Chapter 8—Approaches and Landings

Table of Contents
Normal Approach and Landing
    Base Leg
    Final Approach
    Use of Flaps
    Estimating Height and Movement
    Roundout (Flare)
    Touchdown
    After-Landing Roll
    Stabilized Approach Concept

Intentional Slips
Go-Arounds (Rejected Landings)
    Power
    Attitude
    Configuration
    Ground Effect

Crosswind Approach and Landing
    Crosswind Final Approach
    Crosswind Roundout (Flare)
    Crosswind Touchdown
    Crosswind After-Landing Roll
    Maximum Safe Crosswind Velocities

Turbulent Air Approach and Landing
Short-Field Approach and Landing
Soft-Field Approach and Landing

Power-Off Accuracy Approaches
    90° Power-Off Approach
    180° Power-Off Approach
    360° Power-Off Approach

Emergency Approaches and Landings (Simulated)

Faulty Approaches and Landings
    Low Final Approach
    High Final Approach
    Slow Final Approach
    Use of Power
    High Roundout
    Late or Rapid Roundout
    Floating During Roundout
    Ballooning During Roundout
    Bouncing During Touchdown
    Porpoising
    Wheelbarrowing
    Hard Landing
    Touchdown in a Drift or Crab
    Ground Loop
    Wing Rising After Touchdown

Hydroplaning
    Dynamic Hydroplaning
    Reverted Rubber Hydroplaning
    Viscous Hydroplaning



PORPOISING

In a bounced landing that is improperly recovered, the airplane comes in nose first setting off a series of motions that imitate the jumps and dives of a porpoise— hence the name. [Figure 8-37] The problem is improper airplane attitude at touchdown, sometimes caused by inattention, not knowing where the ground is, mistrimming or forcing the airplane onto the runway.

Porpoising Figure 8-37. Porpoising.

Ground effect decreases elevator control effectiveness and increases the effort required to raise the nose. Not enough elevator or stabilator trim can result in a nose- low contact with the runway and a porpoise develops.

Porpoising can also be caused by improper airspeed control. Usually, if an approach is too fast, the airplane floats and the pilot tries to force it on the runway when the airplane still wants to fly. A gust of wind, a bump in the runway, or even a slight tug on the control wheel will send the airplane aloft again.

The corrective action for a porpoise is the same as for a bounce and similarly depends on its severity. When it is very slight and there is no extreme change in the airplane’s pitch attitude, a follow-up landing may be executed by applying sufficient power to cushion the subsequent touchdown, and smoothly adjusting the pitch to the proper touchdown attitude.

When a porpoise is severe, the safest procedure is to EXECUTE A GO-AROUND IMMEDIATELY. In a severe porpoise, the airplane’s pitch oscillations can become progressively worse, until the airplane strikes the runway nose first with sufficient force to collapse the nose gear. Pilot attempts to correct a severe porpoise with flight control and power inputs will most likely be untimely and out of sequence with the oscillations, and only make the situation worse. No attempt to salvage the landing should be made. Full power should be applied while simultaneously maintaining directional control, and lowering the nose to a safe climb attitude.




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Copyright 2012
PED Publication