Figure 11-20. Conditions notes chart.
,
, ,
maneuvering speed does not provide structural protection
against multiple full control inputs in one axis or full control
inputs in more than one axis at the same time.
VN0—the maximum speed for normal operation or the
maximum structural cruising speed. This is the speed at
which exceeding the limit load factor may cause permanent
deformation of the aircraft structure.
VNE—the speed that should never be exceeded. If flight is
attempted above this speed, structural damage or structural
failure may result.
Performance Charts
Performance charts allow a pilot to predict the takeoff, climb,
cruise, and landing performance of an aircraft. These charts,
provided by the manufacturer, are included in the AFM/POH.
Information the manufacturer provides on these charts has
been gathered from test flights conducted in a new aircraft,
under normal operating conditions while using average
piloting skills, and with the aircraft and engine in good
working order. Engineers record the flight data and create
performance charts based on the behavior of the aircraft
during the test flights. By using these performance charts,
a pilot can determine the runway length needed to take off
and land, the amount of fuel to be used during flight, and the
time required to arrive at the destination. It is important to
remember that the data from the charts will not be accurate
if the aircraft is not in good working order or when operating
under adverse conditions. Always consider the necessity to
compensate for the performance numbers if the aircraft is not
in good working order or piloting skills are below average.
Each aircraft performs differently and, therefore, has different
performance numbers. Compute the performance of the
aircraft prior to every flight, as every flight is different. (See
appendix for examples of performance charts for a Cessna
Model 172R and Challenger 605.)
Every chart is based on certain conditions and contains
notes on how to adapt the information for flight conditions.
It is important to read every chart and understand how to
use it. Read the instructions provided by the manufacturer.
For an explanation on how to use the charts, refer to the
example provided by the manufacturer for that specific chart.
[Figure 11-20]
The information manufacturers furnish is not standardized.
Information may be contained in a table format and
other information may be contained in a graph format.
Sometimes combined graphs incorporate two or more graphs
into one chart to compensate for multiple conditions of
flight. Combined graphs allow the pilot to predict aircraft
performance for variations in density altitude, weight,
and winds all on one chart. Because of the vast amount of
information that can be extracted from this type of chart, it
is important to be very accurate in reading the chart. A small
error in the beginning can lead to a large error at the end.
The remainder of this section covers performance information
for aircraft in general and discusses what information the
charts contain and how to extract information from the charts
by direct reading and interpolation methods. Every chart
contains a wealth of information that should be used when
flight planning. Examples of the table, graph, and combined
graph formats for all aspects of flight are discussed.
Figure 11-21. Interpolating charts.
TAKEOFF DISTANCE
MAXIMUM WEIGHT 2,400 LB
Conditions
Weight
(lb)
2,400
Press
ALT
(ft)
S.L.
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
795
875
960
1,055
1,165
1,285
1,425
1,580
1,755
Total feet
to clear
50 ft OBS
1,460
1,605
1,770
1,960
2,185
2,445
2,755
3,140
3,615
860
940
1,035
1,140
1,260
1,390
1,540
1,710
1,905
Total feet
to clear
50 ft OBS
1,570
1,725
1,910
2,120
2,365
2,660
3,015
3,450
4,015
Grnd
roll
(ft)
Total feet
to clear
50 ft OBS
1,810
2,000
2,220
2,480
2,790
3,160
3,620
4,220
- - -
Grnd
roll
(ft)
Total feet
to clear
50 ft OBS
1,945
2,155
2,395
2,685
3,030
3,455
3,990
- - -
- - -
Lift
off
51
AT
50 ft
56
Takeoff
speed KIAS
0 °C 10 °C 20 °C 30 °C
925
1,015
1,115
1,230
1,355
1,500
1,665
1,850
2,060
Total feet
to clear
50 ft OBS
1,685
1,860
2,060
2,295
2,570
2,895
3,300
3,805
4,480
40 °C
Flaps 10°
Full throttle prior to brake release
Paved level runway
Zero wind
To find the takeoff distance for a pressure altitude of 2,500 feet
at 20 °C, average the ground roll for 2,000 feet and 3,000 feet.
1,115 + 1,230
2
= 1,173 feet
Grnd
roll
(ft)
Grnd
roll
(ft)
Grnd
roll
(ft)
995
1,090
1,200
1,325
1,465
1,620
1,800
2,000
- - -
1,065
1,170
1,290
1,425
1,575
1,745
1,940
- - -
- - -
Interpolation
Not all of the information on the charts is easily extracted.
Some charts require interpolation to find the information for
specific flight conditions. Interpolating information means
that by taking the known information, a pilot can compute
intermediate information. However, pilots sometimes round
off values from charts to a more conservative figure.
Using values that reflect slightly more adverse conditions
provides a reasonable estimate of performance information
and gives a slight margin of safety. The following illustration
is an example of interpolating information from a takeoff
distance chart. [Figure 11-21]
Density Altitude Charts
Use a density altitude chart to figure the density altitude at the
departing airport. Using Figure 11-22, determine the density
altitude based on the given information.
Sample Problem 1
Airport Elevation...............................................5,883 feet
OAT...........................................................................70 °F
Altimeter...........................................................30.10 "Hg
First, compute the pressure altitude conversion. Find 30.10
under the altimeter heading. Read across to the second
column. It reads “–165.” Therefore, it is necessary to subtract
165 from the airport elevation giving a pressure altitude of
5,718 feet. Next, locate the outside air temperature on the
scale along the bottom of the graph. From 70°, draw a line up
to the 5,718 feet pressure altitude line, which is about two-
thirds of the way up between the 5,000 and 6,000 foot lines.
Draw a line straight across to the far left side of the graph
and read the approximate density altitude. The approximate
density altitude in thousands of feet is 7,700 feet.
Takeoff Charts
Takeoff charts are typically provided in several forms and
allow a pilot to compute the takeoff distance of the aircraft
with no flaps or with a specific flap configuration. A pilot can
also compute distances for a no flap takeoff over a 50 foot
obstacle scenario, as well as with flaps over a 50 foot obstacle.
The takeoff distance chart provides for various aircraft
weights, altitudes, temperatures, winds, and obstacle heights.
Sample Problem 2
Pressure Altitude...............................................2,000 feet
OAT..........................................................................22 °C
Takeoff Weight.............................................2,600 pounds
Headwind...............................................................6 knots
Obstacle Height.......................................50 foot obstacle
Refer to Figure 11-23. This chart is an example of a combined
takeoff distance graph. It takes into consideration pressure
altitude, temperature, weight, wind, and obstacles all on one
chart. First, find the correct temperature on the bottom left
side of the graph. Follow the line from 22 °C straight up until
it intersects the 2,000 foot altitude line. From that point, draw
a line straight across to the first dark reference line. Continue
to draw the line from the reference point in a diagonal
direction following the surrounding lines until it intersects
the corresponding weight line. From the intersection of 2,600
pounds, draw a line straight across until it reaches the second
reference line. Once again, follow the lines in a diagonal
manner until it reaches the six knot headwind mark. Follow
Figure 11-22. Density altitude chart.
Outside air temperature
Approximate density altitude (thousand feet)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
S.L.
14,000
13,000
12,000
11,000
10,000
9,000 Pressure altitude (feet)
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
–1,000
Sea level
-18 -12° -7° -1° 4° 10° 16° 21° 27° 32° 38°
0° 10° 20° 30° 40° 50° 60° 70° 80° 90° 100°F
C
Standard temperature
28.0 1,824
28.1 1,727
28.2 1,630
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
Altimeter setting
("Hg)
Pressure altitude
conversion factor
straight across to the third reference line and from here, draw
a line in two directions. First, draw a line straight across to
figure the ground roll distance. Next, follow the diagonal lines
again until they reach the corresponding obstacle height. In
this case, it is a 50 foot obstacle. Therefore, draw the diagonal
line to the far edge of the chart. This results in a 700 foot
ground roll distance and a total distance of 1,400 feet over a
50 foot obstacle. To find the corresponding takeoff speeds
at lift-off and over the 50 foot obstacle, refer to the table on
the top of the chart. In this case, the lift-off speed at 2,600
pounds would be 63 knots and over the 50 foot obstacle
would be 68 knots.
Sample Problem 3
Pressure Altitude...............................................3,000 feet
OAT.........................................................................30 °C
Takeoff Weight............................................2,400 pounds
Headwind............................................................18 knots
Refer to Figure 11-24. This chart is an example of a takeoff
distance table for short-field takeoffs. For this table, first find
the takeoff weight. Once at 2,400 pounds, begin reading from
left to right across the table. The takeoff speed is in the second
column and, in the third column under pressure altitude, find
the pressure altitude of 3,000 feet. Carefully follow that line
to the right until it is under the correct temperature column
of 30 °C. The ground roll total reads 1,325 feet and the total
required to clear a 50 foot obstacle is 2,480 feet. At this point,
there is an 18 knot headwind. According to the notes section
under point number two, decrease the distances by ten percent
for each 9 knots of headwind. With an 18 knot headwind, it
is necessary to decrease the distance by 20 percent. Multiply
1,325 feet by 20 percent (1,325 × .20 = 265), subtract the
product from the total distance (1,325 – 265 = 1,060). Repeat
this process for the total distance over a 50 foot obstacle. The
ground roll distance is 1,060 feet and the total distance over
a 50 foot obstacle is 1,984 feet.
Climb and Cruise Charts
Climb and cruise chart information is based on actual flight
tests conducted in an aircraft of the same type. This information
is extremely useful when planning a cross-country flight to
predict the performance and fuel consumption of the aircraft.
Manufacturers produce several different charts for climb and
cruise performance. These charts include everything from
fuel, time, and distance to climb to best power setting during
cruise to cruise range performance.
The first chart to check for climb performance is a fuel,
time, and distance-to-climb chart. This chart gives the fuel
amount used during the climb, the time it takes to accomplish
the climb, and the ground distance that is covered during
the climb. To use this chart, obtain the information for
the departing airport and for the cruise altitude. Using
Figure 11-25, calculate the fuel, time, and distance to climb
based on the information provided.
Sample Problem 4
Departing Airport Pressure Altitude.................6,000 feet
Departing Airport OAT............................................25 °C
Cruise Pressure Altitude..................................10,000 feet
Cruise OAT..............................................................10 °C
Figure 11-24. Takeoff distance short field charts.
TAKEOFF DISTANCE
MAXIMUM WEIGHT 2,400 LB
Notes Conditions
Weight
(lb)
2,400
2,200
2,000
Press
ALT
(ft)
S.L.
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
S.L.
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
S.L.
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
795
875
960
1,055
1,165
1,285
1,425
1,580
1,755
650
710
780
855
945
1,040
1,150
1,270
1,410
525
570
625
690
755
830
920
1,015
1,125
Total feet
to clear
50 ft OBS
1,460
1,605
1,770
1,960
2,185
2,445
2,755
3,140
3,615
1,195
1,310
1,440
1,585
1,750
1,945
2,170
2,440
2,760
970
1,060
1,160
1,270
1,400
1,545
1,710
1,900
2,125
860
940
1,035
1,140
1,260
1,390
1,540
1,710
1,905
700
765
840
925
1,020
1,125
1,240
1,375
1,525
565
615
675
740
815
900
990
1,095
1,215
Total feet
to clear
50 ft OBS
1,570
1,725
1,910
2,120
2,365
2,660
3,015
3,450
4,015
1,280
1,405
1,545
1,705
1,890
2,105
2,355
2,655
3,015
1,035
1,135
1,240
1,365
1,500
1,660
1,845
2,055
2,305
995
1,090
1,200
1,325
1,465
1,620
1,800
2,000
- - -
805
885
975
1,070
1,180
1,305
1,445
1,605
1,785
650
710
780
860
945
2,145
2,405
2,715
1,410
Total feet
to clear
50 ft OBS
1,810
2,000
2,220
2,480
2,790
3,160
3,620
4,220
- - -
1,470
1,615
1,785
1,975
2,200
2,465
2,775
3,155
3,630
1,185
1,295
1,425
1,570
1,735
1,925
2,145
2,405
2,715
1,065
1,170
1,290
1,425
1,575
1,745
1,940
- - -
- - -
865
950
1,045
1,150
1,270
1,405
1,555
1,730
1,925
695
765
840
920
1,015
1,120
1,235
1,370
1,520
Total feet
to clear
50 ft OBS
1,945
2,155
2,395
2,685
3,030
3,455
3,990
- - -
- - -
1,575
1,735
1,915
2,130
2,375
2,665
3,020
3,450
4,005
1,265
1,385
1,525
1,685
1,865
2,070
2,315
2,605
2,950
Lift
off
51
49
46
AT
50 ft
56
54
51
Takeoff
speed KIAS
0 °C 10 °C 20 °C 30 °C
925
1,015
1,115
1,230
1,355
1,500
1,665
1,850
2,060
750
825
905
995
1,100
1,210
1,340
1,485
1,650
605
665
725
800
880
970
1,070
1,180
1,310
Total feet
to clear
50 ft OBS
1,685
1,860
2,060
2,295
2,570
2,895
3,300
3,805
4,480
1,375
1,510
1,660
1,835
2,040
2,275
2,555
2,890
3,305
1,110
1,215
1,330
1,465
1,615
1,790
1,990
2,225
2,500
40 °C
Grnd
roll
(ft)
Grnd
roll
(ft)
Grnd
roll
(ft)
Grnd
roll
(ft)
Grnd
roll
(ft)
SHORT FIELD
Flaps 10°
Full throttle prior to brake release
Paved level runway
Zero wind
1. Prior to takeoff from fields above 3,000 feet elevation, the mixture should be leaned to give maximum rpm in a full throttle, static runup.
2. Decrease distances 10% for each 9 knots headwind. For operation with tailwind up to 10 knots, increase distances by 10% for each 2 knots.
3. For operation on a dry, grass runway, increase distances by 15% of the “ground roll” figure.
Figure 11-23. Takeoff distance graph.
C -40° -30° -20° -10° 0° 10° 20° 30° 40° 50° 2,800 2,600 2,400 2,200 0 10 20 30 0 50
Outside air temperature Weight Wind component Obstacle
(pounds) (knots) height (feet)
F -40° -20° 0° 20° 40° 60° 80° 100° 120°
6,000
5,000
4,000
3,000
2,000
1,000
0
10,000
8,000
6,000
4,000
2,000S.L.
Guide lines not applicable for
Intermediate
Tailwind
Headwind
Reference line
Reference line
Reference line
Pressure altitude - feet ISA
Obstacle heights
Weight
pounds
kts MPH
Takeoff speed
Lift-off 50 ft
kts MPH
2,950
2,800
2,600
2,400
2,200
66
64
63
61
58
76
74
72
70
67
72
70
68
66
63
83
81
78
76
73
Associated conditions
Power Full throttle 2,600 rpm
Mixture Lean to appropriate fuel
pressure
Flaps Up
Landing Retract after positive
gear climb established
Cowl Open
flaps
Figure 11-25. Fuel, time, and distance climb chart.
20,000
18,000
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
Sea level
-40° -30° -20° -10° 0° 10° 20° 30° 40°C 0 10 20 30 40 50
Outside air temperature Fuel, time and distance to climb
Associated conditions
Maximum continuous power*
3,600 lb gross weight
Flaps up
90 KIAS
No wind
* 2,700 rpm & 36 in M.P. (3-blade prop)
2,575 rpm & 36 in M.P. (2-blade prop)
Pressure ALT - feet
Fuel - gallons
Time - minutes
Distance - nautical miles
Cruise
Departure
Figure 11-26. Fuel time distance climb.
Notes Conditions
Weight
(pounds)
Rate of
climb
fpm
Press
ALT
(feet) Time
(minutes)
Fuel used
(pounds)
Distance
(nautical
miles)
From sea level
S.L.
4,000
8,000
12,000
16,000
20,000
S.L.
4,000
8,000
12,000
16,000
20,000
S.L.
4,000
8,000
12,000
16,000
20,000
4,000
3,700
3,400
605
570
530
485
430
365
700
665
625
580
525
460
810
775
735
690
635
565
0
7
14
22
31
41
0
6
12
19
26
34
0
5
10
16
22
29
0
14
28
44
62
82
0
12
24
37
52
68
0
10
21
32
44
57
0
13
27
43
63
87
0
11
23
37
53
72
0
9
20
31
45
61
NORMAL CLIMB
110 KIAS
Flaps up
Gear up
2,500 rpm
30 "Hg
120 PPH fuel flow
Cowl flaps open
Standard temperature
1. Add 16 pounds of fuel for engine start, taxi, and takeoff allowance.
2. Increase time, fuel, and distance by 10% for each 7 °C above standard
temperature.
3. Distances shown are based on zero wind.
First, find the information for the departing airport. Find the
OAT for the departing airport along the bottom, left side of the
graph. Follow the line from 25 °C straight up until it intersects
the line corresponding to the pressure altitude of 6,000 feet.
Continue this line straight across until it intersects all three
lines for fuel, time, and distance. Draw a line straight down
from the intersection of altitude and fuel, altitude and time, and
a third line at altitude and distance. It should read three and
one-half gallons of fuel, 6 minutes of time, and nine NM. Next,
repeat the steps to find the information for the cruise altitude.
It should read six gallons of fuel, 10.5 minutes of time, and
15 NM. Take each set of numbers for fuel, time, and distance
and subtract them from one another (6.0 – 3.5 = 2.5 gallons of
fuel). It takes two and one-half gallons of fuel and 4 minutes
of time to climb to 10,000 feet. During that climb, the distance
covered is six NM. Remember, according to the notes at the
top of the chart, these numbers do not take into account wind,
and it is assumed maximum continuous power is being used.
The next example is a fuel, time, and distance-to-climb table.
For this table, use the same basic criteria as for the previous
chart. However, it is necessary to figure the information in a
different manner. Refer to Figure 11-26 to work the following
sample problem.
Sample Problem 5
Departing Airport Pressure Altitude..................Sea level
Departing Airport OAT............................................22 °C
Cruise Pressure Altitude....................................8,000 feet
Takeoff Weight.............................................3,400 pounds
To begin, find the given weight of 3,400 in the first column of
the chart. Move across to the pressure altitude column to find
the sea level altitude numbers. At sea level, the numbers read
zero. Next, read the line that corresponds with the cruising
altitude of 8,000 feet. Normally, a pilot would subtract these