SEPANG, Malaysia — The Malaysian authorities now believe that a jetliner missing since Saturday may have radically changed course around the time that it stopped communicating with ground controllers. But there were conflicting accounts of the course change and what may have happened afterward, adding to the air of confusion and disarray surrounding the investigation and search operation.  As criticism of their inability to find any trace of the jet has mounted, the Malaysian authorities have repeatedly insisted that they were doing their best to solve the mystery of Malaysia Airlines Flight 370, with scarce data and almost no precedent. Yet the government and the airline have also released imprecise, incomplete and sometimes inaccurate information, with civilian officials contradicting military leaders.  On Tuesday, the fourth day after the plane disappeared while on an overnight flight to Beijing, the country’s air force chief, Gen. Rodzali Daud, was quoted in a Malaysian newspaper saying the military had received “signals” on Saturday that after the aircraft stopped communicating with ground controllers, it changed course sharply, from heading northeast to heading west, and flew hundreds of miles across Peninsular Malaysia and out over the Strait of Malacca, before the tracking went blank.  The air force chief did not say what kind of signals the military had tracked. But his remarks raised questions about whether the military had noticed the plane as it flew across the country and about when it informed civilian authorities.  According to the general’s account, the last sign of the plane was recorded at 2:40 a.m., and the aircraft was then near Pulau Perak, an island more than 100 miles off the western shore of the Malaysian peninsula.  That assertion stunned aviation experts as well as officials in China, who had been told again and again that the authorities lost contact with the plane more than an hour earlier, when it was on course over the Gulf of Thailand, east of the peninsula. But the new account seemed to fit with the decision on Monday, previously unexplained, to expand the search area to include waters west of the peninsula.  Most of the aircraft’s 227 passengers were Chinese, and the new account prompted an outpouring of anger on Chinese social media sites. “Malaysia, how could you hide something this big until now?” said one posting on Sina.com Weibo, a service similar to Twitter.  David Learmount, operations and safety editor at Flightglobal, a news and data service for the aviation sector, said the Malaysian government seemed evasive and confused, and he questioned why, if the remarks attributed to General Daud were true, the government took so long to reveal evidence about a westward flight path.  Flight MH370 left Kuala Lumpur International Airport just after midnight on Saturday. Malaysian authorities announced Monday that they were expanding the search zones.  Approx. position of plane when  “The relatives of the people who’ve gone missing are being deprived of information about what’s happened to the airplane — that for me is the issue,” he said. “If somebody knows something and isn’t telling, that’s not nice under the circumstances,” he said.  Adding to the confusion, Tengku Sariffuddin Tengku Ahmad, spokesman for the prime minister’s office, said in a telephone interview that he had checked with senior military officials, who told him there was no evidence that the plane had recrossed the Malaysian peninsula, only that it may have attempted to turn back.  “As far as they know, except for the air turn-back, there is no new development,” Mr. Tengku Sariffuddin, adding that the reported remarks by the air force chief were “not true.”  Malaysia Airlines, meanwhile, offered a third, conflicting account. In a statement, the airline said authorities were “looking at a possibility” that the plane was headed to Subang, an airport outside Kuala Lumpur that handles mainly domestic flights.  Without specifying why, the Malaysian authorities vastly expanded the search area to the west on Monday, implying that they believed there was a strong chance the plane had traveled there. No similar expansion was made to the east or the south.  But if the flight traveled west over Peninsular Malaysia, as the air force chief was quoted saying, it would have flown very close to a beacon in the city of Kota Bharu operated by Flightradar24, a global tracking system for commercial aircraft.  Mikael Robertsson, the co-founder of Flightradar24, said the transponder on the jet never sent a signal to that receiver, which means that if the plane did fly that way, its transponder had either been knocked out of service by damage or had been shut off.  “We see every aircraft that flies over there, even if it’s very, very low, so if it flew over there, the transponder was off,” he said.  A pilot can turn off the transponder, Mr. Robertsson said, and the fact that the last contact from the Malaysia Airlines flight’s transponder came at roughly the same time that the cockpit crew stopped communicating with ground controllers by radio suggests that that is what happened, Mr. Robertsson said. “I guess to me it sounds like they were turned off deliberately.” The plane disappeared from Flightradar24’s tracking system at 1:21 a.m. Saturday while flying at 35,000 feet over the Gulf of Thailand; Malaysia Airlines has said that the last radio communication with the pilots was at about 1:30 a.m., but has not given a precise time.  Mr. Robertsson noted that since the plane had been fully fueled for a trip to Beijing, it could have traveled a great distance beyond its last reported position. “The aircraft could have continued another five or six hours out into the ocean,” he said. “It could have gone to India.”  The Malaysian government’s inconsistencies in the handling of the crisis were further highlighted Tuesday when the country’s chief of police said there had been no baggage removed from the aircraft before take-off early Saturday, contradicting what officials had said for the past three days.  Khalid Abu Bakar, the inspector general of the Malaysian police, said previous reports by Malaysian officials that five passengers had failed to board the flight and that their baggage had been removed were false. “Everybody that booked the flight boarded the plane,” he said.  But Malaysia Airlines later issued a clarification, saying that there were four passengers who booked tickets on the flight but failed to check in at the airport or check any bags for the flight.
Malaysian officials said the jetliner may have radically altered its path around the time communications ended with ground controllers, possibly explaining the expansion of the search area.