According to the IIA's Standards, if it has been more than five years since the last external assessment was conducted, the Internal audit activity must cease indicating that it operates in conformance with the Standards.
Regular external assessments are required at least once every five years to validate that an internal audit activity continues to operate in conformance with the Standards.
Institute of Internal Auditors (IIA) - International Professional Practices Framework (IPPF)

According to IIA guidance, many aspects of the related enterprise risk management (ERM) program being informal and undocumented is the strongest indicator of deficiencies in the risk management process.
Informality and lack of documentation can lead to inconsistencies, errors, and omissions in risk management, impairing the organization's ability to effectively identify, assess, and manage risks.
The IIA's guidance on effective risk management and ERM practices.

The most appropriate course of action for the CAE when facing a lack of internal audit staff with necessary skills to audit a high-risk area, like the engineering department, is to supplement the internal audit team with external experts who possess the required competencies. This approach ensures that the audit can be conducted effectively and comprehensively, allowing for an accurate assessment of risks and controls in the engineering department without delaying the review until new auditors can be hired and trained.
Institute of Internal Auditors (IIA) - International Professional Practices Framework (IPPF)

The best description of the board's role in establishing effective organizational governance is that the board has oversight responsibility for organizational resources. This includes overseeing how resources are allocated and managed, ensuring that the organization's governance framework is effective, and monitoring overall organizational performance to align with strategic objectives.
Governance frameworks and the role of boards in corporate governance.

When using the auditing-by-element approach to audit controls around corporate social responsibility (CSR), working conditions would be a relevant element for the internal audit activity to consider. This element is directly related to the social aspect of CSR, which focuses on the welfare and rights of employees within the organization.
IIA guidance on auditing corporate social responsibility initiatives.