A preliminary probe into the crash of an Indonesian airliner that killed 149 people has found a fuel problem with one of the plane?s engines, a transport safety official said yesterday. Setyo Rahardjo, head of the National Transport Safety Committee, told Reuters investigators had found a fault in one of the two engines on the Boeing 737-200, which slammed into a crowded neighbourhood in the city of Medan on Monday.

As investigators sought more answers, authorities buried 33 victims who were too charred to identify in a field next to a mass grave containing the remains of passengers from a previous air crash near Indonesia?s third biggest city. Hundreds of family members wept and some fainted in the sweltering heat as soldiers lowered simple wooden coffins one by one into a freshly dug hole. Two excavators poured earth on top, blotting out the stench of rotting flesh. Rahardjo did not say which engine he was referring to, but added that visually it looked like there had been a problem.

?During our preliminary investigation we have found a fuel problem. To be exact it was on the fan blade, but it needs to be noted that the findings are preliminary and at this stage we cannot conclude engine failure as the cause,? Rahardjo said. The disaster on Monday killed 149 people, 102 of them on board the Mandala flight and 47 others on the ground when the plane burst into flames shortly after take-off. Fifteen passengers in the tail section survived. The engines on the crashed plane were manufactured by Pratt & Whitney, a unit of United Technologies Corp., the Mandala Airlines? senior technician, Muhammad Yusuf told Reuters. A US National Transport Safety Board team of investigators, as well as investigators from aircraft maker Boeing, were helping with the probe in Indonesia, an American embassy statement said.

The plane?s black box and flight recorder are still being examined and officials have said they will be sent overseas. Commercial aircraft are designed to cope with the failure of one engine on take off. Its remaining engines, even if there is only one, should have enough power to get the plane to a safe flying speed before returning to the runway. But a fuel problem might shut down all engines. Some local media have said one of the 24-year-old plane?s engines was found in the airport?s grounds. The plane, bound for Jakarta, came down 500 metres (1,600 feet) from the runway.

In recent years soaring fuel prices have hit Indonesia?s airlines hard, while the growth of budget carriers has brought pressure to keep fares down. Some smaller companies have gone out of business and others have been forced to cut services. But local airline safety experts have largely dismissed speculation that competition has hurt airline maintenance. President Susilo Bambang Yudhoyono has ordered an investigation into aviation safety.

The mass burial took place in a field not far from Medan?s airport. Reflecting the city?s large population of Christians, priests joined a Muslim cleric at the ceremony. The earlier mass grave contains the remains of victims from Indonesia?s worst air accident, when a Garuda Airbus A-300B4 crashed in a mountainous area near Medan in September 1997, killing all 222 passengers and 12 crew. Victims from a 1970s air crash are also buried in the field. Mandala Airlines is one of Indonesia?s oldest private carriers, operating a number of Boeing 737s. The doomed aircraft was fit for eight more years of flying, Mandala has said. Medan lies 1,425 km (885 miles) northwest of Jakarta on Sumatra island.

Tomi SOETJIPTO