Hong Kong investigators have released a preliminary report on a hydraulic failure aboard an Atlas Air Boeing 747-400F at Hong Kong International Airport (HKG) on June 17, 2024.
The incident, which was categorized as serious by the Air Accident Investigation Authority (AAIA), resulted in the closure of a runway at HKG for eight hours. There were four crew members and one passenger on board the cargo jet. No injuries were reported.
The Atlas Air 747-400F, registration N406KZ, departed runway 25L at HKG at 04:09 local time and was bound for Anchorage, Alaska.
During the takeoff roll, the crew felt a slight yawing and shimmy sensation, the preliminary report noted.
“However, in the absence of cockpit indications and other cues that would suggest the aircraft’s flyability was compromised, the take-off continued normally with normal gear retraction,” the report added.
About 26 minutes after takeoff, a warning message from the Engine Caution and Crew Alert Syst em (EICAS) appeared on the cockpit display, indicating that there was a low level of hydraulic fluid in one of the aircraft’s syst ems.
“A warning message indicating low hydraulic syst em fluid level is a signal of hydraulic lines being punctured, causing leakage. The pilot made the right call to return the flight,” Warren Chim Wing-nin, the Deputy Chairman of the Hong Kong Institution of Engineers’ aircraft division, told the South China Morning Post on July 16, 2024.
During landing, the fluid in hydraulic syst ems two and four dropped to zero. After following the appropriate checklist and consulting the Atlas Air’s ground office, the pilot in command decided to return to Hong Kong. The crew dumped fuel and made a PAN-PAN call, before the aircraft made an ILS approach back to runway 25R.
According to the report, the landing was normal with “no reported loss of directional control”. The plane landed at 07:12 local time.
Once the aircraft stopped, smoke started to come from the wheels. Ground authorities reported that two tires were shredded and there was significant damage to the third wheel. Several hydraulic lines in the right wing were broken and there was some damage to the lower front fuselage.
According to Hong Kong International Airport authorities approximately 450 out of 932 scheduled flights between 07:00 and 00:00 were delayed due to the incident on June 17, 2024.