What happened
On 25 October 2022, a Singapore Airlines B777-300ER, registration 9V-SWH, was en route from London Heathrow to Singapore Changi Airport. As the aircraft approached Singapore, heavy thunderstorms and deteriorating visibility at Changi prompted air traffic controllers to implement holding patterns. While the flight crew initially planned to hold at waypoint SAMKO, the weather conditions at Changi remained unfavorable, and the aircraft's fuel levels began to drop significantly.
Faced with the prospect of running out of fuel, the crew decided to divert to Hang Nadim International Airport in Batam, Indonesia, where weather conditions were reported as clear. During the diversion, the crew declared "Mayday Fuel" when the estimated fuel upon arrival at Batam was expected to reach the Final Reserve Fuel limit. During the approach to Batam Runway 22, a strong tailwind forced the crew to abandon the initial approach and reposition for Runway 04. During this second attempt, the crew encountered a "NO AUTOLAND" message on the primary flight display, which led to a go-around.
The investigation
The TSIB investigation examined the flight crew's decision-making process, the coordination between air traffic control services, and the technical information available to the pilots. The inquiry looked into why the crew continued to hold despite declaring low fuel and why the crew was unaware that an automated landing was prohibited by company procedures for that specific runway configuration.
Findings
- The flight crew initially prioritized attempting a landing at Changi over an earlier diversion to the better weather in Batlam.
- The crew offered to perform additional holding patterns and orbits despite having previously communicated that they were approaching minimum fuel levels.
- The crew was unaware that autoland was prohibited on Batam Runway 04 due to a 1-degree offset in the localizer signal.
- The operator's airport briefing document for Batam lacked the specific warning regarding autoland restrictions that was present in briefings for other airports.
- The appearance of the "NO AUTOLAND" alert, combined with the high-stress fuel situation, significantly increased the crew's workload and contributed to the decision to perform a go-around.
- The flight crew's decision to continue holding despite being at minimum fuel levels contributed to the critical fuel state.
Safety action
Following the incident, the operator conducted training sessions for all pilots focusing on threat and error management, effective communication with air traffic control, and managing high-workload situations. The operator also began a review of all airport briefing documents to ensure consistent detail and has integrated this event into simulator training to improve fuel management and diversion procedures.