Incident Overview
On July 8, 2018, at approximately 12:36 JST, a China Airlines Boeing 737-800 (registration B18667) operating scheduled flight CI170 experienced a serious fuel shortage about 15 nautical miles north of Toyama Airport at an altitude of 9,600 feet. The aircraft, which had departed from Taiwan Taoyuan International Airport at 09:09 JST, was unable to land at Toyama after three approach attempts due to gusty wind conditions. The crew subsequently diverted to Chubu Centrair International Airport, declaring an emergency and ultimately landing safely at 13:10 JST with 2,480 lb of remaining fuel.
Sequence of Events
The flight crew, with the captain as pilot flying and first officer as pilot monitoring, prepared for approaches to Toyama's runways 20 or 02. The first approach to runway 02 was abandoned at 12:00:00 at about 400 ft due to a descent rate exceeding the operator's stable approach criteria caused by gusty wind. Remaining fuel at that time was approximately 8,600 lb. The second approach to runway 02 was also terminated at 12:14:40 at about 100 ft when approach speed exceeded criteria; remaining fuel was about 7,300 lb. The third approach targeted runway 20 due to more favorable wind, but at 12:27:47, a strong tailwind led to an excessive descent rate at about 1,000 ft, prompting another go-around. The remaining fuel after the third go-around was about 6,000 lb. The crew then decided to divert to Chubu Airport, informing Toyama Tower.
Upon contacting Tokyo Area Control Center at 12:31:35, the crew requested a change of destination. At 12:36:11, they issued a PAN-PAN emergency communication due to tight fuel, but the transmission was low and muffled; Tokyo ACC did not recognize the urgency initially and issued a heading of 140 degrees magnetic. The crew, concerned about flying over mountainous terrain with diminishing fuel, broadcast a second PAN-PAN at 12:36:49, again unclear. At 12:41:29, a third PAN-PAN clearly conveyed that fuel was critical, prompting the controller to confirm the emergency. At 12:42:40, the crew broadcast a MAYDAY, after which Tokyo ACC gave priority and cleared the aircraft directly to Chubu Airport. The aircraft landed with 2,480 lb of fuel remaining.
Investigation Findings
The Japan Transport Safety Board investigated the incident, categorizing it as a serious incident under Article 166-4 (xii) of the Japanese Civil Aeronautics Act. No injuries or aircraft damage occurred. The flight crew held valid licenses and medical certificates. The incident was attributed to fuel shortage requiring urgent measures, but the report does not assign a probable cause.