Hard landing
Encyclopedia
In aviation a hard landing is an especially rapid or steep descent
.
Landing
is the final phase in flight
where the vehicle
returns to the ground
. A hard landing occurs when the vehicle impacts the ground with a greater vertical speed and force than in a normal landing. The average vertical speed in a landing is around 2 metres per second. Anything above is classed as 'hard'. Hard landings can be caused by weather
conditions, mechanical problems, over-weight aircraft, pilot
decision and/or pilot error
. The term hard landing usually implies that the pilot still has total or partial control over the vehicle, as opposed to an uncontrolled descent into terrain (a crash
) which usually results in the destruction of the vehicle. Hard landings can vary in seriousness from simply causing mild passenger discomfort to situations resulting in serious vehicle damage, structural failure
, and loss of life. When an aircraft has experienced a hard landing it has to be checked for damage before its next flight.
The term hard landing can also be applied to helicopter landings after mechanical failure and/or damage caused by hostile fire. A helicopter
can often return to the ground after engine failure more safely than a fixed-wing aircraft
provided that the rotor(s) are still intact and free to turn. Unpowered helicopter rotors exhibit autorotation
in which airflow over the rotors keeps them turning and provides buoyancy
and limited pilot control during descent. As an unpowered descent, it requires considerable pilot skill and experience to safely execute. Autorotations can also be impeded by obstructions on the ground.
Descent (aircraft)
A descent during air travel is any portion where an aircraft decreases altitude, and is the opposite of an ascent or climb. Descents are an essential component of an approach to landing...
.
Landing
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
is the final phase in flight
Flight
Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....
where the vehicle
Vehicle
A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....
returns to the ground
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
. A hard landing occurs when the vehicle impacts the ground with a greater vertical speed and force than in a normal landing. The average vertical speed in a landing is around 2 metres per second. Anything above is classed as 'hard'. Hard landings can be caused by weather
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
conditions, mechanical problems, over-weight aircraft, pilot
Aviator
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...
decision and/or pilot error
Pilot error
Pilot error is a term used to describe the cause of an accident involving an airworthy aircraft where the pilot is considered to be principally or partially responsible...
. The term hard landing usually implies that the pilot still has total or partial control over the vehicle, as opposed to an uncontrolled descent into terrain (a crash
Aviation accidents and incidents
An aviation accident is defined in the Convention on International Civil Aviation Annex 13 as an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, in which a...
) which usually results in the destruction of the vehicle. Hard landings can vary in seriousness from simply causing mild passenger discomfort to situations resulting in serious vehicle damage, structural failure
Structural failure
Structural failure refers to loss of the load-carrying capacity of a component or member within a structure or of the structure itself. Structural failure is initiated when the material is stressed to its strength limit, thus causing fracture or excessive deformations...
, and loss of life. When an aircraft has experienced a hard landing it has to be checked for damage before its next flight.
The term hard landing can also be applied to helicopter landings after mechanical failure and/or damage caused by hostile fire. A helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
can often return to the ground after engine failure more safely than a fixed-wing aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
provided that the rotor(s) are still intact and free to turn. Unpowered helicopter rotors exhibit autorotation
Autorotation
In aviation, autorotation refers to processes in both fixed-wing and rotary-wing aircraft. The term means significantly different things in each context....
in which airflow over the rotors keeps them turning and provides buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...
and limited pilot control during descent. As an unpowered descent, it requires considerable pilot skill and experience to safely execute. Autorotations can also be impeded by obstructions on the ground.