Figure 9-33. Standard atmosphere table.
Feet inHg mmHg PSI °C °F
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
22,000
24,000
26,000
28,000
30,000
32,000
34,000
36,000
38,000
40,000
42,000
44,000
46,000
48,000
50,000
55,000
60,000
29.92
27.82
25.84
23.98
22.23
20.58
19.03
17.58
16.22
14.95
13.76
12.65
11.61
10.64
9.74
8.90
8.12
7.40
6.73
6.12
5.56
5.05
4.59
4.17
3.79
3.44
2.71
2.14
760.0
706.7
656.3
609.1
564.6
522.7
483.4
446.5
412.0
379.7
349.5
321.3
294.9
270.3
237.4
226.1
206.3
188.0
171.0
155.5
141.2
128.3
116.6
105.9
96.3
87.4
68.6
54.4
14.7
13.66
12.69
11.78
10.92
10.11
9.35
8.63
7.96
7.34
6.75
6.21
5.70
5.22
4.78
4.37
3.98
3.63
3.30
2.99
2.72
2.47
2.24
2.02
1.85
1.68
1.32
1.04
15.0
11.0
7.1
3.1
−0.8
−0.4
−8.8
−12.7
−16.7
−20.7
−24.6
−28.6
−32.5
−36.5
−40.4
−44.4
−48.4
−52.4
−56.3
−56.5
−56.5
−56.5
−56.5
−56.5
−56.5
−56.5
59.0
51.9
44.7
37.6
30.5
23.3
16.2
9.1
1.9
−5.2
−12.3
−19.5
−26.6
−33.7
−40.9
−48.0
−55.1
−62.3
−69.4
−69.7
−69.7
−69.7
−69.7
−69.7
−69.7
−69.7
Temperature
remains constant
Figure 9-35. Determining the total fuel burn for a 4-hour cruise.
Total fuel burn =
Lb/hr/engine × No. engines × Hours flight duration
= 18,160 pounds
= 1,135 × 4 × 4
Figure 9-34. Gross weight table.
Fuel flow—100 lb per hour per engine
Moment of the loaded aeroplane (lb in x 100)
20 15.3 10 0 80 90 100 110 120 130 140 150 160 170 180
16
15
14
13
12
11
10
9
8
7
6
11.35
Pressure altitude—1,000 feet
SL
4
8
12
16
20
36 32
28
24
TT limit
Gross weight—1,000 lb
7. Draw a horizontal line to the left from the intersection
of the Below Standard diagonal and the 15.3 °C
temperature deviation vertical line. This line crosses
the fuel flow–100 pounds per hour per engine index
at 11.35 and indicates that each of the four engines
burns 1,135 (100 × 11.35) pounds of fuel per hour.
The total fuel burn for the 4-hour cruise is shown in
Figure 9-35.
The airplane gross weight was 140,000 pounds at takeoff
with 18,160 pounds of fuel burned during cruise and 1,350
pounds burned during the approach and landing phase. This
leaves a landing weight of 140,000 – (18,160 + 1,350) =
120,490 pounds.
Figure 9-36. Determining the amount of weight the aircraft must
lose to reach the maximum allowable landing weight.
171,000 lb cruise weight
– 142,500 lb maximum landing weight
28,500 lb required reduction
Figure 9-37. Determining the amount of fuel burned from the
beginning of the dump to touchdown.
Fuel flow = 3,170 lb/hr/engine
60
= 52.83 lb/min engine
Figure 9-38. Determining the amount of fuel needed to dump.
28,500.00 lb required weight reduction
– 2,007.54 lb fuel burned after start of dumping
26,492.46 lb fuel to be dumped
Figure 9-39. Determine the time needed to dump fuel.
= 11.52 minutes26,492.46
2,300
Determining Fuel Dump Time in Minutes
Most large aircraft are approved for a greater weight for
takeoff than for landing. To make it possible for them to
return to landing soon after takeoff, a fuel jettison system is
sometimes installed. It is important in an emergency situation
that the flight crew be able to dump enough fuel to lower the
weight to its allowed landing weight. This is done by timing
the dumping process.
In this example, the aircraft has two engines operating and
these specifications apply
Cruise weight .................................................171,000 lb
Maximum landing weight ..............................142,500 lb
Time from start of dump to landing .............. 19 minutes
Average fuel flow during
Dumping and descent .............................3,170 lb/hr/eng
Fuel dump rate .......................................2,300 lb/minute
To calculate the fuel dump time in minutes:
1. Determine the amount of weight the aircraft must
lose to reach the maximum allowable landing weight.
[Figure 9-36]
2. Determine the amount of fuel burned from the
beginning of the dump to touchdown. [Figure 9-37]
For both engines, this is 52.83 × 2 = 105.66 lb/minute.
The engines burn 105.66 lbs of fuel per min for 19 minutes
(the duration of the dump), which calculates to 2007.54
pounds of fuel burned between the beginning of the dump
and touchdown.
3. Determine the amount of fuel needed to dump by
subtracting the amount of fuel burned during the dump
from the required weight reduction. [Figure 9-38]
4. Determine the time needed to dump this amount of
fuel by dividing the number of pounds of fuel to dump
by the dump rate. [Figure 9-39]
Weight and Balance of Commuter Category
Airplanes
The Beech 1900 is a typical commuter category airplane that
can be configured to carry passengers or cargo. Figure 9-40
shows the loading data of this type of airplane in the
passenger configuration
Determining the Loaded Weight and CG
As this airplane is prepared for flight, a manifest is prepared.
[Figure 9-41]
Figure 9-40. Loading data for passenger configuration.
Row 1 F.S. 210
Crew F.S. 129
Fwd. press BHD F.S. 84.0
Aft press BHD F .S. 557.5
Row 2 F.S. 230
Row 3 F.S. 260
Row 4 F.S. 290
Row 5 F.S. 320
Row 6 F.S. 350
Row 7 F.S. 380
Row 8 F.S. 410
Row 9 F.S. 440
Loading Data Standard Seating
F.S. 456.0
F.S. 509.5
F.S. 150.6
F.S. 43.0
F.S. 5177.35
F.S. 513.5
F.S. 453.5
F.S. 175.6
F.S. 150.6
Aft baggage/cargo compt. (Aft section)
Aft baggage/cargo compt. (Fwd. section)
Aft partition
Baggage web
Fwd. cabin baggage compt.
Nose baggage compt.
Baggage/cargo location Maximum Weight Arm
Nose baggage compartment ................... ............................................150 ....................................................................................................65.5
Forward cabin baggage compartment.250................................. 163.5
(includes up to 100 pounds that may be
suspended from clothes rod)
Aft baggage/cargo compartment F wd. section ...................880 ....................................................................................................483.5
Aft section.......................630 ....................................................................................................533.0
Note
For compartment loading that results in only partial utilization of total compartment volume, load items must be
distributed or secured in a manner that precludes shifting under normally anticipated operating conditions.
Figure 9-41. Determining the loaded weight and CG of a Beech 1900 in the passenger configuration.
Item Weight Arm Moment/100 CG
25,823
439
600
575
494
493
608
1,190
722
164
967
3,198
7,866
43,139 292.9
Airplane basic EW
Crew
Passengers
Row 1
Row 2
Row 3
Row 4
Row 5
Row 6
Row 7
Row 8
Row 9
Baggage
Nose
Forward cabin
Aft (forward section)
Aft (aft section)
Fuel jet A @ +25 °C
390 gallons
9,226
340
300
250
190
170
190
340
190
100
200
600
2,633
14,729
129
210
230
260
290
320
350
380
410
440
65.5
163.6
483.5
533.0
Figure 9-42. Weight and moments—occupants.
Weight
Moment/100
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
103
116
129
142
155
168
181
194
206
219
232
245
258
271
284
297
310
323
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
184
207
230
253
276
299
322
345
368
391
414
437
460
483
506
529
552
575
208
234
260
286
312
338
364
390
416
442
468
494
520
546
572
598
624
650
232
261
290
319
348
377
406
435
464
493
522
551
680
609
638
667
696
725
256
288
320
352
384
416
448
480
512
544
576
608
640
672
704
736
768
800
280
315
350
385
420
455
490
525
560
595
630
665
700
735
770
805
840
875
304
342
380
418
456
494
532
570
608
646
684
722
760
798
836
874
912
950
328
369
410
451
492
533
574
615
656
697
738
779
820
861
902
943
984
1025
352
396
440
484
528
572
616
660
704
748
792
836
880
924
968
1012
1056
1100
Useful Load Weights and Moments—Occupants
Crew Cabin seats
F.S.
129
F.S.
200
F.S.
230
F.S.
260
F.S.
290
F.S.
320
F.S.
350
F.S.
380
F.S.
410
F.S.
440
Figure 9-43. Weight and moments—baggage.
Weight
10
20
30
40
50
60
70
80
90
100
150
200
250
300
350
400
450
500
550
600
630
650
700
750
800
850
880
7
13
20
26
33
39
46
52
59
66
98
16
33
49
65
82
98
115
131
147
164
245
327
409
48
97
145
193
242
290
338
387
435
484
725
967
1209
1450
1692
1934
2176
2418
2659
2901
3046
3143
3384
3626
3868
4110
4255
53
107
160
213
266
320
373
426
480
533
800
1066
1332
1599
1866
2132
2398
2665
2932
3198
3358
Moment/100
Useful Load Weights and Moments—Baggage
Nose
baggage
compartment
F.S. 65.5
Forward
cabin
baggage
compartment
F.S. 163.6
AFT baggage/
cargo
compartment
(Forward
section)
F.S. 483.5
AFT baggage/
cargo
compartment
(Aft
section)
F.S. 533.0
Figure 9-44. Density variation of aviation fuel.
−40 −30 −20 −10 0 10 20 30 40
7.5
7.0
6.5
6.0
5.5
Aviation kerosene jet A & Jet A1
Jet B (JP-4)
Aviation gasoline grade 100/130 NOTE: The fuel quantity indicator
is calibrated for correct indication
when using aviation kerosene jet
A and jet A1. When using other
fuels, multiply the indicated fuel
quantity in pounds by 0.99 for jet
B (JP-4) or by aviation gasoline
(100/130) to obtain actual fuel
quantity in pounds.
Aviation
kerosene
Jet A and
Jet A1 0.812
Jet B (JP-4) 0.785
AV gas grade
100/130 0.703
Average
specific
gravity
at 15 °C
(59 °F)
Fuel
Specific weight (lb/US gal)
Temperature (°C)
1. The crew weight and the weight of each passenger is
entered into the manifest. The moment/100 for each
occupant is determined by multiplying the weight by
the arm and dividing by 100. This data is available in
the AFM and is shown in the Weight and Moments—
Occupants table. [Figure 9-42]
2. The weight of the baggage in each compartment used
is entered with its moment/100. This is determined
in the Weights and Moments—Baggage table.
[Figure 9-43]
3. Determine the weight of the fuel. Jet A fuel has
a nominal specific gravity at +15 °C of 0.812
and weighs 6.8 pounds per gallon, but at +25 °C,
according to the Density Variation of Aviation Fuel
Chart [Figure 9-44], it weighs 6.75 lb/gal. Using this
Figure 9-45. Weights and moments—usable fuel.
Gallons
Weight Moment
100
6.5 lb/gal
Weight Moment
100
6.6 lb/gal
Weight Moment
100
6.7 lb/gal
Weight Moment
100
6.8 lb/gal
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
425
65
130
195
260
325
390
455
520
585
650
715
780
845
910
975
1,040
1,106
1,170
1,235
1,300
1,365
1,430
1,495
1,560
1,625
1,690
1,755
1,820
1,885
1,950
2,015
2,080
2,145
2,210
2,275
2,340
2,405
2,470
2,535
2,600
2,665
2,730
2,763
197
394
592
789
987
1,185
1,383
1,581
1,779
1,977
2,175
2,372
2,569
2,765
2,962
3,157
3,351
3,545
3,739
3,932
4,124
4,315
4,507
4,698
4,889
5,080
5,271
5,462
5,651
5,842
6,032
6,225
6,417
6,610
6,802
6,995
7,188
7,381
7,575
7,768
7,962
8,156
8,259
66
132
198
264
330
396
462
528
594
660
726
792
858
924
990
1,056
1,122
1,188
1,254
1,320
1,386
1,452
1,518
1,584
1,650
1,716
1,782
1,848
1,914
1,980
2,046
2,112
1,278
2,244
2,310
2,376
2,442
2,508
2,574
2,640
2,706
2,772
2,805
200
401
601
802
1,002
1,203
1,404
1,605
1,806
2,007
2,208
2,409
2,608
2,808
3,007
3,205
3,403
3,600
3,797
3,992
4,187
4,382
4,576
4,770
4,964
5,158
5,352
5,546
5,738
5,932
6,125
6,321
6,516
6,711
6,907
7,103
7,299
7,495
7,691
7,888
8,085
8,282
8,386
67
134
201
268
335
402
469
536
603
670
737
804
871
938
1,005
1,072
1,139
1,206
1,273
1,340
1,407
1,474
1,541
1,608
1,675
1,742
1,809
1,876
1,943
2,010
2,077
2,144
2,211
2,278
2,345
2,412
2,479
2,546
2,613
2,680
2,747
2,814
2,848
203
407
610
814
1,018
1,222
1,426
1,630
1,834
2,038
2,242
2,445
2,648
2,850
3,053
3,254
3,454
3,654
3,854
4,053
4,250
4,448
4,646
4,843
5,040
5,236
5,433
5,630
5,825
6,022
6,218
6,416
6,615
6,813
7,011
7,210
7,409
7,609
7,808
8,007
8,207
8,407
8,513
68
136
204
272
340
408
476
544
612
680
748
816
884
952
1,020
1,088
1,156
1,224
1,292
1,360
1,428
1,496
1,564
1,632
1,700
1,768
1,836
1,904
1,972
2,040
2,108
2,176
2,244
2,312
2,380
2,448
2,516
2,584
2,652
2,720
2,788
2,856
2,890
206
413
619
826
1,033
1,240
1,447
1,654
1,861
2,068
2,275
2,482
2,687
2,893
3,099
3,303
3,506
3,709
3,912
4,113
4,314
4,514
4,715
4,915
5,115
5,315
5,514
5,714
5,912
6,112
6,311
6,512
6,713
6,915
7,116
7,318
7,520
7,722
7,924
8,127
8,330
8,532
8,640
Useful Load Weights and Moments—Usable Fuel
chart, determine the weights and moment/100 for 390
gallons of Jet A fuel by interpolating between those
for 6.7 lb/gal and 6.8 lb/gal. The 390 gallons of fuel at
this temperature weighs 2,633 pounds, and its moment
index is 7,866 lb-in/100.
4. Add all of the weights and all of the moment indexes.
Divide the total moment index by the total weight, and
multiply this by the reduction factor of 100. The total
weight is 14,729 pounds; the total moment index is
43,139 lb-in/100. The CG is located at fuselage station
292.9. [Figure 9-45]
5. Check to determine that the CG is within limits for
this weight. Refer to the Weight and Balance Diagram.
[Figure 9-46] Draw a horizontal line across the
envelope at 14,729 pounds of weight and a vertical
line from the CG of 292.9 inches aft of the datum.
These lines cross inside the envelope, verifying the
CG is within limits for this weight.