Transportation plays a crucial role in connecting people and places worldwide. While road transport remains the most commonly used mode, air travel stands as the safest, with air traffic management systems ensuring security and efficiency. Among these systems, the Traffic Collision Avoidance System (TCAS) is a key technology that ensures the safety of air travel by preventing mid-air collisions.
Undoubtedly, air travel is considered the safest means of transportation in the world to date. Its efficiency, cost-effectiveness, and safety are unparalleled by any other form of transportation. Air travel is becoming increasingly popular and safer each day, thanks to rapid technological advancements. The highly trained crews operating these million-dollar aircraft contribute significantly to making air travel the safest method of transportation worldwide.
Due to the rapid increase in demand for air travel, the number of aircraft in the sky continues to rise. To maintain the efficiency and safety of air travel, aircraft manufacturers have introduced new technologies in the latest generation of aircraft. One such technology is TCAS (Traffic Collision Avoidance System), a vital safety system designed to prevent unintentional collisions between aircraft, not only within radar-covered Air Traffic Control (ATC) zones, but more importantly, in areas lacking radar coverage, such as oceanic air routes.
It is a privilege to recount an event that took place over the Indian Ocean on 18th May 2024, involving a SriLankan Airlines Airbus A330, carrying over 300 passengers, Simultaneously, two aircraft from a prominent foreign airline were en route to the Middle East, also over the Indian Ocean. One of the foreign aircraft was an Airbus A380, carrying over 400 passengers, while the other was a Boeing B777, carrying over 300 passengers. In total, over 1,000 human lives were at stake.
TCAS is like an onboard collision warning system for aircraft, constantly scanning the skies for potential threats. When a possible collision is detected, it sends alerts and instructions to pilots, allowing them to take quick action to avoid danger. In the event of a potential collision, the system provides clear directions, either to climb or descend, and if both planes are equipped with TCAS, they communicate with each other to ensure coordinated action, avoiding accidents.
How TCAS Works – A Simple Explanation for Everyone
- Scanning the Sky
- TCAS constantly monitors the area around the aircraft using signals from other planes.
- It looks for airplanes nearby and checks their distance, altitude, and speed to see if they are getting too close.
- Warning the Pilot (Traffic Advisory – TA)
- If TCAS detects another plane approaching, it gives a warning alert (e.g., “Traffic, Traffic”).
- Avoiding a Collision (Resolution Advisory – RA)
- If TCAS determines that two planes might collide, it issues a Resolution Advisory (RA)
- Pilot Takes Action
- The pilot must take immediate actions for TCAS, even if air traffic control (ATC) gives different instructions.
- Once the danger is gone, the pilot returns to normal flight and informs ATC.
SriLankan Airlines flight was cruising at an altitude of 39,000 feet above sea level. Simultaneously, the Airbus A380 was at 40,000 feet, while the Boeing 777 was at 38,000 feet. Notably, the two foreign aircraft were separated from SriLankan Airlines’ flight by just 1,000 feet.
Meanwhile, the approaching A380, at 40,000 feet, began losing altitude rapidly, descending toward the SriLankan Airlines aircraft. TCAS immediately issued an alert to the SriLankan crew, advising them to perform a “Descent Resolution Advisory” maneuver to avoid a potential collision.
However, the situation did not end there. As the SriLankan crew descended below 39,000 feet, TCAS warned them again of another imminent threat, this time from the B777, which was flying at 38,000 feet. Once again, TCAS instructed the crew to perform a “Climb Resolution Advisory” maneuver to ensure the aircraft stayed clear of the other plane.
Performing a TCAS maneuver at high altitudes can potentially cause long-term damage to the aircraft’s structure, which may compromise passenger safety. To mitigate this risk, newer generations of aircraft are equipped with a system known as ‘AP/FD TCAS mode.’ This system enables the aircraft’s autopilot to perform TCAS maneuvers more efficiently and safely. However, it is designed to assist pilots by reducing their workload and executing maneuvers more smoothly than a human can, not to relieve pilots of their responsibilities.
To perform a TCAS maneuver correctly and safely, pilots must undergo simulator training every six months, during which they practice handling various in-flight emergencies. These emergency scenarios require pilots to possess a unique set of skills, remaining calm while responding quickly and effectively to sudden, potential dangers. Developing these abilities is not easy; it takes years of dedication, rigorous simulator training, and experience to become a skilled and safe pilot.
Thanks to the exceptional training and experience of SriLankan Airlines’ pilots, they were able to navigate both TCAS advisories smoothly, ensuring the safety of over 1,000 lives aboard all three aircraft. The ‘AP/FD TCAS mode’ system failed to react promptly due to the high rate of descent of the A380. The swift and decisive action of the pilots, particularly in manually overriding the autopilot system when necessary, highlights the critical importance of human intervention in emergency situations, even in an era of advanced technology like Auto TCAS.
I must take this opportunity to highlight that dual TCAS incidents have become extremely rare, with very few, if any, reported globally due to the advancement of modern air traffic control systems. However, such an incident did occur, making it a unique example that underscores the critical importance of having highly trained pilots in the cockpit, regardless of the advancements in autopilot technology.
SriLankan Airlines, a government-owned entity since its inception in 1979, has faced numerous financial challenges over the years. Despite these difficulties, the airline’s pilots, engineers, cabin crew, and other departments have consistently performed outstandingly around the clock. It is widely acknowledged that pilots are the backbone of any major airline, and SriLankan Airlines is no exception. In recent years, numerous international airlines in the region have actively recruited SriLankan Airlines pilots due to their exceptional standards within the industry. In fact, not only are SriLankan Airlines pilots in high demand, but the airline’s engineers and cabin crew members are also sought after by other airlines worldwide, thanks to their superior skills and professionalism.
At the helm of SriLankan Airlines flight during the TCAS incident were Captain Chamath Dharmasiri and First Officer Aminda Samarawickrama, both seasoned pilots with over a decade of experience with the airline, having acquired their pilot licenses in the United States. Graduates of prestigious universities and proud alumni of Royal College Colombo, they have gained invaluable experience and training, which has made them some of the most skilled pilots in the industry. Also accompanying them was Captain Bandu Kumbalatara, a distinguished Air Force war veteran, who served as the relief pilot during the flight.
This rare and remarkable event highlights the importance of skilled pilots, advanced technology, and effective safety systems. SriLankan Airlines’ unwavering commitment to safety and professionalism ensures that passengers can continue to trust the airline for their travel needs. Through the combined efforts of its experienced crew, state-of-the-art aircraft, and cutting-edge safety systems, SriLankan Airlines continues to stand as a leader in aviation safety.
Let’s continue to support and celebrate the exceptional work of SriLankan Airlines, its pilots, and its dedicated team. Their commitment to the safety and wellbeing of passengers is second to none, ensuring that air travel remains a safe and reliable mode of transportation.
Source: Daily Mirror
