HOMEWORK

PHAK CHAPTER 10JEPPESEN Chapter 8 section A

GLEIM CHAPTER 55.1-5.6

ASA CHAPTER 88-21 TO 8-35

The next test will be 100% ASA

Private Pilot Ground School Class #7

Content of Lesson

Meterlogical conditions and their effect on performance.

Density altitude effect on takeoff and climb.

Use of Various performance charts.

Safe and efficient operation of aircraft

Meterological Conditions

Weather greatly effects aircraft performance.

Wind, Atmospheric Pressure, Temperature, Humidity all affect how an aircraft performs.

TermsDensity altitude; measurement of

the density of the air expressed in terms of altitude. Density altitude is pressure altitude corrected for a non standard temperature.

High density altitude; a condition in which the air is less dense

High Density Altitude

4 things contribute to a high density altitude:

1. High field elevationDensity altitude is increased by

an increase in field elevation i.e. Seattle to Denver

18,000 feet atmospheric pressure is roughly halved

High Density Altitude

2. Low pressure systemDensity altitude is increased

by a decrease in pressureLow pressure weather system

= lower pressure

High Density Altitude

3. High temperatureDensity altitude is increased

by an increase in temperatureSpreads out molecules makes

air less dense

High Density Altitude

4. High humidityDensity altitude is increased

by an increase in humidityA given volume of dry air is

more dense than the same volume of moist air

High Density Altitude

The atmosphere is 78% nitrogen 21% oxygen 1% inert gases

Water vapor varies from almost none to 5% by volume

Water vapor then displaces oxygen molecules

High vs. Low Density Altitude

Hot, humid, high elevation and low pressure = High density altitude

Cold, dry, low elevation and high pressure = Low density altitude

High Density Altitude

Airplane effected several ways:1. Wing is less effective2. Propeller is less effective3. Engine puts out less

horsepower

Performance is effected High Density Altitude:

1. Rate of climb is lower2. Time to climb is longer3. Takeoff roll is longer4. Acceleration is slower5. Higher true airspeed means

faster approach 6. Longer landing roll

So how can the pilot minimize the effects of High

density altitude?1. Leave in the morning when its

cooler2. Off load some baggage and or

passengers3. Make two trips4. Take a higher performing

aircraft

Continued

5. Lean the engine for more horsepower unless POH says not to

6. Do your calculations ahead of time and make the go, no go decision early.

Do not let the people you travel with or Boss make you compromise safety

Density Altitude

The primary reason for computing density altitude is to determine aircraft performance

Remember Density altitude is Pressure altitude corrected for nonstandard temperature

Density Altitude

It can be found 2 ways1. Use the chart2. Use the computer

Standard Atmosphere

29.92, 1013.2 millibars, 14.69 psi standard sea level

59 F or 15 C standard temp. at sea level

Computing Density Altitude

1st step: convert elevation or altitude to pressure altitude.

can be done by setting 29.92 into altimeter or by subtracting 29.92 from the current pressure then multiplying by 1000 then either adding or subtracting from the current pressure value

Computing Density Altitude

E.G. Field elevation 1185 pressure 30.55

29.92- 30.55 - .63 x 1000 = -630’1185 + -630 = 555’ Pressure

Altitude

Computing Density Altitude

So the airplane thinks its flying at 555 feet because of the extra pressure

555 is closer to sea level than 1185

Computing Density Altitude

E.G. Field elevation 1185 pressure 29.62

29.92-29.62 .30 x 1000 = 300 1185 +

300 = 1485

Computing Density Altitude

So the airplane thinks its flying at 1485 feet because of the decrease in atmospheric pressure

2nd step: Take the pressure altitude and the temperature at your elevation or altitude and follow the lines on the density altitude chart until they intersect.

DENSITY ALTITUDE CHART

Summary of Effects of Density Altitude (P153)

Low-Density Altitude - made with Low temperature, Dry air and High Pressure

High-Density Altitude - made with high temperature, humid air, low pressure.

Performance ChartsConversion chartsWind component

chartTake-off distance

chartClimb chartTime, Fuel and

distance to Climb chart

Cruise Power Settings

Cruise SpeedsRange/Endurance

ChartsLanding Distance

Chart

Crosswind chart

B-19 CROSSWIND

DENSITY ALTITUDE CHART

Takeoff distance chart

Cruise Performance Chart

Landing Distance Chart

Landing Distance

Vy & Vx

Vy=best rate of climb (most altitude over any unit of time)

Vx=best angle of clime (most altitude over a given distance)

B-19 Vy=72 knotsVx=65 knots

Maximum Range & Endurance

Maximum Range=gives longest distance for a given amount of fuel.

Maximum Endurance=gives you most time for a given amount of fuel.

PERFORMANCE #2

B-19 CHARTSAirspeed CalibrationAltimeter CorrectionCrosswindTakeoff DistanceClimb chartsCruise Landing distance charts

BRING A CALCULATOR, B-19 MANUAL AND SECTIONAL CHART NEXT CLASS PLEASE

AIRSPEED CALIBRATION

ALTIMETER CORRECTION

CROSSWIND CHART B-19

Sample X-Wind problemsRunway 18, Wind

210@25ktsWhat is the

headwind & crosswind components?

Runway 22, wind 260@32 knots

What is the headwind and crosswind components?

Sample X-Wind problemsRunway 18, Wind

210@25ktsWhat is the

headwind & crosswind components?

Runway 22, wind 260@32 knots

What is the headwind and crosswind components?

H.W. = 21.65 knotsC.W. = 12.5 knots

H.W. = 5.56 knotsC.W. = 31.51 knots

Takeoff Distance B19

Takeoff Distance B19GivenWind 0 knots, Temp. 7 degrees C, Pressure Altitude 2000 ftWhat is the Takeoff distance?

Takeoff Distance B191 degree = 106211 degrees = 11787 degrees = ? (you need to interpolate)

Takeoff Distance B19

1 degree = 106211 degrees = 11787 degrees = ? (you need to interpolate)

11-1=10 1178-1062=11611-7= 4 116x.4=46.44/10 or .4 1178-46.4=1131.6

Takeoff Distance B19

1 degree = 106211 degrees = 11787 degrees = ? (you need to interpolate)

11-1=10 1178-1062=1167-1= 6 116x.6=69.66/10 or .6 1062+69.6=1131.6

Takeoff Distance B19What if the Pressure Altitude was 1000 feet instead of 2000 feet

We have already solved for 2000 feet the next step would be to solve for sea level for 7 degrees C.

15-5=10 1030-930=10015-7= 8 100x.8=808/10 or .8 1030-80=950

Takeoff Distance B19 (7 Degrees)

Takeoff distance at 2000 feet Pressure altitude = 1131.6

Takeoff distance at sea level = 950

Last step is to interpolate for 1000 feet Pressure altitude

2000-0=2000 1131.6-950=181.62000-1000= 1000 181.6x.5=90.81000/2000 or .5 1131.6-90.8=1040.8

CLIMB CHARTS B19

CRUISE CHART B19

LANDING DISTANCE CHART B19