Investigation continues into the crash of a four-seat Cessna 172 aircraft in a Melancthon field early Monday, in which three men who had taken off from the Brampton Flying Club were injured, two of them seriously.

The plane landed on a farmer's field on the 270th Sideroad near the Eighth Line SW in Melancthon, about two miles north of Highway 89.

Two of the men were airlifted to St. Michael's Hospital in Toronto with life-threatening injuries.

Matthew Jacob, 22, remained in critical condition and on life support Wednesday, while the craft's pilot, 20-year-old Vrushank Patel, was in serious but stable condition after surgery.

A third occupant of the Cessna, 20-year-old Webster George, was treated and released from Headwaters Health Care Centre in Orangeville.

OPP were first alerted to the crash Monday by a 4:51 a.m. call from a man who happened upon the crash site while walking his dog and had heard cries of help coming from the field.

The wreckage was mostly contained to a small portion of the field, but was extensive enough to make investigation difficult, says Rae Simpson, Transportation Safety Board of Canada's regional senior investigator for air operations.

"So far, our examination hasn't yielded anything that it was an airplane malfunction," said Mr. Simpson. He added, however, that the possibility cannot be entirely discounted.

Mr. Simpson says Mr. Patel, a properly qualified pilot with a night flying rating, rented the aircraft with the aim of picking up some of the night hours necessary for a commercial pilot's certification.

His flight included touching down at, and taking off from, three locations; the last one being Wiarton. Mr. Simpson says Mr. Patel was returning to Brampton from Wiarton when the crash occurred.

Mr. Simpson says three factors are examined during a crash investigation: Man, machine, and environment. These factors will be taken into account as the investigation continues, he says.

"We are continuing to gather information, so we can then go where the evidence takes us."