KUALA LUMPUR, May 3 — Foreign audio experts believe the audio recordings of the final voice transmissions between MH370 and air traffic controllers were edited before Malaysia released them to the public on Thursday.
The experts told American broadcast network NBC News that their initial analysis of the transmissions indicated that the full recording had come from two audio sources, with one segment likely recorded by a digital recorder held up to a speaker.
Primeau Forensics’ Ed Primeau, an audio-video forensic expert and registered investigator, told the news channel that the beginning and the final parts of the recording were of high-quality with a “low noise floor”.
But the middle, he said, seemed different.
“It’s very strange,” he was quoted saying in an online report on NBC News’ website.
“At approximately 1:14, the tone of the recording change to where to me, it sounds like someone is holding a digital recorder up to a speaker, so it’s a microphone-to-speaker transfer of that information.
“That’s a pretty big deal because it raises the first red flag about there possibly being some editing,” he explained.
Between 2:06 and 2:09, he said, noise can be heard in the room.
“I can hear a file door being closed, I can hear some papers being shuffled, so I’m further convinced that, beginning at 1:14 continuing through 2:06 to 2:15, it’s a digital recorder being held up to a speaker,” he was quoted saying.
Long gaps in communication throughout the over seven minute-long video could also imply that the audio clip had been edited, he said.
At 6:17, he pointed out, the conversation was completely cut off before the tone changes again, indicated a “huge edit”.
“The noise floor, when you’re authenticating a recording from a forensic perspective, is a very important part of the process.
“All of a sudden, we go back to the same quality and extremely low noise floor that we had at the beginning of the recording,” Primeau was quoted saying.
NBC News also spoke to forensic audio examiner Kent Gibson who reportedly agreed that it sounded like the middle part of the voice transmission was recorded with a microphone near a speaker.
“You can hear, at 4:07, pages turning or a person breathing, which is unusual,” said Gibson, who works with Forensic Audio in Los Angeles.
The expert also observed that there were noises in the background even after cockpit communication was turned over from ground control to air controllers some time four minutes into the recording.
He said it was “unusual” to have disturbances during this time.
As such, he said the tapes may have been edited by the Malaysian authorities “if the pilot dropped a hint that they didn’t want to get out, if he said something that doesn’t fit with the Malaysian government’s party line.”
But, according to NBC News, Gibson added that this was more likely to be inadvertent, even though it is “not the way to handle evidence”.
Another expert, Tom Owen who is a consultant for Owen Forensic Services audio analysis and chairman emeritus of the American Board of Recorded Evidence, said, however, that edits are to be expected.
“There’s things that have to do with timelines and radar that they have available, but they don’t make them available.
“They wouldn’t give you anything that would be enlightening for the public to any secretive information. I don’t see that as a problematic issue,” he was quoted saying.
The audio recording from MH370 was released by Putrajaya on Thursday along with a preliminary report on the investigation into the jet’s mysterious disappearance on March 8, and a cargo manifest.
The cargo manifest was a source of controversy earlier on, when Malaysia Airlines was accused of trying to hide that lithium-ion batteries, a possible fire hazard, were in the plane’s cargo hold.
The audio recordings also address a discrepancy over the last words issued from the cockpit of the plane.
Other documents included in the cache were a report detailing the action taken between 1.38am and 6.14am when the plane disappeared on March 8, a map showing MH370’s flight path, and the seating plan for the 227 passengers on board.
In an interview with CNN last week, Prime Minister Datuk Seri Najib Razak told the global news channel’s aviation expert Richard Quest that the report, now in the hands of the International Civil Aviation Organization (ICAO), will be made publicly available.
“I have directed an internal investigation team of experts to look at the report, and there is a likelihood that next week we could release the report,” Najib said, according to CNN’s online report of the interview.
Previous refusal to disclose the contents of the report and associated information had fuelled the mistrust and suspicion over Malaysia’s handling of the search for the missing plane.
Searchers scouring the vast swathes of the remote Indian Ocean off the coast of Perth in Australia have yet to find any evidence of MH370, and have begun scaling back the search for the plane that has been missing for nearly two months.
The five files are meant to be played back sequentially, starting with “Audio – ATC delivery”.