Conformance with The IIA's Code of Ethics is mandatory for internal auditors because it provides the basis for stakeholder trust and confidence in the validity of the profession of internal auditing and the internal audit activity's findings. Ethical behavior in internal auditing ensures that auditors are trusted by those who rely on their conclusions, advice, and information, thereby enhancing the integrity and credibility of the audit results.References: Institute of Internal Auditors (IIA) - International Professional Practices Framework (IPPF)

If the internal audit activity lacks the necessary skills and competencies to complete an ad-hoc assurance engagement, the most appropriate and professional action is to politely decline the engagement due to a lack of qualified staff. This decision upholds the IIA's standards on professional proficiency and due professional care.References: The Institute of Internal Auditors (IIA) - International Standards for the Professional Practice of Internal Auditing.

According to IIA guidance, an internal audit charter should detail the responsibilities of the audit committee.
The charter is a formal document that defines the purpose, authority, and responsibility of the internal audit activity. Including the audit committee's responsibilities ensures clarity on the committee's role in overseeing the internal audit function, enhancing governance, and providing a framework for accountability and support.
References:
* The IIA Standards: Standard 1000 - Purpose, Authority, and Responsibility: "The purpose, authority, and responsibility of the internal audit activity must be formally defined in an internal audit charter, consistent with the Definition of Internal Auditing, the Code of Ethics, and the Standards."
* IIA Practice Guide: "Internal Audit Charter: Understanding the Components": Highlights the importance of specifying the audit committee's responsibilities in the charter.