If the first fuel sample is contaminated, what should you do?

The appropriate action when the first fuel sample is contaminated is to notify Maintenance Control and provide the samples to Quality Assurance (QA). This response is vital because it ensures that any potential issues with fuel contamination are logged and investigated properly. Contaminated fuel can lead to serious malfunctions in aircraft systems, so it's essential to follow protocol and ensure safety.

By involving Maintenance Control, it allows for a coordinated approach to assessing the extent of the contamination and determining the necessary steps to address it. Quality Assurance plays a critical role in analyzing the samples and ensuring compliance with safety and operational standards.

In contrast, ignoring the contamination, draining the fuel and taking a new sample, or checking the fuel sensors would not adequately address the underlying issue or adhere to standard operating procedures for maintenance and safety in aviation environments. Therefore, notifying the relevant authorities and seeking their expertise is essential in this scenario.