predicting performance

Predicting Performance

Density Altitude

• Pressure altitude corrected for nonstandard temperature

Density Altitude

• High

• Hot

• Humid

Density Altitude

• Common methods of calculating include:

• Flight computer

• Density Altitude Chart

Density Altitude• Moisture - effects not shown on

performance charts

• High Humidity - engine horsepower reduction of 7%

• Takeoff and Climb performance 10%

Surface Winds

• Headwind or tailwind component–a 10 knot headwind might improve

performance by 10%

–a 10 knot tailwind might degrade performance by 40%

Surface Winds

• Crosswind component

• Demonstrated crosswind component

Runway Conditions• Gradient

–greater than .3% it will be listed in A/FD

• Braking Effectiveness–good, fair, poor, and nil

• Hydroplaning

Hydroplaning

• Dynamic Hydroplaning

• = X 8.6

• = 30 X 8.6 = 47 Kts

PSI

POH

• Prior to 1979 Owners Manual varied in content and format

Determine the density altitude for these conditions

Altimeter Setting……………30.35

Runway Temperature………+25oF

Airport Elevation……3,894 ft MSL

2,000 feet

The surface wind is 180° at 30 knots.

What is the crosswind component for a RWY 15 landing.

• 15 knots

The surface wind is 180° at 20 knots.

What is the headwind component for a RWY 12 landing.

• 10 Knots

Performance Charts

• Experience Test Pilots

• Factory new Airplanes

• Repeated Tests using Best Results

• Format -Table -Graphic

Takeoff Charts

• Ground Roll

• Distance to clear a 50 foot barrier

Rate of Climb

• Takeoff power

• Maximum continuous power–Temperature

–Pressure Altitude

–Airplane Weight

Rate of Climb

• Provide information on time, fuel and distance required to climb from one altitude to another

• Subtract values from starting altitude

Cruise Charts

• Range is the distance an airplane can travel with a given amount of fuel

• Endurance is the length of time the airplane can remain in the air

Cruise Charts

• Maximum range is at L/Dmax or best glide speed

• Maximum endurance is about 76% or best glide speed

• Generally close to stall speed

Descent Charts• Not found for most aircraft

• Often overlooked by pilots

• As you start flying higher and faster, you must start planning your descents farther from the intended point of landing

Glide Charts

• With GPS and the ability to have navigation data to the nearest airfield with the touch of a button, you should be able to mentally calculate if you can glide to the nearest airfield

Stall Speeds

• As angle of bank increases, stall speed increases

• As flap deflection is increased, stall speed decreases

Landing Charts

• Ground roll

• Over a 50 foot obstacle