A second Boeing whistleblower has died after a sudden illness.

Joshua Dean, a former quality auditor at Spirit AeroSystems, went public with claims that the company’s leadership ignored manufacturing defects in Boeing’s 737 MAX. Spirit AeroSystems is a Boeing supplier.

Dean, 45, had an active lifestyle and was believed to be in good health prior to his “sudden” death on Tuesday, following the onset of a fast-moving infection. He was stricken with Influenza B and MRSA, and developed pneumonia, according to Fox59.

He spent two weeks in critical condition before he died on Tuesday in Oklahoma, according to The Seattle Times.

“My handsome brother Joshua passed away this morning and is with our baby brother. I don’t know how much more my family can take. I don’t know how much more I can take honestly,” his sister, Taylor Rae Roberts, wrote in a Facebook post.

“Our thoughts are with Josh Dean’s family. This sudden loss is stunning news here and for his loved ones,” Spirit spokesperson Joe Buccino said.

Dean, from Wichita, is the second whistleblower to die this year after coming forward about safety issues in the aviation manufacturing industry. Boeing whistleblower John Barnett, 62, was found dead in his truck in a hotel parking lot in South Carolina in March.

The whistleblower’s death is the latest in a string of incidents related to embattled Boeing over the past year. In January, an Alaska Airlines Boeing 737 MAX 9’s door plug blew off in mid-air, leading to the grounding of all 171 MAX 9 jets by the FAA and instigating an investigation.

Soon afterwards, at least four people came forward — including both of the now-dead whistleblowers — to allege that corner cutting in the jets’ manufacturing process was causing safety risks. In the wake of the chaos, Dave Calhoun, Boeing CEO, announced in March that he would step down at the end of the year. Boeing reported a $355 million net loss for the first quarter of 2024.

Joshua Dean came forward to raise issues of aircraft safety. He said that “serious and gross misconduct by senior quality management of the 737 production line” had taken place at Spirit, in a complaint to the Federal Aviation Administration (FAA).

He also testified in a shareholder lawsuit against Spirit AeroSystems, filed in December 2023. The shareholders alleged that Spirit “concealed from investors that Spirit suffered from widespread and sustained quality failures,” and that “quality failures” occurred because the company was chasing profits, Supply Chain Dive reports.

“Such constant quality failures resulted in part from Spirit’s culture which prioritized production numbers and short-term financial outcomes over product quality, and Spirit’s related failure to hire sufficient personnel to deliver quality products at the rates demanded by Spirit and its customers including Boeing,” the plaintiffs argued.

Those “quality failures” were so egregious that Boeing put Spirit AeroSystems on probation between 2018 until at least 2021, which prohibited the supplier from shipping parts to Boeing without managerial approval, the lawsuit claims.

In January, Dean told the Wall Street Journal that he had been fired for pointing out that holes in jet fuselages had been drilled wrong. He was fired from Spirit Aerosystems in April 2023, and he complained later that his termination was in retaliation.

“It is known at Spirit that if you make too much noise and cause too much trouble, you will be moved,” Dean said. “It doesn’t mean you completely disregard stuff, but they don’t want you to find everything and write it up.”

Spirit AeroSystems told the WSJ that it disagreed with Dean’s characterisation and that the company would defend itself in court.

Other members of Dean’s family shared their grief on social media. On 20 April, Dean’s aunt, Jenny Dean, shared a message from his mother, Ginger Green, saying that he had been diagnosed with Influenza B and MRSA, and was “fighting for his life” in the hospital.

“My son is fighting for his life. He tested positive for influenza B and MRSA that went into pneumonia. His infection spread throughout his whole body and into his blood stream. His lungs are completely whited out and they had to intubate him,” Dean’s mother wrote.

“His condition worsened and he needed to be transferred to a hospital in Oklahoma City … he is on dialysis too because he has so much fluid throughout his body and they say that his kidneys and liver aren’t doing well.”

His attorney, Brian Knowles, told The Seattle Times that he did not want to speculate on the nature of his client’s death but stressed the importance of whistleblowers.

“Whistleblowers are needed. They bring to light wrongdoing and corruption in the interests of society. It takes a lot of courage to stand up,” Mr Knowles said. “It’s a difficult set of circumstances. Our thoughts now are with John’s family and Josh’s family.”

The attorney also represented Barnett who had spoken out about alleged safety problems at Boeing and had been giving evidence in a lawsuit against the company prior to his death. Barnett alleged that Boeing intentionally used defective parts in its planes and warned that passengers on its 787 Dreamliner might face a lack of oxygen if a sudden decompression occurred.

Barnett was a former quality control engineer, and spent 32 years at Boeing until his retirement for health reasons in March 2017.

Barnett gave his initial testimony just days before he was found dead in March at a hotel in Charleston. His death appeared to be from a self-inflicted gunshot wound, the Charleston County coroner told BBC News.