 Washington Approach, PN 452, we have the airport in sight. PN 452, Washington Approach, cleared visual approach runway 34R, contact Washington Tower 119.0, good day. PN 452, cleared visual 34R. Washington Approach, November 26124, approaching the mall. PN 26124, Washington Approach, traffic 1 o'clock, 5 miles westbound, Boeing 757 descending through 5,000 for runway 34R. Do you have that traffic in sight? Did he say 757? Property of Washington, I have the 757 in sight. PN 124, you're 4 miles behind the Boeing 757, caution wake turbulence. Follow that traffic, cleared visual approach runway 34R, contact Washington Tower 119.0. PN 22, can you connect 34R, following traffic 34R? Roger, Washington 34R, no problem. The introduction of wide-body airplanes in the 70s was instrumental in satisfying the public's desire for traveling. In order to safely avoid the wake turbulence associated with these aircraft, separation standards were developed that established aircraft weight categories and distances. At that time, aircraft were easily categorized, wide bodies, B727, B737, DC-9 and others. As the aircraft within the categories increased in number and size, the potential for wake turbulence encounters increased as well. Today there is almost a continuum of aircraft sizes as manufacturers developed the airplane family concept of new transport and corporate aircraft. Airports of various sizes are handling increased air traffic that includes everything from heavy wide bodies to small business and recreational aircraft. Along with this increased mix of aircraft comes an increased concern about wake turbulence. Wake turbulence, being a natural byproduct of powered flight, is generated by the lift created by the aircraft wings and helicopter rotor systems. It develops when air rolls up off the wingtips, forming two counter-rotating vortices. The strength and effect of a trailing vortex is predominantly determined by the size, weight, speed and wing configuration of the aircraft producing it. The strongest and potentially most dangerous wake turbulence is produced when the aircraft is heavy and flying slowly. The vortices from larger aircraft sink initially at about 300 to 500 feet per minute to a maximum of 900 feet below the flight path of the generating aircraft. Vortex strength diminishes with time and is affected by atmospheric conditions and contact with the ground. In calm wind, as the vortices sink close to the ground, they tend to move laterally over the ground at approximately 2 to 5 knots. The vortices are strongly influenced by ambient wind. A strong enough wind will dissipate the turbulence. A light crosswind will decrease the lateral movement of the upwind vortex and increase the movement of the downwind vortex. A tailwind condition can move the vortices forward into the touchdown area. One of the most hazardous situations is a light, quartering tailwind. The location and strength of wake turbulence still remains fairly difficult to determine and usually invisible to both the pilot and controller. There are, however, some basic recommended procedures which can be used to assist pilots in avoiding the preceding aircraft's wake. Your aircraft's performance and capability should be considered when applying these procedures. When landing behind a larger aircraft on the same runway, stay at or above its flight path, noting its touchdown point and landing beyond it. In the case of parallel runways closer than 2,500 feet, landing behind a larger aircraft requires the pilots to be aware of possible wind drift towards their runway. Stay at or above the larger aircraft's flight path and note its touchdown. If you are landing behind a larger aircraft on crossing runways, cross above the larger aircraft's flight path. If the larger aircraft is departing on the same runway, note its rotation point and land well prior to that point. Here, the larger aircraft is departing on a crossing runway. Note the rotation point. If it has passed the intersection, continue your approach and land prior to the intersection. If it rotates prior to the intersection, avoid flying below the larger aircraft's flight path. Abandon the approach unless you can land well before the intersection. Be alert for any critical takeoff situation which could lead to a vortex encounter. In takeoff situations, note the departing aircraft's rotation point and rotate prior to it. Be sure to evaluate aircraft performance and determine if it is possible. If necessary, or there is any doubt, delay the takeoff. After takeoff, continue your climb above and upwind of the larger aircraft's climb path until turning clear of its way. Avoid any headings which will place you behind a preceding aircraft path. In the case of an intersection takeoff on the same runway or parallel runways, be alert to adjacent large aircraft, particularly upwind of your position. Avoid subsequent headings which will cause you to cross below a large aircraft path. In the case of an aircraft making a low missed approach or touch and go, weight turbulence may exist along the runway and in your flight path, especially if a light quartering wind exists. Leave an interval of at least two minutes before executing a takeoff after a heavy aircraft. If you are en route via far and you observe a large aircraft above on the same track, avoid the area below and behind its path by adjusting your position laterally, preferably upwind. The other key player directly involved with avoiding weight turbulence is air traffic control. Air traffic controllers are required to provide radar and weight turbulence separation or visual separation until the pilot accepts visual separation or a visual approach. The primary considerations that affect the controller's ability to control traffic safely, orderly and expeditiously are the types of approaches available, instrument flight rules or visual flight rules, mix of traffic, jet, propeller or helicopter, traffic density, weight turbulence separation and noise abatement requirements. Traffic density is the major factor in the amount of airplanes that can be safely, orderly and expeditiously landed or departed. The busiest airport schedule takeoffs and landings based on weather conditions. Visual conditions and visual separation allow air traffic control to handle more aircraft in the traffic control system. Air traffic controllers can gain more flexibility in handling aircraft still under IFR control by clearing aircraft to maintain visual separation or a visual approach. There are several factors a controller should consider before clearing an aircraft to maintain visual separation or for a visual approach when weight turbulence separation must be applied. An aircraft upwind from a larger aircraft is unlikely to encounter any weight turbulence. However, it is not always possible or practical to have a smaller aircraft follow a larger aircraft on the upwind side. Another consideration controllers need to make is the flight path of the preceding aircraft compared to the flight path of the following aircraft. A steep descent of larger aircraft could create a hazard for smaller aircraft following on a normal descent to the same runway. As you can see, at some time, the smaller aircraft would be below the flight path of the larger jet. When practical, air traffic controllers should advise the following aircraft of the leader's steep descent. Faster aircraft following slower aircraft can create a serious weight turbulence problem by easily getting too close. The separation distance provides time for the weight turbulence to dissipate as well as descend. Intersecting runways can also create a hazard when a small aircraft is cleared to land on a runway where the flight path will take it through the flight path of a larger aircraft that was landing already parting on a different runway. The best method for avoiding weight turbulence is both pilot and controller awareness. Controllers must know where weight turbulence could occur and how it will affect other following aircraft. Crosswinds, steep descents, different air speeds, and crossing runways are just some of the factors controllers should consider. Pilots also have to be aware of where potential hazards exist. Sometimes giving a caution weight turbulence advisory is not enough. The pilots need to know if the aircraft they are following is on a steeper than normal descent, is flying slower than they are, or if it is landing on another runway. If there is a potential for weight turbulence hazard, the controller needs to inform the pilot of it and allow the pilots to adjust their flight paths accordingly. Conversely, it is the pilot's responsibility to keep air traffic controllers informed of flight profiles outside of the normal operation. When it is operationally beneficial, air traffic control may authorize the pilot to conduct a visual approach to an airport or to follow another aircraft in VFR weather conditions. The pilot must have the airport or the preceding aircraft in sight before the clearance is granted. The pilot is solely responsible for avoiding weight turbulence. The task of maintaining proper visual relationship with the lead aircraft in order to remain at or above its flight path becomes greater and more complicated when aircraft of different sizes and speeds approaching from various altitudes and directions are involved. Changing from an instrument approach to a visual approach and landing, when conditions permit, is routinely accomplished. The pilot's situational awareness, up until the time of transition from IMC to VMC, is usually limited to information received from radio communications. So that's 2-10 traffic is 10-12 miles east of the mall is a 0.757 for 34R, caution possible, wake turbulence. While ATC will issue information and cautionary instructions, the pilot must be prepared to determine the traffic situation and apply proper avoidance procedures. In order for pilots to avoid weight turbulence by staying on or above the flight path of the leader aircraft, trailing pilots must make some assumptions on where the leader has flown since there is no available visual reference to indicate this. The use of visual glideslope indicators such as VASI or PAPI or instrument precision approach aids will assist in establishing and maintaining a normal approach flight path. When available to the pilot, the ILS glideslope can assist in determining the flight path of a leader aircraft. However, it is not foolproof. In fact, the leader aircraft may have flown above the glideslope for wake turbulence avoidance or other reasons. If external aids are not available and obstacles are not a factor, a descent rate of 300 feet per nautical mile traveled approximates a 3-degree flight path. The aircraft should be stabilized on a flight path as early as possible, but not later than 500 feet above the ground. One way to determine the flight path the leader aircraft has flown is to line up the leader aircraft with the anticipated or normal runway touchdown point. Visualize an extension of the line between those two points. This technique assumes the leader has flown a consistent flight path and is using a normal touchdown point. While following an aircraft, extending an imaginary line from your aircraft through the leader to the runway should end at the normal runway touchdown point. If it ends at a point down the runway, the trilling aircraft is probably below the flight path of the leader. If the line extension is prior to the touchdown point, as in an overrun, the trilling aircraft is probably above the leader flight path. When ILS approaches are being used in VMC, consideration may be made by the pilot of the trilling aircraft to fly at or above the ILS glideslope. This assumes the leader aircraft is positioned on the glideslope. However, this assumption is not always valid. Pilots should be cautious of leader aircraft intercepting the glideslope from above. A nose-high pitch attitude of the leader aircraft should not be used as an indicator of flight path because pitch attitudes vary among aircraft types and manufacturers. During crosswind conditions, pilots may consider flying offset on the upwind side of the localizer centerline as a means of avoiding the leader's weight turbulence. This assumes the leader is flying on the localizer course. Pilots may also establish longitudinal separation from a leader aircraft so as to allow time for the weight turbulence to move or dissipate. Judging in-flight distances is not always easy to do. Air traffic controllers are willing to provide separation distance information to pilots. They can also provide airspeed differential between aircraft if applicable. One technique available is for the trilling pilot to start timing the leader aircraft when it or its shadow passes a recognizable geographical reference point. Radio call points can also be used for timing references. After determining the amount of time it takes for the trilling aircraft to pass over the same point, convert that time into distance. Most heavy and large aircraft produce some smoke from tires during touchdown on landing. Pilots of trailing aircraft upon observing the smoke can estimate their own position from touchdown as well as determining a point to land beyond. Knowing the distance from the runway to an instrument final approach fix or an available landmark can be helpful in determining relative distances. There are multiple ways to increase separation distances while following an aircraft on final approach. Several factors should be considered however before implementing these techniques. Aircraft performance, in-flight visibility, coordination with ATC and other traffic in the pattern that are taking off or preparing to take off. Airspeed reduction is an obvious choice of most pilots for increasing separation. But it is usually limited to small changes because of aircraft performance or ATC restrictions. Pilots must not reduce airspeed below the aircraft's minimum safe operating speed. Be aware that recovery from an inadvertent wake turbulence encounter is more difficult at slower speeds. Performing S turns is another way to gain separation. Flying a 360 degree turn will greatly increase the distance from the leader but the impact on other aircraft may preclude its use. The decision to abort the approach or landing and go around is always an alternative for avoiding wake turbulence. Speedbird 87 heavy to traffic now 12 to 1 o'clock, 8 miles northeast, bounce in MD-8500 for 3, 4 left UC. Listening to all radio communications, not just those directed at you, can be helpful in providing information that can improve wake turbulence situational awareness. Prior to entering a visual pattern or initiating an instrument approach, radio communications between ATC and other airplanes can alert pilots on where they may fit in the landing sequence or what type aircraft they may follow. Takeoff and landing clearances for other aircraft provide pilots information that can be useful for spacing considerations as well as anticipating the location of generated wake turbulence. In other words, don't overlook any information that can aid your planning and flying an approach, takeoff, landing or go around. The number of aircraft continues to increase each year for reasons that reach from the desire for greater recreational use to responding to commercial requirements. As this number has increased, so has the necessary support or infrastructure. We have evolved from few pilots to many pilots, from few air traffic controllers to many air traffic controllers. This situation coupled with high air traffic density creates an environment that requires pilots and air traffic controllers to cooperate in order to safely and efficiently conduct flight operations. Air traffic controllers should understand that many times the pilot's situational awareness is limited to information provided by air traffic until the pilot enters visual conditions. This means initially that it may be difficult for us to visually detect whether we may be overtaking the leader aircraft or where we are relative to the leader's flight path. We as pilots can assist air traffic in several ways. One way is to understand the controllers are continually challenged in sequencing arrivals with departures, planning for different aircraft with different performance characteristics, and applying wake turbulence separation criteria. If we initiate an unusual request or make a change in our flight operations from what is normally expected by air traffic, it will probably increase an already high workload for most controllers at major airports. Timely precise and disciplined radio communications with air traffic improves the flow of vital information. Now let's review the re-enactment of the wake turbulence encounter you watched at the beginning of this video and see where increased awareness might have prevented the incident. The leader aircraft is coming in high and slow because its descent was delayed. Although not typically a problem, it contributes to the situation which arises. The citation should have been aware of the location of the 757's flight path and that the citation's current flight path would be below the flight path of the 757. The pilots lacked sufficient situational awareness of the possibilities. Putting the 757 on the left runway with the trailing citation on the right positioned the citation downwind from the 757. Light winds enabled the wake turbulence from the 757 to drift to the right. Additionally, if the controller had been aware that there was potential for reduced separation upon landing and of the 757's higher approach path, he could have worn the citation of its closure with the 757 and he could have given important information regarding the 757's flight path by advising the following aircraft that the leader aircraft was higher. For example, your traffic departed the outer marker at 3,000 feet. Wake turbulence is one of many factors that pilots and air traffic controllers must overcome to fly safely. It takes cooperation, awareness and the understanding of each other's requirements to safely avoid wake turbulence.