Air France Plane Hit the Water Intact

July 2, 2009— -- The list of what is known for sure about the crash of Air France flight 447 grew longer today as France's investigation bureau said the plane was intact when it plunged into the Atlantic Ocean, and there was no trace of fire or explosive found amid the plane's debris.

Those facts were among several announced today when investigators from the Bureau D'Enquetes et D' Analyses, France's equivalent of the National Transportation Safety Board, released its first factual report on the crash.

Watch "World News With Charles Gibson" tonight at 6:30 ET for the full report

The latest developments include the following:

"In particular, examination of the tail fin indicates that it did not break up in flight, but upon point of impact," said Alain Bouillard, BEA's head of investigation, speaking today through a translator. "It hit the water in line of flight with a very high vertical acceleration."

Today Bouillard said, "We do not yet have any direct link between the pitot tubes and the cause of the accident."

The investigators did not say what other factors may have contributed to the plane's crash.

"We're far from establishing the causes of the crash" Bouillard said.

The two most important clues to the mystery -- the flight data recorder and cockpit recorder, known as the plane's black boxes -- have still not been recovered.

The hunt for the black boxes will continue until July 10.

Black box batteries are required to last 30 days, and it's already been more than one month since the flight went down. But investigators are hopeful that their pinging signals have not yet faded entirely, and search teams are racing against the clock to find the flight's most vital clues. The company that makes the black boxes said they could emit pinging sounds a little bit longer than 30 days, but will eventually fade out.

Even this late in the game, the search for the black boxes is not a lost cause. Cutting edge technology could help searchers hone in on the specific underwater spot where clues might lie.

John Springer, sales manager for Dukane Corp. Seacom Division, the company that manufactured the flight's black boxes, said the search equipment can sift through noises in the ocean because it knows what to look for -- much as party guests can do at a loud gathering if they know the sound of a friend's voice.

"By knowing exactly what they're saying or what the person's saying, you can get closer to that person and you can hear them and you eliminate all the sound in the back," he explained.

Black boxes also emit a pinging sound once every second, whereas "noises in nature are usually not that consistent in their repetition," Springer said.

The world's best teams and equipment are in the remote Atlantic Ocean trying to detect the signals. The French nuclear sub Emeraude, equipped with high-tech sonar equipment, is listening for the acoustics, as is a U.S. Navy underwater listening device that can pick up the pinging sound from the black boxes at depths of 20,000 feet. A French research vessel, the Pourquoi Pas, is on hand with underwater robots to retrieve the black boxes if the signals are heard.

See ABC News photo gallery of the search effort here.

Watch ABC News Video on the Crash:
Air France Crash Questions Sensor Safety (June 9, 2009)
Search Intensifies for Black Boxes (June 8, 2009)
Plane Disappears Off Radar (June 1, 2009)

Read ABC News Stories on the Crash:
French Sub Joins Black Box Search (June 10, 2009)
Carriers Rush to Replace Speed Sensors (June 9, 2009)
Jet's Tail Could Lead to Answers (June 8, 2009)
Air France Official: 'We Can Fear the Worst' (June 1, 2009)

Young Crash Survivor Arrives in Paris (July 2, 2009)
Plane Lands After Pilot Dies In-Flight (June 18, 2009)
FAA Holds Regional Airline Safety Summit (June 15, 2009)
Capt. Sully Sullenberger Recounts Landing on Hudson River (June 9, 2009)
Regional Airlines Under Scrutiny (May 14, 2009)
The Black Holes of Plane Crashes (June 4, 2009)
Fear of Flying Causes Families to Split Flights (June 4, 2009)

ABC News' Lisa Stark, Zoe Magee, Ammu Kannampilly, Renata Araujo and The Associated Press contributed to this report.