 | This article needs additional citations for verification .(June 2009) |
In aviation, a crosswind landing is a landing maneuver in which a significant component of the prevailing wind is perpendicular to the runway center line.
| | This article needs additional citations for verification .(June 2009) |
In aviation, a crosswind landing is a landing maneuver in which a significant component of the prevailing wind is perpendicular to the runway center line.
Aircraft in flight are subject to the direction of the winds in which the aircraft is operating. For example, an aircraft in flight that is pointed directly north along its longitudinal axis will, generally, fly in that northerly direction. However, if there is a west wind, the actual track of the aircraft will be slightly to the east of north. If the aircraft were landing north on a north-south runway, it would need to compensate for this easterly drift caused by the west crosswind.
In situations where a crosswind is present, the aircraft will drift laterally as it approaches the runway. This drift poses significant safety issues because safe operation of the undercarriage requires the body and track of the aircraft to be aligned with the runway at touch down. The landing gear designs of the "pioneer era" 1909 Bleriot XI, and the much later Cold War B-52 strategic jet heavy bomber, were designed and each built with an unusual feature to counteract the problem: with the B-52, all four of its landing gear bogies could be steered, allowing the aircraft to land with the wheels facing the direction of travel even if the nose was not pointed in the same direction. The Bleriot XI had pivoting main gear legs, which passively allowed the main gear wheels to castor together about each of their vertical axes as a unit to allow small-angle crosswind landings, with bungee-cord loaded rigging members between the lower ends of the main wheel forks, to bring the wheels back to a "directly-ahead" orientation after touchdown.
If the crosswind landing is not executed safely, the aircraft may experience a wingstrike, where a wing hits the runway.
The following guidelines are advised by Boeing for a crosswind landing. These guidelines assume steady wind (no gusting). These winds are measured at 10 metres (33 ft) tower height for a runway 45 metres (148 ft) in width. Basically, there are 3 landing techniques which may be used to correct for cross winds: de-crab, crab, and sideslip.
The objective of this technique is to maintain wings level and the aircraft position near the runway centerline during approach. The nose points into the wind so that the aircraft approaches the runway slightly skewed with respect to the runway centerline (crabbing). This gives the impression of approaching the runway flying sideways, which can be disorienting for the pilot. Position is maintained by balancing the crosswind component, or more accurately the drag force arising from it, with engine thrust. Wings are maintained level throughout the approach. Just before the flare, opposite rudder (downwind rudder) is applied to eliminate the crab, with a simultaneous application of opposite aileron to maintain a wings-level attitude, so that at touch down, the body, velocity vector, and bank angle are all aligned with the runway, and the aircraft is positioned near the center.
The airplane can land using crab only (zero side slip) up to the landing crosswind guideline.
On dry runways, upon touchdown the airplane tracks towards the upwind edge of the runway while de-crabbing to align with the runway. Immediate upwind aileron is needed to ensure the wings remain level while rudder is needed to track center line. The greater the amount of crab at touchdown, the larger the lateral deviation from the point of touchdown. For this reason, touchdown in a crab only condition is not recommended when landing on a dry runway.
On very slippery runways, landing the airplane using crab only reduces drift towards the downwind side of a touchdown, and may reduce pilot workload since the airplane does not have to be de-crabbed before touchdown. However, proper rudder and upwind aileron must be applied after touchdown to ensure directional control is maintained.
The sideslip crosswind technique is to maintain the aircraft's heading aligned with the runway centerline. The initial phase of the approach is flown using the crab technique to correct for drift. The aircraft heading is adjusted using opposite rudder and ailerons into the wind to align with the runway. This places the aircraft at a constant sideslip angle, which its natural stability will tend to correct. Sufficient rudder and aileron must be applied continuously to maintain the sideslip at this value. The dihedral action of the wings has a tendency to cause the aircraft to roll, so aileron must be applied to check the bank angle.
With a slight residual bank angle, a touchdown is typically accomplished with the upwind main wheels touching down just before the downwind wheels. Excessive control must be avoided because over-banking could cause the engine nacelle or outboard wing flap to contact the runway/ground. In strong crosswind conditions, it is sometimes necessary to combine the crab technique with the sideslip technique.
A forward slip is used whenever the aircraft is too high on approach, and there needs to be a rapid reduction of altitude without a gain of airspeed in order to conduct a safe landing.
The following techniques are recommended by Airbus for a crosswind landing:
Crabbed Approach
Airplane approaches the runway with airplane's nose into the wind. During flare, the rudder is used to align the nose with the runway centerline and opposite aileron is used to create sideslip to prevent the airplane drifting away from the centerline. This is a mix of crab and sideslip and it is a recommendation from Airbus. Crab angle is removed before the touchdown in order to reduce the side loads on the landing gear of the airplane.
Sideslip Approach
Airplane approaches the runway in steady sideslip, maintains the sideslip during flare and touch down. Sideslip is maintained by lowering the wing into the wind and applying opposite rudder just enough to prevent the heading from changing. The longitudinal axis of the airplane is aligned with the runway centerline. Though, it is a sideslip but airplane actually doesn't slip in the direction of lower wing because of the crosswind pushing the airplane back on the desired track. This technique is not recommended by Airbus because the bank angle required to fly the steady sideslip is large and places the airplane close to the geometry and roll/rudder limits. Excessive bank angle close to the ground may lead to wing/engine scraping the ground.
Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or "splashdown" as well. A normal aircraft flight would include several parts of flight including taxi, takeoff, climb, cruise, descent and landing.
An airfield traffic pattern is a standard path followed by aircraft when taking off or landing while maintaining visual contact with the airfield.
Aircraft flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude.
Wake turbulence is a disturbance in the atmosphere that forms behind an aircraft as it passes through the air. It includes several components, the most significant of which are wingtip vortices and jet-wash, the rapidly moving gases expelled from a jet engine.
A slip is an aerodynamic state where an aircraft is moving somewhat sideways as well as forward relative to the oncoming airflow or relative wind. In other words, for a conventional aircraft, the nose will be pointing in the opposite direction to the bank of the wing(s). The aircraft is not in coordinated flight and therefore is flying inefficiently.
Aquaplaning or hydroplaning by the tires of a road vehicle, aircraft or other wheeled vehicle occurs when a layer of water builds between the wheels of the vehicle and the road surface, leading to a loss of traction that prevents the vehicle from responding to control inputs. If it occurs to all wheels simultaneously, the vehicle becomes, in effect, an uncontrolled sled. Aquaplaning is a different phenomenon from when water on the surface of the roadway merely acts as a lubricant. Traction is diminished on wet pavement even when aquaplaning is not occurring.
In aviation, a ground loop is a rapid rotation of a fixed-wing aircraft in the horizontal plane (yawing) while on the ground. Aerodynamic forces may cause the advancing wing to rise, which may then cause the other wingtip to touch the ground. In severe cases, the inside wing can dig in, causing the aircraft to swing violently or even cartwheel. In their early gliding experiments, the Wright Brothers referred to this action as well-digging.
Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail. The term taildragger is also used.
Dutch roll is a type of aircraft motion consisting of an out-of-phase combination of "tail-wagging" (yaw) and rocking from side to side (roll). This yaw-roll coupling is one of the basic flight dynamic modes. This motion is normally well damped in most light aircraft, though some aircraft with well-damped Dutch roll modes can experience a degradation in damping as airspeed decreases and altitude increases. Dutch roll stability can be artificially increased by the installation of a yaw damper. Wings placed well above the center of gravity, sweepback and dihedral wings tend to increase the roll restoring force, and therefore increase the Dutch roll tendencies; this is why high-winged aircraft often are slightly anhedral, and transport-category swept-wing aircraft are equipped with yaw dampers. A similar phenomenon can happen in a trailer pulled by a car.
In a straight flight, the tail of the airplane aligns the fuselage into the relative wind. However, in the beginning of a turn, when the ailerons are being applied in order to bank the airplane, the ailerons also cause an adverse yaw of the airplane. For example, if the airplane is rolling clockwise, the airplane yaws to the left. It assumes a crab-like attitude relative to the wind. This is called a slip. The air is flowing crosswise over the fuselage. In order to correct this adverse slip, the pilot must apply rudder. If the pilot applies too much rudder, the airplane will then slip to the other side. This is called a skid.
Braking action in aviation is a description of how easily an aircraft can stop after landing on a runway. Either pilots or airport management can report the braking action according to the U.S. Federal Aviation Administration.
Jackson County Airport, also known as Reynolds Field, is a county-owned, public-use airport located two nautical miles (3.7 km) west of the central business district of Jackson, in Jackson County, Michigan, United States. It is a class D airport with operating control tower. It is included in the Federal Aviation Administration (FAA) National Plan of Integrated Airport Systems for 2017–2021, in which it is categorized as a regional general aviation facility.
Ohio State University Airport is a public airport six miles (10 km) northwest of downtown Columbus, in Franklin County, Ohio, United States. It is owned and operated by Ohio State University in Columbus. It is also known as the OSU Don Scott Airport, named after Donald E. Scott, an OSU alumnus who died during his training as a pilot in the United Kingdom during World War II. The airport's main entrance is located on Case Road, and is easily accessible from OH-315 and Interstate 270.
Campbell Airport is a public-use airport located two miles (3 km) southwest of the central business district of Grayslake, a village in Lake County, Illinois, United States. It is privately owned by Kane Illinois Properties, Inc.
Continental Airlines Flight 1404 was a Continental Airlines domestic flight from Denver International Airport in Denver, Colorado, to George Bush Intercontinental Airport in Houston, Texas. On the evening of December 20, 2008, the flight crashed while taking off from Denver, resulting in two critical injuries, 36 noncritical injuries, and a hull loss of the Boeing 737-524 aircraft.
Griffing Sandusky Airport was a public airport in Erie County, Ohio, next to Sandusky Bay three miles southeast of Sandusky. The airport permanently closed on December 31, 2013 and the FAA A/FD and VFR sectional charts no longer show the airport as open or operational. Instrument approach procedures are no longer available from the FAA's website. All hangars and the entrance were demolished in April, 2016. The Sandusky Register confirmed that the city announced that a sports park will replace the airport and now has opened in spring 2017 called the Cedar Point Sports Center.
Wingstrike is contact between an aircraft's wing and the ground during takeoff or landing, most often as a complication of a crosswind landing.
The minimum control speed (VMC) of a multi-engine aircraft is a V-speed that specifies the calibrated airspeed below which directional or lateral control of the aircraft can no longer be maintained, after the failure of one or more engines. The VMC only applies if at least one engine is still operative, and will depend on the stage of flight. Indeed, multiple VMCs have to be calculated for landing, air travel, and ground travel, and there are more still for aircraft with four or more engines. These are all included in the aircraft flight manual of all multi-engine aircraft. When design engineers are sizing an airplane's vertical tail and flight control surfaces, they have to take into account the effect this will have on the airplane's minimum control speeds.
A power-off accuracy approach, also known as a glide approach, is an aviation exercise used to simulate a landing with an engine failure. The purpose of this training technique is to better develop one's ability to estimate distance and glide ratios. The variation in each angle refers to the degrees an aircraft must turn to be aligned with the runway. Consideration of the wind and use of flaps are important factors in executing power-off accuracy approaches.
Riverview Airport is a privately owned, public use airport located three miles (4.8 km) northwest of Jenison, Michigan. The airport sits on 60 acres (24 ha) of land at an elevation of 603 feet (184 m).
