A go around is terminology generally used during VFR flightgenerally used during VFR flight. If a pilot is approaching the runway to land and decides that conditions are not conducive to a safe landing, he can opt to “go around”. This can be for a wide variety of reasons including the pilot or aircraft being unprepared for the landing, the descent to landing being performed poorly, or even animals/FOD on the runway.
In a go around, the pilot will first apply power, then “clean up” by retracting flaps/gear as necessary to reduce drag (down to 20 degrees in a C172). Once a positive rate of climb has been established, the pilot will remove the remaining flaps and radio that he is going around. Generally the pilot will re-enter the traffic pattern and attempt to land again.
A missed approach is terminology used exclusively with instrument approachesused exclusively with instrument approaches. Instrument approaches always have a missed approach procedure in case the pilot is unable to complete the approach. This most often happens when cloud cover and visibility are poorer than allowed by the approach. If a pilot fliesdescends to a certain altitude and is unable to see the landing environment or at least the airport lights, he will “clean up” similarly to the go around procedure discussed above, tell ATC that they have “gone missed” and then follow the steps outlined on the instrument approach plate. These steps generally involve the aircraft climbing to a safe altitude and entering a hold. At this point the pilot can choose what their next course of action is.
Missed approaches can also be used if the pilot decides that he isn’t well prepared for the approach, and the missed approach procedure must be initiated if the pilot doesn’t stick to the approach closely enough.