Opinion
Safe landing
Despite little formal training, the air traffic controller at TIA was once forced to use radar vectoring to save an aircraftTri Ratna Manandhar
Back in 2003, I was Director of the Flight Operations Department at the Tribhuvan International Airport (TIA). Apart from other duties, air traffic control was one of my responsibilities. As a qualified controller, I used to monitor the Controller/Pilot VHF (very high frequency) communication whenever I had time. One day, just when I had arrived at the office, I switched to radar control frequency 122.5 mhz and sensed something wrong. I immediately rushed to the radar control room and discovered that the situation was not normal. I immediately started giving instructions to the controller.
Total navigational failure
The problem was that an east-bound jet aircraft, while on a four-mile arc flight following the Standard Instrument Departure and making a circle overhead, had reported a glitch in the navigational system on passing west of the airfield. The pilot had requested to return for landing. In accordance with established procedure, he was cleared direct to Dharke on a climb to 12,500 feet, then onto a 15-mile arc flight to approach Runway 02 (from the south). As the aircraft was not able to follow an arc flight, it was requested to proceed to Simra and come back for landing from there. While heading to Simra, the aircraft once again informed that it would rather proceed to the Bhairahawa side.
In another moment, the pilot declared a total failure of the navigation system and relayed his intention to go to Delhi as better services and facilities were expected there. He also requested the controller to inform Delhi and Varanasi about the situation and to provide radar vectoring (guidance according to radar coverage). While heading towards Bhairahawa on a climb to Flight Level 260 (26,000 feet), the aircraft asked for Kathmandu weather, which was cloudy and overcast, except for a few small holes with visibility about eight kilometre. Upon receiving this update, the aircraft informed that it would rather come back to Kathmandu for VFR (visual flight rules) landing and also requested radar vectoring.
In the hot seat
The aircraft was unaware of its actual position, was totally lost and was requesting the Air Traffic Controller (ATC) to guide it to Kathmandu for landing. The ATC was reluctant to use radar vectoring because there was no established procedure at TIA for arriving aircraft. So it was not authorised. But the situation was very serious and tense. It was a question of the life and death of hundreds of persons on board the aircraft, a real emergency. The controller on the hot chair (the main controller instructing the pilot) was very uncomfortable. He seemed to be wishing to quit the chair. I encouraged him, don’t worry I am behind you. It was a tough decision for me to take but there was no time to wait and no one to consult. So I firmly decided, yes, we would provide radar vectoring to the troubled aircraft.
The controller started to issue instructions to the aircraft to guide it towards Kathmandu with reference to three dimensional information, ie, distance, level and direction of the aircraft observed in the radar scope. The purpose of radar vectoring is to assist the aircraft to intercept its final approach track and bring down the aircraft till it encounters Visual Meteorological Conditions. Every precaution was taken while vectoring and issuing clearance to the aircraft. After some time, all high-level Civil Aviation Authority Nepal (CAAN) officials gathered in the radar operation room. But there was no one to give definite instructions; no one wanted to be involved.
As the aircraft was totally lost, it was very difficult for the controller to guide the aircraft along a correct path. Its heading had to be corrected several times. The aircraft used to disappear momentarily from the radar scope due to blind spots (areas not covered by radar). The most heart-pounding time was when the aircraft crossed almost 10 miles into the Kathmandu Valley and descended to 10,800 feet. Instead of continuing the final approach track, the aircraft deviated to the right. This meant that craft could collide with any terrain at any moment. The ATC issued warnings and thankfully, we heard the pilot’s reply, “We are trying VFR, Stand by, OK, We are VFR. Will come overhead for a circling approach for Runway 02.”
When the aircraft reported VFR, it was transferred to Kathmandu Tower 118.1 mhz. When the aircraft completed VFR and the pilot was confident that he could now land safely, he expressed sincere gratitude to the controller from the air itself. The pilot’s wording, as far as I can remember, was as follows, “Thank you very much. For the first time, in the history of Nepali aviation, a jet aircraft was saved by the controller. Thanks a lot.”
The right decision
The TIA and its ATC had no experience of vectoring the aircraft, except for during training periods. But despite this shortcoming, the controller guided the aircraft very skillfully. During the arrival of the troubled aircraft, the airport was closed off to other traffic for the time being and Airport Rescue and firefighting service was kept on alert.
With expert ATC guidance and with the efforts of skilled and experienced crew members, the aircraft landed safely. This type of incident is very rare, and very few will even believe that such a sophisticated aircraft experienced total navigation failure. What the ultimate findings were, I do not know. I still remember those moments, when after landing, all the crew, CAAN and airlines officials gathered in my office to review the incident. The captain, upon entering the room, asked for the controller and proceeded to hug the man who had vectored the aircraft.
We had expected that our job would be appreciated. However, serious questions were raised about the aircraft being vectored by deviating from approved procedures. It took great effort to convince the authorities that we had to vector the aircraft to save it. I pleaded very strongly that the controllers must be rewarded for their commendable job and to also encourage them to take such initiatives in the future. Finally, I was able to convince the authorities and two controllers were rewarded by CAAN. For me, the trust and appreciation I received from all the controllers was more important than any official reward. Sometimes I think what would have happened if the aircraft had not landed safely.
I do not know whether the pilot’s decision to come back to Kathmandu was right or not. But my decision to provide vectoring service, although not within the approved procedure, was the best and most appropriate decision I have ever made in my life.
Manandhar is a former Director General of CAAN