The other day, I was flying along and overheard a conversation between a controller and a pilot attempting to depart IFR from an uncontrolled field nearby. The controller gave the pilot a clearance with a void time. When the pilot read back the clearance I noticed that he made no mention of the void time.
A few minutes later, I overheard the pilot saying something about being ready for departure. The controller responded, but did not clarify that he had a void time and was able to take off as long as he did it before that time was up.
Around 10 to 15 minutes later the pilot queried the controller again about a departure clearance. By that time, the void time had passed and the controller gave the pilot a new clearance.
Departing IFR from an uncontrolled field can be a bit confusing if you don’t understand the clearance. Knowing what a controller says is critical whether you are flying IFR or VFR. If you are confused about what a controller is telling you, it is always best to ask for clarification.
Taking off or proceeding when you are unclear about what the controller wants you to do can be a serious risk to yourself and your fellow pilots in the sky.