As the search for the missing Malaysian jetliner continues, The Post's Joel Achenbach explains several possible scenarios for what could have happened and why this case is puzzling experts. (Gillian Brockell and Kate M. Tobey/The Washington Post)

As the search for the missing Malaysian jetliner continues, The Post's Joel Achenbach explains several possible scenarios for what could have happened and why this case is puzzling experts. (Gillian Brockell and Kate M. Tobey/The Washington Post)

Ships, helicopters and planes from a dozen nations widened the hunt for a missing Malaysian airliner Wednesday after newly divulged radar data suggested that the aircraft veered hundreds of miles off course before vanishing.

The information prompted the Malaysian government to ask India to join the search on the theory that Malaysia Airlines Flight MH370 might have flown west toward the Indian Ocean after it vanished from civilian air-traffic control systems at 1:30 a.m Saturday en route from Kuala Lumpur to Beijing.

Adding to the welter of confusing and contradictory reports in the aviation mystery, a report from a Chinese government agency raised the possibility that the wreckage might actually be in the sea on the opposite side of Malaysia.

China’s State Administration for Science, Technology and Industry for National Defense said one of the government’s satellites spotted “floating objects” in the “suspected crash area” of the Malaysian airliner. There was no immediate confirmation that the unidentified pieces were part of the plane’s wreckage, and a Malaysian military spokesman said he wasn’t aware of the report.

A branch within the Chinese agency, the China Center for Resource Satellite Data and Application, said a satellite called Gaofen-1 found “three suspected floating objects” at coordinates that would put them in waters northeast of Kuala Lumpur and south of Vietnam. The biggest was about 72 by 79 feet. It said images of the objects were captured Sunday, a day after the plane disappeared. It is possible the objects could have since drifted far from where they were spotted, complicating the search.

1 of 84 Full Screen Autoplay Close Skip Ad × Malaysia Airlines flight vanishes over South China Sea View Photos An international fleet of vessels has expanded its search for a Boeing 777 that disappeared Saturday with 239 people on board. Caption In the most comprehensive account to date of the missing Malaysia Airlines Flight 370’s fate, Malaysian Prime Minister Najib Razak on Saturday said that the plane was steered off course after its communications systems were intentionally disabled and that it could have flown for seven additional hours. March 15, 2014 Crew members look outside windows from a Malaysian air force CN235 aircraft during a search-and-rescue operation to find the missing Malaysia Airlines Flight 370 over the Strait of Malacca. Prime Minister Najib Razak said on Saturday that Malaysia was ending its search for the vanished jetliner in the South China Sea after investigations indicated the missing plane likely turned far to the west. Mohd Rasfan/AFP/Getty Images Buy Photo Wait 1 second to continue.

The center did not explain why the information was not posted to the agency’s Web site until Wednesday. It went unnoticed by news agencies for several hours. China’s civil aviation chief, Li Jiaxiang, told reporters Wednesday morning that there was no confirmation the floating objects came from the missing aircraft.

Throughout the five-day search there have been several false leads. An oil slick in the Gulf of Thailand was inspected and found not to have come from a jet. Debris spotted by Vietnam, upon closer inspection, turned out to be trash or wood.

China, which has expressed mounting frustration with the Malaysia-led investigation, announced Monday that it had deployed 10 satellites to help in the search.

Hishammuddin Hussein, Malaysia’s defense minister and acting transport minister, said

42 ships and 39 aircraft were scouring more than 35,000 square miles to the east and west of the Malay Peninsula for the aircraft.

Malaysia’s air force chief, Gen. Rodzali Daud, said Wednesday an “unidentified plot” was seen on military radar intermittently for about 45 minutes after the plane disappeared. He said the radar trail ended at a point over the sea 200 miles northwest of Penang, on Malaysia’s west coast.

“It’s a plot. An unidentified plot,” Rodzali said. “I am not saying it’s MH370.”

However, aviation experts are questioning the quality of the radar data, which would indicate that the plane made a sharp left turn and flew hundreds of miles in the wrong direction.

View Graphic Denise Lu and Richard Johnson

“There are issues about the quality of this information,” said Steven B. Wallace, former director of the Office of Accident Investigation at the Federal Aviation Administration, said when asked whether the turnaround scenario was plausible. He referred to the fact that the military radar did not pick up the specific information about the flying object that a functioning transponder would have provided.

If the information is accurate, Wallace said, it could suggest an unauthorized takeover of the plane’s controls.

“What happened here, if you believe this information [from the Malaysian military], was that the changing of course appeared to happen pretty much concurrently with the loss of the transponder,” Wallace said. “That has to suggest that control of the airplane was taken over by someone unauthorized.”

Malaysia’s uncertainty about the data largely explains why the search for evidence has been so chaotic. Authorities here still don’t know whether the plane carrying 227 passengers and nine crew members crashed or went on a ghost flight across the country and perhaps beyond.

The final words heard by air-traffic controllers from the cockpit before the plane vanished were “All right, good night,” relatives of the passengers were told Wednesday, according to the Associated Press. The routine transmission shed no light on what happened to the Boeing 777.

Malaysian authorities have faced mounting criticism about their transparency and their handling of the case, and they struggled Wednesday to say why they were only now revealing the military data. A day earlier, Malaysian military officials gave a series of conflicting statements about whether the plane had indeed tacked west.

Malaysia’s military said it noticed the recorded data only after the fact, not in real time.

Malaysia is hoping for U.S. assistance in determining whether the radar plot is that of Flight MH370. On Wednesday, Malaysia shared both its civilian and military data with the FAA and the National Transportation Safety Board.

Both military and civilian authorities track aircraft using radar, but all radar has a limited range. In this case, land- or ship-based military radar may have been better positioned to pick up a plane that went off course.

One reason the disappearance of the Malaysia Airlines jet is so mysterious is that its transponders stopped communicating when it was east of the Malaysian peninsula. Transponders send signals that identify the plane.

The radar “plot” cited by Malaysian authorities is essentially a chart showing the course of the flying object.

The search has turned into one of the most difficult on record for a downed airliner, sparking rumors and conspiracy theories. In the aftermath of a comparable aviation disaster — the 2009 disappearance of an Air France flight over the Atlantic — the first baggage and bodies were found after five days.

Some aviation experts say that even Malaysia’s current search area is not large enough. If the plane indeed tacked west, it would have had enough fuel to make it to India.

India’s coast guard joined the effort Wednesday, dispatching an aircraft based in the Andaman and Nicobar Islands to look for the missing plane, officials said. Nothing has been found, they said.

“Right now it’s like a murder mystery with no body,” said David Gallo, director of special projects at Woods Hole Oceanographic Institution in Massachusetts, who co-led the search for Air France Flight 447. “They should calculate how far the plane could have gone with the fuel it had, and that is the radius for the search. Because that is the realm of possibility, absurd as it sounds.”

The Malaysia Airlines red-eye flight bound for Beijing disappeared from civilian radar about one hour after takeoff, while over the Gulf of Thailand.

Both the gulf and the Malacca Strait to the west are heavily trafficked sea lanes and are relatively shallow. If the plane traveled farther west, though, it could have ended up in the Andaman Sea or Bay of Bengal, where depths can reach nearly three miles.

“Unless we get the aircraft and the black box, it is unlikely we are able to answer a lot of speculative issues,” Hishammuddin, the defense minister, said Wednesday, referring to the cockpit recorders.

With India, Japan and Brunei now involved, Hishammuddin said 12 countries were searching for the plane.

Hishammuddin rejected criticism of Malaysia’s coordination of the search, which he said was an “overwhelming” and “unwavering” operation.

China, which had 153 passengers on board, has been the most vocal critic of Malaysia’s response, and an editorial Wednesday in the state-run Global Times asked whether the Malaysian military “was hiding anything on purpose.”

“We hope Malaysia can face its own shortcomings, and cooperate with China with a more open and candid attitude,” the editorial said.

At a hotel in Beijing, Malaysia’s ambassador to China and several officials from Malaysia’s civil aviation department met with relatives of passengers on the flight. The officials faced a barrage of questions about why they have struggled to pinpoint the last known location of the aircraft.

“We are here for five days, you see our situation, and we are here only for one thing,” one of the relatives said. “We wait for the information, and we wait for a miracle.”

With a lack of information, social media users seized on an Australian report that detailed how two female teenagers on a 2011 international flight were invited into the cockpit by the same co-pilot who was on the MH370 flight. That co-pilot, Fariq Abdul Hamid, posed for pictures and smoked cigarettes. The women — one of whom supplied photos to the Australian program, “A Current Affair” — stayed in the cockpit from takeoff until landing. Fariq also asked the guests to extend their stay in Kuala Lumpur so he could take them out on the town.

“Possibly a little sleazy,” one of the women, Jonti Roos, said.

In a statement, Malaysia Airlines said it was “shocked by these allegations.”

“We have not been able to confirm the validity of the pictures and videos of the alleged incident,” the airline said. “As you are aware, we are in the midst of a crisis, and we do not want our attention to be diverted.”

Wan reported from Beijing. William Branigin and Ashley Halsey III in Washington and Simon Denyer, Liu Liu, Gu Jinglu and Xu Jing in Beijing contributed to this report.