Speculation is on the rise that the pilot of the doomed Air India passenger plane which crashed in the southern Indian city Mangalore Saturday could have made a mis-calculation of the runway, as one of the plane wheels failed to touch the runway, said civil aviation sources.

Rescuers work at the scene of the air crash in Mangalore, southern Indian state of Karnataka, May 22, 2010. At least 159 people were killed when a state-run Air India Express aircraft, with 166 people on board, overshot a runway during landing and crashed near Mangalore airport in the southern Indian state of Karnataka early Saturday morning. [Xinhua]

One of the wings of the plane then hit a cliff near the runway and ran into a ball of fire, before plunging into a nearby gorge, killing 159 people out of 166 onboard, said the sources.

However, Indian Secretary of Civil Aviation Madhavan Nambiar said earlier Saturday it is too early to speculate on the cause of the Air India plane crash in the southern city of Mangalore.

He said at a press conference that the black box of the doomed plane is yet to be found, contrary to an early report by local TV Times Now that it was found already.

The official refused to speculate on any possible cause of the crash, saying that the airfield and runway have seen 32,000 landings of plane since its opening in 2006, and the plane's Serbian pilit had more than 12,000 flight hours.

A survivor (R1) has meal at a hospital in Mangalore, southern Indian state of Karnataka, May 22, 2010. The 7 survivors get treatment at the hospital on Saturday. At least 159 people were killed when a state-run Air India Express aircraft, with 166 people on board, overshot a runway during landing and crashed near Mangalore airport in the southern Indian state of Karnataka early Saturday morning. [Xinhua]

Local media said that most likely the cause of the crash could be pilot's error, including his misjudgment of runway length, as the plane got out of control after touching the ground and rushed into a gorge.

A survivor recalled that the plane span out of control after a loud thud was heard on the left side of the plane, presumably that of the tyre explosion.

Indian External Affairs Minister S.M. Krishna inspected the disaster site on helicopter, saying the airfield runway was "tricky"

The Mangalore airport was re-opened later Saturday and at least three planes had took off from the sinistered runway.

So far 146 bodies of 158 victims of the crash have been found, said Indian officials. Eight survivors are being treated in hospital. Among the bodies was that of the plane commander.

The Indian government has declared a two-day national mourning after the crash, which is the worst in some 14 years.