The relationship between Boeing and the Federal Aviation Administration, which has set the global standard in aviation safety for decades, will come under unprecedented scrutiny this week after two deadly airline crashes.

Both accidents involved a Boeing jet green-lighted by the U.S. regulator, which relied heavily on safety assessments made by Boeing employees.

In a startling break from the past, other nations and airlines grounded the Boeing 737 Max en masse after the second fatal crash this month while the same model of plane continued to carry tens of thousands of passengers a day in the United States.

This week, Congress joins the investigation into Boeing and the FAA. On Wednesday, the Senate aviation subcommittee will examine how the FAA oversees safety in the commercial aviation industry.

The acting FAA chief is scheduled to testify. So is the Transportation Department’s inspector general, who is conducting a separate probe of the FAA’s decision to approve the Boeing 737 Max aircraft, the type of plane that crashed in Indonesia in October, and then in Ethiopia two weeks ago.

The U.S. House plans to hold its own hearings and The Associated Press has reported that the Justice Department is also investigating.

At the very least, it looks like Boeing and the FAA are going to be under more intense scrutiny for some time.

Here are some questions that lawmakers are almost certain to ask:

CAN FAA EFFECTIVELY REGULATE BOEING?

For decades, the FAA has relied heavily on safety certifications performed by employees of aircraft manufacturers, whose work is overseen by the FAA.

The FAA defends this delegation of work, saying it improves safety by involving more skilled professionals into the review of what companies do. Agency officials stress that the last fatal crash of a U.S. airliner took place a decade ago.

Sen. Richard Blumenthal, D-Conn., called the FAA arrangement with manufacturers “safety on the cheap,” and said he wants to know more about the role that Boeing employees played in the FAA’s decision to certify the Max.

SHOULD FAA’S BUDGET BE INCREASED?

The agency concedes that it doesn’t have resources to keep pace with growth in the aviation industry. Outside experts say the FAA is overmatched — it can’t pay enough to attract and keep people with the technical expertise to regulate such a complex industry.