AIRCRAFT PERFORMANCE Pressure Altitude and Density Altitude
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Density Altitude
Federal Aviation Administration Density Altitude FAA–P–8740–2 • AFS–8 (2008) HQ-08561 Density Altitude Note: This document was adapted from the original Pamphlet P-8740-2 on density altitude. Introduction Although density altitude is not a common subject for “hangar flying” discussions, pilots need to understand this topic. Density altitude has a significant (and inescapable) influence on aircraft and engine performance, so every pilot needs to thoroughly understand its effects. Hot, high, and humid weather conditions can cause a routine takeoff or landing to become an accident in less time than it takes to tell about it. Density Altitude Defined Types of Altitude Pilots sometimes confuse the term “density altitude” with other definitions of altitude. To review, here are some types of altitude: • Indicated Altitude is the altitude shown on the altimeter. • True Altitude is height above mean sea level (MSL). • Absolute Altitude is height above ground level (AGL). • Pressure Altitude is the indicated altitude when an altimeter is set to 29.92 in Hg (1013 hPa in other parts of the world). It is primarily used in aircraft performance calculations and in high-altitude flight. • Density Altitude is formally defined as “pressure altitude corrected for nonstandard temperature variations.” Why Does Density Altitude Matter? High Density Altitude = Decreased Performance The formal definition of density altitude is certainly correct, but the important thing to understand is that density altitude is an indicator of aircraft performance. The term comes from the fact that the density of the air decreases with altitude. A “high” density altitude means that air density is reduced, which has an adverse impact on aircraft performance. -
Altimetry for Mountaineers and Hikers a Brief Summary
Altimetry for Mountaineers and Hikers A brief summary • Understanding Altimetry How changes in weather can affect your pressure altimeter. How elevation effects your pressure altimeter How air temperature effects air density and your climbing performance By: Derek Taylor . WTS Senior Instructor . BMS Assistant Instructor . Aerosciences, Lockheed Martin Astronautics . Certified Flight Instructor (MEI, CFII) Altimetry – Why is Altimetry Important? You need to understand how to use an altimeter, but also what factors can effect its accuracy. Good mountaineering /hiking practice usually requires the use of an altimeter. Topography and Contour maps are very limited without knowing what your “correct” elevation is. A map & compass provides you with information about where you are horizontally. If you know exactly where you are on a map then you can determine your elevation. But an altimeter can “directly” provide you with elevation. Since we move about in a 3-dimenisonal world, then knowing how to use an altimeter, and what its limitations are, is just as important as knowing how to use a compass. – With an Altimeter you can Perform Bearing-Elevation Intersects: The point at which a compass bearing intersects an elevation contour line. Use your compass and altimeter collectively to locate your position. Perform Feature-Elevation Intersects: The point at which a known feature, such as a creek, road, or ridge intersects your known elevation. Use your altimeter/barometer to predict weather changes. High pressure systems are generally associated with stable, dry weather. Low pressure systems are the predictors of possible rain, snow, thunder activity, and cooler temperatures. Use your altimeter to estimate elevation gain per hour, and adjust your pace accordingly. -
ASA Private Pilot Syllabus
The Complete Pilot Series The Complete Private Pilot Syllabus Pilot Private Complete The The Complete Private Pilot Syllabus Fourth Edition The Complete Private Pilot Syllabus Fourth Edition Flight and Ground Training Private Pilot Certification Course: Airplane Meets 14 CFR Part 141 and Part 61 Requirements Includes Sport Pilot Certification Course: Airplane Aviation Supplies and Academics, Inc. 7005 132nd Place SE Newcastle, WA 98059-3153 The Complete Private Pilot Syllabus Fourth Edition © 1994–2011 Aviation Supplies & Academics, Inc. All rights reserved. Published 2011 This syllabus is designed to be used with the textbook, The Complete Private Pilot, by Bob Gardner. Aviation Supplies & Academics, Inc. 7005 132nd Place SE Newcastle, Washington 98059-3153 Email: [email protected] Visit the ASA website often, as any updates due to FAA regulatory and procedural changes will be posted there: www.asa2fly.com Printed in the United States of America 2014 2013 2012 2011 9 8 7 6 5 4 3 2 1 ASA-PPT-S4 ISBN 1-56027-866-8 978-1-56027-866-5 03 ii The Complete Private Pilot Syllabus Contents Page Student Information ..............................................................................................................................................v Introduction ........................................................................................................................................................vii Private Pilot Course Hours .............................................................................................................................. -
Density Is Directly Proportional to Pressure
Density Is Directly Proportional To Pressure If all-star or Chasidic Ozzy usually ballyragging his jawbreakers parallelises mightily or whiled stingily and permissively, how bonded is Sloane? Is Bradley always doctrinal and slaggy when flattens some Lipman very infrangibly and advertently? Trial Arvy theorised institutionally. If kinetic theory is proportional to identify a uniformly standard atmospheric condition is proportional to density is directly pressure. The primary forces which affect horizontal motion despite the pressure gradient force the. How does pressure affect density of fluid engineeringcom. Principle five is directly proportional or enhance core. As a result temperature and pressure can greatly affect your volume of brown substance especially gases As with mass increasing and decreasing the playground of. The absolute temperature can density is directly proportional to pressure on field. Is directly with their energy conservation invariably lead, directly proportional to density pressure is no longer possible to bring you free access to their measurement. Gas Laws. Chem Final- Ch 5 Flashcards Quizlet. The volume of a apology is inversely proportional to its pressure and directly. And therefore volumetric flow remains constant and long as the air density is constant. The acceleration of thermodynamics is permanent contact us if an effect of the next time this happens to transfer to the pressure to aerometer measurements. At constant temperature and directly proportional to density is pressure and directly proportional to fit atoms further apart and they create a measurement unit that system or volume of methods to an example. Pressure and Density of the Atmosphere CK-12 Foundation. Charles's law V is directly proportional to T at constant P and n. -
Aircraft Performance: Atmospheric Pressure
Aircraft Performance: Atmospheric Pressure FAA Handbook of Aeronautical Knowledge Chap 10 Atmosphere • Envelope surrounds earth • Air has mass, weight, indefinite shape • Atmosphere – 78% Nitrogen – 21% Oxygen – 1% other gases (argon, helium, etc) • Most oxygen < 35,000 ft Atmospheric Pressure • Factors in: – Weather – Aerodynamic Lift – Flight Instrument • Altimeter • Vertical Speed Indicator • Airspeed Indicator • Manifold Pressure Guage Pressure • Air has mass – Affected by gravity • Air has weight Force • Under Standard Atmospheric conditions – at Sea Level weight of atmosphere = 14.7 psi • As air become less dense: – Reduces engine power (engine takes in less air) – Reduces thrust (propeller is less efficient in thin air) – Reduces Lift (thin air exerts less force on the airfoils) International Standard Atmosphere (ISA) • Standard atmosphere at Sea level: – Temperature 59 degrees F (15 degrees C) – Pressure 29.92 in Hg (1013.2 mb) • Standard Temp Lapse Rate – -3.5 degrees F (or 2 degrees C) per 1000 ft altitude gain • Upto 36,000 ft (then constant) • Standard Pressure Lapse Rate – -1 in Hg per 1000 ft altitude gain Non-standard Conditions • Correction factors must be applied • Note: aircraft performance is compared and evaluated with respect to standard conditions • Note: instruments calibrated for standard conditions Pressure Altitude • Height above Standard Datum Plane (SDP) • If the Barometric Reference Setting on the Altimeter is set to 29.92 in Hg, then the altitude is defined by the ISA standard pressure readings (see Figure 10-2, pg 10-3) Density Altitude • Used for correlating aerodynamic performance • Density altitude = pressure altitude corrected for non-standard temperature • Density Altitude is vertical distance above sea- level (in standard conditions) at which a given density is to be found • Aircraft performance increases as Density of air increases (lower density altitude) • Aircraft performance decreases as Density of air decreases (higher density altitude) Density Altitude 1. -
Problems in World-Wide Standardization of the Units of Altitude Measurement
NBSIR 77-1386 Problems in World-Wide Standardization of the Units of Altitude Measurement Judith F. Gilsinn Applied Mathematics Division National Bureau of Standards Washington, D C. 20234 February, 1978 Technical Report to: Office of Systems Engineering Management Federal Aviation Administration Washington, D.C. 20591 NBSIR 77-1386 PROBLEMS IN WORLD-WIDE STANDARDIZATION OF THE UNITS OF ALTITUDE MEASUREMENT Judith F. Gilsinn Applied Mathematics Division National Bureau of Standards Washington, D C. 20234 February, 1978 Technical Report to: Office of Systems Engineering Management Federal Aviation Administration Washington, D.C. 20591 U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary Dr. Sidney Harman, Under Secretary Jordan J. Baruch, Assistant Secretary for Science and Technology NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director ABSTRACT The U.S. committment to a voluntary conversion to metric units raises changeover problems in the fields of air traffic control and airspace manage- ment. This report begins by discussing current practice in altitude measure- ment and the rules for height maintenance now in effect worldwide. Four desirable features are given for an altitude measurement system, encompassing both the units of height measurement and the designation of cruising levels. Three alternative bases for the design of such a system are discussed and related to the desirable characteristics. Problems associated with each of the approaches are discussed and the many factors to be considered and the many interrelationships involved are examined. measurement Key Words ; Altimetry; altitude; aviation; height measurement; units; metric; standardization; vertical separation. TABLE OF CONTENTS Page 1. Introduction 1 2. Executive Summary and Conclusions 3 3. Current Height-Keeping Regulations and Practice 4 4. -
Ac 61-107A - Operations of Aircraft at Altitudes Above 25,000 Feet Msl And/Or Mach Numbers (Mmo) Greater Than .75
AC 61-107A - OPERATIONS OF AIRCRAFT AT ALTITUDES ABOVE 25,000 FEET MSL AND/OR MACH NUMBERS (MMO) GREATER THAN .75 {New-2003-09} Department of Transportation Federal Aviation Administration 1/2/03 Initiated by: AFS-820 1. PURPOSE. This advisory circular (AC) is issued to alert pilots who are transitioning from aircraft with less performance capability to complex, high-performance aircraft that are capable of operating at high altitudes and high airspeeds, of the need to be knowledgeable about the special physiological and aerodynamic considerations involved in these kinds of operations. 2. CANCELLATION. AC 61-107, Operations of Aircraft at Altitudes Above 25,000 Feet MSL and/or Mach Numbers (Mmo) Greater Than .75, dated January 23, 1991, is cancelled. 3. DEFINITIONS. a. Aspect Ratio is the relationship between the wing chord and the wingspan. A short wingspan and wide wing chord equal a low aspect ratio. b. Aileron buzz is a very rapid oscillation of an aileron, at certain critical air speeds of some aircraft, which does not usually reach large magnitudes nor become dangerous. It is often caused by shock- induced separation of the boundary layer. c. Drag Divergence is a phenomenon that occurs when an airfoil's drag increases sharply and requires substantial increases in power (thrust) to produce further increases in speed. This is not to be confused with MACH crit. The drag increase is due to the unstable formation of shock waves that transform a large amount of energy into heat and into pressure pulses that act to consume a major portion of the available propulsive energy. -
Chapter 4: Principles of Flight
Chapter 4 Principles of Flight Introduction This chapter examines the fundamental physical laws governing the forces acting on an aircraft in flight, and what effect these natural laws and forces have on the performance characteristics of aircraft. To control an aircraft, be it an airplane, helicopter, glider, or balloon, the pilot must understand the principles involved and learn to use or counteract these natural forces. Structure of the Atmosphere The atmosphere is an envelope of air that surrounds the Earth and rests upon its surface. It is as much a part of the Earth as the seas or the land, but air differs from land and water as it is a mixture of gases. It has mass, weight, and indefinite shape. The atmosphere is composed of 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases, such as argon or helium. Some of these elements are heavier than others. The heavier elements, such as oxygen, settle to the surface of the Earth, while the lighter elements are lifted up to the region of higher altitude. Most of the atmosphere’s oxygen is contained below 35,000 feet altitude. 4-1 Air is a Fluid the viscosity of air. However, since air is a fluid and has When most people hear the word “fluid,” they usually think viscosity properties, it resists flow around any object to of liquid. However, gasses, like air, are also fluids. Fluids some extent. take on the shape of their containers. Fluids generally do not resist deformation when even the smallest stress is applied, Friction or they resist it only slightly. -
Training Fact Sheet - Density Altitude
Training Fact Sheet - Density Altitude ______________________________________________________________________________________________ The Invisible Factor of Helicopter Performance. actual temperature. But let’s not worry too much about the math….simply put, increasing temperature at a particular atmospheric pressure causes the density of the air at that pressure to appear as though it resides at a higher altitude. The problem of density altitude for pilots begins with the fact that helicopters fly through an atmosphere of air that is composed of invisible gases. Only when there is an excess of particulate matter or water vapor in the air can anything actually be seen in the flight environment. It is not possible to see that air becomes thinner due to increased spacing between air molecules when an air mass is Have you ever run out of power up a mountain raised in elevation (high), when it is warmed and weren’t sure why? (hot), or when water vapor is added to it (humid). Do you always consult your performance graphs Any mix of high, hot or humid atmospheric whenever you move to a new geographical conditions creates what is called “high density operating area? altitude” situations. Density altitude can be quite dangerous, especially if the helicopter is Of the 3 factors that govern helicopter operating at, or close to, its maximum gross performance, density altitude is the most difficult weight. to perceive. Wind (speed & direction) and gross weight are very recognizable in flight operations. With elements of pressure, elevation, humidity Density altitude on the other hand takes some and temperature considered, density altitude is head work and situational awareness. -
Barometric Altitude and Density Altitude
Teodor Lucian Grigorie, Liviu Dinca, WSEAS TRANSACTIONS on CIRCUITS and SYSTEMS Jenica-Ileana Corcau, Otilia Grigorie Aircrafts’ Altitude Measurement Using Pressure Information: Barometric Altitude and Density Altitude TEODOR LUCIAN GRIGORIE Avionics Department University of Craiova 107 Decebal Street, 200440 Craiova ROMANIA [email protected] http://www.elth.ucv.ro LIVIU DINCA Avionics Department University of Craiova 107 Decebal Street, 200440 Craiova ROMANIA [email protected] http://www.elth.ucv.ro JENICA-ILEANA CORCAU Avionics Department University of Craiova 107 Decebal Street, 200440 Craiova ROMANIA [email protected] http://www.elth.ucv.ro OTILIA GRIGORIE Carol I, High School 2 Ioan Maiorescu Street, 200418 Craiova ROMANIA [email protected] Abstract: - The paper is a review of the pressure method used in the aircrafts’ altitude measurement. In a short introduction the basic methods used in aviation for altitude determination are nominated, and the importance of the barometric altitude is pointed. Further, the atmosphere stratification is presented and the general differential equation, which gives the dependence of the static pressure by the altitude, is deduced. The barometric and the hypsometric formulas for the first four atmospheric layers are developed both in the analytical and numerical forms. Also, the paper presents a method to determinate the density altitude with an electronic flight instrument system. A brief review of the flight altitudes is performed, and the calculus relations of the density altitude are developed. The first two atmospheric layers (0÷11 Km and 11÷20 Km) are considered. For different indicated barometric altitudes an evaluation of the density altitude, as a function of non-standards temperature variations and of dew point value, is realized. -
ASA Private Pilot Syllabus
The Pilot’s Manual Private Pilot Syllabus Seventh Edition A Flight & Ground Training Course for Private Pilot Airplane Certification based on The Pilot’s Manual Ground School Meets Part 61 and 141 Requirements by Jackie Spanitz Includes an Appendix providing Aviation Training Device (ATD) integration with your existing instructional methods Aviation Supplies & Academics, Inc. Newcastle, Washington The Pilot’s Manual: Private Pilot Syllabus Seventh Edition ©1995–2017 Aviation Supplies & Academics, Inc. All rights reserved. Seventh Edition published 2016. Aviation Supplies & Academics, Inc. 7005 132nd Place SE Newcastle, Washington 98059-3153 (425) 235-1500 Internet: www.asa2fly.com Email: [email protected] Visit the ASA website often, as any updates due to FAA regulatory and procedural changes will be posted there: www.asa2fly.com ASA-PM-S-P7-PD ii The Pilot’s Manual Series Private Pilot Syllabus Contents About this Syllabus ...................................................................................................................... v Compliance Tables ..................................................................................................................... vii Enrollment/Graduation Certificates ............................................................................................ ix Stage 1 Introduction to Flying ................................................................................................. 1 Module 1 ..................................................................................................................................... -
Understanding the Altimeter
Understanding the altimeter What you see isn't always what you have by Jack Willams Flying is an adventure for most pilots--sometimes more adventure than they really want. A pilot's report to Canada's Aviation Safety Reporting Program about an attempt to land through low clouds on a remote, icy runway is an example. The airplane's altimeter indicated that the airplane was still 300 feet above the ground when "the nosewheel struck the ice," the report says. The pilot immediately applied full power, climbed away from the ground, and returned safely to the departure airport. What happened? The air pressure was lower at the destination airport than at the departure airport, but the pilot had not reset the altimeter because the airport didn't have radio weather data, which includes information on altimeter settings. A student pilot could get by without learning much about the aircraft's altimeter because landings during training are made when the lowest clouds are well above the runway. An altimeter reading that's 300 feet too high could go unnoticed with no consequences. This doesn't mean the correct altimeter setting isn't important until a pilot begins flying in poor visibility. For one reason, air traffic controllers expect all aircraft to fly at assigned altitudes. A would-be pilot should begin to learn how altimeters work and how to properly use them soon after training begins. In aviation, altitude refers to how high an aircraft is above mean sea level; that is, how high the aircraft is above the average level of the Earth's oceans.