ARAIC) of Japan investigated the incident, appointing investigators on May 8, 2005. An accredited representative from the United States participated as the state of design and manufacture. The investigation included aircraft examination, interviews, analysis of flight data and cockpit voice recorders, and functional tests of equipment. The investigation status report was submitted to the Minister of Land, Infrastructure, and Transport on July 28, 2006, and made public.