Officials investigating why a Boeing 737 Max 9 panel ruptured during an Alaska Airlines flight last week say they are having a hard time figuring out exactly what happened because the voice recorder in the plane's cockpit overwrote itself, before he could be restored.
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 record up to 25 hours of audio before automatically resetting. However, the Federal Aviation Administration is hesitant to require longer records.
The FAA last month proposed 25-hour recorders for new planes, but argued that installing them on the existing U.S. aircraft fleet would be too expensive. Additionally, a pilots' union has opposed the move to 25-hour recordings unless Congress adopts protections that would prohibit their release to the public.
Safety Committee Chairwoman Jennifer Homendy said agency investigators have conducted 10 investigations since 2018 in which the cockpit voice recorder was overwritten and critical recordings were lost forever. The voice recorders are among the most important pieces of evidence investigators use to reconstruct the events that led to accidents and determine the cause.
Ms. Homendy said a recording of the Alaska Airlines flight would have contained a lot of important information, including the bang the crew heard shortly after the plane took off from Portland, Oregon, on Friday. She said the recording would have allowed investigators to hear communications between the crew during the incident and identify any communication problems, including any audible alarms in the cockpit.
“We can get so much information from CVR that goes beyond just communication between the flight crew,” Ms. Homendy said. “This is important evidence of improving safety. Without that, we piece things together 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 didn't hear any alarms. Federal investigators have not suggested that the pilots or flight crew made any mistakes.
“So they don’t remember that and we have no evidence that it happened,” Ms Homendy said. “So if any verbal warning fails, we don’t know about it.”
Alaska Airlines said in a statement Wednesday that due to the active investigation, it could not comment on why audio from the cockpit recorder was not restored in a timely manner. However, the airline added that it welcomed the FAA's proposal to extend the recording time.
“We support these efforts, which would better align the U.S. airline industry with international regulations,” the airline said.
The United States lagged behind much of the world in mandating the use of longer voice recordings on commercial aircraft. In 2016, the International Civil Aviation Organization, a branch of the United Nations, adopted a standard requiring recorders that can record the last 25 hours of audio on all new aircraft starting in 2021. The European Union's 25-hour aviation safety mandate has been lifted and will come into effect for new aircraft in January 2021.
Cockpit voice recordings begin the moment pilots start a plane. This allows the recording to capture pilots' preflight checks, passenger boarding, and other activities as the crew prepares for takeoff.
The two-hour limit means that the recorder can quickly be overwritten, even on short flights, especially if there are delays on the runway. As soon as the two-hour limit is reached, the recording automatically starts again.
Recorders are designed to automatically stop in the event of an accident, but they do not stop in incidents like the one on Alaska Airlines' 737 Max 9. In such cases, someone would have to remove a circuit breaker on the plane to prevent the device from restarting. That didn't happen in this case.
After a harrowing 2017 incident at San Francisco International Airport, when an Air Canada plane nearly landed on a taxiway instead of a nearby runway, the safety board began recommending that recording time be extended. Four planes loaded with passengers were waiting on the tarmac. The incident could have been one of the worst aviation disasters in history, but federal investigators still have no idea what happened in the cockpit because the recording automatically started over before it could be retrieved.
Robert Sumwalt, then chairman of the safety committee, said recordings of serious aviation incidents could give federal investigators a more complete picture of what happened and how to prevent it from happening again.
“This means you can practically see first-hand what conversations and noises are going on in the cockpit,” he said. “People can think they remember things clearly, but sometimes our memory fails.”
The FAA in December proposed a rule requiring new aircraft to be equipped with 25-hour voice recorders, but stopped short of requiring commercial airlines to install voice recorders on all aircraft, as the NTSB had recommended.
The FAA estimated that upgrading each aircraft would cost $741 million. Installing the new recorders just on new aircraft would cost $196 million.
“Our proposed rule is consistent with the regulations of the International Civil Aviation Organization and the European Aviation Safety Agency,” the agency said in a statement.
Ms Homendy said saving lives should be more important than any financial concerns. She also pointed out that the lasting impact of a catastrophic plane crash would be far greater than the immediate costs of safety improvements borne by airlines and ultimately travelers.
“The costs would be significant, not only in terms of finances, but also in terms of the reputation of the company, in terms of the reputation of the manufacturer and suppliers and everyone else involved, and in terms of the cost to the public's trust in the US “Aviation system,” said Ms. Homendy. “That’s what would be lost immediately.”
Congress has also taken note of the issue. FAA reauthorization bills pending in the House and Senate would extend the length of recording on all aircraft to 25 hours within four years.
Since the San Francisco incident in 2017, Rep. Mark DeSaulnier, a California Democrat on the House Transportation and Infrastructure Committee, said he supported the security committee's recommendation on voice recorders because important data was often lost because investigators didn't process it quickly enough could retrieve.
“The move to 25-hour cockpit voice recorders is an essential part of improving air travel safety that has already been adopted as an international standard,” DeSaulnier said.
But the Air Line Pilots Association, which represents pilots for Alaska, Delta Air Lines, United Airlines and other companies, has long opposed the move to a 25-hour voice recorder, citing privacy concerns. In a statement, the union said that while voice and flight data recorders provide important information, the group wants lawmakers to ensure that investigators only use the recordings to improve the aviation system.
Federal law prohibits the Safety Board from releasing copies of cockpit voice recorders under freedom of information laws. However, the law does not prevent the FAA or airlines from issuing copies.
“Unfortunately, the law protecting the privacy of the cockpit voice recorder only applies to NTSB,” the statement said. “In addition to the NTSB, the protections in this law must be strengthened and applied to airlines and the FAA before considering an extension of its duration.”
Sen. Ted Cruz, a Republican from Texas, said he and other members of Congress planned to push forward legislation to extend the recording period despite opposition from the pilots' union.
“Without access to cockpit voice recordings, investigators are missing critical information about any concerning incident, be it a near miss, an equipment failure or the most recent Alaska Airlines flight,” Cruz said in an interview.
Niraj Chokshi contributed reporting.