What must be done to fuel samples if they have been sitting for a couple of days?

When fuel samples have been sitting for a couple of days, it is essential to take new samples to ensure the accuracy and reliability of the analysis. Over time, the conditions or contaminants present in the fuel could alter the sample, potentially leading to inaccurate assessments of fuel quality. This is particularly important in aviation, where fuel integrity is crucial for safety and performance.

By taking new samples, you can ascertain the current state of the fuel, check for any changes that may have occurred since the last sampling, and ensure that you are working with the most relevant data. This practice helps to avoid any decisions based on outdated or compromised samples, ensuring that proper measures can be taken if the fuel quality is found to be lacking.