SEPANG, Malaysia — A signaling system was disabled on the missing Malaysia Airlines jet before a pilot spoke to air traffic control without mentioning trouble, a senior Malaysian official said Sunday, reinforcing theories that one or both of the pilots may have been involved in diverting the plane and adding urgency to the investigation of their pasts and possible motivations.
With the increasing likelihood that Flight 370 was purposefully diverted and flown thousands of miles from its planned route, Malaysian officials faced more questions about an investigation, marked by days of contradictory government statements, that has ballooned into a global goose chase for information.
Prime Minister Najib Razak acknowledged Saturday that military radar and satellite data raised the possibility that the plane could have ended up somewhere in Indonesia, the southern Indian Ocean, or along a vast arc of territory from northern Laos across western China to Central Asia. Malaysian officials said they were scrambling to coordinate a 25-nation effort to find the plane.
And on Sunday, Malaysia’s defense minister added a critical detail about investigators’ understanding of what transpired in the cockpit in the 40 minutes of flight time before ground controllers lost contact with the jet. The determination that the last verbal message to the control tower — “All right, good night,” someone said — came after a key signaling system had stopped transmitting, perhaps after being shut off, was likely to refocus scrutiny on the plane’s veteran pilot, Capt. Zaharie Ahmad Shah, 53, and his first officer, Fariq Abdul Hamid, 27.
Commercial passenger planes use radio or satellite signals to send data through ACARS, the Aircraft Communications Addressing and Reporting System. The system can monitor engines and other equipment for problems that may need attention when a plane lands.
Although officials have already said that ACARS was disabled on the missing plane, it had been unclear whether the system stopped functioning before or after the captain radioed his last, brief words to the control tower, in which he did not indicate that anything was wrong with the signaling system or the plane as a whole.
During a news conference Sunday, the defense minister, Hishammuddin Hussein, who is also acting minister of transportation, gave a terse answer: “Yes, it was disabled before.”
The fate of the plane and the people it carried has become a formidable riddle, raising questions about possible terrorism, the identities of passengers and crew members and aviation technology and searching an enormous area that includes both the Indian Ocean and rugged, remote terrain in Asia.
“It’s something of the scope I’ve never seen before,” Cmdr. William Marks, the spokesman for the U.S. Navy 7th Fleet, which sent two guided-missile destroyers to join the search, said in a telephone interview. Of the size of the Indian Ocean, he added: “Essentially, it’s like looking for a person somewhere between New York and California. It’s that big.”
Malaysian officials on Sunday briefed representatives from 22 countries that could help search along the two corridors where satellite data indicate the plane may have wound up, having flown up to six hours after its disappearance beyond the range of military radar in western Malaysia. Hishammuddin said Malaysia would also ask China, France, the United States and other countries to provide satellite data.
But establishing what happened to the plane also depends on reconstructing events in the cockpit in the early-morning of March 8 when the jet was passing over the Gulf of Thailand between northern Malaysia and southern Vietnam. At that time, its communications links were severed and it changed direction, flying across the Malay Peninsula and out over the Strait of Malacca.
Given the complexity of that feat, experts and U.S. government officials say, experienced aviators, possibly one or both of the pilots, were probably involved, either willingly or under coercion.
The plane took off at 12:41 a.m. March 8, carrying 239 people headed for Beijing, and reached a cruising altitude of 35,000 feet at 1:01 a.m. Six minutes later, at 1:07 a.m., the Malaysian authorities say the plane sent its last ACARS message, which reported nothing amiss.
Investigators have not said how they concluded the system was disabled or when they believe that took place. It does not send a message when it is turned off. But Najib said it shut down just before the jet reached the east coast of Peninsular Malaysia, which independent radar tracking recorded at 1:08 a.m.
If the Malaysian account is accurate, and if one of the pilots shut off the system, that would mean he did so just after it transmitted a message.
The authorities have not specified what time the last verbal exchange between the cockpit and the air traffic controllers took place. But Hishammuddin’s statement means it would have occurred between 1:08 a.m. and 1:21 a.m., when the plane’s transponder stopped transmitting and ground control lost contact with the jet.
The sequence of events does not rule out the possibility of someone taking control of the cockpit and forcing the pilot to disable the system, say good night to air traffic control and turn off the transponder. But if that is what happened, it means the hijacker would have had to seize the cockpit in the first 26 minutes of the flight.
On a modern aircraft, it would be unlikely that a pilot would miss warning indications from onboard monitors that ACARS had malfunctioned or been disabled, said Cengiz Turkoglu, a senior lecturer in aeronautical engineering at City University London who specializes in aviation safety.
“I think they would certainly notice it,” Turkoglu said in a telephone interview. “ACARS system failure or downgrading would be alerted, the crew would be alerted.”
Turkoglu emphasized that a great deal was still unknown but that the accumulating evidence about the plane’s disappearance appeared to point to a deliberate act.
“There is an argument that something, somebody, who has the expertise, had something planned,” he said. “Who? I don’t know.”
The Malaysian authorities have not singled out the pilots or crew members as the only potential suspects. Officials said Sunday that they would scrutinize the backgrounds of all passengers and crew members onboard, as well as ground crew and engineers who worked on the Boeing 777 jet.
“I understand the hunger for new details, but we do not want to jump to conclusions,” Hishammuddin said.
According to the airline, he said, “the pilot and co-pilot did not ask to fly together” on Flight 370. If true, that might undermine speculation that the two men acted in unison in the plane’s disappearance.
Hishammuddin confirmed that the Malaysian police had searched the homes of the captain and co-pilot in Kuala Lumpur on Saturday. The police took a flight simulator that the pilot, Zaharie, had kept at his home, and reassembled it for experts to examine, Khalid Abu Bakar, the inspector general of the Malaysian police, told reporters.
Rohan Gunaratna, a professor at Nanyang Technological University in Singapore who studies security and terrorism in Asia, said that while the weight of suspicion would inevitably fall on the pilots and other crew members, investigators were following established procedure by examining everyone on the missing plane.
Soon after the plane disappeared, FBI officers and other U.S. investigators “scrubbed” the names of the pilots and passengers, including two Iranian men who were traveling on stolen passports, to determine whether they had any connections to terrorists. They have found no such connections, officials said Sunday, while cautioning that the home countries of some passengers had not yet supplied full background checks on their citizens who were aboard the plane.
“You can’t rule anything out, so everyone on the plane must be treated as a potential suspect,” Gunaratna said in a telephone interview.
Even knowing where to continue the search for the plane is difficult. Until Najib’s announcement about the likely course of the plane, many aircraft and ships were devoted to scanning the seas off Malaysia’s east coast — precisely the opposite direction from the new focus of the hunt.
“Malaysian officials are currently discussing with all partners how best to deploy assets along the two corridors” indicated by satellite data, the Malaysian transport ministry said in a written statement. “Both the northern and southern corridors are being treated with equal importance.”
A satellite orbiting 22,250 miles over the middle of the Indian Ocean received the final transmission, which, based on the angle from which the plane sent it, came from somewhere along one of the two corridors investigators are exploring.
The northern arc touches southern Kazakhstan and northern Kyrgyzstan in Central Asia before running across a huge portion of western and southwestern China, and ending in northern Laos. To reach most of those areas, the aircraft would have had to traverse heavily militarized areas in China, India or Pakistan, although it could have tried to fly across Myanmar.
The southern corridor, from Indonesia to the southern Indian Ocean, travels over open water with few islands. If the aircraft took that path, it might have passed near the Cocos Islands. Yet those remote Australian islands, with a population of fewer than 1,000 people, have a small airport.
“It is a daunting task to even begin to plan how you would search an entire ocean,” said Marks, the spokesman for the 7th Fleet.
Meanwhile, in the upscale western suburbs of Kuala Lumpur, the families of the pilot and the first officer kept a low profile on Sunday, as local and foreign journalists continued to camp outside their homes.
Neighbors said that Fariq was the eldest of five children and that the family had moved to the neighborhood, popular with faculty members from a nearby university, about a decade ago. Residents said the family was kind, decent and pious.
“He’s a very nice man,” Ayop Jantan, a retiree who lives two doors down from the family, said of Fariq. “When he comes back with his luggage, he greets me like an uncle.”