KUALA LUMPUR, Malaysia — An aviation industry group is creating a task force to make recommendations this year for continuously tracking commercial airliners because "we cannot let another aircraft simply vanish" like Malaysia Airlines Flight 370.
As low clouds, rain and choppy seas off western Australia hampered Tuesday's hunt for the missing jet, the head of the operation warned that the 25-day-old search "could drag on for a long time," and Malaysian investigators said they were scrutinizing the last-known conversation between the plane and ground control.
The search has turned up no sign of the Boeing 777, which vanished March 8 with 239 people aboard bound for Beijing from Kuala Lumpur. A multinational team of aircraft and ships are searching the southern Indian Ocean for the plane, which disappeared from radar and veered off-course for reasons that are still unexplained.
The aviation mystery has highlighted the need for improvements in tracking aircraft and security, according to the International Air Transport Association, a trade association for the world's airlines meeting in Kuala Lumpur.
"In a world where our every move seems to be tracked, there is disbelief that an aircraft could simply disappear," said Tony Tyler, the director general of the group whose 240 member airlines carry 84 percent of all passengers and cargo worldwide.
"We cannot let another aircraft simply vanish," he said in announcing the high-level task force to make recommendations on tracking commercial aircraft.
But the Air Line Pilots Association, the world's biggest pilot union, warned that live-streaming of information from the flight data recorder, as an alternative to the current black boxes, could lead to the release or leak of clues that could make pilots look bad before all the facts about an accident are known.
"That data is there for safety analysis," said Sean Cassidy, an ALPA officer and a pilot with Alaska Airlines. "Unfortunately, if you have this massive wave of data that's getting out there — if it's not safeguarded and protected — there's going to be a real rush to judgment, especially towards the pilots in event of an accident."
ALPA said if the goal is to better track airplanes, the answer is a beefed-up, satellite-based navigation system called NextGen.
In Washington, a congressman is considering introducing a bill that would require the installation of second black box as a backup measure on new commercial passenger aircraft that are used on longer flights, over oceans or in remote locations. The devices, known as deployable flight recorders, would eject before a crash to make them easier to find, and can be designed to float and transmit a signal to searchers.
At a March 12 congressional hearing, Rep. David Price said the disappearance of Flight 370 had once again demonstrated the need for such devices, which are costly, but could save time and money by providing critical data to help explain a crash. His spokesman, Andrew High, said the North Carolina Democrat is considering re-introducing a bill he sponsored several years ago.
U.S. Transportation Secretary Anthony Foxx said his department is conducting a cost-benefit analysis of the recorders, but has not made any commitments.
Tyler, the IATA director general, also urged improvements in screening passengers before boarding.
The presence of two men on the Malaysia Airlines flight with stolen passports had raised speculation of a possible terrorist link, but it is now thought they were asylum seekers bound for Europe. Nonetheless, Tyler said their easy access to the flight "rings alarm bells."
Malaysia's government, responding to repeated media requests, released a transcript of the conversation between Flight 370 and air traffic control, which showed normal exchanges as the pilots requested clearance for takeoff, reported it had reached cruising altitude and left Malaysian airspace.
"Good night Malaysian three-seven-zero," were the final words received at 1:19 a.m. on March 8 by ground controllers at Kuala Lumpur's international airport. That was a change from what had been originally transcribed as "All right, good night."
There was no explanation for the change. The conversation was in English, the universal language of aviation.
Investigators were scrutinizing the conversation to determine if there was any stress or tension in the voice of whoever was communicating with ground control, the government said.
It added that investigations were trying to confirm if the voice in the final conversation was that of the co-pilot, as was earlier believed.
Malaysia has been criticized for its handling of the search, particularly its communications to the media and families of the passengers.
Malaysian Prime Minister Najib Razak was expected to travel to Perth on Wednesday, where he will meet with Australian Prime Minister Tony Abbott and visit the joint agency coordinating the multinational search effort.
Angus Houston, who heads the agency, said the operation was the most challenging one he has ever seen.
The starting point for any search is the last known position of the vehicle or aircraft, the former Australian defense chief said.
"In this particular case, the last known position was a long, long way from where the aircraft appears to have gone," he said. "What we really need now is to find debris, wreckage from the aircraft. This could drag on for a long time."
The focus of the search has shifted as experts analyzed limited radar and satellite data from the plane, moving it from the seas off Vietnam to several areas in the Indian Ocean west of Australia. The current search zone is a 254,000-square-kilometer (98,000-square-mile) area roughly a 2½-hour flight from Perth.
The search resumed Wednesday, with the first of nine planes heading out to the search zone, about 1,500 kilometers (930 miles) west of Perth, the Australian Maritime Safety Authority said. Another nine ships were scouring the area.
On Tuesday, Australia deployed an airborne traffic controller to prevent collisions. An Australian air force E-7A Wedgetail equipped with advanced radar made its first operational flight, AMSA said.
Under normal circumstances, ground-based air traffic controllers use radar and other equipment to track all aircraft in their area of reach and direct planes so they are at different altitudes and distances. But the planes searching for Flight 370 are operating over a patch of ocean that is hundreds of kilometers (miles) from any air traffic controller.
Britain's Ministry of Defense said Tuesday that Royal Navy nuclear submarine HMS Tireless had joined the search for the missing plane's flight recorder. British Survey ship HMS Echo is also due to join the search effort Wednesday.
"Lord of the Rings" director Peter Jackson's private jet had also joined the search. The New Zealander's spokesman Matt Dravitzki confirmed on Wednesday that the Gulfstream G650 was in Perth and had been chartered.