What happened
On July 8, 2018, a China Airlines Boeing 737-800, registered B1lar667, was operating a scheduled flight from Taipei to Toyama Airport when it encountered severe weather conditions. During its approach to Toyama, the crew executed three separate go-around maneuvers due to gusty winds and unstable approach criteria. The first two attempts were aborted at altitudes of approximately 400 feet and 100 feet, respectively, while the third attempt was abandoned at 1,000 feet due to a strong tailwind.
Following the third failed approach, the flight crew diverted the aircraft to Chubu Centrair International Airport. During the transit, the aircraft's fuel levels dropped significantly. At approximately 12:36 JST, while flying 15 nm north of Toyama, the crew initiated emergency communications using the PAN-PAN signal to notify Tokyo Air Traffic Control (ACC) of their critical fuel situation. The aircraft later issued a MAYDAY distress signal at 12:42 JST to ensure the urgency of the situation was recognized. The aircraft landed safely at Chubu Airport at 13:10 JST with 2,480 lb of fuel remaining.
The investigation
The Japan Transport Safety Board (JTSB) examined flight data recorder (FDR) records, air traffic control communications, and radar tracks. The investigation focused on the fuel consumption during the repeated approaches and the clarity of the communications between the flight crew and Tokyo ACC. Investigators also reviewed the operator's Flight Operation Manual (FOM) regarding the use of specific terminology for low fuel and emergency situations.
Findings
- The repeated landing attempts at Toyama Airport consumed a significant amount of fuel, with each approach costing approximately 1,300 lb.
- By the time the aircraft reached Chubu Airport, the remaining fuel was approaching the final reserve fuel level.
- The flight crew's emergency communications were initially difficult for controllers to understand due to muffled and unclear audio, likely caused by atmospheric or topographical interference rather than equipment failure.
- The crew did not utilize the specific "MINIMUM FUEL" terminology prescribed by the operator's manual during the initial stages of the fuel depletion.
- While the aircraft reached a critical state, the investigation determined the aircraft was not in an actual shortage of fuel at the time of landing, as the remaining quantity did not fall below the final reserve requirement.