Investigators said the "black boxes" from the Air France jet that crashed in the Atlantic may never be found, while new details of automated warnings sent by the plane suggested a violent breakup amid severe thunderstorms.

As more information emerged Wednesday about the extreme weather that apparently engulfed the Airbus A330 in its final moments, some industry safety experts said they suspect that intense turbulence&mdash;created by winds as high as 100 miles an hour&mdash;might have rocked the plane so violently that it touched off a deadly series of mechanical, electrical and computer problems.

People familiar with the investigation cautioned that it is too early to know what transpired. Only the black boxes or the recovery of large amounts of debris can likely provide definitive answers, making unraveling the cause unusually difficult. Turbulence may have combined with some pre-existing problem to escalate into a crisis, aviation experts said.

On the other hand, some safety experts say a cascading sequence of on-board malfunctions may have been a symptom, rather than the cause, of the crash. Over a roughly three-minute interval, the plane's computerized brain sent at least two bursts of warning messages via a satellite communications network normally used to alert maintenance on the ground about mundane problems, according to two people familiar with the details. The signals weren't distress calls, but were sent on a system designed to provide routine updates to identify equipment needing attention after the flight.

Air France employees at a memorial service outside Notre-Dame cathedral in Paris for the 228 passengers and crew of Flight 447, which disappeared early Monday in the Atlantic Ocean on its way to Paris from Rio de Janeiro. AFP/Getty Images

In this case, according to one person briefed about the matter, the messages revealed problems with the plane's flight-control computers, malfunctions of certain speed and directional sensors and, ultimately, they indicated cabin depressurization, suggesting some type of major structural failure.

"Everything we're seeing, from the messages to the debris pattern, points to a disastrous encounter with extreme weather," said Bill Voss, president of the Flight Safety Foundation, a nonprofit group in Alexandria, Va.

The prospect that the two black boxes&mdash;which record flight data and cockpit conversations&mdash;may not be retrieved has sparked renewed aviation-industry interest in developing broadcasting systems that allow critical safety data to stream automatically from a troubled plane to receivers on the ground.

Without the flight recorders, for example, investigators could have difficulty determining one of the biggest mysteries: how the plane ended up in such severe weather, with the crew apparently struggling to thread its way through towering thunderheads that may have been difficult to spot with onboard radar. Passengers , airlines, safety regulators and Airbus want to know if the jetliner plunged because of a one-time event, fundamental design flaws, or for other reasons.

In the wake of the crash, investigators and officials at Airbus, a unit of European Aeronautic Defence & Space Co., have started discussing possible ways to ensure crucial data are saved even if the black boxes are never recovered.

"If an aircraft has big problems, this would give it the capability to instantly downlink data" from the flight-data recorder, said Robert Francis, a former member of the U.S. National Transportation Safety Board who is among the safety experts advocating for new systems. "I am sure the idea will be explored after this crash."

At a news conference near Paris Wednesday, Paul-Louis Arslanian, director of France's Bureau d'Enqu&ecirc;tes et d'Analyses, or BEA, said there were no indications of problems before Air France Flight 447 took off from Rio de Janeiro for Paris with 228 people aboard.

Modern jets are designed and tested to survive and get away from severe turbulence, but their flight controls and other systems aren't intended to take extended pounding by flying through such conditions. Based on information released by investigators so far, the Air France-KLM SA plane may have undergone such stress for about 15 minutes.

Brazilian military officials on Wednesday reported finding four areas of debris in the Atlantic Ocean off the country's northeast coast, including "various objects" spread over 30 square miles and an oil slick 12 miles long.

Investigators will try to determine where and how the two-engine plane hit the water and where its wreckage is on the sea bed. But considering the ocean depth and rough undersea terrain in the area, investigators said retrieving the units could be hard.

"I am not optimistic," about locating the black boxes, Mr. Arslanian said. "The sea [bed] is not only deep but mountainous." Adding to the problem: The boxes have only enough battery power to last around 30 days.

Monday's crash has sparked discussion of a new way to use on-board information to enhance safety: transmit real-time operational data to the ground in emergency situations.

Airplane Crashes in the Atlantic

Planes such as the Air France Airbus already relay routine maintenance information to operations centers, which allows ground staff to fix systems quickly and reduce delays. Such messages were the final transmissions from the plane shortly before it disappeared.

Safety experts say that suggests the plane didn't immediately break up in the air and would have had time to instantaneously transmit safety data, had it been equipped to do so.

Safety officials propose doing that by using existing systems to beam flight-data recorder measurements, such as engine parameters, pilot commands or acceleration forces. Installing the systems, they say, might require only software adjustments.

Some big airlines as well as engine makers including General Electric Co. and Rolls-Royce PLC already use live streaming data to monitor the performance of planes.

A number of helicopter operators also use satellite communication systems to track the location of their choppers and to gather data signaling potential mechanical or electrical problems.

Richard Healing, another former NTSB board member, said Wednesday that a burst of real-time data transmitted in emergency situations "is a very good idea" and "technically, it's totally possible today." According to Mr. Healing, some helicopter fleets rely on sophisticated maintenance-management systems that keep track of unusual inflight events and "can notify an operator to ground an aircraft or complete a specific repair before flying again."

Potential obstacles include the cost of changing the software and the possible need for more satellite-transmission capacity, which can be expensive. Monitoring information as it arrives would also require more sophisticated systems than those used now for looking at maintenance updates hours or days later.

With surveillance planes and an armada of international ships gathering to try to find the black boxes, industry officials already are looking ahead to extract lessons from the tragedy. Airlines may opt to install more-expensive but more-capable models of weather radar, and they may look at ways to stream real-time weather information into cockpits.

Brazilian government officials and safety expert familiar with the details said the plane was beyond the reach of ground-based weather radars but had no ability to receive real-time weather data from satellites. "This storm blew up like an atomic bomb," one safety expert said, and the crew apparently didn't realize the extent of it earlier in the flight.

An international team of government and industry investigators, with the participation of the NTSB, will study the location of debris to try to determine whether the crew belatedly realized the danger and attempted to reverse course to escape the brunt of the storm. Investigators also will scour records to determine if the pilots attempted to send any text messages using the maintenance-data transmission system.

—Antonio Regalado contributed to this article.

Write to Daniel Michaels at, Andy Pasztor at and Max Colchester at

Distraught relatives and friends of passengers of Air France flight 447 arrive at the crisis center at Charles de Gaulle airport near Paris Monday.