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Pilot's Handbook of Aeronautical Knowledge



Table of Contents

Chapter 1, Introduction To Flying
Chapter 2, Aircraft Structure
Chapter 3, Principles of Flight
Chapter 4, Aerodynamics of Flight
Chapter 5, Flight Controls
Chapter 6, Aircraft Systems
Chapter 7, Flight Instruments
Chapter 8, Flight Manuals and Other Documents
Chapter 9, Weight and Balance
Chapter 10, Aircraft Performance
Chapter 11, Weather Theory
Chapter 12, Aviation Weather Services
Chapter 13, Airport Operation
Chapter 14, Airspace
Chapter 15, Navigation
Chapter 16, Aeromedical Factors
Chapter 17, Aeronautical Decision Making




HAT. See height above touchdown elevation.

Hazardous attitudes. Five aeronautical decision-making
attitudes that may contribute to poor pilot judgment: antiauthority,
impulsivity, invulnerability, machismo, and

Hazardous Inflight Weather Advisory Service (HIWAS).
Service providing recorded weather forecasts broadcast to
airborne pilots over selected VORs.

Head-up display (HUD). A special type of flight viewing
screen that allows the pilot to watch the flight instruments
and other data while looking through the windshield of the
aircraft for other traffic, the approach lights, or the runway.

Heading. The direction in which the nose of the aircraft is
pointing during flight.

Heading indicator. An instrument which senses airplane
movement and displays heading based on a 360° azimuth,
with the final zero omitted. The heading indicator, also called
a directional gyro (DG), is fundamentally a mechanical
instrument designed to facilitate the use of the magnetic
compass. The heading indicator is not affected by the forces
that make the magnetic compass difficult to interpret.

Headwork. Required to accomplish a conscious, rational
thought process when making decisions. Good decision making
involves risk identification and assessment,
information processing, and problem solving.

Height above airport (HAA). The height of the MDA above
the published airport elevation.

Height above landing (HAL). The height above a designated
helicopter landing area used for helicopter instrument
approach procedures.

Height above touchdown elevation (HAT). The DA/DH or
MDA above the highest runway elevation in the touchdown
zone (first 3,000 feet of the runway).

HF. High frequency.

Hg. Abbreviation for Mercury, from the Latin

High performance aircraft. An aircraft with an engine of
more than 200 horsepower.

Histotoxic hypoxia. The inability of cells to effectively use
oxygen. Plenty of oxygen is being transported to the cells
that need it, but they are unable to use it.

HIWAS. See Hazardous Inflight Weather Advisory

Holding. A predetermined maneuver that keeps aircraft
within a specified airspace while awaiting further clearance
from ATC.

Holding pattern. A racetrack pattern, involving two turns
and two legs, used to keep an aircraft within a prescribed
airspace with respect to a geographic fix. A standard pattern
uses right turns; nonstandard patterns use left turns.

Homing. Flying the aircraft on any heading required to keep
the needle pointing to the 0° relative bearing position.

Horizontal situation indicator (HSI). A flight navigation
instrument that combines the heading indicator with a CDI,
in order to provide the pilot with better situational awareness
of location with respect to the course line.

Horsepower. The term, originated by inventor James Watt,
means the amount of work a horse could do in one second.
One horsepower equals 550 foot-pounds per second, or
33,000 foot-pounds per minute.

Hot start. In gas turbine engines, a start which occurs with
normal engine rotation, but exhaust temperature exceeds
prescribed limits. This is usually caused by an excessively
rich mixture in the combustor. The fuel to the engine must
be terminated immediately to prevent engine damage.

HSI. See horizontal situation indicator.

HUD. See head-up display.

Human factors. A multidisciplinary field encompassing the
behavioral and social sciences, engineering, and physiology,
to consider the variables that influence individual and
crew performance for the purpose of optimizing human
performance and reducing errors.

Hung start. In gas turbine engines, a condition of normal
light off but with rpm remaining at some low value rather than
increasing to the normal idle rpm. This is often the result of
insufficient power to the engine from the starter. In the event
of a hung start, the engine should be shut down.