Getting Crossed-eyed with Crosswinds and Turbulence
The Effects of Turbulent Conditions on GA Pilots
By Steve Sparks
Source: FAA Safety Briefing March/April 2015
There’s a lot to like about the spring flying season, but gusty winds can be on the rise. Turbulence is one of Mother Nature’s most feared (and invisible) forces. While current technology has helped to provide better prediction models, pinpointing turbulence location or intensity is still far from exact.
Since you can’t always avoid it — and since Mother Nature doesn’t read (much less heed) the weather forecast — your best defense is a good offense. This starts with making sure you’re up to the challenge; so I encourage you to inaugurate your flying year by getting some crosswind flying practice with your favorite flight instructor.
No Easy Breeze
Once you’ve scrubbed the winter rust off your flying skills, it’s a good idea to review some of the best practices and procedures for dealing with winds and turbulence. If you’re heading out on a windy day, you can benefit from the common pilot practice of reporting ride conditions to air traffic control. ATC uses this information to suggest smoother altitudes and/or routes to other pilots operating in the vicinity. This helps to increase comfort and overall safety for all those involved, so make it a point to give as well as receive this information.
When it comes to giving reports, it’s a good idea to be familiar with the standard reporting terms and procedures. The Aeronautical Information Manual (AIM) identifies four levels of turbulence: light, moderate, severe, and extreme. Light turbulence is when even loose objects and materials remain at rest inside the cockpit. Moderate turbulence is when unsecured objects inside the aircraft are dislodged and pilots are strained against their seat belts, and severe turbulence is when occupants are jolted violently against their seat belts and aircraft control is momentary lost. Finally, “extreme” turbulence can lead to structural damage to the aircraft and potentially harmful effects to passengers.
The AIM also includes a duration scale indicating whether turbulence is occasional, intermittent, or continuous. When you report turbulence, include your location, altitude, and type of aircraft in order to better predict how these conditions may influence other aircraft in the area.
The “Whew” Factor
Since most crosswind landing accidents do not happen on short final, but rather, occur directly on or over the runway, it’s easy to understand why some pilots have anxiety about crosswind landings. The majority of crosswind landing accidents occur within feet of the runway centerline. Fortunately, most crosswind incidents/accidents only result in wingtip strikes, collapsed landing gears, and bruised egos.
Regardless of technique, landing in gusty conditions requires pilots to continue flying their aircraft even after touchdown. Taking a breather is out of the question just because a pilot hears their aircraft’s wheels squeak on the runway. Any momentary letdown could result in loss of control. Remember, it could happen in flash so never ever
stop flying the aircraft even when confidently on the runway. That means applying appropriate flight control inputs until the aircraft is safely parked on the ramp.
Nervous Pitfalls
When discussing turbulence, there are three different types that can make for a bad flying experience and those are pilot-induced turbulence, mechanical turbulence, and clear-air turbulence.
Pilot-induced-turbulence (P-I-T) is a strange phenomenon roaming the halls of aviation, and it can influence pilot performance regardless of experience. It is often worse than plain-old turbulence itself. Sound strange? Not to the subconscious pilot reflexes. This condition happens all too frequently in both small and large aircraft. Even airline transport pilots can be affected. In fact, some pilots create more turbulence from sloppy and erratic behavior than that caused by Mother Nature.
Pilots striving for maximum smoothness, professionalism, and passenger comfort should be aware of the “P-I-T falls.” It is easy to notice and even easier to feel, especially in the seat of the pants. Being herky-jerky with the controls is troubling behavior, but a little self-awareness goes a long ways in smoothing things out.
Mechanical turbulence is another factor pilots need to consider, especially during landings. Mechanical turbulence is generated by seemingly harmless winds blowing around man-made or natural contours causing airflow to churn from its natural path. These conditions often lead to unpredictable circumstances for unsuspecting pilots. Mechanical turbulence can interfere with a pilot’s stabilized approach without warning throwing them off kilter in relationship to the runway centerline. The unintended consequences from hangars and other poorly planned structures near runways can be upsetting. Some pilots are aware of these unique airport circumstances, however, those pilots who are not familiar with the airport should be triggered for a go-around anytime landing conditions become unstabilized.
Clear-air turbulence is one of the strongest forces in Mother Nature’s recipe book. It is often generated from rapid atmospheric changes, narrow pressure gradients, erratic jet streams, and thunderstorm development. Clear-air turbulence packs a mean punch leaving pilots feeling dazed and confused. Unfortunately, pilots cannot quickly tap-out of these conditions. Even short durations in moderate turbulence can cause significant fatigue on both pilots and their aircraft.
For unexpected encounters with clear-air turbulence, pilots should try to maintain aircraft attitude. Pilots often have to sacrifice deviation on heading and altitude in order to maintain control. From a priority perspective, maintain attitude control, slow the aircraft to minimum controllable airspeed and relay your situation to ATC. Once accomplished, it’s time to plan an exit strategy. Changing altitude or directions sometimes will do the trick. In certain cases, pilots might have to make an unplanned stop to wait out these conditions. Regardless, exiting areas of turbulence is always a welcomed relief.
Buckle Up
Since turbulence can lurk at any altitude, pilots and passengers should keep their seatbelts tightly secured and, if installed, shoulder harnesses fastened at all times. This is the surest way to prevent injury and defend against unintentionally bumping flight controls or switches in the cockpit. There have been cases where turbulence has knocked pilots unconscious from hitting their heads on cockpit structures.
Landing in gusty crosswind conditions requires skill in a multi-dimensional phase of flight. Pilots have to quickly handle a variety of forces being exerted on the aircraft. Keeping one’s cool while maintaining positive aircraft control is the name of the game.
Go Ahead and Go
Executing a timely go-around in response to a botched crosswind landing is smart. Conversely, trying to salvage a landing in these same conditions can land pilots somewhere other than on the runway. Cutting your losses early and getting out of dodge and away from the surface is the surest way to avoid disaster. Staying ahead of the aircraft and not
letting external factors control your destiny is shrewd advice. Pilots who are prepared and triggered to fly away from potential danger will greatly reduce workload and stress on themselves and their aircraft.
Prior to landing, pilots should always review what Plan B is going to be should an excessive crosswind or turbulence factor in. It’s much easier (and safer!) to execute a well-thought-out contingency plan than to make radical decisions during critical phases of flight.
As the saying goes, takeoffs are optional, but landings are mandatory. This thought particularly resonates when carrying passengers during blustery conditions. Unfortunately, a near perfect condition usually turns out to be just that; “near” perfect. It seems that crosswinds and turbulence are delighted to hang out near runways just waiting to ensnare their next victim without warning. Pilot proficiency is the best way to safeguard you and your passengers from potential harm from these relentless weather conditions.
The next time crosswinds or turbulence pays you an unexpected visit, don’t just cross your fingers and hope for the best. Instead, prepare yourself ahead of time by staying proficient with an instructor and/or having a Plan B — even if it means flying away to another airport. The taxi fare will be worth not getting crossed up with crosswinds!
Steve Sparks is an aviation safety inspector with the General Aviation and Commercial Division specializing in human factors, helicopter operations, and educational outreach initiatives. He is a certificated flight instructor on both airplanes and helicopters. |