property of lear siegler. physics of the atmosphere

Property of Lear Siegler

PHYSICS OF THE ATMOSPHERE


TERMINAL LEARNING OBJECTIVE

At the completion of this lesson, the student will:

ACTION: Demonstrate an understanding of theatmosphere’s physical properties and their impacton the operation of the TH-67 pressure instruments.

CONDITION: In a classroom environment giveninformation on the pressure instruments and the atmosphere.

STANDARD: Answer questions pertaining to theatmosphere’s physical properties and their impact on the operation of the TH-67 pressure instruments. Receive a “GO” by correctly answering the required number of questions on criterion referenced examination 011-0050.

A: Enabling Learning Objective

Action: Identify the characteristics of the standard atmosphere

Condition: Given information about the standard atmosphere

Standard: IAW FM 3-04.240 and FAA-H-8083-25A,Pilot’s Handbook of Aeronautical Knowledge.


The “Standard Atmosphere”

“A hypothetical vertical distribution of atmospheric temperature, pressure, and density which by

international or national agreement is taken to be representative of the atmosphere for the purpose

of altimeter calibrations, aircraft design, performance calculations, etc.”


29.9

2”


53,000

18,000Sea Level 50%

90%

Sea Level

MSL 29.92”Hg

1000’ 28.92”Hg

2000’ 27.92”Hg

3000’ 26.92”Hg

4000’ 25.92”Hg

5000’ 24.92”Hg

Standard Pressure Lapse Rate

1” Hg per 1000’


7500’ 22.42”Hg

MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

Standard Temp Lapse Rate

2°C per 1000’


7500’ 0°C

29.92”Hg 15°C

AIR DENSITY

29.92”Hg 15°C29.92”Hg 15°C 28.92”Hg 15°C29.92”Hg 23°C


AIR DENSITY

Press

Hum

Temp

Good Bad

H

L

L

L

H

H

Property of Lear SieglerProperty of Lear Siegler

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B: Enabling Learning Objective

Action: Identify the pressures used in the pitot static system

Condition: Given information about the pitot static system pressures

Standard: IAW FM 3-04.240


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Weight of a column of airStatic Pressure --

Impact Pressure -- Static + Dynamic


Dynamic Pressure – Additional pressure caused by air in motion

Stagnation point


Static pressure only

Impact pressure = Static + Dynamic


Note: Impact = Ram = Total = Pitot Pressure

LEFT

PITOT TUBE

RIGHT

STATIC VENTS


HEATER

Construction of the Pitot System


Notice that the Pitot Tube goesonly to airspeed indicator!

The Static Pressure is ventedto all three instruments.


The diaphragm in the Airspeed Indicatoris connected to the Pitot Tube. It

only senses Pitot Pressure. The caseis vented to Static Pressure.


The diaphragm in the Vertical Speed Indicator is vented to Static Pressure.The case is vented to Static Pressure

through a calibrated leak.


The aneroids in the Altimeter are sealed. The case is vented to Static Pressure.


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C: Enabling Learning Objective Action: Identify the operational characteristics of the airspeed indicator

Condition: Given information about the airspeed indicator



AIRSPEED INDICATOR


LEFT

PITOT TUBE

RIGHT

STATIC VENTS


STATIC VENTPITOT TUBE


Impact pressure = Static + Dynamic



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?? ?

?

?

D: Enabling Learning Objective Action: Identify the uses of the airspeed indicator

Condition: Given information on the uses of the airspeed indicator



Uses for the airspeed indicator


1: Keep aircraft within “Never Exceed Speed"

2: Determine best operational speed for best climb, best endurance, and best range

3: Determine rate of movement for navigation

4: Aircraft attitude

Airspeed fast-Pitch attitude low

Airspeed low-Pitch attitude high


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E: Enabling Learning Objective

Action: Identify the errors associated with the airspeed indicator

Condition: Given information about airspeed indicator errors



ERRORS

Instrument Error – Minor, caused by friction


Installation Error – Caused by misalignment of the pitot tube and/or the static vents with the relative wind

Density Error – Caused by changes in air density


TRUE AIRSPEED (TAS) IS THE SAME,AIR IS LESS DENSE AT ALTITUDE,

THEREFORE, CALIBRATEDAIRSPEED (CAS) IS LESS THAN TAS.


CAS IS THE SAME, AIR ISLESS DENSE AT ALTITUDE, THEREFORE,

TAS IS MORE THAN CAS AT ANYALTITUDE ABOVE

ZERO FEET DENSITY ALTITUDE.


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F: Enabling Learning Objective

Action: Identify the types of airspeed

Condition: Given information about types of airspeed



Types of Airspeed

TAS – True Airspeed - Calibrated Airspeed corrected for density error

CAS – Calibrated Airspeed – Indicated Airspeed corrected for installation error


IAS – Indicated Airspeed – read from the airspeed indicator

Airspeed Indicator in Review…


Can you identify the pressures used, the errors and the types of airspeed?


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G: Enabling Learning Objective

Action: Identify the operational characteristics of the vertical speed indicator

Condition: Given information about the operation of the vertical speed indicator



Vertical Speed Indicator


LEFT

PITOT TUBE

RIGHT

STATIC VENTS


PITOT TUBE

STATIC VENTS



CalibratedCalibratedLeakLeak


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H: Enabling Learning Objective

Action: Identify the uses of the vertical speed indicator

Condition: Given information about the uses of the vertical speed indicator



Uses of the vertical speed indicator


1: Determine rate of climb or descent

2: Trend instrument-shows attitude changes immediately when in level flight

Vertical Speed IndicatorPreflight Check



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I: Enabling Learning Objective

Action: Identify the errors associated with use of the vertical speed indicator

Condition: Given information about vertical speed indicator errors



Errors of the vertical speed indicator


1: Six to nine second lag when leveling off from a climb or descent caused by the calibrated leak


CalibratedCalibratedLeakLeak

Errors of the vertical speed indicator


1: Six to nine second lag when leveling off from a climb or descent caused by the calibrated leak

2: Erratic in rough air

Vertical Speed Indicator in Review…


Can you identify the pressures used, the errors and preflight procedures?


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J: Enabling Learning Objective

Action: Identify the operational characteristics of the altimeter

Condition: Given information about the operational characteristics of the altimeter



ALTIMETER


LEFT

PITOT TUBE

RIGHT

STATIC VENTS


PITOT TUBE

STATIC VENTS



Aneroid wafers sealed at factory

Dial – three pointers

10,000’ IndicatorTick marks in increments of 2000’

1,000’ IndicatorTick marks in increments of 200’

100’ IndicatorTick marks in increments of 20’

1,040’

8,000’

18,980’

Kollsman window – corrects for atmospheric pressure changes

28.10”Hg to 31.00”Hg

Set field elevation

ATIS – “Altimeter setting three zero two four”

AIMS Counter Drum Pointer

ATC Radar Beacon System

Identification Friend or Foe

MARK 12

SYSTEM


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K: Enabling Learning Objective

Action: Identify the uses of the altimeter

Condition: Given information about the uses of the altimeter



Uses of the altimeter


Terrain clearance

Vertical separation

Attitude control


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L: Enabling Learning Objective

Action: Identify the types of altitude

Condition: Given information about the types of altitude



Identify the types of altitude

a. Indicated

b. True

c. Absolute

d. Pressure (PA)

e. Density (DA)


Indicated Altitude

Read from instrument with correctly set Kollsman window (sea level pressure).


True Altitude – Altitude above Mean Sea level

MSL

1000’


MSL

Absolute Altitude– Altitude above the surface (AGL)


MSL

Pressure Altitude (PA) – Altitude above the standard datum plane

29.92 Standard datum plane

1000’


MSL 29.92 Standard datum plane

Standard Day

TrueAltitude

PressureAltitude=

1000’

1000’

Pressure Altitude


Max torque available, max gross weight,and performance are all

affected by Density Altitude


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Density Altitude (DA) : Is the densitycorresponding to a given altitude

in a standard atmosphere.

Density Altitude (DA) : Pressure Altitude corrected for non standard temperature


DA = PA + (120 Tv )

PA = Pressure AltitudeTv = Temperature Variation

Mean Sea Level (MSL)MSL 29.92”Hg 15°C

1000’ 28.92”Hg 13°C

2000’ 27.92”Hg 11°C

3000’ 26.92”Hg 9°C

4000’ 25.92”Hg 7°C

5000’ 24.92”Hg 5°C

7500’ 22.42”Hg 0°C


29.92”Hg 15°C 29.92”Hg 32°CMSL

2040’ PA


29.92”Hg 15°C 29.92”Hg 32°CMSL

2040’


PA = 0’

OAT = 36°DA = 2500’


MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C PA = 6000’

OAT = 5°C

OAT is Higher than standardDA is Higher than PA


MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C

PA = 4000’

OAT = 5°C

OAT is Lower than standardDA is Lower than PA


MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C

PA = 5000’

OAT = 5°C

DA = PA +120’


One hour later

OAT = 6°C


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M: Enabling Learning Objective

Action: Identify the errors associated with the use of the altimeter

Condition: Given information about altimeter errors



Altimeter errors

a. Instrument Error

b. Pressure Error

c. Temperature Error


MSL

TrueAltitude

1000’


Instrument Error

1000’

FieldElevation

Caused by friction inside instrument

MSL

TrueAltitude

1000’


Instrument Error

30.24 hg”

“Altimeter three zero two four”

30.26-30.24

= .02= 20 foot error

1000’

FieldElevation

Maximum Error + / - 70 ft


Pressure Error – caused when flying intoareas that have different altimeter settings than those set in the Kollsman window.

TRUE ALT

TRUE ALT

IND ALTIND ALT


Pressure Error

Temperature Error

MSL MSL

1000’ 1000’

Sta

ndar

d te

mp

29.92

28.92

29.92

28.92

Col

der

29.92

28.92

War

mer


TRUE ALT

TRUE ALT

IND ALTIND ALT


Pressure Error

Sta

ndar

d te

mp

28.92

28.92

War

mer

29.92 29.92 29.92

28.92

Col

der

MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C

Indicated Altitude = 6000’

OAT = 20°C

True Alt. is Higher than Indicated


MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C


OAT = 5°C

True Altitude is lower than Indicated


MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C


OAT = 5°C

Indicated Altitude = True altitude



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N: Enabling Learning Objective

Action: Identify pitot static system malfunctions

Condition: Given information about pitot static system malfunctions



STATIC VENT PITOT TUBEProperty of Lear Siegler

Pitot Static System Malfunctions

Altimeter – No change in indication

VSI – Level off at zero


Airspeed Indicator – opposite of clogged pitot tube


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The endThe end

STOPSTOP

Abandon hope all ye who enter hereAbandon hope all ye who enter here

You are entering the hidden slide ZoneYou are entering the hidden slide Zone

0C H 0 2

M N

248.2GD

TX

LEFT

PITOT TUBE

RIGHT

STATIC VENTS


HEATER

PA = 6000’

OAT = 5°C

DA is Higher than PAProperty of Lear Siegler

Is the DA higher or lower than PA

MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C

Standard temperatures

PA = 4000’

OAT = 5°C

DA is lower than PAProperty of Lear Siegler

Is the DA higher or lower than PA

MSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C


Temperature Error

MSL MSL

1000’ 1000’

Sta

ndar

d te

mp

29.92

28.92

29.92

28.92

Col

der

29.92

28.92

War

mer



OAT = 20°C

True Alt. is Higher than Indicated

Property of Lear SieglerMSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C



OAT = 5°C

True Altitude is lower than Indicated

Property of Lear SieglerMSL 15°C

1000’ 13°C

2000’ 11°C

3000’ 9°C

4000’ 7°C

5000’ 5°C

6000’ 3°C


TRUE ALT

TRUE ALT

IND ALTIND ALT


Pressure Error

property of lear siegler. physics of the atmosphere

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