What can CASA randomly test for regarding license holders performing or available to perform an applicable SSAA?

The correct choice pertains to the regulations surrounding drug and alcohol testing for pilots holding a license under CASA (Civil Aviation Safety Authority). CASA has established strict protocols to ensure safety in aviation, which include random testing for substance abuse.

Pilots can be randomly tested for any presence of drugs and alcohol, as these substances can significantly impair their ability to operate an aircraft safely. This testing is critical to maintain safety standards and ensure that all licensed pilots are fit to fly before they undertake any flight duties or are on standby to perform flight-related responsibilities.

The focus on drug and alcohol is crucial because they can adversely affect a pilot's cognitive and motor skills, judgment, and overall performance, thereby posing risks not only to the pilot but also to passengers and crew members. The adherence to such regulations underscores how seriously CASA takes flight safety and the responsibilities of license holders.

In contrast, assessing flight hours, blood alcohol levels in isolation, or aircraft maintenance records focuses on different aspects of aviation operations and regulations, which are certainly important but do not directly address the random testing aspect specifically catered to drug and alcohol use in the context of maintaining pilot availability and fitness for duty.