Technique: Windy Day Departures

Don't get blown away

April 1, 2008

Wow, it’s windy this morning. Definitely a hold-onto-your-hat kind of day. Strong and swirly, this is no poet’s zephyr. Leaves are doing handsprings as they clatter-dance across the pavement. A nav chart or approach plate that gets loose today will be history. Let’s be blunt. This wind could be a real pain.

And it’s only going to get worse. Strong wind this early in the day is rarely good news. Pressure is rising rapidly now as the cold front that pushed through overnight moves away to the east. Add some thermal destabilization from the early spring sun and you can expect a super-lumpy ride. Even if the morning’s weather isn’t a total surprise—after all you saw frontal passage approaching days ahead—its precise timing or intensity could be. That will mean a late round of recomputing groundspeeds and fuel burns. While you’re at it, compare the winds aloft at adjacent altitudes to see if any radical changes in speed or direction suggest wind shear. Definitely give pireps on turbulence or post-frontal snow squalls. Also scan en route METARs for telltale details such as surface wind variability and peak gusts, and research runway information such as temporary closures for post-storm cleanup.

Just stay home? Sure. But it may not be that simple. If this were just a pleasure outing, the virtues of retreat are many. But if more pressing concerns attach to this flight, a pilot can find himself squeezed against the limit of his tolerance for going, but not clearly beyond that limit. Round trips with prolonged ground time at the outbound port of call often challenge you to make a quality decision about the return trip. If your plan called for an overnight or a weekend stay, there’s an excellent chance that the weather awaiting you for your return won’t resemble what your outlook briefing advertised. Could be better or worse. But odds are it will be different. You knew that from the start.

Such is the case today. And you have opted for “go.” It’s stipulated here that this is a reasonable decision considering your aircraft and your skills. Now the question is, what can you expect to face? You already have some idea, because the wind has been flogging you since you stepped outside.

The airplane is making odd creaking noises as you approach it on the ramp: it’s the sound of rope chafing against metal tiedown rings. Today it’s easy to grade yourself or the line crew on your aircraft tiedown skills. Did your knots hold up? Rather than continue the unfastening process, consider tightening the ropes for the time being, or at least leaving them on, while you preflight.

The matter of gust locks and control locks is a bit tricky. External locks need to be removed in an orderly fashion, but once they’re off, be prompt about getting into the cockpit and finishing up your ground chores. Hold onto that yoke after removing the control lock. If the yoke is jerking from side to side, or back and forth, so are ailerons and elevators.

A peak gust, badly timed, could be upsetting. As soon as possible, taxi out of parking and position yourself into the wind before you call for any required clearances, or to request permission to taxi. Now’s when you’ll find out if you remembered to undo the tail rope or remove a wheel chock.

Taxiing today should be by the book, including a sterile-cockpit advisory to any passengers aboard. Taxiing by the book means correctly positioning the controls for taxiing upwind, downwind, and with a crosswind component.

Need a refresher on that? Generally, taxiing downwind means keeping the elevator control forward and the ailerons deflected away from the wind (wind from left of the tail, elevator control forward and ailerons deflected to the right).

Taxiing upwind with a left crosswind component calls for elevator neutral (aft in a taildragger) and ailerons deflected to the left. Upwind or down, taxi slowly. Be light of foot and throttle—no need to show the bad form of brakes and power struggling for dominance on a lurching walk down the yellow line.

Coordinate your control-input changes so they keep up with your taxi turns. Be extra alert for gusts when the airplane is broadside to the wind, as it may be when approaching a taxiway parallel to the active runway from a taxiway perpendicular to it, and when taxiing onto the runway. You may feel the fuselage attempting to weathervane.

Check the windsock often. Line up as closely as possible into the wind for your runup, if space permits. Of course you remembered to remove all external gust locks from control surfaces before you left the ramp, but if you didn’t, the pre-takeoff checks are your chance for salvation.

Setting radios ahead to frequencies you’ll need after takeoff is always good, but especially today when it may be difficult to twist knobs in bumpy conditions. Maybe you’ve never placed a lot of value on the use of rudder trim for departure climbs. That may be about to change.

And, not to be alarmist about it, but it can’t be a bad idea to ponder how you’d handle a return to the airport soon after takeoff. Of course you remembered to lock the baggage compartments and cabin doors, and of course the engine isn’t going to quit. Do me a favor and have a return plan anyway.

My guess is that you gave the upcoming takeoff a lot of thought. Aside from ordering coffee at the drive-through, I’ll bet the takeoff is what you were thinking about most of the way to the airport. What’s the technique of choice?

Regardless of the kind of airplane you fly, basic considerations apply. I’ve put you in the position of preparing to take off into a fresh breeze that is mostly headwind, partly crosswind, and capriciously variable. So your goal is to become airborne with maximum control effectiveness, requiring that you hold the airplane on the ground until you have achieved a few extras knots of airspeed (also allowing for a gust factor).

A true, straight ground run, gradually easing crosswind-control input as the ailerons gain effect, will reward you, allowing you to focus on timing the liftoff. Aggressive rudder will keep you from excursions. Aggressive refers to timing, not foot pressure. I recall how the owner of the FBO where I earned my private pilot certificate two-plus decades ago in Nashua, New Hampshire, described the process: “I hold it on the ground and then I snap it off,” he said, describing a takeoff in a twin-engine Beechcraft Baron. Today’s a good day to snap it off.

You snapped it off, you are airborne, and it’s choppy. First thing, keep up that airspeed but get some air between yourself and the pavement. Next task, find the crab angle that keeps the centerline directly below. The airplane will do most of the work here by weathervaning into the wind as soon as you break ground. Stay relaxed and avoid overcontrolling as you fine-tune the drift-correction angle. Do just enough work to keep the wings more or less level and the pitch attitude constant. Make a pitch trim adjustment at the first good opportunity, but let tweaking come later.

Even in these rock-and-roll conditions it remains true that tiny taps of rudder work best to keep the nose on your chosen heading. The key to the whole thing is patience. To passengers it looks like you’re just sitting there on the way up.

And how high is up today? If your weather briefing revealed any solid information about smooth air aloft, that’s where you’ll be heading. If the airflow aloft is stiff but smooth and the turbulence is only associated with surface effects, you’ll have it made as soon as you’re above about 1,000 feet agl. If there are passengers aboard it would have been part of your preflight to brief them on what to expect, both the bad news about bumps and the good news about getting out of them.

No back-seat passengers? The rear bench makes a good place for baggage if your weight and balance checks allow. Having the center of gravity forward of where it might have been with your stuff in the baggage compartment could be an advantage for stability in severe turbulence. Run the rear seatbelts through suitcase handles or duffel-bag straps for security. Avoiding load shifts is important to maintain stability.

Understand that if you are heading from high pressure toward low, the winds you depart into may not be as strong as those you’ll face when it’s time to land. Check your altimeter setting against all available stations en route. Even over flatlands, apply the mountain-flying concept of maintaining extra altitude over irregular terrain. That can avoid those sudden jolts of terrain-induced turbulence that make passengers ill or scared.

Keep a sharp ear out for ride reports, or call up and request them. Learn what an altocumulus standing lenticular cloud (ACSL) looks like. Think about landing soon if you spot one along your route or hear about one in a pirep. Why? ACSLs are associated with mountain-wave conditions that can extend hundreds of miles downrange from the mountains. In any case ACSLs are a warning sign for the worst kinds of turbulence.

Chances are your flight will be a smooth cruise with a few minutes of fun on takeoff and a nice display of airmanship when you land. If nobody notices how much work went into your making it look so simple, don’t be disappointed. Be proud.

Dan Namowitz is an aviation writer and flight instructor. A pilot since 1985, he lives in Maine.