Aviation In Canada

Wednesday, May 11, 2005

Flight Plan "Window of Validity"

In response to a couple of questions posted recently, this article deals with flight plans and the length of time in which they are valid.

First off, I have yet to see an official figure for the length of time a flight plan is considered valid, or active. I was taught in the ATC world that a flight plan on an IFR aircraft should be held for a period of 6 hours, and that is what I use today at the boards unless I am aware of something that makes the flight plan invalid. For example, I have two flight plans on the same aircraft, one from CYHZ to CYSJ and one from CYSJ to CYFC, but the aircraft landed in CYFC instead of CYSJ on the first leg due to bad weather in CYSJ. Obviously, he can't leave CYSJ for CYFC if he didn't land. If the aircraft is departing an airport without a TWR or FSS (no ATS facility), then the status of the aircraft and the flight plan must be confirmed at some point. Read on...

If the flight plan is has a departure point that is not served by an ATS facility, we go looking for his departure message if we haven't heard from the pilot within one hour of the proposed departure time. This is part of "alerting services". The time frame of 60 minutes is used to give the pilot some flexibility on departure, since not all flights depart on time. The assumption is that if ATC doesn't hear about a flight, in controlled airspace or not, within 60 minutes of the proposed time, the flight may have attempted to get airborne and failed, leaving the pilot in no position to communicate his departure message. In practice, we often end up looking for information on the pilot's movements before the 60 minutes, but that is the standard time for provision of alerting services. At an airport served by an ATS unit, this is less of a concern since a TWR or FSS is based there, and communications with these units is required prior to taxi, and often these guys could look across the field with binoculars to confirm the aircraft is, in fact, safely still on the ground. If a pilot is to be delayed beyond 60 minutes from the proposed time, there is a requirement to contact ATC or FSS and advise of the delay and a new proposed departure time, though this is really only important for aircraft departing airports without an ATS unit. Note that CARS, UNICOM and other such airport services are not connected with NAVCANADA, and are therefore not ATS units. Advising UNICOM that you'll be departing late is not sufficient. ATC will begin a communications search and may initiate search and rescue operations if they haven't heard from you within 60 minutes of your proposed time.