Eyewitnesses said that the plane was seen hurtling down in the narrow Jeevadaya Lane area and crashed with a deafening sound before breaking into pieces and bursting into flames around 1.15 p.m. There were two pilots and as many engineers on board.

The fuselage had broken into several pieces and one piece was recovered at least 50 metres away while some other portions of the plane burnt in the premises of an under-construction building. The fire was brought under control within half an hour by the fire brigade.

The aircraft's crucial Flight Data Recorder or Black Box was recovered.

A local passerby in the vicinity of the crash was burnt fatally when some burning ATF fuel from the aircraft fell on him, said an eyewitness who was among the first to reach the spot.

The cause of the crash is not known and it occurred in the compound of the under construction Jagruti apartments, thereby averting a potentially major disaster.

There are usually at least four dozen labourers working on the premises but they had taken a lunch break when the aircraft hurtled there, creating a crater by its impact.

Aviation expert and Executive Airways Managing Director Pradeep Thampi said the aircraft was a 30-year-old King Air C-90, purchased from the Uttar Pradesh government by private company UY Aviation Pvt Ltd in Mumbai around a couple of years ago.

"Its call sign was VT-UPZ and it was a regular 12-seater on a test flight. The tragedy has claimed the pilot, co-pilot and two engineers. We cannot say immediately what may have led to the sudden crash," Thampi told IANS.

An Uttar Pradesh government spokesperson confirmed that the Mumbai-based UY Aviation Pvt Ltd had bought the aircraft a few years ago.

Union Minister for Civil Aviation Suresh Prabhu, who hails from Mumbai, expressed "deep shock" over the tragedy and directed the ministry officials concerned to rush to the accident site and provide all assistance possible.

Prabhu said he has ordered the Director-General of Civil Aviation to conduct an investigation into the crash and a team has left for the spot for a preliminary probe.

Mumbai Police, fire brigade, disaster relief agencies, besides local BJP MP Kirit Somaiya, legislators and others are at the site and further details of the victim crew members and pedestrians are awaited.