Mastering Weather: Compliance Overview of AC 91-92, Pilot’s Guide to a Preflight Briefing
Weather isn’t just something you “check”—it’s something you interpret. AC 91-92 pushes pilots to move beyond static information and develop a deeper sense of what the atmosphere is becoming. This is where great briefings transform into great decisions and pilots can begin mastering weather.
The Essential Weather Toolkit
A solid self-briefing uses tools that reveal movement and patterns, not just isolated snapshots. Radar loops highlight development or dissipation, satellite imagery shows structure and moisture, forecast discussions reveal forecaster concerns, and PIREPs provide the raw truth from pilots already in the system. When you combine these tools, you build a dynamic view of the atmosphere—you understand not only what it’s doing, but where it’s heading.
Key Tools at a Glance:
- Radar loops: Show development, weakening, boundaries, and storm motion
- Satellite imagery: Highlights cloud growth, tops, moisture patterns, and upstream threats
- Forecast discussions: Reveal uncertainty, confidence, and alternate outcomes
- PIREPs: Confirm real-world tops, bases, ice layers, turbulence, and inversions
These tools turn your briefing into a forward-looking analysis, not a moment-in-time snapshot.
Interpreting the Big Four Hazards
Weather hazards rarely arrive unannounced—each has early warning signs. Ceilings and visibility depend heavily on trends: falling ceilings, tightening dewpoint spreads, and thickening clouds signal deterioration long before conditions hit IFR. Turbulence becomes more predictable when a pilot notices wind shifts, jet streaks, and terrain-induced wave potential. Icing interpretation hinges on moisture depth, tops, inversions, and PIREP trends. Convective threats reveal themselves through CAPE increases, vertical cloud growth, boundaries, and rising instability.
Red Flags Worth Slowing Down For:
- Ceilings trending down across multiple stations
- Dewpoint spread shrinking toward saturation
- Increasing icing PIREPs
- Boundaries or rapid cloud growth on satellite
- LLWS, jet streaks, or mountain wave signatures
Spotting these early allows you to adjust long before a hazard becomes unavoidable.
Scenario: Static Good, Dynamic Concerning
A pilot planning a VFR morning cross-country might see perfect METARs, clean TAFs, and no AIRMETs. But an AC 91-92-style interpretation digs deeper: a warm front creeping north, rising dewpoints, thickening mid-level clouds on satellite, and PIREPs reporting lowering bases all indicate a trend toward marginal conditions. The flight may still be safe—but only with mitigation such as leaving earlier, adjusting routing around terrain, or selecting a stronger alternate.
Conclusion
Weather interpretation is about trends, triggers, and subtle clues. AC 91-92 teaches pilots to think like detectives—spotting what the atmosphere is preparing to do. When you brief with movement, not moments, you build the confidence to stay ahead of the weather instead of reacting to it.
In Part 3, we’ll bring it all together and show you how AC 91-92 turns weather insight into real-world risk management and confident go/no-go decisions.
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