Flight plans expire when not opened after how long post ETOD?

• A. 1 Hour After ETOD
• B. 2 Hours After Departure
• C. 2 Hours After ETOD
• D. 24 Hours After ETOD

Answer: (C)

Opening an instrument flight plan after you file it is how ATC sees you in the system as an actual flight. If you don’t activate that plan within a set window after the estimated time you intend to depart (ETOD), the plan is canceled so ATC isn’t tracking a flight that isn’t going to happen.

The standard window is two hours after the ETOD. That means if ETOD is, say, 1200 and you haven’t opened/activated the plan by 1400, the plan expires. If you still want to fly IFR, you’d need to file again with a new ETOD and reopen the plan.

The other timings don’t fit this rule: one hour after ETOD is too short a window, two hours after actual departure would blur the link to ETOD, and 24 hours after ETOD is unnecessarily long. The key point is the expiration tied to ETOD, not to when you actually depart.