Aircraft Performance

The KOCH Chart for Altitude and Temperature Effects(image)
Density Altitude Chart(image)
Center of Gravity Limits for Cessna 182(image)
Takeoff Distance Performance for Cessna 182 #1(image)
Takeoff Distance Performance for Cessna 182 #2(image)
Pressure Altitude Correction Chart
Sample Weight and Balance for Cessna 182
Procedures for Working Weight and Balance Sheet
Examples using charts to determine High Density Altitude Performance
Using KOCH Chart to determine Performance

PRESSURE ALTITUDE CORRECTION CHART [top]

ALITITUDE SETTING IN HG. ALTITUDE ADDITION FOR OBTAINING PRESSURE ALTITUDE
   
28.3 1,533
28.4 1,436
28.5 1,340
28.6 1,244
28.7 1,148
28.8 1,053
28.9 957
29.0 863
29.1 768
29.2 673
29.3 579
29.4 485
29.5 392
29.6 298
29.7 205
29.8 112
29.9 20
29.92 0
30.0 -73
30.1 -165
30.2 -257
30.3 -348
30.4 -440
30.5 -531
30.6 -622
30.7 -712
30.8 -803

 

 

Sample Weight and Balance for Cessna 182 [top]

Weight Arm Moment
Empty Weight 1772 35.72 63300
Fuel (56 gal. max) __________ 46.0 __________
6# per gallon
Pilot & Passenger __________ 37.0 __________
Rear Passengers __________ 74.0 __________
Baggage A __________ 97.0 __________
120# max
Baggage B __________ 115.0 __________
80# max
Total Weight __________ Total Moments __________

MAXIMUM TAKEOFF WEIGHT-2950#             MAXIMUM LANDING WEIGHT 2950#
2950    39.5 - 48.5                                            2400     34.4 - 48.5
2900    39.0 - 48.5                                            2300     33.4 - 48.5    Total Moment = CG
2800    38.1 - 48.5                                            2200     33.0 - 48.5    Total Weight
2700    37.2 - 48.5                                            2100     33.0 - 48.5
2600    36.2 - 48.5                                            2000     33.0 - 48.5
2500    35.4 - 48.5

PROCEDURES FOR WORKING WEIGHT AND BALANCE SHEET [top]

STEP 1- Using your aircraft's weight and balance information, determine the empty weight of the aircraft and the ARM for that weight. Multiply the weight times the ARM and you will get the Moments. If you are only given the Empty Weight and the Moment, just divide the Moment by the Weight and you will get the ARM for the empty weight.

STEP 2- Determine the number of gallons of fuel your aircraft will hold. Refer to the Sample Loading Problems or your Weight and Balance information and obtain the ARM for the fuel.

STEP 3- Determine the ARM for the pilot and front passenger seats, the rear passenger seats and baggage areas.

STEP 4- Using your aircraft's Center Of Gravity Limits chart, start at gross weight and list the CG Limits for that weight. Then proceed down on the CG Limits chart and determine the forward and aft limits for each 100# of weight. List those limits at the bottom of the weight and balance sheet you are developing.

STEP 5- To work a weight and balance problem, place the weight in each weight category. Then multiply the Weight times the ARM and record the Moments.

STEP 6- Add up the total Weight and then add up the total Moments. Your total Weight should not exceed your gross weight. If so, make adjustments so that the weight does not exceed gross weight.

STEP 7- Next, divide the Total Moments by the Total Weight. This will give you a figure that will tell you the CG location at the calculated weight of the aircraft.

STEP 8- Refer to the information you recorded on the CG Limits for each weight. If the CG falls within the limits of the forward and aft limits for that weight, then your aircraft is loaded within the proper CG Limits. If it does not fall within the CG Limits, them rearrange the weight so that it does fall within the proper limits for that weight.

This Weight and Balance Sheet is aircraft specific. Make one up for each aircraft that you fly. Then, working a weight and balance problem stops being a problem as the time required to work this form is less than 3 minutes. Therefore, there is NO EXCUSE FOR FLYING AN AIRCRAFT OVER GROSS WEIGHT AND OUT OF CG LIMITS.

BE SURE, RATHER THAN SORRY

 

EXAMPLES USING CHARTS TO DETERMINE HIGH DENSITY ALTITUDE PERFORMANCE IN SAMPLE AIRCRAFT*[top]

Using the charts provided in this section one can work sample problems to determine aircraft performance.

Example #1
South Lake Tahoe, California-
field elevation 6264 feet MSL.

Runway length- 8544 feet 8544 feet
Temperature- 85º F 30º C
Field elevation- 6264 feet 6264 feet
Altimeter setting- 29.92 30.00
Pressure Altitude- 6264 MSL 6190 MSL
Density Altitude- 9310 feet 9220 feet

Example #2
Truckee Airport, Truckee, California-
field elevation 5900 feet MSL.

Runway length-  7000 feet 7000 feet
Temperature- 90º F 33º C
Field Elevation- 5900 feet 590 feet
Altimeter setting- 29.92 30.00
Pressure Altitude- 5900 feet 5826 feet
Density Altitude- 9186 feet 9096 feet

Example #3
Gansner Field, Quincy, California-
field elevation 3415 feet MSL

Runway length- 4100 feet 4100 feet
Temperature-  94º F 33º C
Field elevation- 3415 feet 3415 feet
Altimeter setting- 29.92 30.00
Pressure Altitude- 3341 feet 3338 feet
Density Altitude- 6397 feet 6307 feet

 

Example #4
Alpine County Airport, Markleeville, CA-
field elevation 5867 feet MSL

Runway length- 4440 feet
Temperature- 90º F
Field elevation- 5867 feet
Altimeter setting-  29.92
Pressure Altitude- 5867
Density Altitude- 9146 feet

*Note: The temperatures and altimeter settings shown here represent actual temperatures and altimeter settings recorded at the above airports.

USING KOCH CHART TO DETERMINE PERFORMANCE[top]

Example #1
South Lake Tahoe Airport, Cessna 182.

Takeoff Weight- 2950#
Pressure Altitude- 6264 feet MSL
Temperature- 85º F
Sea level takeoff distance- 1490 feet
% increase in takeoff distance- 200% or 2980 feet
Total takeoff distance- 1490 + 2980 = 4370 feet
% reduction in rate of climb- 70% ( if aircraft climbs at 500 fpm at sea level then subtract 70% or 350 fpm for a climb rate of just 150 feet per minute.)

Takeoff Weight- 2400#
Pressure Altitude- 6264 feet MSL
Temperature- 85 degrees F
Sea level takeoff distance- 930 feet
% increase in takeoff distance- 200% or 1860 feet
Total takeoff distance- 930 + 1860 = 2790 feet
% reduction in rate of climb- 70% (if aircraft climbs at 700 fpm at sea level then subtract 70 % or 490 fpm for a climb rate of just 210 feet per minute.)

Example #2
Truckee Airport, Cessna 182.

Takeoff Weight 2950#
Pressure Altitude- 5900 feet MSL
Temperature- 90º F
Sea level takeoff distance- 1650 feet
% increase in takeoff distance- 200% or 3300 feet
Total takeoff distance- 1650 + 3300 = 4960 feet
% reduction in rate of climb- 74% (if aircraft climbs at 500 fpm at sea level then subtract 74% or 370 fpm for a climb rate of just 130 feet per minute.)

Takeoff Weight 2400#
Pressure Altitude- 5900 feet MSL
Temperature- 90 degrees F
Sea level takeoff distance- 950 feet
% increase in takeoff distance- 200% or 1900 feet
Total takeoff distance- 950 + 1900 = 2850 feet
% reduction in rate of climb- 74% (if aircraft climbs at 700 fpm at sea level then subtract 74% or 518 fpm for a climb rate of just 182 feet per minute.

Example #3
Gansner Airport, Quincy, CA

Takeoff Weight- 2950#
Pressure Altitude- 3341 feet MSL
Temperature- 94º F
Sea level takeoff distance- 1540 feet
% increase in takeoff distance- 100% or 1540 feet
Total takeoff distance- 1540 + 1540 = 3080 feet
% reduction in rate of climb- 56% ( if aircraft climbs at 500 fpm at sea level then subtract 56% or 280 fpm for a climb rate of just 220 feet per minute.)

Takeoff Weight- 2400#
Pressure Altitude- 3341
Temperature- 94 degrees F
Sea level takeoff distance- 960 feet
% increase in takeoff distance- 100% or 960 feet
Total takeoff distance- 960 + 960 = 1920 feet
% reduction in rate of climb- 56% ( if aircraft climbs at 700 fpm at sea level then subtract 56% or 392 fpm for a climb rate of just 308 feet per minute.)

Example #4
Alpine County Airport, Markleeville, CA

Takeoff Weight- 2950#
Pressure Altitude- 5867 feet
Temperature- 90º F
Sea level takeoff distance- 1510 feet
% increase in takeoff distance- 180% or 2718 feet
Total takeoff distance- 1510 + 2718 = 4218 feet (Note: Runway length of 4440’)
% reduction in rate of climb- 72% (if aircraft climbs at 500 fpm at sea level then subtract 72% or 360 fpm for a climb rate of just 140 fpm.)

Takeoff Weight- 2400#
Pressure Altitude- 5867 feet
Temperature- 90º F
Sea level takeoff distance- 960 feet
% increase in takeoff distance- 180% or 1728 feet
Total takeoff distance- 960 + 1728 = 2688 feet
% reduction in rate of climb- 72% (if aircraft climbs at 700 fpm at sea level then subtract 72% or 504 fpm for a climb rate of just 196 feet per minute.)