U.S. planemaker Boeing faces a "long road" to address safety issues, the head of the Federal Aviation Administration said on Thursday as it prepares to receive the company's plan to address concerns.

In late February, FAA Administrator Mike Whitaker gave Boeing 90 days to develop a comprehensive plan to address "systemic quality-control issues" and barred it from expanding 737 MAX production.

Boeing has faced mounting questions after a door panel detached during a Jan. 5 flight on a new Alaska Airlines (ALK.N)

An autopsy report for John Barnett, the Boeing whistleblower who was found dead on the day he was due to testify against the jetliner giant, was released Friday — and the coroner writes “the manner of death is best deemed, ‘Suicide.'”

Questions have been raised about the sudden death of Barnett, 62, on March 9 ahead of giving testimony against his former employer, prompting his lawyers to urge Charleston, South Carolina, police “to investigate this fully and accurately,” and adding: “We need more information about what happened to John.”

At a U.S. Senate hearing last month, a Boeing whistleblower claimed that small gaps in Boeing’s 787 Dreamliner could cause a catastrophic accident. The following week at the 787 assembly plant in South Carolina, Boeing insisted the gaps pose no risk and the jet is safe.

The dueling narratives, emerging as Boeing’s credibility is near an all-time low, left industry observers and the public at a loss as to the risk.

The Securities and Exchange Commission has opened an investigation into Boeing over concerns it may have misled investors, reported Bloomberg.

The investigation pertains specifically to comments made to investors about safety practices following an incident in January in which a panel flew off an Alaska Airlines-run 737 Max 9 plane midair because of a poorly installed door plug.

In response to a request for comment, a spokesperson for Boeing told Newsweek: "We don't have anything to add."

A Boeing 737 skidded off a runway at an airport in Senegal’s capital, injuring at least 11 people and grounding all operations while crew assisted with an evacuation of the aircraft.

The Air Senegal flight operated by TransAir was set to take off from the Blaise Diagne airport in the country’s capital of Dakar and fly to the city of Bamako in Mali on Thursday around midnight when the plane "came off the runway during its take-off phase," Senegal Transport Minister El Malick Ndiaye told reporters. 

The Federal Aviation Administration says it's opened an investigation into Boeing regarding inspections of the 787 Dreamliner that "may not have been completed."

The FAA said Monday Boeing "voluntarily informed us in April" that the plane maker may not have completed required inspections to confirm that there was adequate bonding and grounding where the wings join the carbon fiber fuselage on certain 787 jets.

The Federal Aviation Administration has opened a new investigation into Boeing’s 787 Dreamliner after Boeing disclosed that inspection records on work at the wing-to-body join were falsified.

Boeing informed the FAA in April that it may not have completed required inspections on some 787s to confirm adequate bonding and electrical grounding where the wings join the fuselage body. Inspection records were falsified at the jet’s final assembly site in South Carolina.