Overview
• Operator 1: MNG Airlines
• Aircraft 1: Airbus A330-300 Freighter
• Registration: TC-MCN
• Flight Number: MB-380
• Route: Hong Kong (HKG) to Istanbul (IST)
• Incident Type: Loss of separation on departure
• Operator 2: Silk Way Airlines
• Aircraft 2: Boeing 777-200 Freighter
• Registration: VP-BMU
• Flight Number: 7L-625
• Route: Hong Kong (HKG) to Baku (GYD)
• Incident Type: Loss of separation on departure
• Date: 27 February 2025
• Location: Hong Kong International Airport (HKG), China
• Casualties: None
• Nature of Incident: Loss of separation between two departing aircraft on parallel runways
Incident Summary
A MNG Airlines Airbus A330-300 freighter (TC-MCN), operating flight MB-380 to Istanbul, was departing from Hong Kong’s Runway 07C, climbing through 2,500 feet and preparing to turn right onto its departure route.
Simultaneously, a Silk Way Airlines Boeing 777-200 freighter (VP-BMU), operating flight 7L-625 to Baku, was departing from Runway 07R, also climbing through 2,500 feet and preparing to turn right onto its departure route.
The Hong Kong Civil Aviation Department (CAD) confirmed that both aircraft had been cleared to separate altitudes (5,000 feet and 3,000 feet, respectively). However, differences in their actual climb rates caused the intended vertical separation to not be achieved.
At 23:02:06 UTC, the horizontal separation between the aircraft reduced to just 800 meters (0.45 nautical miles), with 0 feet vertical separation—placing them dangerously close to each other in controlled airspace.
The crew of the Silk Way B777 received a TCAS (Traffic Collision Avoidance System) Resolution Advisory (RA) instructing them to descend to avoid a potential midair collision.
Both aircraft successfully resolved the conflict, resumed their climbs, and continued to their respective destinations without further incident.
Sequence of Events
Pre-incident Conditions:
• MNG A330 (MB-380) was departing from Runway 07C, cleared to climb to 5,000 feet.
• Silk Way B777 (7L-625) was departing from Runway 07R, cleared to climb to 3,000 feet.
• Both aircraft were following standard departure procedures, which included right turns after takeoff.
• ATC expected adequate vertical separation to be established through differing climb profiles.
Loss of Separation Event:
• The MNG A330 climbed faster than anticipated, while the Silk Way B777 climbed slower than expected.
• As a result, both aircraft reached 2,500 feet at the same time.
• The aircraft converged on similar flight paths, bringing them into unsafe proximity.
• The Silk Way B777 received a TCAS RA instructing a descent to avoid conflict.
Resolution & Safe Continuation:
• The B777 complied with the TCAS descent instruction, increasing separation.
• The MNG A330 maintained its climb, and both aircraft successfully deconflicted.
• After resolving the issue, both aircraft resumed their original flight plans and continued to their destinations without further issues.
Investigation & Findings
Hong Kong CAD Initial Report:
• Both aircraft had been cleared to different altitudes (5,000 ft vs. 3,000 ft) to ensure vertical separation.
• Unexpected variations in climb rates caused the aircraft to reach the same altitude simultaneously, leading to a temporary loss of vertical separation.
• Both aircraft were visually aware of each other, meaning neither was in immediate danger of an undetected collision.
• The B777’s TCAS system issued a descent instruction, which was successfully followed to reestablish safe separation.
Analysis & Safety Recommendations
For Air Traffic Control (ATC):
• Review departure procedures for simultaneous takeoffs on parallel runways, ensuring that climb profiles account for variable aircraft performance.
• Improve climb clearance coordination to prevent unexpected convergence of flight paths.
• Enhance monitoring of aircraft climb performance in real time to detect potential conflicts earlier.
• Consider issuing speed or climb restrictions to aircraft to prevent close-proximity departures.
For Airlines & Pilots:
• Ensure adherence to ATC altitude clearances and climb rates, avoiding unintended level-offs or excessive climbs that could disrupt separation.
• Maintain heightened situational awareness during departures, especially when operating in parallel runway environments.
• Follow TCAS advisories immediately to ensure separation and avoid further conflicts.
For Airport & Aviation Authorities:
• Consider refining Standard Instrument Departures (SIDs) at Hong Kong International Airport to mitigate the risk of departure conflicts.
• Improve real-time ATC oversight of departing aircraft using predictive tracking tools to anticipate and prevent conflicts.
Conclusion
This loss of separation event highlights the risks associated with simultaneous departures from parallel runways, particularly when aircraft performance deviates from ATC expectations.
Although both aircraft were visually aware of each other, the convergence of flight paths at the same altitude posed a serious risk. Fortunately, the TCAS system provided an effective safety net, issuing a Resolution Advisory (RA) to the Silk Way B777, which successfully prevented a potential midair collision.
The Hong Kong Civil Aviation Department (CAD) has opened an investigation, which will likely examine whether procedural adjustments or improved ATC monitoring could help prevent similar occurrences in the future.
This incident reinforces the importance of strict adherence to departure climb profiles, proactive ATC monitoring, and the effectiveness of TCAS in preventing midair collisions.
Disclaimer
“This report is based on available information as of 28 February 2025. While every effort has been made to ensure accuracy, the completeness of the details cannot be guaranteed. If you are the rightful owner of any referenced materials and wish them removed, please email takedown@cockpitking.com.”
