KUALA LUMPUR, March 11 — Malaysia widened the search area for a missing jetliner, dispatching ships to check debris in the South China Sea, as the hunt for clues spread to space with satellite surveillance in a mystery entering its fourth day.

Vietnam’s coastal waters will be a target for patrol planes today after some objects were spotted on the surface. That moved the inquiry east of the route of Malaysian Airline System Bhd.’s Flight 370 after focusing on the Gulf of Thailand, where an oil slick once seen as a crash marker proved to be marine fuel.

Earth orbit offers the latest vantage point from which to seek the Boeing Co. 777-200. A Vietnamese satellite will photograph the Tho Chu Island area in the Gulf of Thailand, the news website Infonet said, while China’s Xinhua news agency reported that the country also is deploying satellites. The probe into two fliers using stolen passports continued.

“Where you have an airplane go down in the water, it’s not unusual to have a period where you are searching and don’t know where it is yet,” said John Hansman, a professor of aeronautics and astronautics at Massachusetts Institute of Technology. “Everybody wants to have an answer right away. It takes a while to find the evidence.”

Australia and the US are part of a nine-nation, air-sea search for the twin-aisle jet, which was en route to Beijing from Kuala Lumpur with 239 people when it vanished from radar screens on March 8.

Awaiting daylight

Surface vessels kept searching overnight, and aircraft will rejoin the probe today “as soon as the sun comes out,” Doan Huu Gia, chief commander of the country’s aviation search and rescue coordination center, said yesterday at a briefing in Hanoi.

The possible debris area is 60 kilometres southeast of the Vietnamese coastal city of Vung Tau, said Lai Xuan Thanh, chief of the country’s civil aviation agency. Vietnam is also sending ships to investigate what appears to be metal pieces.

A plane alerted Hong Kong air traffic controllers about the discovery, the Civil Aviation Authority of Vietnam said in a statement on its website. Malaysian officials said they were directing ships toward the Hong Kong region, and Vietnam said the multinational search flotilla totalled 40 vessels, backed by 34 aircraft.

The latest sighting came as the search for Flight 370 left authorities confounded as to how a jet with one of the industry’s best safety records could vanish from radar without a distress call and leave no trace over water or land, even after days of patrols by surface vessels, planes and helicopters.

Malaysia’s Department of Civil Aviation (DCA) Director General Datuk Azharuddin Abdul Rahman speaks at a news conference in Sepang March 10, 2014. — Reuters pic

Watery search

“This was a relatively long flight going over large areas of water,” MIT’s Hansman said by telephone. “So there’s a reasonably large area that has to be searched to find something. I’m convinced something will turn up in the next few days.”

Closed-circuit television footage of the two travellers with stolen passports gave investigators another set of clues to examine. Austria and Italy said the passports were stolen from their nationals. The Royal Thai Police is probing the two thefts, which occurred in Phuket in 2012 and last year, spokesman Piya Uthayo said in Bangkok.

“We are trying to ascertain if the two holders of false passport entered Malaysia, legally or illegally,” Inspector-General of Police Tan Sri Khalid Abu Bakar said in a mobile-phone text message. The Financial Times reported that Malaysian authorities have given US investigators biometric details on the travellers with the stolen passports.

Ticket numbers

Tickets purchased with the pilfered passports on the flight, which belonged to Luigi Maraldi of Italy and Christian Kozel of Austria, had consecutive numbers, according to the Chinese e-ticket verification system Travelsky.

Men using the passports purchased the tickets on March 6 from Six Star Travel Co. in Pattaya, Thailand, city police Commander Supachai Phuykaeokam said by phone. The person with Maraldi’s documents had a final destination of Copenhagen, while Frankurt was listed as the last stop for the person posing as Kozel, the commander said.

An officer at Six Star Travel declined to comment. The Financial Times cited a travel agent as saying she was asked to arrange the trips for the two men by an Iranian contact. Neither Maraldi nor Kozel was on the Malaysian aircraft, their governments said.

Evidence that typically might be spotted after a terrorist incident is lacking so far, said two US officials. At the same time, the absence of clues isn’t enough to rule out such an attack, said the officials, who asked not to be identified while discussing intelligence activities.

A police officer stands guard next to security regulation signage at the departure hall of the Kuala Lumpur International Airport in Sepang on March 10, 2014. — AFP pic

No anomalies

The early warning system for the North American Air Defence Command detected no anomalies related to Flight 370, said one of the officials. Norad’s infrared and visual imagery can pick up heat sources such as explosions and missile launches, the official said.

US intelligence agencies also haven’t turned up a burst of chatter online or on the airwaves of the type that often follows an attack, the second official said.

Before takeoff from Kuala Lumpur, Malaysian Airline removed the baggage of five passengers who didn’t board after checking in, said Datuk Azharuddin Abdul Rahman, director general of Malaysia’s Department of Civil Aviation. “There are issues about the passengers that did not fly on the aircraft,” he said without elaborating.

China passengers

Chinese travellers accounted for the largest group aboard Flight 370, with 153 people, and that country’s government prodded the carrier to hasten the inquiry. Also aboard were three US citizens, according to the US State Department. The US Navy sent two destroyers and aircraft into the region, according to the Defense Department.

Flight 370 departed Kuala Lumpur at about 12:41am local time March 8 and was scheduled to land in Beijing at 6:30am. Security screening was performed as usual, Malaysia Airports Holdings Bhd. said. Controllers lost radar contact about an hour into the flight as the plane neared Vietnamese airspace.

The aircraft, which disappeared without providing any distress signal, may have made an “air turn-back,” said Malaysian Acting Transport Minister Datuk Seri Hishammuddin Hussein. That means the plane may have deviated from its planned route, said Malaysian Air Chief Executive Officer Ahmad Jauhari Yahya.

Finding the jet’s flight-data and cockpit-voice recorders, the units known collectively as an aircraft’s black box, would help investigators unravel what happened in the final moments of Flight 370.

Journalists attempt to interview a woman who is the relative of a passenger on Malaysia Airlines flight MH370, as she crouches on the floor crying, at the Beijing Capital International Airport in Beijing March 8, 2014. — Reuters pic

Honeywell’s equipment

Honeywell International Inc. manufactures the 777’s recorders and the so-called emergency locator transmitter, a separate beacon that sends a homing signal in the event of a sharp impact such as a crash. The black-box unit emits a ping when underwater, where the ELT won’t work.

Steve Brecken, a Honeywell spokesman, declined to comment beyond a company statement expressing sympathy for relatives and loved ones of Flight 370’s passengers and crew.

A team from the US National Transportation Safety Board is in Malaysia, joined by specialists from the Federal Aviation Administration and Boeing.

While Muslim-majority Malaysia hasn’t seen any recent major terrorist attacks on home soil, it has been used as a transit and planning hub, according to a 2012 report by the US State Department. China has occasionally been the target of what it calls terrorist attacks by Uighurs, a mainly Muslim ethnic group from the nation’s northwest Xinjiang region.

Malaysia Airline said it dispatched more than 150 “Go Team” members, consisting of senior managers and caregivers, to Beijing to attend to passengers’ families. The stock fell 4 per cent to 24 sen in Kuala Lumpur. Allianz SE, Europe’s biggest insurer, said it provides liability coverage to the airline. — Bloomberg