The statements came hours after Ethiopian officials said pilots of a doomed plane had followed the company's recommended procedures prior to a crash that left 157 people dead.
Sethi said that she made the above request numerous times, since the October 29 crash near Jakarta which claimed 189 lives, including Suneja.
The findings were based on flight recorder data and represented the strongest indication yet that the system, known as MCAS, malfunctioned in both the Ethiopian Airlines crash and the Lion Air crash.
Flight ET 302 crashed on March 10 just minutes into its flight to Nairobi.
The company is tweaking the system designed to prevent an aerodynamic stall if sensors detect that the plane's nose is pointed too high.
The accidents on Lion Air in Indonesia and Ethiopian Airlines, which killed 346 people between them, have raised major concerns about the safety certification of the 737 MAX 8 model.
That extra pilot, who was seated in the cockpit jumpseat, correctly diagnosed the problem and told the crew how to disable a malfunctioning flight-control system and save the plane.
Industry sources caution that the MCAS upgrade does not point to a cause of the Ethiopian crash, something Muilenburg's statement also indicated.
Black Box shows similarities between Lion Air and Ethiopian Airlines crashes involving Boeing 737 Max 8
The Ethiopian Airlines plane crashed March 10 minutes after it took off from Ethiopia’s capital, killing all 157 people on board.
Ethiopian Airlines Flight 302 plummeted into a field minutes after taking off from Addis Ababa bound for Nairobi last Sunday, killing all on board.
There are other similarities that alarmed airlines and regulators and stirred public opinion, leading to the grounding of the 737 Max fleet of more than 350 planes.
The evidence helped persuade U.S. regulators to ground the model, said the person, who requested anonymity to discuss the inquiry.
The FAA's oversight duties are coming under greater scrutiny after deadly crashes involving Boeing 737 Max jets operated by airlines in Ethiopia and Indonesia, killing a total of 346 people.
The so-called jackscrew, used to set the trim that raises and lowers the plane’s nose, indicates the jet was configured to dive, based on a preliminary review.
Boeing executives announced that they had paused delivery of the Max, although the company planned to continue building the jets while it weighs the effect of the grounding on production.