The defective warning light alerts pilots when two sensors that measure the angle between the airflow and the wing disagree. Faulty "angle of attack" data is suspected of playing a role in two deadly crashes involving Boeing's best-selling 737 MAX in Indonesia in October and in Ethiopia in March.

Those crashes, which killed 346 people, have triggered investigations by aviation regulators and U.S. lawmakers and left Chicago-based Boeing facing one of the biggest crises in its more than 100-year history.

Boeing decided in November 2017 to defer a software update to correct the so-called AOA Disagree alert defect until 2020, three years after discovering the flaw, U.S. Congressmen Peter DeFazio and Rick Larsen said in a press release on Friday. Boeing only accelerated this schedule after the Lion Air accident in Indonesia, they added.

Boeing spokesman Gordon Johndroe said by email that a company safety review found the absence of the AOA Disagree alert did not adversely impact airplane safety or operation.

"Based on the safety review, the update was scheduled for the MAX 10 entry into service in 2020," Johndroe said. "We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again."

Boeing has said it discovered the problem in 2017, soon after it began delivering its top-selling 737 MAX aircraft to customers. But it did not inform the U.S. Federal Aviation Administration (FAA) about the defect until after the Lion Air crash more than one year later, the lawmakers said.

The House of Representatives Committee on Transportation and Infrastructure sent letters to Boeing, supplier United Technologies Corp and the FAA requesting further details on the AoA Disagree alert, the lawmakers said.

The letter was the second such records request sent by the committee to Boeing and the FAA related to its investigation into the MAX aircraft. </s> FILE PHOTO: The cockpit of Jet Airways Boeing 737 MAX 8 aircarft is pictured during its induction ceremony at the Chhatrapati Shivaji International airport in Mumbai, India, June 28, 2018. Picture taken June 28, 2018. REUTERS/Abhirup Roy/File Photo

SEATTLE (Reuters) - Boeing Co learned that a cockpit warning light on its 737 MAX jetliner was defective in 2017 but decided to defer fixing it until 2020, U.S. lawmakers said on Friday.

The defective warning light alerts pilots when two sensors that measure the angle between the airflow and the wing disagree. Faulty “angle of attack” data is suspected of playing a role in two deadly crashes involving Boeing’s best-selling 737 MAX in Indonesia in October and in Ethiopia in March.

Those crashes, which killed 346 people, have triggered investigations by aviation regulators and U.S. lawmakers and left Chicago-based Boeing facing one of the biggest crises in its more than 100-year history.

Boeing decided in November 2017 to defer a software update to correct the so-called AOA Disagree alert defect until 2020, three years after discovering the flaw, U.S. Congressmen Peter DeFazio and Rick Larsen said in a press release on Friday. Boeing only accelerated this schedule after the Lion Air accident in Indonesia, they added.

Boeing spokesman Gordon Johndroe said by email that a company safety review found the absence of the AOA Disagree alert did not adversely impact airplane safety or operation.

“Based on the safety review, the update was scheduled for the MAX 10 entry into service in 2020,” Johndroe said. “We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again.”

Boeing has said it discovered the problem in 2017, soon after it began delivering its top-selling 737 MAX aircraft to customers. But it did not inform the U.S. Federal Aviation Administration (FAA) about the defect until after the Lion Air crash more than one year later, the lawmakers said.

The House of Representatives Committee on Transportation and Infrastructure sent letters to Boeing, supplier United Technologies Corp and the FAA requesting further details on the AoA Disagree alert, the lawmakers said.

The letter was the second such records request sent by the committee to Boeing and the FAA related to its investigation into the MAX aircraft. </s> Two key lawmakers said Friday that Boeing planned to delay fixing a nonworking safety alert on its 737 Max aircraft for three years and sped up the process only after the first of two deadly crashes involving Max planes last October.

U.S. Reps. Peter DeFazio of Oregon and Rick Larsen of Washington disclosed the decision in letters sent to Boeing and the Federal Aviation Administration seeking details on what the plane maker and the agency knew and when, and at what point airlines were told of the defect. Both said they were concerned about delays in notifying regulators and the airlines.

The feature, called an angle of attack alert light, was designed to warn pilots when sensors measuring the direction of the plane's nose up or down relative to oncoming air might not be working.

Boeing admitted in May that within months of the plane's 2017 debut, engineers realized that the sensor warning light only worked when paired with a separate, optional feature.

The sensors malfunctioned during flights in Indonesia in October and Ethiopia in March. Pilots were unable to regain control of both planes and they crashed, killing a total of 346 people.

The sensors fed incorrect information to computers on board the Lion Air Max plane that crashed in Indonesia last year and the Ethiopian Airlines Max that crashed in March. However, neither of those airlines ordered the extra safety feature for their planes.

The legislators, both leaders of a House committee that's investigating the Max crashes and the FAA's regulation of Boeing, said in a statement Friday that the committee has information that Boeing knew about the problem in 2017, soon after the first Max was delivered. Yet the company decided in November of 2017 to defer a software update to fix the flaw until 2020, the statement said.

But after the Lion Air crash in Indonesia last year, the company accelerated its timeline for the update, the legislators wrote.

DeFazio, chairman of the Transportation and Infrastructure Committee, and Larsen, who heads an aviation subcommittee, said the fact that Boeing knew about the defect for more than a year before disclosing it to the FAA is a big problem.

Larsen questioned why Boeing didn't consider the problem critical to safety “and I am concerned it took Boeing so long to report this defective feature to the FAA and its customers.”

It's not clear whether the warning light would have prevented either the Lion Air crash or the March 10 crash of an Ethiopian Airlines Max near Addis Ababa. But the delayed notification of the FAA raises questions about Boeing's candour with regulators and airline customers.

On Friday, the FAA re-issued a May statement that said Boeing briefed the agency's Seattle office about the problem in November of 2018, and the matter was forwarded to an agency review board. The board considered the issue to be “low risk,” and required it to be addressed as part of the software update after the Indonesia crash. “However, Boeing's timely or earlier communication with the operators would have helped to reduce or eliminate possible confusion,” the statement said.

FAA Acting Administrator Daniel Elwell, during testimony last month before the committee, said he wasn't happy with the 13-month gap between Boeing discovering the problem and telling the agency. “We will make sure that software anomalies are reported more quickly,” said Elwell, who called the problem a maintenance issue rather than a critical safety item.

Boeing has said the Max was safe to fly without the sensor alert. Other gauges tell pilots enough about the plane's speed, altitude, engine performance and other factors to fly safely, the company has said. Messages were left Friday seeking comment about the legislators' letter.

Koenig reported from Dallas, while Krisher reported from Detroit. </s> Boeing has known a cockpit warning light on its 737 MAX jetliner was defective since 2017 - but did not plan to fix it until next year, US lawmakers revealed.

The model has been involved in two crashes, in Indonesia and Ethiopia, which claimed 346 lives.

It has been grounded since the two tragedies, with around 300 planes affected worldwide.

The affected light warns pilots when two sensors which measure the angle between the airflow and the wing disagree.

Faulty "angle of attack" data is suspected of playing a role in October's crash in Indonesia and the Ethiopian Airlines crash in March.

All 157 people on board died in the Ethiopia incident, while all 189 on Lion Air Fight 610 were killed on October 29 last year.

The crashes have triggered investigations by aviation regulators and US lawmakers and left Boeing facing one of the biggest crises in its history.

Boeing decided in November 2017 to defer a software update to correct the so-called AOA Disagree alert defect until 2020, US Congressmen Peter DeFazio and Rick Larsen said in a press release on Friday.

Boeing only accelerated this schedule after the Lion Air accident in Indonesia, they added.

Boeing spokesman Gordon Johndroe said that a company safety review found the absence of the AOA Disagree alert did not adversely impact airplane safety or operation.

"Based on the safety review, the update was scheduled for the MAX 10 entry into service in 2020," Johndroe said.

"We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again."

Boeing has said it discovered the problem in 2017, soon after it began delivering its top-selling 737 MAX aircraft to customers.

But it did not inform the US Federal Aviation Administration (FAA) about the defect until after the Lion Air crash more than one year later, the lawmakers said.

The House of Representatives Committee on Transportation and Infrastructure has requested further details. </s> Boeing planned to delay a fix for a critical cockpit warning light on its now-grounded Max 737 airliner, leaders of a congressional committee said Friday, but then accelerated the timeline late last year after the first of two deadly crashes that killed 346 people.

In a letter to Boeing, the Federal Aviation Administration and a Boeing subcontractor, Reps. Peter DeFazio (D-Ore.) and Rick Larsen (D-Wash.) said they'd obtained information suggesting that even though the plane maker knew the safety alert wasn't working when it began 737 Max deliveries in 2017, it decided to wait until 2020 to implement a fix. The warning light tells flight crews when an angle-of-attack sensor is giving false readings. The faulty sensor was linked to both the Lion Air crash in Indonesia in October and the Ethiopian Airlines crash in March.

As part of an ongoing investigation of the crashes by the House transportation committee, which DeFazio chairs, the lawmakers are asking Boeing to disclose when the company knew the light was defective and when it informed airlines.

"An important part of the Committee's investigation is finding out what Boeing knew, when the company knew it and who it informed," Larsen, chair of the House subcommittee on aviation, said in a statement. "I have questions about the decision to not deem the AOA Disagree alert as safety critical and I am concerned it took Boeing so long to report this defective feature to the FAA and its customers."

Boeing admitted in April that the alert was not operating on all Max 737 aircraft, but a few days later said that the absence of such an alert didn't adversely affect airplane safety or operation. In response to the DeFazio and Larsen letter, a Boeing spokesman on Friday reiterated that finding in a statement to CNET.

"Based on the safety review, the update was scheduled for the MAX 10 rollout in 2020," the statement said. "We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again."

When the Max returns to service, the safety alert will be included as a standard feature on all aircraft delivered. Prior to the Lion Air crash, though, it was sold as part of an optional package of equipment, a package that Lion Air didn't purchase for its planes.

The 737 Max has now been grounded for almost three months, dragging down Boeing's earnings and reputation as it heads into the Paris Air Show later this month. Though the company says a software update to the Max's Maneuvering Characteristics Augmentation System is complete, there's still no timeline for the airliner to carry passengers again. </s> The majority of Boeing 737 MAX aircraft had a non-working alert for faulty sensor data. The company scheduled the problem to be fixed three years after discovering it and didn’t inform the FAA until one of the planes crashed.

Two Boeing 737 MAX airliners operated by Lion Air and Ethiopian Airlines crashed five months apart, killing a total of 346 people, and leading to a worldwide grounding of the new model. Both accidents were apparently caused by faulty data from Angle of Attack (AoA) sensors, which made the aircraft software falsely detect impending stalling and pushed the aircraft’s nose down.

Pilots were supposed to be alerted about possible problems with the sensors by an AoA Disagree alert, which should light up when data coming from two AoA sensors does not match. But the alert required an optional set of indicators to be installed to actually work, and only 20 percent of the aircraft sold had them. Boeing learned about the situation in November 2017, but considered it a low-risk issue and scheduled a fix for 2020, the company reported to a House committee.

After Lion Air flight 610 crashed in October 2018, the company decided to accelerate its timeline, Boeing said in response to a letter sent by Representatives Peter DeFazio and Rick Larsen, who head a House committee that is investigating the crashes and possible mismanagement by the Federal Aviation Administration (FAA) regarding the rollout of the 737 MAX. Boeing first informed the FAA about the faulty alert after one of the planes crashed.

The aviation giant reported the issue earlier in May. Neither the Lion Air aircraft nor Ethiopian Airlines flight 302, which crashed in March, had the optional feature that allows the alert to work, although it was not immediately clear if the pilots could have averted the disasters if they had known that the AoA sensors were failing.

The Lion Air aircraft, however, narrowly avoided a similar incident a day before its final demise thanks to an off-duty pilot who was in the cockpit and instructed the crew to turn off the anti-stalling system.

If you like this story, share it with a friend! </s> After discovering a problem in 2017 with a cockpit warning light on the 737 MAX, Boeing decided it would defer an update to fix the issue until 2020, congressional officials said Friday.

Even as it continued delivering MAX airplanes to customers, Boeing had kept quiet the details of the problem, which prevented a light from warning pilots when there was disagreement between the plane’s angle-of-attack sensors. Those sensors are now suspected of playing in a role in two MAX crashes.

The company didn’t disclose the issue to the FAA until after a 737 MAX crash in Indonesia last year, something that frustrated FAA leadership. Now, leaders with a transportation committee in the U.S. House said they have obtained information about the planned fix in 2020. They have sent letters to Boeing, the FAA and supplier United Technologies requesting documents around the problematic alert.

“An important part of the Committee’s investigation is finding out what Boeing knew, when the company knew it and who it informed,” said Rep. Rick Larsen, a Washington state Democrat who leads the aviation subcommittee. “I have questions about the decision to not deem the AOA Disagree alert as safety critical and I am concerned it took Boeing so long to report this defective feature to the FAA and its customers.”

Boeing has said its engineers discovered that the warning light wasn’t functioning in 2017. The company determined that the issue did not adversely impact the safety or operation of the plane.

The warning light, which is standard on the MAX and included in the pilot manuals, is designed to light up if there’s a disagreement between the two sensors on either side of the plane’s nose that measure the jet’s angle of attack — the angle between the oncoming air flow and the airplane’s wing.

At the time of the crashes, the alert worked only on planes flown by airlines that had bought a different indicator added to the main flight-display panel. Lion Air and Ethiopian Airlines did not have those packages.

If it had been working, the warning light would have lit up on the fatal flights of both the Lion Air and Ethiopian jets. It’s not clear that it would have made a difference, as Lion Air pilots were unaware of the MAX’s new automated maneuvering system that pushed the plane’s nose down in response to the erroneous angle-of-attack data.

With knowledge of the overall system in the wake of the Lion Air crash, the Ethiopian pilots might have benefited from the information, but a preliminary report suggests they were ultimately able to diagnose the problem. They still weren’t able to maintain control of the plane. </s> After discovering a problem in 2017 with a cockpit warning light on the 737 MAX, Boeing decided it would defer an update to fix the issue until 2020, officials said Friday.

Even as it continued delivering MAX airplanes to customers, Boeing had kept quiet the details of the problem, which prevented a light from warning pilots when there was disagreement between the plane’s angle-of-attack sensors. Those sensors are now suspected of playing a role in two MAX crashes.

The company didn’t disclose the issue to the Federal Aviation Administration (FAA) until after a 737 MAX crash in Indonesia last year, something that frustrated FAA leadership. Now, leaders with a transportation committee in the U.S. House said they have obtained information about the initial plan to fix the issue in 2020. They have sent letters to Boeing, the FAA and supplier United Technologies requesting documents around the problematic alert.

“An important part of the Committee’s investigation is finding out what Boeing knew, when the company knew it and who it informed,” said Rep. Rick Larsen, a Washington state Democrat who leads the aviation subcommittee. “I have questions about the decision to not deem the AOA Disagree alert as safety critical and I am concerned it took Boeing so long to report this defective feature to the FAA and its customers.”

Boeing has said that its engineers discovered that the warning light wasn’t functioning in 2017, but the company concluded that the issue did not adversely impact the safety or operation of the plane. In a statement Friday, the company said it determined that it was acceptable to wait to modify the system software on its next planned display system update, which was scheduled for the rollout of the 737 MAX 10 in 2020.

“We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again,” Boeing said.

The warning light, which is standard on the MAX and included in the pilot manuals, is designed to light up if there’s a disagreement between the two sensors on either side of the plane’s nose that measure the jet’s angle of attack — the angle between the oncoming air flow and the airplane’s wing.

At the time of the crashes, the alert worked only on planes flown by airlines that had bought a different indicator added to the main flight-display panel. Lion Air and Ethiopian Airlines did not have those packages.

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If it had been working, the warning light would have lit up on the fatal flights of both the Lion Air and Ethiopian jets. It’s not clear that it would have made a difference, as Lion Air pilots were unaware of the MAX’s new automated maneuvering system that pushed the plane’s nose down in response to the erroneous angle-of-attack data.

With knowledge of the overall system in the wake of the Lion Air crash, the Ethiopian pilots might have benefited from the information, but a preliminary report suggests they were ultimately able to diagnose the problem. They still weren’t able to maintain control of the plane.

Dan Elwell, the head of the FAA, has expressed concern that Boeing took 13 months to inform the FAA about the problematic disagree light, but he has also endorsed Boeing’s perspective that the light wasn’t a safety-critical issue. FAA leaders characterized it as an advisory light for the sake of maintenance, and Elwell told lawmakers there are no actions that pilots are to take when a disagree light engages.

At a hearing before a House committee investigating issues around the 737 MAX last month, Elwell encouraged members of Congress not to focus so much attention on the light.

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“Don’t make something that isn’t a critical safety item a critical safety item, because there’s enough critical safety items for us to focus on,” he said.

The Aviation Subcommittee of the House Committee on Transportation and Infrastructure is scheduled to hold a second hearing on the 737 MAX on June 19. </s> (Bloomberg) -- House lawmakers demanded records from Boeing Co., one of its suppliers and U.S. aviation regulators on why a cockpit alert that might have helped pilots in two recent fatal 737 Max crashes was installed with a defect that made it inoperable.

Representative Peter DeFazio, the Oregon Democrat who heads the House Transportation and Infrastructure Committee, on Friday sent letters to Boeing, United Technologies Corp. and the Federal Aviation Administration requesting a timeline and other documents related to the alerting system.

Boeing had installed an indicator light on a cockpit display that was supposed to illuminate when weather-vane-like sensors on the nose of the 737 were malfunctioning, but software issues prevented it from working in some configurations. Airlines operating the new plane weren’t told about the faulty alert until after the accidents, even though Boeing knew about the issue in 2017. Failures of that sensor, known as angle-of-attack, were what led the planes to automatically try to dive in both deadly crashes.

“The fact that Boeing knew about a defect for more than a year before disclosing it to the FAA is of great concern to me,” DeFazio said in a press release.

DeFazio was joined by Representative Rick Larsen, a Washington Democrat who is chairman of the aviation subcommittee, in making the request. It was the second call for records in the committee’s investigation of the two crashes on the 737 Max that have claimed the lives of 346 people and resulted in the grounding of Boeing’s best-selling jet.

Software for the cockpit alert on the angle-of-attack sensor is made by Rockwell Collins Inc., which was acquired by United Technologies. Another United Technologies division makes the angle-of-attack vanes for the plane.

FAA Acting Administrator Daniel Elwell told House lawmakers at a May hearing that regulators didn’t believe the defective alert was a safety-critical item because pilots had other ways to detect a failure, but the agency was concerned the manufacturer hadn’t disclosed it.

Boeing’s internal experts reviewed the issue after it was discovered and determined the flaw wouldn’t affect safety and they planned to fix it during the next software update for the plane, the company said in May.

The cockpit alert only worked on airplanes that displayed the position of angle-of-attack sensors. Most airlines opted not to purchase the extra display, rendering it unworkable on most of the delivered 737 Max aircraft.

It’s not clear whether having a working cockpit alert would have made a difference in either the October crash of a Lion Air jet off the coast of Indonesia or the March accident near Addis Ababa, Ethiopia. In the Ethiopia Airlines crash, for example, pilots recognized the type of failure they faced, but still couldn’t control the plane, according to a preliminary investigative report.

To contact the reporter on this story: Alan Levin in Washington at alevin24@bloomberg.net

To contact the editors responsible for this story: Jon Morgan at jmorgan97@bloomberg.net, Elizabeth Wasserman, Steve Geimann
U.S. Representatives Peter DeFazio and Rick Larsen of the House Transportation committee report Boeing discovered the 737 Max AOA Disagree alert problem in 2017 but decided to defer fixing it until 2020, and sped up the process only after the Lion Air Flight 610 crash.