Officials investigating why a panel on a Boeing 737 Max 9 exploded during an Alaska Airlines flight last week say they are struggling to understand exactly what happened because the plane’s cockpit voice recorder overwrote itself before it could be recovered.
This is not a new problem. The National Transportation Safety Board, which is leading the investigation, has recommended for years that recorders be programmed to capture up to 25 hours of audio before automatically resetting themselves, but the FAA has been reluctant to mandate longer recordings.
The Federal Aviation Administration last month proposed 25-hour loggers on new planes, but said adding them to the existing fleet of US planes would be too expensive. In addition, the pilots’ union has opposed moving to 25-hour recordings unless Congress establishes protections that would prohibit their release to the public.
Safety Board Chairwoman Jennifer Homendy said agency investigators have conducted 10 investigations since 2018 in which the cockpit voice recorder was overwritten, with important recordings lost forever. Audio recorders are among the essential pieces of evidence investigators use in reconstructing the events leading up to accidents as they work to determine the cause.
Ms. Homendy said the recording from the Alaska Airlines flight would have contained a lot of important information, including the explosion the crew described hearing shortly after the plane took off on Friday from Portland, Oregon. She added that the recording would have enabled investigators to hear communications between the crew during the accident and identify any communications problems, including any audible alerts in the cockpit.
“There is a lot of information that we can get from the CVR system that is beyond just communication between the flight crew,” Ms Homendy said. “This is an essential guide to improving safety. Without it, we only collect things from interviews and lose a lot.”
Flight crew members told federal investigators that they were so focused on going through their emergency checklist, communicating with air traffic control, and getting the plane to the ground that they did not hear any alerts. Federal investigators did not indicate that any mistakes were made by the pilots or flight crew.
“So that’s what they don’t remember now, and we have no evidence it happened,” Ms Homendy said. “So if there was some kind of failure with any kind of verbal alert, we wouldn’t know about it.”
Alaska Airlines said in a statement on Wednesday that because of the ongoing investigation, it could not comment on why audio from the cockpit recorder was not recovered in a timely manner. But the airline added that it welcomed the FAA’s proposal to extend the registration period.
“We support this effort, which would bring the US aviation industry more in line with international regulations,” the airline said.
The United States has lagged behind much of the world in requiring the use of longer voice recordings on commercial aircraft. In 2016, the International Civil Aviation Organization, an arm of the United Nations, adopted a standard calling for recorders capable of capturing the last 25 hours of audio on all new aircraft starting in 2021. The European Union Aviation Safety Agency’s mandate for 25 hours went into effect. Implementation in January 2021 for new aircraft.
Cockpit voice recordings begin the moment pilots start the plane. This allows recording to capture initial pilot checks, passenger boardings and other activities as the crew prepares for takeoff.
The two-hour limit means that the recorder may be quickly overwritten even on short flights, especially if there are any delays on the runway. Once the two-hour limit is reached, recording automatically starts again.
The recorders are designed to automatically stop when an accident occurs, but they do not stop in accidents like the one on Alaska Airlines’ 737 MAX 9. In such cases, someone will have to remove the circuit breaker on the plane to prevent the device from turning on. Starting over. This did not happen in this case.
The safety board began recommending increased check-in time after a horrific accident in 2017 at San Francisco International Airport when an Air Canada plane nearly landed on a runway instead of a nearby runway. Four planes loaded with passengers were waiting on the runway. The crash could have been one of the worst aviation disasters in history, but federal investigators still have no idea what was happening in the cockpit because the recording automatically started over again before it could be retrieved.
Robert Sumwalt, who was chairman of the safety board at the time, said recordings of major aviation accidents could give federal investigators a more complete picture of what happened and how to prevent it from happening again.
“It gives you a pretty straightforward description of the conversations and sounds in the cockpit,” he said. “People may think they remember things clearly, but sometimes memory fails us.”
The Federal Aviation Administration in December proposed a rule requiring new aircraft to be equipped with 25-hour voice recorders, but it stopped short of requiring commercial airlines to install recorders on all planes, as the National Transportation Safety Board had recommended.
The Federal Aviation Administration estimated that upgrading each plane would cost $741 million. Just putting the new recorders on new planes would cost $196 million.
“Our proposed rule is consistent with regulations established by the International Civil Aviation Organization and the European Union Aviation Safety Agency,” the agency said in a statement.
Ms Homendy said saving lives should outweigh any financial concerns. She also noted that the lasting impact of a catastrophic plane crash would be far greater than the direct cost of improving safety to airlines and, ultimately, travelers.
“The cost will be significant, not just in terms of finances but in terms of the reputation of the company, in terms of the reputation of the manufacturer and the suppliers and everyone else involved, and the cost of public confidence in the American aviation system,” Ms. Homendy said. “This is what we will lose immediately.”
Congress has taken note of this issue as well. Bills pending in the House and Senate to reauthorize the FAA would extend the registration period to 25 hours on all aircraft within four years.
Since the incident in San Francisco in 2017, Rep. Mark DeSaulnier, a California Democrat on the House Transportation and Infrastructure Committee, has said he supports the safety board’s recommendation on voice recorders because important data is often lost because investigators can’t recover it quickly enough. .
“The move to 25-hour cockpit voice recorders is a key element of enhancing air travel safety that has already been adopted as an international standard,” Mr Desaulnier said.
But the Airline Pilots Association, which represents pilots at Alaska, Delta Air Lines, United Airlines and other companies, has long opposed the move to a 25-hour voice recorder due to privacy concerns. The union said in a statement that although voice and flight data recorders provide important information, the group wanted lawmakers to ensure that investigators only used the recordings to improve the flight system.
Federal law prohibits the Safety Board from releasing copies of cockpit voice recorders under freedom of information laws. But the law doesn’t prevent the FAA or airlines from issuing copies.
“Unfortunately, the statutory rule that protects the privacy of the cockpit voice recorder only applies to the NTSB,” the statement read. “In addition to the NTSB, the protections in this law must be strengthened and applied to airlines as well as the FAA before an extension is considered.”
Sen. Ted Cruz, a Republican from Texas, said that despite pilot union opposition, he and other members of Congress planned to push legislation to increase check-in time.
“Without access to cockpit audio recordings, investigators lack essential information about any incident of concern, whether it be a near-miss, an equipment malfunction, or a recent Alaska Airlines flight,” Cruz said in an interview.
Neeraj Chokshi Contributed to reports.