In the last six years, the commercial jet manufacturer suffered two worldwide groundings, leading to its current crisis.

Since 1916, Boeing has carefully built up a proud history that reached almost a century without a grounded fleet.

But in the last six years, the US-based commercial jet manufacturer has suffered two worldwide groundings.

The Federal Aviation Authority (FAA) halted operation of the 787 Dreamliner in 2013 following two battery failures and then acted earlier this year on the 737 Max after two plane crashes killed 346 people.

The events in Indonesia in October 2018 and in Ethiopia in March 2019 have prompted a criminal investigation into the plane’s certification by the US Department of Justice, according to a Seattle Times report.

The US Transportation Department’s inspector general is also reported to be examining the plane’s design certification.

On April 10, Boeing’s shareholders filed a lawsuit accusing the company of defrauding them by concealing safety deficiencies.

The complaint said that Boeing “effectively put profitability and growth ahead of airplane safety” by rushing the 737 Max in order to catch up with its rival Airbus, and by making some safety features “extra” or “optional”.

The comments echo what Boeing engineers have been saying for several years. Dozens of current and former workers expressed concern over Boeing’s quality procedures on the 787 as far back as 2013.

Broken Dreams: The Boeing 787, a 2014 Al Jazeera investigation released in the wake of the Dreamliner’s brief grounding, revealed the fears of Boeing workers in Charleston in the southern state of South Carolina, where the company launched a new manufacturing plant in 2011.

At the time, Boeing lambasted the investigation as “neither balanced nor accurate”.

The 737 Max and the 787 Dreamliner were two of Boeing’s biggest projects for the 21st century and sold more quickly and in greater numbers than previous models. In each case, analysts and engineers said Boeing was focused on making planes that would be cheap for airlines to operate.

‘Delegating safety assessments’

In 2015, as Boeing rushed to certify the 737 Max and catch up with Airbus, managers at the FAA pushed its safety engineers to delegate safety assessments to the company, resulting in a safety analysis with crucial flaws, according to the Seattle Times.

“There was constant pressure to reevaluate our initial decisions,” one former FAA engineer directly involved in certifying the 737 Max told the Times. “And even after we had reassessed it … there was continued discussion by management about delegating even more items down to the Boeing Company.”

Cynthia Cole, a retired Boeing engineer with a 30-year career and a stint as union president, criticised the regulatory failures, telling the Times things were “complicated by the FAA using Boeing engineers for many of the certification tasks, then pressuring people who disagreed with findings to keep quiet”.

Engineers have long recognised the potential conflict of interest in the FAA allowing Boeing’s own staff to assess their planes’ safety when they are developed and certified.

Al Jazeera can reveal that during the 2014 investigation, in previously unreported comments, an engineer directly involved in 787 oversight said they “felt Boeing was pushing too hard” to get certifications done.

Another said Boeing’s oversight representatives “were often going to the FAA and asking for deviations to the regulations”. The quality control department “was doing whatever management wanted to meet schedule and engineers were furious,” another Boeing worker told Al Jazeera.

All spoke on the condition of anonymity for fear of retaliation.

Al Jazeera also found that dozens of engineers responsible for 787 regulation had complained to the FAA about Boeing managers pressuring them to certify before they felt ready.

FAA documents showed that when they tried to enforce official standards they came under “undue pressure” and were either “talking to a brick wall” or subjected to “verbal abuse and verbal ridicule”.

The documents suggest Boeing impeded its workers’ communication with regulators, making it harder for them to do their job.

Boeing emphatically denied the claims, saying “safety is our highest priority as we design, build and support our airplanes”. The company said that the regulatory system is “robust and effective”.

It added that no engineers were barred from talking to the FAA, and “each verified that they were not subject to any undue pressure”.

Workers at Boeing say the problems today are the result of a slow but certain cultural change that can be traced to the company’s 1997 merger with McDonnell Douglas, the creator of the DC-10 grounded in 1979 after American Airlines Flight 191 crashed, killing 271 people.

Stan Sorscher of engineering union SPEEA told Al Jazeera that Boeing had shifted from a business model “based on problem-solving and worker engagement” to “a top-down cost-cutting” system “popularised by Wal-Mart”, the world’s largest retailer based in the US.

“All of these issues have their roots in the merger and the slow eroding of The Boeing Way,” said Cole.

Boeing’s new plant in Charleston was launched in 2011 with lower labour costs and tax breaks totalling over $1bn. But workers at the company’s facilities in the western city of Seattle say that came at the cost of the so-called tribal knowledge that they had developed over generations.

Three years later, Al Jazeera captured footage showing 10 workers at the Charleston plant saying they would not fly on the planes they were building.

“I wouldn’t fly on one of these planes,” a worker told his colleague, “because I see the quality of the f****** s*** going down around here.”

Another said, “We’re not building them to fly. We’re building them to sell. You know what I’m saying?”

One customer, later revealed to be Qatar Airways, refused to accept planes from the plant after a number of manufacturing problems and sent a video in which the airline’s chief executive lectured workers on the quality of their product.

Neither Boeing nor Qatar Airways has commented, although Boeing says it has the highest confidence in its workers in South Carolina.

As part of Al Jazeera’s 2014 investigation into Boeing’s 787, Kevin Sanders, a 30-year employee across Boeing business units, expressed the passion workers feel about the changes. With tears in his eyes, he said he felt the institution’s legacy had been “hijacked by a bunch of corporate thugs”.

Others spoke of a “cultural war” between heritage engineers and modernisers, which only one side can win.

“The legacy people are just waiting for retirement,” said one engineer.