Let's say I filed a VFR flight plan with ETD (1500), en route (2 hours), ETA (1700)

If I depart and activate the plan at 1600, now the new ETA will be 1800 which is an hour later the the filed ETA. Is the ETA changed automatically on the system? or do I have to contact FSS and change to prevent initiation of the search and rescue?

  • 5
    $\begingroup$ When you call FSS to activate your flight plan you give them your time of departure. Unless your estimated time en route changes, the ETA will be amended correctly. $\endgroup$
    – JScarry
    Commented Jan 28, 2017 at 21:14
  • 1
    $\begingroup$ Are you asking about a specific country or jurisdiction? $\endgroup$
    – Pondlife
    Commented Jan 29, 2017 at 16:48

2 Answers 2


Assuming that you've submitted a Delay Message in order to prevent your flightplan from being deleted you have to do nothing at all.

In your flightplan you only state your ETD (Expected Time of Departure) and ETE (Estimated Time Enroute). Your ETA (Estimated Time of Arrival) will be calculated and relayed to all stations in need of the ETA by AIS (Aeronautical Information Service).

To pick up your example:

Filed ETD: 1500
Filed ETE: 0200

AIS will relay ETA 1500+0200=1700 to your aerodrome of destination.

Let's say you've departed at 1554. Your aerodrome of departure will pass a departure message to AIS (so they know you are on your way) together with your ATD (actual time of departure) which would be 1554 in the example.

AIS will then calculate ATD+ETE => 1554+0200=1754 and relay the corrected ETA to your aerodrome of destination where the data in your flightstrip gets corrected.

  • $\begingroup$ In the U.S., a pilot can open (activate) a filed VFR flight plan beginning one hour before the filed departure time. The flight plan will expire out of the system two hours after the ETD. For an IFR flight plan, the period is two hours before to two hours after your ETD. If the flight plan expires, the pilot needs to refile. $\endgroup$
    – ammPilot
    Commented Jan 30, 2017 at 16:41

You don't have to do anything. Your flightplan does not contain an ETA, and one is not calculated until you actually depart. You've only filed an estimated time of departure (ETD) and estimated elapsed time (EET).

When you depart and open your flightplan, a DEP message is sent to the reporting office responsible for alerting service at your destination containing your actual time of departure (ATD). They (their system) will then calculate an ETA as ATD+EET. This is the ETA that is used for the purpose of alerting service. The ETD of your flightplan is not used for anything related to alerting service. If you never depart and thus never open your flightplan, no DEP message is sent, and an ETA is never calculated - so alerting service is never activated. It's fairly common for VFR pilots to abandon their filed flightplan for some reason, e.g. file a flightplan and then never actually perform the flight. Such a flightplan is automatically deleted after a number of hours. It is never considered active unless you actually depart and have it opened.


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