Decisions based on weather/fuel

A good diversion decision is one you can say out loud in a single sentence: here's the problem, here are the options, here's my choice, and here's why.

Making the call

That sentence is structured aeronautical decision-making. The FAA's study hook is the DECIDE model from PHAK Ch. 2 — Detect, Estimate, Choose, Identify, Do, Evaluate — but the cockpit version is shorter: problem → options → choice → reason, then commit and fly it.

The discipline is committing. A decision you re-open every two minutes is worse than a good-enough one you actually execute — second-guessing burns the very fuel and time the diversion was meant to protect. Decide, then fly.

Said out loud, a real one sounds like this: "Destination's reporting seven-hundred overcast — below my personal minimum. I've got eight gallons. Plainview is fifteen miles, VFR, with fuel. Diverting to Plainview, heading two-seven-zero." That's the whole decision in one breath — problem, constraint, option, choice, action — and it's exactly the reasoning the examiner wants to hear you work through, not a silent turn they have to guess the logic behind.

And "divert" isn't the only valid answer. Sometimes the right call is "continue, but monitor" — the destination's holding, the trend is stable, you have fuel and a named bail-out point. That's a legitimate decision as long as it's an actual decision — made on the numbers and revisited — not a default you slid into by never choosing. State it the same way: problem, options, choice ("continue to the destination, decision point at the river, alternate is Plainview"), reason.

But notice the final E — Evaluate. Committing isn't the same as going blind: after you turn, keep checking that the choice still holds — the weather at the alternate, the fuel trend, the airplane's behavior. If any of those moves against you, the model loops — you re-Detect and re-Choose. That's the line between committing and fixating: you fly the chosen plan, but you never stop watching whether it's still the right one.

Updating weather in flight

The decision isn't frozen at the moment you make it. Pull fresh weather as you go:

• FIS-B / ADS-B In — subscription-free weather right in the cockpit (see VI.B.K3).
• Flight Service on the radio for a current picture and PIREPs.
• The ATIS or AWOS/ASOS at the alternate as you come into range — the most relevant report of all.

If the picture changes, change the plan. That's not indecision; it's airmanship — the "Evaluate" step doing its job.