The term arises from the traditional use of traffic patterns at airfields. A landing aircraft will first join the traffic pattern/circuit pattern and prepare for landing. If for some reason, the pilot decides not to land, the pilot can simply fly back up to traffic pattern altitude/circuit height, and complete another circuit. The term "go-around" is still used even for modern airliners, though they may not use traditional traffic patterns/circuit patterns for landing.
Reasons for use
Initiation of a go-around procedure may be either ordered by air traffic control or initiated by the pilot in command of the aircraft. In naval aviation, the term wave-off is used instead of go-around. When touching down on an aircraft carrier, a pilot always initiates a wave-off by applying full thrust as a fail-safe measure. If the plane's tail hook fails to catch any of the arrestor cables the aircraft can climb again. If the tailhook catches a cable, the aircraft will stop in short order regardless. Conversely, if a wave-off were not initiated and the aircraft were not arrested, it would not have enough power and/or runway to fly off the carrier safely. Many airlines and aircraft operators state a list of conditions that must be satisfied so that a safe landing can be carried out. If one or more of these conditions cannot be satisfied then a go-around should be considered in some cases and must be carried out in others. This list is usually written in the operations manual which has to be approved by the relevant aviation authority. The operator's list of conditions allows pilots to use their individual judgment outside of this scope.
Procedure
When the pilot is instructed or decides to go around, the pilot applies full power to the engine, adopts an appropriate climb attitude and airspeed, raises the landing gear when the airplane is positively climbing, retracts the flaps as necessary, follows the instructions of the control tower, and typically climbs into the traffic pattern for another circuit if required. Many modern aircraft, such as the Boeing and Airbus series, have autothrottles/autothrust systems that will set go-around thrust if they are engaged. On other aircraft, the pilot configures manually for a go-around. In a typical small aircraft, such as those found in general aviation, this might involve:
Applying go around power.
Adopting an appropriate climb attitude and airspeed.
Retracting the flaps fully when the aircraft achieves a certain safe airspeed and altitude.
Climbing to cleared altitude, or pattern altitude if at an uncontrolled airfield.
Advising ATC if go around was pilot initiated, or acknowledges ATC instructions if at a controlled airfield.
Safety
Go-arounds occur with an average rate of 1–3 per 1000 approaches. There is a large variation of go-around rates among different aircraft operators and operational environments. A go-around is not an emergency, and may be necessary for a number of reasons. Some of those include; unstable, unable to land in the touchdown zone, not in correct configuration, directed by ATC, obstacle on the runway, or aircraft controllability issues. The majority of accidents over the last 10 years have occurred during the approach, landing and go-around flight phases. In 2011 68% of accidents in commercial aviation occurred during these phases of flight. The lack of go-around decision is the leading risk factor in approach and landing accidents, and it is also the primary cause of runway excursions during landing. Yet, less than 5% of unstabilised approaches lead to a go-around. One in ten go-around reports record a potentially hazardous go-around outcome, including exceeded aircraft performance limits or fuel endurance. Go-around is a relatively rare manoeuvre for most commercial pilots. On average, a short-haul pilot may make a go-around once or twice a year, and a long-haul pilot may make one every 2 to 3 years. Going around carries risks which include:
Ineffective initiation of go-around can lead to Loss of Control.
Failure to maintain control during go-around can lead to LOC, including abnormal contact with the runway, or to Controlled Flight Into Terrain.
Failure to fly required track can lead to CFIT or Mid Air Collision.
Failure to maintain traffic separation can lead to MAC.
Wake turbulence generated may create a hazard to another aircraft that can lead to LOC.
