| Home | Privacy | Contact |

Airplane Flying Handbook
Approaches and Landings

Faulty Approaches And Landings

| First | Previous | Next | Last |

Airplane Flying Handbook


Table of Contents

Chapter 1,Introduction to Flight Training
Chapter 2,Ground Operations
Chapter 3,Basic Flight Maneuvers
Chapter 4, Slow Flight, Stalls, and Spins
Chapter 5, Takeoff and Departure Climbs
Chapter 6, Ground Reference Maneuvers
Chapter 7, Airport Traffic Patterns
Chapter 8, Approaches and Landings
Chapter 9, Performance Maneuvers
Chapter 10, Night Operations
Chapter 11,Transition to Complex Airplanes
Chapter 12, Transition to Multiengine Airplanes
Chapter 13,Transition to Tailwheel Airplanes
Chapter 14, Transition to Turbo-propeller Powered Airplanes
Chapter 15,Transition to Jet Powered Airplanes
Chapter 16,Emergency Procedures



When landing in a crosswind, there may be instances
when a wing will rise during the after-landing roll. This
may occur whether or not there is a loss of directional
control, depending on the amount of crosswind and the
degree of corrective action.

Any time an airplane is rolling on the ground in a
crosswind condition, the upwind wing is receiving a
greater force from the wind than the downwind wing.
This causes a lift differential. Also, as the upwind wing
rises, there is an increase in the angle of attack, which
increases lift on the upwind wing, rolling the airplane

When the effects of these two factors are great enough,
the upwind wing may rise even though directional
control is maintained. If no correction is applied, it is
possible that the upwind wing will rise sufficiently to
cause the downwind wing to strike the ground.
In the event a wing starts to rise during the landing roll,
the pilot should immediately apply more aileron pressure
toward the high wing and continue to maintain
direction. The sooner the aileron control is applied,
the more effective it will be. The further a wing is
allowed to rise before taking corrective action, the
more airplane surface is exposed to the force of the
crosswind. This diminishes the effectiveness of the

Hydroplaning is a condition that can exist when an
airplane is landed on a runway surface contaminated
with standing water, slush, and/or wet snow.

Hydroplaning can have serious adverse effects on
ground controllability and braking efficiency. The
three basic types of hydroplaning are dynamic
hydroplaning, reverted rubber hydroplaning, and viscous
hydroplaning. Any one of the three can render
an airplane partially or totally uncontrollable anytime
during the landing roll.

Dynamic hydroplaning is a relatively high-speed
phenomenon that occurs when there is a film of water
on the runway that is at least one-tenth inch deep. As the
speed of the airplane and the depth of the water increase,
the water layer builds up an increasing resistance to
displacement, resulting in the formation of a wedge of
water beneath the tire. At some speed, termed the
hydroplaning speed (VP), the water pressure equals the
weight of the airplane and the tire is lifted off the runway
surface. In this condition, the tires no longer contribute to
directional control and braking action is nil.

Dynamic hydroplaning is related to tire inflation
pressure. Data obtained during hydroplaning tests have
shown the minimum dynamic hydroplaning speed (VP)
of a tire to be 8.6 times the square root of the tire
pressure in pounds per square inch (PSI). For an
airplane with a main tire pressure of 24 pounds,
the calculated hydroplaning speed would be

approximately 42 knots. It is important to note that the
calculated speed referred to above is for the start of
dynamic hydroplaning. Once hydroplaning has
started, it may persist to a significantly slower speed
depending on the type being experienced.

Reverted rubber (steam) hydroplaning occurs during
heavy braking that results in a prolonged locked-wheel
skid. Only a thin film of water on the runway is
required to facilitate this type of hydroplaning.

The tire skidding generates enough heat to cause the
rubber in contact with the runway to revert to its
original uncured state. The reverted rubber acts as a
seal between the tire and the runway, and delays
water exit from the tire footprint area. The water
heats and is converted to steam which supports the
tire off the runway.

Reverted rubber hydroplaning frequently follows an
encounter with dynamic hydroplaning, during which
time the pilot may have the brakes locked in an attempt
to slow the airplane. Eventually the airplane slows
enough to where the tires make contact with the
runway surface and the airplane begins to skid. The
remedy for this type of hydroplane is for the pilot to
release the brakes and allow the wheels to spin up
and apply moderate braking. Reverted rubber
hydroplaning is insidious in that the pilot may not
know when it begins, and it can persist to very slow
groundspeeds (20 knots or less).

Viscous hydroplaning is due to the viscous properties
of water. A thin film of fluid no more than one
thousandth of an inch in depth is all that is needed. The
tire cannot penetrate the fluid and the tire rolls on top
of the film. This can occur at a much lower speed than
dynamic hydroplane, but requires a smooth or smooth
acting surface such as asphalt or a touchdown area
coated with the accumulated rubber of past landings.
Such a surface can have the same friction coefficient
as wet ice.

When confronted with the possibility of hydroplaning,
it is best to land on a grooved runway (if available).
Touchdown speed should be as slow as possible
consistent with safety. After the nosewheel is
lowered to the runway, moderate braking should be
applied. If deceleration is not detected and
hydroplaning is suspected, the nose should be raised
and aerodynamic drag utilized to decelerate to a
point where the brakes do become effective.

Proper braking technique is essential. The brakes
should be applied firmly until reaching a point just
short of a skid. At the first sign of a skid, the pilot
should release brake pressure and allow the wheels to
spin up. Directional control should be maintained as
far as possible with the rudder. Remember that in a
crosswind, if hydroplaning should occur, the
crosswind will cause the airplane to simultaneously
weathervane into the wind as well as slide downwind.