On the Ethiopian flight, the pilots struggled to turn the wheel while the plane was moving at a high speed, when there is immense pressure on the tail. The simulators did not properly match those conditions, and Boeing pilots found that the wheel was far easier to turn than it should have been.

Regulators are now trying to determine what training will be required.

When the Max was introduced, Boeing believed that pilots did not need experience on the flight simulators, and the Federal Aviation Administration agreed. Many pilots learned about the plane on iPads. And they were not informed about the anti-stall system.

The limited training was a selling point of the plane. It can cost airlines tens of millions of dollars to maintain and operate flight simulators over the life of an aircraft.

After the first crash, Boeing gave airlines and pilots a full rundown of MCAS. But the company and regulators said that additional training was not necessary. Simply knowing about the system would be sufficient.

In a tense meeting with the American Airlines pilots union after the crash, a Boeing vice president, Mike Sinnett, said he was confident that pilots were equipped to deal with problems, according to an audio recording review by The New York Times. A top Boeing test pilot, Craig Bomben, agreed, saying, “I don’t know that understanding the system would have changed the outcome of this.”

[Before Ethiopian crash, Boeing resisted pilots’ calls for aggressive steps on 737 Max.]

Since the Ethiopian Airlines disaster in March, lawmakers and regulators are taking a closer look at the training procedures for the 737 Max, and whether they should be more robust. At a congressional hearing this week, the acting head of the F.A.A., Daniel Elwell, testified that MCAS should “have been more adequately explained.”

Boeing said on Thursday that it had completed its fix to the 737 Max. Along with changes to the anti-stall system, the fix will include additional education for pilots.