The head of the Federal Aviation Administration is set to pilot the 737 Max Wednesday in Seattle -- a key step in the aircraft's eventual re-certification.

"I'm not going to sign off on this airplane until I fly it myself," FAA chief Steve Dickson has repeatedly said.

Dickson, a former pilot and executive at Delta Air Lines, will undergo the new proposed training for Max pilots before entering the cockpit.

The Boeing 737 Max has been grounded for over a year and a half after it was involved in two crashes that killed a total of 346 people.

Investigators found that both crashes involving the 737 Max were tied to a software called the Maneuvering Characteristics Augmentation System (MCAS). MCAS was designed to help stabilize the 737 Max after heavier, re-positioned engines placed on the aircraft caused the plane's nose to point too far upward in certain circumstances.

In both crashes, incorrect data from a faulty sensor caused MCAS to misfire, forcing the plane to nose down repeatedly even as pilots struggled to regain control and gain altitude. MCAS was not mentioned in the pilot manual.

Boeing not only rewrote the software for the MCAS flight control system, but also the entire flight computer software.

The FAA, European Union Aviation Safety Agency, and Canada have already completed their own Max test flights. The test pilots tried to replicate scenarios where the old MCAS misfired -- forcing the plane into dives and tight turns.

Although the Max is getting closer to receiving the FAA's stamp of approval, there are still a number of steps that remain before it can return to the skies with paying passengers including airlines drafting their own pilot training, getting it approved and training their pilots.

Last week American Airlines began scheduling training for its 737 Max pilots in November and said it expects to have completed training for all Max pilots by the end of January 2021, according to an internal memo obtained by ABC News.

The 737 Max has been the subject of multiple investigations from congressional committees and U.S. agencies, including the Department of Justice and the Securities and Exchange Commission.

Two weeks ago the House Committee on Transportation and Infrastructure released a scathing report which concluded technical design flaws, faulty assumptions about pilot responses and management failures by both Boeing and the FAA were to blame for the fatal crashes.

Lawmakers are now pushing for a reform of the aircraft certification process in the U.S. that they say would strengthen federal oversight over manufacturers.