By Ainur Rohmah

JAKARTA

Indonesia deployed search and rescue teams Monday to try and trace the whereabouts of a helicopter with five people on board that went missing over the western island of Sumatra.

National search and rescue agency spokesman Zainul Thahar told Anadolu Agency that an investigation was being carried out in the vicinity of Toba Lake.

"We have sent around 200 personnel to search for the helicopter," he said.

The chopper -- carrying a pilot, an engineer and three passengers -- lost contact with air traffic control Sunday while crossing the island.

It took off from Samosir in Sumatra's north at 11.33 a.m. (0433GMT) and should have arrived at Kualanamu International Airport (in the island's north/south/east west) just over an hour later.

It last made contact at around 11.50 a.m.

Luis Sihotang told reporters Monday that he saw a helicopter lose control 150 meters above Toba Lake, and then heard a blast, but a thick haze had obstructed his view.

"At that time, we saw a helicopter fly low over us and spin around three times. Shortly after that, we heard a loud explosion," the man - who claimed to have been fishing with three friends when the helicopter appeared told Tribun News 

"And then, there was suddenly a big wave," he added.

Head of search and rescue for Medan city, Rochmali -- many Indonesians go by only one name -- told Anadolu Agency that the air search had been hampered by the smog, but did not want to confirm that the helicopter had downed.

"Up to now, the status of the helicopter is still 'lost contact'," he said.

Indonesia has a poor aviation safety record and has suffered major disasters in recent months, including plane crashes in December in which 162 people lost their lives and in August in which 54 died.

Ten people were killed when a domestic passenger plane crashed in the jungles on the island of Sulawesi early this month.