What happened
On 17 June 2024, an Atlas Air Boeing 747-400F freighter, registered as N406KZ, departed from runway 25L at Hong Kong International Airport at 04:09 a.m. Approximately 26 minutes after takeoff, the pilot in command decided to return to the airport following the failure of the hydraulic #1 system. To comply with landing weight requirements, the crew performed a fuel jettison before touching down on runway 25R at 07:12 a.m.
While the landing itself was executed without a loss of directional control, the aircraft experienced a rapid depletion of fluid in hydraulic systems #2 and #4 during the landing roll. This depletion triggered warning messages on the aircraft's Engine Caution and Crew Alert System (EICAS). No evacuation was required following the stop.
The investigation
The AAIA is currently conducting an investigation to determine the circumstances surrounding the event. Post-flight inspections revealed that the #9 and #10 tires had been shredded, with significant damage to the #9 wheel and missing components from both wheels. Investigators identified fractured and punctured hydraulic lines within the right-hand wing landing gear wheel well, which resulted in the total loss of fluid from hydraulic systems #1, #2, and #4.
Additionally, the inspection noted damage to the lower forward fuselage, the lower right wing sections, and various components inside the wheel well. The investigation team has examined retained aircraft components, some of which were sent to overseas laboratories for specialized testing. The scope of the inquiry includes reviewing the operator's procedures, evaluating crew actions, and analyzing the operational risks associated with the simultaneous tire failure and hydraulic loss.