There are no reports of any casualties in the fire that broke out around midnight at the maintenance shed of Andhra Pradesh Aviation Academy at the airport located in the heart of the city at Begumpet, popularly known as Begumpet airport.
Earlier, Ports and Airports Minister G. Srinivasa Rao told reporters on Tuesday that five training aircraft of the academy and an AgustaWestland helicopter of the state government were destroyed in the fire.
The Cessna aircraft were being used for pilot training by the academy.
The 15-seater Agusta AW 139 was purchased by the state government in 2008 from AgustaWestland Italy for Rs 63 crore. The minister said the chopper was insured and the government would claim the money.
The initial estimates by the officials have put the loss at over Rs 100 crore.
Ten fire engines, including those belonging to the Indian Air Force, battled the blaze for over four hours to bring it under control. The firefighting personnel remained at the scene till Tuesday afternoon to completely douse the fire.
The airport was being used for non-commercial purposes since 2008 when the new airport became operational at Shamshabad, about 30 kilometres from the city.
Besides the Aviation Academy, the airport is used for VIP flights, private chartered aircraft and by the Indian Air Force.
Media persons were not allowed inside the airport area and the officials were tight-lipped about the exact damage.
However, the huge flames and explosions spread panic among people in Bowenpalli and surrounding areas in Secunderabad.
The state government ordered a high-level probe into the incident. The state home secretary will head the investigations to find out if there was any sabotage or if the fire was caused by an electrical short-circuit, said the minister.
Several parts of other aircraft and equipment kept at the hangar were also destroyed.
"Everything is reduced to ashes," said an official after visiting the site.
The presence of large quantity of aviation fuel made the task of firefighting more difficult. Eye witnesses said within few seconds, the fire engulfed the entire area.
The hangar, built almost 100 years ago during the times of Nizam, the ruler of then Hyderabad State, collapsed due to the fire.
Various government agencies launched probe into the fire.
Chief Minister N. Kiran Kumar Reddy, who is currently visiting Visakhapatnam, ordered an inquiry by the Crime Investigation Department (CID). Officials of the Directorate General of Civil Aviation (DGCA) and Airports Authority of India (AAI) also visited the scene.
CID officials launched their probe with the forensic experts gathering clues. Additional Director General, CID, Krishna Prasad said they would probe the incident from all angles. He quoted some eye witnesses as saying that loud explosions were heard from the hangar before they saw the flames.
Meanwhile, the minister said they would make alternate arrangements for the chief minister's travel.
Kiran Kumar Reddy was using the spacious helicopter, which can fly long distances.
His predecessors K. Rosaiah and Y.S. Rajasekhara Reddy also used to fly in the Agusta AW 139. Though it was purchased during Rajasekhara Reddy's tenure, he was using both the new one as well as a Bell 430. He was killed on September 2, 2009 when the Bell helicopter crashed in bad weather in Kurnool district.
The Agusta helicopter was also used for rescue and relief operations in the floods in Kurnool district in 2009 and after the Maoist attack on policemen in the Andhra-Orissa border area.
The government was spending Rs 1.25 crore every month on the maintenance of the chopper.