When a customer requirement change is identified, the project manager should first validate the change with the product owner and the development team. This ensures that the change is feasible and assesses its impact on the project. The PMBOK Guide outlines the importance of involving stakeholders in decision-making processes and the need for integrated change control to manage changes effectively.
The response is based on general project management principles as outlined in the PMBOK Guide and the standard practices of stakeholder engagement and integrated change control that are part of the PMP's body of knowledge

In the context of software development for controlling airplanes, it is critical to ensure that the software complies with all relevant standards and regulations. This is not only a matter of meeting project requirements but also a matter of safety and legal compliance. The project manager should conduct a validation process to confirm that the software meets all the necessary regulatory criteria. This process typically includes a series of tests, audits, inspections, and reviews of documentation to ensure that every aspect of the software adheres to the required standards21. Reference:
AC 43-216 - Software Management During Aircraft Maintenance2.
Exam PMP topic 1 question 740 discussion - ExamTopics1.