Mystery surrounds the crash of the mini aircraft that crashed in Jawaharnagar locality in Faridabad near the Delhi airport yesterday night.

While initial reactions have blamed strong winds for smashing the nine-seater onto a house -- killing three women on the roof of the house -- air traffic records show that the plane lost an inordinate amount of altitude suddenly before the crash.

The plane, according to air traffic authorities, was flying at the usual cruising height of 11,000 feet (3.5 km) up in the air.

"We told the plane to keep at 11,000 feet as there were five other planes to touch down before it," pointed out a source in the airport.

While the plane should have circled at 11,000 feet, it started losing altitude and descended rapidly. "We have to see why it came down so rapidly.. whether there was wind at the high altitude or whether it got caught in the wind only after climbing down from the high altitude," the source pointed out.

Sudden wind movements are usually confined to either the lower atmosphere.

The P-12 turboprop plane, which is reported to have been in very good condition, was ferrying a 20 year old student who had passed into a coma in Patna after suffering from Jaundice for several days.

The plane was in regular use by Delhi's Apollo Hospital as an air-ambulance. It was hired from Delhi-based Air Chartered Services India Pvt Limited and had two doctors and one male nurse from Patna. It is considered extremely dangerous for small aircraft to land in stormy or windy conditions as they don't have the mass to withstand the strong gusts.

The crash killed the wife, daughter and daughter in law of the person who owned the ill-fated building on which the plane came down. Three people were injured, including two with burn injuries, when trying to rescue the victims, and are in hospital.