You plan to fly Portland to North Bend the next morning. You’ve been watching the weather at North Bend and are pretty comfortable you can get in without the need to file an alternate. You base this information using your standard 1-2-3 rules.
- During the time 1 hour before to 1 hour after the estimated arrival time
- Ceiling less than 2,000 feet
- Visibility less than 3 miles
The forecast for North Bend at an hour before and an hour after is 2,500ft ceilings and getting better with 3 miles visibility. For the last two days the weather has been similar and always improved as the day continues.
You open up your IFR flight plan with Lockheed and proceed on your course of clearance.
Should you have filed the alternate? While it was not required would it have been a good idea?
The key thing to remember is the not all airports and their approaches can be used as an alternate.
Beyond that you have specifications about your alternate for IFR and criteria for the approaches in general.
If the airport has an instrument approach published, the weather must be forecast to be (at the ETA) better than the alternate airport minima specified in that approach or the following standard conditions:
- Precision Approach: 600ft ceiling and 2SM visibility
- Non-Precision Approach: 800ft ceiling and 2SM visibility
As a practice, while it was not required to file an alternate, it is often a good idea to have the alternate determined, approached validated and a plan established before proceeding on your flight plan. This is in the event that during your route ceilings drop or visibly lessens. It’s far better to have your options to plan before leaving the ground.