It was a cold Delhi morning on 17th February 2011. We reached the runway at Palam airport at 8 AM. The fog was so dense that we could not see anything beyond 50 meters. So we had to wait till the visibility improved. A western disturbance (WD) had passed over Delhi 2 days ago spraying rains that left abundant moisture in the cold atmosphere conducive for formation of dense fog. It took almost 5 hours to clear the fog for a safe takeoff with visibility around 1500 meters. But by that time there were many passenger airlines waiting impatiently in the queue for departure. Therefore, it was only around 2 PM that the pilot was given clearance to takeoff.

The WC-130J is a US Air Force Hurricane Hunter aircraft. We were on a test flight with a mission to collect aircraft reconnaissance observations during the next cyclone season for reducing uncertainties in the 24-96 hours forecast errors which have potentially large societal impact. It is estimated that the cost of evacuation is about 1 Million Dollar per mile on the coastal areas. The data collected by the hurricane hunters make forecasts 25-30 % more accurate. It is fitted with sophisticated instruments including a Stepped Frequency Microwave Radiometer (SFMR) for pinpointing the centre of a cyclone by measuring the surface wind, sea level pressure and other crucial observations. It can launch up to 10 dropsondes in each mission for measuring the vertical profiles of temperature, humidity, wind speed and direction. It can fly continuously for 8-12 hours and transmit data in real time sampling every 10 seconds. It can fly 500-1500 meters above water at a minimum cruising speed of about 170-180 kts and it can also take observations from 8-10 km altitude. It can be used for 24 hours operations per day with 3 storms at a time. Apart from taking special observations during cyclones, the aircraft is also used for collecting targeted observations in areas of most uncertainty where different computer models disagree the most. The hurricane hunter is also used for deploying buoys in the ocean for measuring air and sea surface parameters during a cyclone.

We were on a test flight trying to chase some bad weather, but the hailstorm associated with the WD had already passed over north India and gone towards China through Nepal on the previous day. We flew along the Shivalik range about 100 km off the mountains for about 2 hours. The weather was generally good en-route with the sky filled with many towering cumulus clouds. We flew up to Lucknow and finally returned to Delhi safely landing around 4 PM. Some of the photos shot during the mission are shown above.