Part 3: Chapter 13 —… | FAA Weight-Shift…

Figure 13-10. Digital panel with attitude indicator and direction indicator used on some WSC aircraft.

• Maintaining control of the aircraft.

• Obtaining the appropriate assistance in getting the

aircraft out of IMC conditions.

Recognition

A VFR pilot is in IMC conditions anytime he or she is unable

to maintain aircraft attitude control by visual reference to

the natural horizon, regardless of the circumstances or the

prevailing weather conditions. Additionally, the VFR pilot

is in IMC any time he or she is inadvertently or intentionally

and for an indeterminate period of time unable to navigate

or establish geographical position by visual reference to

landmarks on the surface. These situations must be accepted

by the pilot involved as a genuine emergency requiring

immediate action.

As discussed earlier, when entering conditions in which

visibility is decreasing or IMC, the pilot should turn around,

climb, or descend immediately and return to where ground

visibility is known. Do not continue assuming that conditions

will clear and visibility will be regained.

Maintaining Aircraft Control

Once the pilot recognizes and accepts the situation, he or she

must understand that the only way to control the aircraft safely

is by using and trusting the ﬂ ight instruments. Attempts to

control the aircraft partially by reference to ﬂ ight instruments

while searching outside the ﬂ ight deck for visual conﬁ rmation

of the information provided by those instruments results in

inadequate aircraft control. This may be followed by spatial

disorientation and complete loss of control.

The most important point to be stressed is that the pilot must

not panic. Recognize the situation and take immediate action.

The task at hand may seem overwhelming, and the situation

may be compounded by extreme apprehension. The pilot

must make a conscious effort to relax and understand that the

only concern at this point is to ﬂ y toward known visibility.

If climbing into a cloud, reduce throttle and descend. If

descending into a cloud, increase throttle and climb out of the

cloud. If visibility is suddenly lost (e.g. ﬂ ying into a cloud),

turn 180° and ﬂ y toward known visibility.

Figure 13-11. Analog magnetic compass.

The pilot should remember that a person cannot feel control

pressures with a tight grip on the controls. Relaxing and

learning to control with the eyes and the brain instead of

muscles usually takes considerable conscious effort.

The pilot must believe that the ﬂ ight instruments show the

aircraft’s pitch attitude and direction regardless of what the

natural senses tell. The vestibular sense (motion sensing by

the inner ear) can confuse the pilot. Because of inertia, the

sensory areas of the inner ear cannot detect slight changes

in aircraft attitude nor can they accurately sense attitude

changes which occur at a uniform rate over a period of time.

On the other hand, false sensations are often generated,

leading the pilot to believe the pitch attitude or direction

attitude of the aircraft has changed when, in fact, it has not.

These false sensations result in the pilot experiencing spatial

disorientation.

Attitude Control

Attitude is defined as “The position of an aircraft as

determined by the relationship of its axes and a reference,

usually the earth’s horizon.” For WSC, the pitch and the roll

are the relevant attitudes.

Most aircraft are generally, by design, inherently stable

platforms and, except in turbulent air, maintain approximately

straight-and-level ﬂ ight if properly trimmed and left alone.

They are designed to maintain a state of equilibrium in

pitch, roll, and yaw. The pilot must be aware, however, that

a change about one axis affects the other axes. The WSC

aircraft is stable in the yaw and pitch axes, but less stable in

the roll axis. The yaw and pitch axes of the WSC are easy

to control, but the roll axis is the challenge for WSC aircraft

control in IMC. The key to emergency aircraft attitude and

directional control, therefore, is to:

• Fly at the normal trim speed. To climb, increase

throttle; to descend, decrease throttle. To ﬂ y level,

ﬂ y at the throttle setting that provides level ﬂ ight.

The vertical speed indicator or altimeter provides

information regarding pitch attitude.

• Resist the tendency to overcontrol the aircraft. Fly

with ﬁ ngertip control. No attitude changes should be

made unless the ﬂ ight instruments indicate a deﬁ nite

need for a change.

• Make all attitude changes smooth and small, yet with

positive pressure.

The primary instrument for roll control is the attitude

indicator if so equipped. [Figures 13-9 and 13-10]

For aircraft not equipped with an attitude indicator, a

magnetic compass [Figure 13-11] or a GPS [Figure 13-12]

are the instruments that can be used for roll control. The

compass stays stationary and the WSC aircraft rotates around

the compass dial. A pilot is ﬂ ying wings level if the compass

heading is not changing. If the compass is changing direction,

the aircraft is banked into a turn. Similarly, the GPS provides

ground track. If ﬂ ying wings level, the GPS ground track is

steady. If the GPS ground track is changing, the aircraft is

in a bank and turning.

Turns

Turns are perhaps the most potentially dangerous maneuver

for the untrained instrument pilot for two reasons:

• The normal tendency of the pilot to overcontrol,

leading to steep banks.

• The inability of the pilot to cope with the instability

resulting from the turn.

As an example, a 180° turn would be the most likely turn to

exit a cloud and return to where there is visibility with the

surface. The direction the turn started should be noted in order

to determine the direction needed to exit the IMC conditions.

For example, if heading North when ﬂ ying into the cloud,

turn 180° and head South to exit the cloud.

Figure 13-12. Global positioning system (GPS).

Figure 13-13. Level turn.

30.029.929.8

When a turn must be made, the pilot should anticipate and

cope with the relative instability of the roll axis. The smallest

practical bank angle should be used—in any case no more

than 10° bank angle. [Figure 13-13] A shallow bank takes

very little vertical lift from the wings, resulting in little if

any deviation in altitude, and the WSC aircraft can continue

to be ﬂ own at trim speed. It may be helpful to turn 90° and

then reduce the bank and return to level ﬂ ight. This process

may relieve the progressive overbanking that often results

from prolonged turns. Repeat the process twice until heading

in the opposite direction of entry in order to exit. Once on

the proper heading to exit the IMC conditions, maintain this

heading until obtaining visual reference with the surface.

Turns with a magnetic compass or a GPS would be similar

but the only indication of bank angle is the rate at which the

compass or GPS is rotating. The rotation should be slow and

steady and not increase in speed. Any increase in compass

or GPS rotation should be slowed by decreasing the bank

back to level ﬂ ight to avoid increasing the bank. Practicing

gentle turns and observing the rotational speed of the compass

and GPS under VFR conditions will help a pilot recognize

an acceptable rotational speed ﬂ ying at trim speed should

need ever arise.

Chapter Summary

Most emergency situations can be avoided through proper

maintenance and preﬂ ight planning. The following summarizes

emergency procedures when they are warranted.

• Emergency landings require careful thought to

evaluate wind and terrain for a successful outcome.

• Emergency descents may be required because of

weather, avoiding other aircraft, or aircraft ﬁ re.

• Corrective action for system malfunction depends on

the speciﬁ c aircraft procedures.

• High winds and turbulence are less of a threat when

the WSC aircraft is a signiﬁ cant distance above the

ground. It is takeoff and especially landing where high

winds and turbulence become the biggest problem. Do

not takeoff, ﬂ y, or land when the winds and turbulence

exceed aircraft limitations or pilot capabilities.

• If the VFR pilot ﬂ ies into IMC conditions, the pilot

should return to an area of known VFR conditions.

• The BPS should be used as a last option and only if

total loss of control with no chance of recovery, pilot

incapacitation, or engine failure over hostile terrain.

100-hour inspection. An inspection required by 14 CFR

section 91.409 for FAA-certificated aircraft that are operated

for hire, or are used for flight instruction for hire. A 100-

hour inspection is similar in content to an annual inspection,

but it can be conducted by an aircraft mechanic who holds

an Airframe and Powerplant rating, but does not have an

Inspection Authorization. A list of the items that must be

included in an annual or 100-hour inspection is included in

14 CFR part 43, Appendix D.

14 CFR. See Title 14 of the Code of Federal Regulations.

14 CFR Part 1. Federal Aviation Regulation from 14 CFR,

pertaining to definitions and abbreviations of terms.

14 CFR Part 61. Federal Aviation Regulation from 14 CFR,

pertaining to the issuance of pilot and instructor certificates

and ratings.

14 CFR Part 67. Federal Aviation Regulation from 14 CFR,

pertaining to medical standards and certification for pilots.

14 CFR Part 91. Federal Aviation Regulation from 14 CFR,

pertaining to general operating and flight rules.

800-WX-BRIEF. Phone number for reaching an FAA

Automated Flight Service Station 24 hours a day almost

anywhere in the United States.

Aborted takeoff. To terminate a planned takeoff when it is

determined that some condition exists which makes takeoff

or further flight dangerous.

Above ground level (AGL). The actual height above ground

level (AGL) at which the aircraft is flying.

Acceleration. Force involved in overcoming inertia, and

which may be defined as a change in velocity per unit of

time.

Glossary

AD. See Airworthiness Directive.

ADM. See aeronautical decision-making.

Adverse yaw. A flight condition at the beginning of a turn in

which the nose of the aircraft starts to move in the direction

opposite the direction the turn is being made, caused by

the induced drag produced by the downward-deflected tip

holding back the wing as it begins to rise.

Aerodynamics. The science of the action of air on an object,

and with the motion of air on other gases. Aerodynamics

deals with the production of lift by the aircraft, the relative

wind, and the atmosphere.

Aeronautical chart. A map used in air navigation containing

all or part of the following: topographic features, hazards and

obstructions, navigation aids, navigation routes, designated

airspace, and airports. See also Sectional Chart.

Aeronautical decision-making (ADM). A systematic

approach to the mental process used by pilots to consistently

determine the best course of action in response to a given

set of circumstances.

A/FD. See airport/facility directory.

AFM. See aircraft flight manual.

AFSS. See automated flight service station.

Aircraft. A device that is used or intended to be used for

flight in the air.

Aircraft accident. An occurrence associated with the

operation of an aircraft that takes place between the time

any person boards the aircraft with the intention of flight

and all such persons have disembarked, and in which any

person suffers death or serious injury or in which the aircraft

receives substantial damage. (NTSB 830.2)

Aircraft categories. (1) As used with respect to the

certification, ratings, privileges, and limitations of airmen,

means a broad classification of aircraft. Examples include:

powered parachute, airplane, rotorcraft, glider, lighter-than-

air, and weight-shift control. (2) As used with respect to the

certification of aircraft, means a grouping of aircraft based

upon intended use or operating limitations. Examples include:

transport, normal, utility, acrobatic, limited, restricted, and

provisional.

Aircraft flight manual (AFM). Also called the Pilot’s

Operating Handbook (POH), a document developed by the

aircraft manufacturer and approved by the FAA. It is specific

to a particular make and model aircraft by a serial number,

and contains operating procedures and limitations.

Aircraft operating instructions (AOI). An alternative to

the approved term, Pilot's Operating Handbook.

Airfoil. Any surface, such as a wing or propeller, which

provides aerodynamic force when it interacts with a moving

stream of air.

Airmanship. A sound acquaintance with the principles of

flight, the ability to operate an airplane with competence and

precision both on the ground and in the air, and the exercise

of sound judgment that results in optimal operational safety

and efficiency.

Airmanship skills. The skills of coordination, timing, control

touch, and speed sense in addition to the motor skills required

to fly an aircraft.

Airport. An area of land or water that is used or intended to

be used for the landing and takeoff of aircraft, including its

buildings and facilities, if any.

Airport/facility directory (A/FD). A publication of the

Federal Aviation Administration containing information

on all airports, seaplane bases, and heliports open to the

public. The A/FD contains communication data, navigational

facilities, and certain special notices and procedures.

Airspace. The space above a certain geographical area.

Airworthiness. A state in which an aircraft or component

meets the conditions of its type design and is in a condition

for safe operation.

Airworthiness Certificate . A certificate issued by the

FAA to aircraft that have been proven to meet the minimum

standards set down by the Code of Federal Regulations.

Airworthiness Directive (AD) . A regulatory notice sent

out by the FAA to the registered owner of an aircraft

informing the owner of a condition that prevents the aircraft

from continuing to meet its conditions for airworthiness.

Compliance with AD notes must be within the required time

limit, and the fact of compliance, the date of compliance, and

the method of compliance must be recorded in the aircraft’s

maintenance records.

Altimeter. A flight instrument that indicates altitude by

sensing pressure changes.

AME. See Aviation Medical Examiner.

Ammeter. An instrument installed in series with an electrical

load used to measure the amount of current flowing through

the load.

Angle of attack (AOA). The acute angle between the chord

line of the airfoil and the direction of the relative wind.

Angle of incidence. The angle formed by the chord line

of the wing at the keel of a WSC and a line parallel to the

longitudinal axis of the WSC carriage. The angle of incidence

changes in the WSC controlled by the pilot.

Anhedral. A downward slant from root to tip of an aircraft’s

wing opposite from dihedral.

Annual inspection. A complete inspection of an aircraft and

engine, required by the Code of Federal Regulations, to be

accomplished every 12 calendar months on all certificated

aircraft. Only an A&P technician holding an Inspection

Authorization can conduct an annual inspection.

AOA. See angle of attack.

AOI. See aircraft operating instructions.

Arm. The horizontal distance in inches from the reference

datum line to the center of gravity of an item. Used in weight

and loading calculations.

AROW. Certificates and documents required to be onboard

an aircraft to determine airworthiness: Airworthiness

certificate, Registration certificate, Operating limitations,

Weight and balance data.

ASOS. See Automated Surface Observing System.

Aspect ratio. Span of a wing divided by its average chord.

Asymmetrical airfoil. An airfoil section that is not the same

on both sides of the chord line.

ATC. Air traffic control.

ATIS. See Automatic Terminal Information Service.

Attitude. The position of an aircraft as determined by the

relationship of its axes and a reference, usually the earth’s

horizon.

Attitude of pilot. A personal motivational predisposition to

respond to persons, situations, or events in a given manner

that can, nevertheless, be changed or modified through

training as sort of a mental shortcut to decision-making.

Attitude management of pilot. The ability to recognize

hazardous attitudes in oneself and the willingness to modify

them as necessary through the application of an appropriate

antidote thought.

Automated flight service station. An FAA air traffic facility

that provides pilot briefings, en route radio communications,

and VFR search-and-rescue services.

Automated Surface Observing System (ASOS). Weather

reporting system which provides surface observations every

minute via digitized voice broadcasts and printed reports.

Automated Weather Observing System (AWOS).

Automated weather reporting system consisting of various

sensors, a processor, a computer- generated voice subsystem,

and a transmitter to broadcast weather data.

Automatic Terminal Information Service (ATIS). The

continuous broadcast (by radio or telephone) of recorded

noncontrol, essential but routine information in selected

terminal areas.

Aviation Medical Examiner (AME). A medical doctor

authorized to perform aviation medical exams for aviators.

Axes of an aircraft. Three imaginary lines that pass through

an aircraft’s center of gravity. The axes can be considered

as imaginary axes around which the aircraft turns. The three

axes pass through the center of gravity at 90° angles to each

other. The axis from nose to tail is the longitudinal axis, the

axis that passes side to side along the wingspan is the lateral

axis and the axis that passes vertically through the center of

gravity is the vertical axis.

Ballistic parachute system (BPS). An optional parachute

system activated by the pilot where the parachute is extracted

for the WSC by a rocket.

Balloon. The result of a roundout (flare) that is too aggressive

during landing, causing the aircraft to climb.

Bank attitude. The angle of the lateral axis relative to the

horizon.

Base leg. A flight path at right angles to the landing runway

off its approach end. The base leg normally extends from

the downwind leg to the intersection of the extended runway

centerline.

Battens. The airfoil ribs of a WSC that are removed to fold

up the wing.

Best-angle-of-climb speed (V X). The speed at which

the aircraft produces the most gain in altitude in a given

distance.

Best glide. The airspeed at which the aircraft glides the

furthest for the least altitude lost when in non-powered

flight.

Best-rate-of-climb speed (V Y). The speed at which the

aircraft produces the most gain in altitude in a given amount

of time.

BPS. See ballistic parachute system.

Calibrated airspeed (CAS). Indicated airspeed corrected

for installation error and instrument error. Although

manufacturers attempt to keep airspeed errors to a minimum,

it is not possible to eliminate all errors throughout the

airspeed operating range. This error is generally greatest at

low airspeeds. In the cruising and higher airspeed ranges,

indicated airspeed and calibrated airspeed are approximately

the same. Refer to the airspeed calibration chart to correct

for possible airspeed errors.

Camber. The curvature of a wing when looking at a cross

section. A wing has upper camber on its top surface and lower

camber on its bottom surface.

Carburetor. (1) Pressure: A hydromechanical device

employing a closed feed system from the fuel pump to the

discharge nozzle. It meters fuel through fixed jets according

to the mass airflow through the throttle body and discharges

it under a positive pressure. Pressure carburetors are

distinctly different from float-type carburetors, as they do not

incorporate a vented float chamber or suction pickup from a

discharge nozzle located in the venturi tube. (2) Float-type:

Consists essentially of a main air passage through which the

engine draws its supply of air, a mechanism to control the

quantity of fuel discharged in relation to the flow of air, and a

Chapter 13 — Abnormal and Emergency Procedures — Part 3