What must a pilot provide when notifying crew scheduling of being unable to report for duty?

When a pilot notifies crew scheduling of their inability to report for duty, they must communicate a reason for their absence. This requirement ensures that the scheduling team can accurately account for staffing levels and make necessary adjustments. Providing a reason helps maintain operational integrity and safety, as it informs the scheduling department about potential issues affecting the crew's ability to fulfill their duties.

The reasoning for absence can range from personal health issues to unforeseen emergencies and is crucial for record-keeping and follow-up actions. While proof of leave or attempts to get on flights may be relevant in specific contexts, they do not fulfill the fundamental obligation of communicating the reason for not being able to report for duty.