Investigators began a probe into the cause of an Indonesian jetliner crash on Monday that killed at least 149 people, including dozens on the ground who lived in a crowded neighborhood in the city of Medan, officials said. An airline official said 13 passengers seated in the tail section survived.

Human error and mechanical failure are among the possibilities being explored in the crash of the Boeing 737-200 flown by budget carrier Mandala Airlines, said Setio Rahardjo, chairman of the National Transportation Safety Committee.

Rahardjo said that the aircraft's black box recorder had been recovered and that investigators hoped it would yield clues. The jet, which was built in 1981 and underwent comprehensive maintenance in June, hit the ground nose first shortly after takeoff, officials said. It was bound for Jakarta with a full load of 112 passengers and five crew members.

Medan, on the western island of Sumatra, is about 885 miles northwest of Jakarta. It is Indonesia's third-largest city and was a major hub for rescue efforts following the earthquake and tsunami in December.

"The plane had actually taken off, but somehow it started to shake heavily and swerved to the left, and then -- wham, a ball of fire came from the front of the plane toward the back," said Rohadi Sitepu, interviewed by Indonesia's Metro Television from his hospital bed.

"From our side of the plane, there were maybe 10 people who survived," including his wife, he said. He escaped, he said, through a hole in the fuselage.

The survivors also included a 17-month-old girl and her mother. Doctors said neither suffered life-threatening injuries.

Firefighters battled an inferno that engulfed dozens of houses and vehicles, sending choking billows of black smoke into the air.

Identifying the dead was difficult because most were burned beyond recognition, officials said. Television footage showed badly charred bodies being carried on stretchers and laid on the ground in hospital morgues, with anxious relatives trying to find their loved ones.

Among the dead was Teuku Rizal Nurdin, the governor of North Sumatra province, who had been on his way to a governors' meeting about the economy with President Susilo Bambang Yudhoyono. The former provincial governor, Raja Inal Siregar, also died in the crash.

Initial news reports that Aceh province's acting governor, Azwar Abubakar, was on board were incorrect. He was not listed on the flight's passenger list.

Search and rescue officials in Medan said 30 people on the ground had been killed, according to the Reuters news agency.

"The president was very shocked to hear the news," said Yudhoyono's spokesman, Dino Patti Djalal. "There was some good news about the survivors."

Mandala, partially owned by the Indonesian military, recently reduced its flights to cut costs and compete with newer budget airlines. It operates mainly domestically and most of its jets are more than 10 years old.

Indonesia's worst airplane accident was in September 1997, when a Garuda Airlines A-300 Airbus crashed near Medan, killing all 234 people aboard. The Mandala crash followed five major airline accidents in August, the deadliest month for plane disasters since May 2002. At least 330 people died in accidents in Peru, Venezuela, Greece and Sicily last month.

Special correspondent Yayu Yuniar contributed to this report.

Indonesians in Medan examine the wreckage of the 737 that hit the ground nose first with a full load of passengers, including the provincial governor.A piece of the plane's wreckage bears the Mandala Airlines logo. An airline official said 13 passengers seated in the tail section survived.