In a statement, a Boeing spokesman said, “Boeing and Collins Aerospace are working side by side to update the Max software and safely return the fleet to service.”

Officials from the Federal Aviation Administration and the European Union Aviation Safety Agency were in Iowa last week, auditing the software updates that Boeing and Collins hope will persuade regulators to allow the Max to resume flying, both agencies said.

The heightened focus on Collins’s work highlights the scrutiny that can come from working with the world’s largest aircraft manufacturer. Another of the company’s Boeing collaborations, a critical system on a long-delayed plane for the Air Force, has been deemed deficient by Defense Department officials and come under review by the Government Accountability Office.

When Boeing announced in 2012 that Collins had edged out rivals to provide the flight deck displays for the 737 Max, then still in development, it was cause for celebration within both the company and the community. For Collins executives, it was also validation of a dramatic transformation the company had undertaken years earlier, in response to demands from Boeing, to do more with less.

But with the Max crashes now in the news almost daily, few executives or employees wanted to discuss their work on the plane when a reporter visited recently.

None would agree to be quoted by name, and some referred questions to Collins’s corporate parent, United Technologies, based in Connecticut. A spokeswoman for the parent company declined to comment and threatened unspecified legal action if Collins employees continued to be approached with questions about the Max.

Another company owned by United Technologies, Rosemount Aerospace, also has been pulled into the Max investigations because it made the sensors that allegedly provided faulty data, triggering the erroneous computer commands in the two crashes.