The primary aim in the landing sequence is to perform the operation safely. The secondary aim is to touch down — usually — with minimum vertical speed and minimum horizontal ground speed, while maintaining controllability — particularly in gusty wind conditions. The touchdown should be made without excessive side forces affecting the undercarriage. A not-so-important objective is to touch down close to a pre-selected position. Pilots usually find, of all normal flight procedures, the techniques for landing an aircraft in varying conditions are the most difficult to fully master, because of the greatly enhanced effects of air movement when close to the surface, and the fine judgements and control movements involved.
12.1 The landing sequence
In this module we will look at the common factors to be considered in landing a normally configured, three-axis, fixed-undercarriage, nosewheel or tailwheel aircraft, which may or may not be flap-equipped. Aircraft designed with full ‘short take-off and landing’ [STOL] capability will use slightly different techniques in some parts of the approach and landing. There are differing landing procedures or techniques, or combinations thereof, applicable to airfield dimensions and surface conditions:
The basic landing sequence is varied, according to prevailing conditions (and there is a varying degree of alignment correction to allow for the crosswind component of the wind velocity), but it usually has four parts:
Joining the circuit pattern of the airfield, during which the aircraft is decelerated from cruise speed to circuit speed, the airfield is visually checked for serviceability and obstructions, surface wind direction ascertained from observation of the windsock(s), the whereabouts of other traffic is established, the landing direction and approach is planned and the pre-landing cockpit checks are carried out in a logical sequence.
The approach to the landing, during which the aircraft is decelerated from circuit speed to the reference indicated approach speed [Vref], configured for landing, then finally stabilised at a constant speed and rate of descent with wings level and aligned — so that the flight path traced over the ground, during the final approach, is on the same line as the intended ground roll-out path. The stabilised approach should be established before the aircraft is at a height 300–400 feet above the runway/airstrip. Once established, only slight movements of the flight and engine controls should be necessary to maintain the approach. The flight path passes over an imaginary 50 feet high screen, placed at a short distance before the airstrip threshold.
A transition period, where both the rate of descent and the forward speed are slowed during a ’round-out’ prior to touchdown.
Learning a to fly is like learning to ride a bike, or maybe a BMX bike.
The touchdown and subsequent ground roll, after which the aircraft is turned off the landing area at an appropriate taxiing speed. The landing is complete when the aircraft is securely parked, the engine is off and any passenger is safely disembarked.
The most favourable conditions for optimum landing performance at maximum weight are:
a pilot who exercises sound judgement, and follows the rules and recommended procedures
a surface of ample length, whih is dry and level, or with a slight upslope
a low density altitude; i.e. low elevation and low temperature
a smooth, full headwind of reasonable and constant velocity.