Recovery techniques, avoidance, and knowledge must combine in the face of windshear encounters.
This month's CALLBACK from NASA ASRS discusses several windshear encounter stories from pilots, along with their choices and thought processes along the way. All of these anecdotes have clear, useful lessons about the relationship between pilots, windshear, and decision-making, but we want to focus on the first of the stories: "Teasing a Toronto Tailwind." Here, an A319 pilot encounters windshear during heavy rain and moderate turbulence, resulting in an unstable approach. Then, he makes a series of calls as to how to handle the event:
2. [I saw] a positive trend in the wind.
3. [I was] prepared for the missed approach (at 500 feet) IF the winds and IAS stayed as they were earlier in the approach.
Here, we have a pilot who deliberately opts to continue an approach into potential windshear for a variety of reasons: he recognizes that the problem wind is about to dissipate; he is confident his aircraft can make the landing if conditions do not drastically worsen; he is prepared to take the missed approach if windshear becomes a problem. The result was a completely uneventful landing (not shown in the excerpt above).
If you balked at the conditions for the approach, then obviously the go-around was the correct decision. With an airliner like an A319, the options available to a pilot may be different than what might be available to a smaller aircraft. But the takeaway here isn't what the A319 can or can't do. What is notable in this story is the way the pilot made a clear, decisive choice devoid of panic response or doubt, and left himself an out he knew he could take if things did not turn out the way he planned. Waffling and uncertainty in such situations can waste valuable time, landing a pilot in a situation where a decision has already been made for them.
Whether your choice is a go-around or a continued approach, these kinds of quick, firm decisions are necessary to avoid windshear encounters. But the ability to make such decisions hinges upon your own knowledge: how often have you practiced recovery techniques? How well do you understand the conditions most closely tied to windshear? When looking at a weather map, do you see the possibility for windshear when looking at a fast-moving front with a wide temperature difference, or a forming thunderstorm?
Simulator time and regular practice can help you better understand how your aircraft will handle, giving you confidence to make the right decisions when windshear possibilities become a reality. Above all, remember that the best defense against windshear is avoiding it altogether, making your decision-making easier than you might think: If you are ever in doubt, don't hesitate. Go around or otherwise adjust your flight path to avoid the hazards of windshear, and always leave an out. After all, the best windshear recovery techniques are ones that are well-practiced, but that you never have to use.Related CTS Training: