MILITARY MEDICINE, 177, 7:863, 2012
The Future of Vertical Lift: Initial Insights for Aircraft
Capability and Medical Planning
CPT Nathaniel D. Bastian, MS USA*; Lawrence V. Fulton, PhD†; COL Robert Mitchell, MS USA‡;
Wayne Pollard, MS§; David Wierschem, PhD†; Ronald Wilson, MS§
+
ABSTRACT The U.S. Army continues to evaluate capabilities associated with the Future of Vertical Lift (FVL)
program—a future program (with a time horizon of 15 years and beyond) intended to replace the current helicopter fleet.
As part of the FVL study, we investigated required capabilities for future aeromedical evacuation platforms. This study
presents two significant capability findings associated with the future aeromedical evacuation platform and one doctrinal
finding associated with medical planning for future brigade operations. The three results follow: (1) Given simplifying
assumptions and constraints for a scenario where a future brigade is operating in a 300 300 km2, the zero-risk aircraft
ground speed required for the FVL platform is 350 nautical miles per hour (knots); (2) Given these same assumptions
and constraints with the future brigade projecting power in a circle of radius 150 km, the zero-risk ground speed required
for the FVL platform is 260 knots; and (3) Given uncertain casualty locations associated with future brigade stability
and support operations, colocating aeromedical evacuation assets and surgical elements mathematically optimizes the
60-minute set covering problem.
INTRODUCTION
The U.S. Army continues to evaluate capabilities associated
with the Future of Vertical Lift (FVL) program—a futures
program (with a time horizon of 15 years and beyond)
intended to replace the current helicopter fleet.1 As part of
the FVL study, we conducted a DOTMLPF (doctrine, organization, training, maintenance, leadership, personnel, facilities) assessment using a mixed-methods (quantitative and
qualitative) approach to determine gaps in the current force
structure and solutions for future force design.2 In another
part of the FVL study, we investigated the required capabilities (airspeed, altitude, cabin space, etc.) for future aeromedical evacuation platforms. Previous studies and research
efforts have tackled problems concerning aeromedical evacuation asset requirements, allocation, and emplacement decisions using different modeling, simulation, and optimization
techniques.3–6 During the FVL study, however, doctrinal ideas
and insights emerged, and some of these insights are particularly poignant for military medical planners. The Medical
Evacuation Proponency Directorate (MEPD) funded this FVL
study as a subset of ongoing analyses.
*Center for AMEDD Strategic Studies, Medical Capabilities Integration
Center, U.S. Army Medical Department Center & School, 1608 Stanley
Road, Fort Sam Houston, TX 78234-5047.
†Department of Computer Information Systems & Quantitative Methods,
McCoy College of Business Administration, Texas State University, McCoy
Hall 404, San Marcos, TX 78666-4616.
‡Medical Evacuation Proponency Directorate, Medical Capabilities Integration Center, U.S. Army Medical Department Center & School, Building
4103, Gladiator Street, Fort Rucker, AL 36362.
§Navigator Development Group, 116 South Main Street, Suite 214,
Enterprise, AL 36330.
This article was presented at 2011 Annual Meeting of the Institute
for Operations Research and the Management Sciences, Charlotte, NC,
November 16, 2011.
MILITARY MEDICINE, Vol. 177, July 2012
Background
For the FVL planning process, the primary fighting forces are
Army brigades, a force of 3000+ personnel, according to
Colonel Robert Mitchell, Director of the MEPD. For the
FVL analysis, the area of operations for the future brigade is
a 300 km by 300 km (162 nautical miles [NM] by 162 NM)
square box (slightly more area than the state of Maine),
possibly deriving from an Army white paper written in 2004
as referenced by.7 This box assumes unequal projection of
power since the distance from the brigade center to any corner is 212 km (114.5 NM), whereas the closest distance from
the center to the side is 150 km (81 NM). As part of the study
analysis, we assumed that the brigade might also exert uniform radial projection of power over a more conservative
area, a circle of radius 150 km (81 NM) corresponding to the
shortest distance from the center of the brigade to its force
projection boundary. The reason for this assumption and secondary analysis is that brigades operating independently in
stability and support operations might project power uniformly from the headquarters. Additionally, the planning
assumption of square battle space may perhaps be a vestige
of Cold War planning, where the assumption of a linear battle
was commonplace. Figure 1 depicts both the square box and
circular arrangements analyzed for this study.
Analysis of required FVL support for a brigade operating
in either square or circular configurations includes the assessment of aeromedical evacuation. One of the known requirements for aeromedical evacuation is the 1-hour evacuation
standard imposed by the former U.S. Secretary of Defense
Robert Gates. The reason the former Secretary of Defense
provided this standard is best expressed in his own words:
“The standard for medical evacuation [from the battlefield] in Iraq was an hour. . . . .Everybody had to be
‘MedEvaced’ within an hour. But Afghanistan is a lot
863
Initial Insights From the Future of Vertical Lift Study
systems. Although we investigated several research questions, ideas and insights generated from 1 question were
particularly relevant. That research question follows:
“What FVL aircraft ground speed would ensure appropriate aeromedical evacuation coverage in current or
future operations to support the mandated Secretary of
Defense 1-hour evacuation standard given doctrinal combat brigade support areas?”
FIGURE 1. Shown are 2 possible arrangements of the future brigade. The
brigade headquarters are depicted using military symbols as flags with an
“X” above them and a diagonal line pointing to its location. The left diagram
shows force projection as a function of a square box, whereas the right shows
force projection as emanating uniformly from a circle. The distances in
kilometers and nautical miles are shown.
tougher terrain. And so it came to my attention that they
had settled on two hours. And I said: ‘Bulls–t. It’s going
to be the same in Afghanistan as in Iraq.’ And the medical guys, the medical bureaucracy, pushed back on me
and said: ‘No, no, it really doesn’t matter.’ And I said:
‘Well, if I’m a Soldier and I’m going out on patrol, it
matters to me.’ And so we sent a bunch of new helicopters, three new field hospitals, a whole bunch of stuff.
And so now we have the ‘golden hour’ in Afghanistan.”8
This standard requires that the time between medical
evacuation notification to the time of patient drop-off at a
surgical facility must not exceed 60 minutes. This standard
most probably derived from the concept of the “Golden Hour,”
a maligned conjecture that survivability of seriously wounded
individuals decreases dramatically after 60 minutes.9 Regardless of the merit of this conjecture, the certainty in planning
(and potential psychological advantage for those participating
in combat, expressed admirably by the former Secretary of
Defense) makes the 60-minute directive an outstanding tool
for medical planning and for analysis of alternatives.
Purpose and Research Question
The U.S. Army Medical Department (AMEDD), specifically
the MEPD, was asked to evaluate capabilities required for the
FVL program. The task assigned to MEPD is of significant
importance as inclusion of aeromedical evacuation requirements into the future planning process would help ensure the
acquisition of a capable life-saving vehicle. In previous acquisition efforts, the AMEDD did not have its requirements
appropriately integrated. For example, according to Ronald
Wilson, consultant for MEPD, the UH-60 aeromedical evacuation platform was initially unable to handle a “NATO-standard”
litter. The current process, however, is well integrated.
MEPD received several requests for analysis. Part of the
analysis required an assessment of the minimal FVL capability given doctrinal constraints, whereas another part required
more holistic analyses of the entire aeromedical and aviation
864
To answer this research question, we performed 2-dimensional
and 3-dimensional geographical analysis. We viewed this problem as a “set covering problem” in 2 or 3 dimensions with
uncertain (uniformly distributed) casualties. During this analysis,
ideas and insights relevant to military medical planners emerged.
METHODS
Investigation of this research question required an analysis
of how casualties might occur. If a medical planner had
perfect knowledge of where and when casualties would
occur, then he or she would place appropriate treatment and
evacuation assets as close as safely possible a priori. These
casualty cluster areas and safe locations, however, are
unknowable and exceedingly difficult to forecast accurately,
at least in early operations. Because of this uncertainty, for
initial medical planning we assume a uniform distribution of
casualties across the battle space, which means that casualties might occur anywhere in the brigade with equal probability. Even if casualties are assumed to cluster around the
maneuver brigade, a uniform distribution around that brigade
is a typical assumption reflecting lack of knowledge.5,6
Before answering this research question, we also analyzed
how might the surgical facility and evacuation assets be best
located to maximize the coverage assuming flat terrain and zero
wind conditions (adjustments for nonflat terrain and wind are
discussed later). In other words, should evacuation assets be
colocated with surgical facilities or positioned separately in
geographically dispersed locations? This problem concerns
maximizing over the long and short axes the area of an ellipse,
FIGURE 2. The diagram below illustrates the 60-minute boundary for
2 configurations, a circle and an ellipse. The circular boundary is 60-minute
coverage to any patient on the boundary (illustrated with a 4-pointed star)
with colocated assets. The ellipse is also 60-minute coverage; however, the
assets are not colocated.
MILITARY MEDICINE, Vol. 177, July 2012
Initial Insights From the Future of Vertical Lift Study
FIGURE 3. The square box represents the brigade coverage in both diagrams. The circle represents the evacuation coverage. In the box on the left,
calculating the area left uncovered is trivial (area of the square minus area of
the circle all divided by the area of the square.) In the box on the right, the
formula is similar; however, the area of the four circular segments shown in
black is subtracted from the numerator.
because by definition, an ellipse has 2 foci (e.g., the evacuation
and surgical locations) and every point to the curved line connecting these foci is a fixed value (60 minutes of distance).10
Given fixed and geographically disparate positions of the evac-
uation site location, e, and the surgical team, s, the ellipse
derives from connecting these 2 locations and drawing the
boundary, b, for all other distances radial from this point that
make e + s + b = 60 minute boundary measured in distance.
Upon mathematical analysis of this problem, we found that
colocating the surgical element with the evacuation element
results in maximization of the area covered (see Appendix A).
For establishing that colocation results in maximizing the covered area, the necessary and sufficient conditions are a gradient
of zero at the optimal point and a negative definite Hessian (table
of second partial derivatives).11 Figure 2 illustrates area coverage based on aeromedical evacuation and surgical treatment.
By understanding that colocation of evacuation and treatment assets maximizes the area covered, we proceeded in providing decision support for aircraft speed considerations by
calculating the brigade area left uncovered given certain airspeeds and round-trip distances. The importance of calculating
the area uncovered over speeds and round-trip distances is that
it provides military decision-makers the opportunity to assess
FIGURE 4. This map of Afghanistan contains an overlay of casualty densities (shown in white) recreated from CNN. The large, unfilled circles are
illustrative of coverage areas for evacuation assets capable of achieving 125 knots ground speed and which are colocated with surgical elements. Thirteen
coverage areas are hypothesized.
MILITARY MEDICINE, Vol. 177, July 2012
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Initial Insights From the Future of Vertical Lift Study
risk by addressing the question of what area would be uncovered if an aircraft with speed of X was selected for the aeromedical evacuation mission. This procedure was conducted
for the analysis of the brigade occupying a square and a circle.
Certain flexible assumptions regarding aeromedical evacuation operations provided the basis for the final analysis. First,
notification to aircraft run-up was fixed at 7 minutes based on
recent reports in Afghanistan from Colonel Mitchell. Second,
“patient packaging” (preparing the patient for movement) was
set to 10 minutes. (Loading varies based on patient; however,
this value is congruent with qualitative analysis from theater.)
Third, patient drop-off time was set to 5 minutes. All of these
times (run-up, loading, and drop-off) became flexible parameters in a decision support tool, so that decision-makers could
evaluate other values. Finally, helicopter climb and descent are
assumed nominal. For the initial analysis, a 60-minute boundary represents 48 minutes of actual travel time.
We generated the calculations for percent of area left
uncovered based on round-trip distances from 0 NM to
229 NM (the maximum distance associated with a brigade
operating in the square) and ground speeds from 100 NM to
400 NM per hour (knots). Mathematical calculations for percent of area uncovered were based on both square and circular arrangements (Fig. 3) (see Appendix B).
To account for the effect of terrain requires the assumption
that the altitudes would be known a priori. Nonetheless, a
simple method for estimating terrain considerations is to carve
out segments by evaluating near-peak altitudes for any areas
for which altitude is not assumed to be nominal and for which
low-level traversing is impossible. The 60-minute boundary
would then be calculated based on the ascent line (drawn from
the aircraft location) and assumed climb speed coupled with
the descent line (drawn from the location of peak elevation)
and assumed cruise speed. Specific sectors would then need to
have only segments carved out to adjust for the aircraft climbout. Such adjustments are not needed when terrain is unknown,
and the assumption that brigades would not reduce the size of
their operating area regardless of terrain considerations is
FIGURE 5. This map of Afghanistan contains an overlay of casualty densities (shown in white) recreated from CNN. The large, unfilled circles are
illustrative of coverage areas for evacuation assets capable of achieving 250 knots ground speed and which are colocated with surgical facilities. Eight
coverage areas are hypothesized.
866
MILITARY MEDICINE, Vol. 177, July 2012
Initial Insights From the Future of Vertical Lift Study
+
RESULTS
Using the previously stated assumptions and equations, we
generated a decision support tool for evaluating area left
uncovered, which provides military decision-makers risk analysis information. (The more area uncovered is a proxy for
increased risk.) Appendix C depicts the results of the analysis.
Given the assumptions previously stated, the aircraft ground
speed necessary to cover all of the brigade operating space
when the brigade is assigned a square is 350 knots, whereas
the ground speed necessary for full coverage of the brigade
in circular space is 260 knots. At 260 knots ground speed,
19% of the area of the brigade square remains uncovered.
To assist decision-makers in understanding the coverage
capabilities of aircraft with different airspeeds, we designed
maps of Afghanistan recreated from Cable News Network
(CNN) casualty maps superimposed.12 The map of Afghanistan,
created with Generic Mapping Tools13 and terrain data sets
in 2005, is freely available from Wikipedia Commons.14
Figures 4–6 are representative overlays for future airspeed
capability of 125 knots, 250 knots, and 300 knots. The increased
capability of aeromedical evacuation assets reduces the support
locations required (and thus the associated logistical support
footprint such as forward operating bases, refueling points,
resupply points, and perhaps even the number of aircraft). In
Figure 4, the mock-up map demonstrates that 13 locations
(shown as circles) partially cover the casualty densities (shown
as white blotches). The number of locations reduces to 8 and
then 6 for Figures 5 and 6, respectively. Given that doctrinal
emplacement of aeromedical evacuation assets is (at a minimum) in groups of 3, the resulting reduction in airframes
required by increasing attainable ground speed from 125 knots
to 300 knots is (13 3) – (6 3) = 21.
+
fallacious as well. Without a priori knowledge of terrain, we
used flat terrain as a base case for analysis.
DISCUSSION
Upon conclusion of this work, we returned to the initial research
question: What FVL aircraft ground speed would ensure appropriate aeromedical evacuation coverage in current or future
FIGURE 6. This map of Afghanistan contains an overlay of casualty densities (shown in white) recreated from CNN. The large, unfilled circles are
illustrative of coverage areas for evacuation assets capable of achieving 300 knots ground speed and which are co-located with surgical elements. Six
coverage areas are hypothesized.
MILITARY MEDICINE, Vol. 177, July 2012
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Initial Insights From the Future of Vertical Lift Study
operations to support the mandated Secretary of Defense 1-hour
evacuation standard given doctrinal combat brigade support
areas? Unconstrained and given the assumptions provided,
the airspeed that ensures zero risk for brigade circular and
square arrangements is 350 knots. Such an airspeed capability is certain to be associated with a significant cost factor. If
the brigade influences battle space in a circle, then a ground
speed of 260 knots would provide complete coverage over
flat terrain. These 2 recommendations are zero-risk solutions;
however, Appendix C provides the capability for decisionmakers to evaluate risk by evaluating distance to be traveled
(total) versus airspeed and time.
Because of the uncertainty involved with casualty estimation, our analysis only considered the uniform distribution of
casualty clusters in the brigade operations space despite the
casualty densities depicted in Figures 4–6. As a limitation to
our work, therefore, we did not contrast our uniform distribution assumption with clusters of casualties in only twothirds of the battle space. Additionally, our work did not
account for the specific surgical facility capabilities and capacities nor the aeromedical evacuation requirements after casualty care at the surgical facility. Once the casualty receives
proper medical treatment, we assume that the patient is either
returned-to-duty or transferred to a higher level of care via a
different evacuation platform.
Interesting to this analysis is the fact that the additional
speed capability might allow for a reduction in the logistical
and support footprint as shown by Figures 4–6. Any reduction, however, assumes that the footprint is a function of area
support rather than casualty demand. In other words, casualty
streams may require a larger logistical footprint. Additional
assets and basing requirements offset risk associated with
weather, environment, and the chaotic nature of military operations. Our analysis, however, does not consider differences
in the types of logistical footprint (e.g., a single location of
6 evacuation assets versus 2 separate locations with 3 evacuation assets each). The potential reduction in logistical and
support footprint of the evacuation assets is only one part of
the equation. Building on the assumptions made, an increase
in aircraft speed may have significant implications on the total
number of surgical facilities needed in a given arena.
CONCLUDING REMARKS
As part of this FVL study, we investigated the required capabilities for future aeromedical evacuation aircraft and developed
a decision support tool for military medical planners in evaluating risk associated with aeromedical evacuation platform capability and coverage within the brigade operating space. In
addition to the 2 significant capability findings previously
discussed, we also uncovered 1 doctrinal finding associated with
medical planning for future brigade operations. Specifically, we
determined that colocation of aeromedical evacuation assets
and surgical elements provide the optimum coverage for a
single brigade when casualty clusters are indeterminable or
868
random. These insights have proven extremely useful to military medical planners within the U.S. AMEDD.
ACKNOWLEDGMENTS
We thank the Medical Evacuation Proponency Directorate of the Medical Capabilities Integration Center of the U.S. Army Medical Department Center &
School, Fort Rucker, AL, who funded the research and analysis of this study.
APPENDIX A
For completeness, the following demonstration is included (noting that the area of an
ellipse is pab and that C is any distance boundary associated with achievable time
traveled):
Max f
= pab – C
a, b
ð1Þ
j pb
j=j 00 j, pb – pa = 0, b = a
pa
ð2Þ
j p0 p0 j, D= − p
ð3Þ
rf =
r2 f =
2
Solving both systems of equations in the gradient (Eq. 2) results in pb − pa = 0, so
b = a is either a minimum or maximum. Checking the determinant of the Hessian (the
discriminant) to ensure it is negative definite (Eq. 3) illustrates that b = a maximizes
the area of an ellipse. If b = a (and letting b = r, then the area of that shape is f = pr2, the
well-known area of a circle. Therefore, colocating aeromedical evacuation aircraft and
medical treatment facilities results in maximizing the area covered.
APPENDIX B
For the square arrangement, the percent of area uncovered was a piecewise function
based on radius, r:
8
>
162NM2 − pr 2
>
>
, 0 < r £ 81NM
>
>
162NM2
>
>
>
>
>
0
1
>
>
>
>
>
r2
>
C
2 B 2
>
>
>162NM −@pr −4∗ 2 ðq−sinðq ÞÞA
<
g=
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
:
162NM2
0
1
ð4Þ
,
B81C
q =2ar cos@ A, 81NM< r £ 114:5 NM
r
1, r > 114:5 NM
ð5Þ
ð6Þ
The numerator in Equation 4 simply takes the area of the brigade square and
subtracts the area of the circle covered (assuming that no overlap exists). Dividing that
numerator by the area of the square provides the proportion covered. The numerator in
Equation 5 calculates the area of the square and subtracts the area of the circle less the
area of the 4 segments that extend beyond the square. A single overlap is a circular
2
r2
(See Figure 3). The denomsegment with well-known area of r2 ðq – sinðqÞÞ 2ðq – sin
½ðqÞÞ:
inator in Equation 5 represents the area of the square, and Equation 6 captures the
circular coverage over the entire square.
The location of the “surgical-evacuation” team for the scenario described by Equation 4 is restricted only by ensuring that the team’s coverage circle is completely
inscribed by the brigade’s operating area. For Equation 5, the “surgical-evacuation”
team is assumed to be centered on the brigade, as centering ensures maximum coverage
over the brigade square (proof omitted). Equation 6 assumes superscription.
For the brigade in circular arrangement, the proportion left uncovered is a simple
piecewise function as shown in Equations 7 and 8:
8
2
2
2
2
>
< p81 − pr = 81 − r , 0 £ r £ 81 NM
p812
812
h=
>
:
1, r > 81 NM
ð7Þ
ð8Þ
In Equation 7, the area uncovered is simply the complement of the area covered
by the 60-minute aeromedical evacuation time divided by the area of the brigade’s
MILITARY MEDICINE, Vol. 177, July 2012
MILITARY MEDICINE, Vol. 177, July 2012
22
27.5
32.9
38.4
43.8
49.3
54.7
60.2
65.6
71.1
76.5
82
87.5
92.9
98.4
103.8
110.4
82%
114.7
120.2
125.6
131.1
136.5
142
146.9
85%
124
130
136
142
148
154
159.4
88%
110
22
28
34
40
46
52
58
64
70
76
82
88
94
100
106
112
119.2
85%
100
107
112
117
122
127
132
136.5
83%
22
27
32
37
42
47
52
57
62
67
72
77
82
87
92
97
103
78%
120
100.5
105.1
109.7
114.3
118.9
123.5
127.7
80%
22
26.6
31.2
35.8
40.5
45.1
49.7
54.3
58.9
63.5
68.2
72.8
77.4
82
86.6
91.2
96.8
74%
130
94.9
99.1
103.4
107.7
112
116.3
120.1
76%
22
26.3
30.6
34.9
39.1
43.4
47.7
52
56.3
60.6
64.9
69.1
73.4
77.7
82
86.3
91.4
70%
140
90
94
98
102
106
110
113.6
73%
22
26
30
34
38
42
46
50
54
58
62
66
70
74
78
82
86.8
66%
150
85.8
89.5
93.3
97
100.8
104.5
107.9
69%
22
25.8
29.5
33.3
37
40.8
44.5
48.3
52
55.8
59.5
63.3
67
70.8
74.5
78.3
82.8
61%
160
82
85.5
89.1
92.6
96.1
99.6
102.8
65%
22
25.5
29.1
32.6
36.1
39.6
43.2
46.7
50.2
53.8
57.3
60.8
64.4
67.9
71.4
74.9
79.2
56%
170
APPENDIX C
78.7
82
85.3
88.7
92
95.3
98.3
61%
22
25.3
28.7
32
35.3
38.7
42
45.3
48.7
52
55.3
58.7
62
65.3
68.7
72
76
50%
180
75.7
78.8
82
85.2
88.3
91.5
94.3
57%
22
25.2
28.3
31.5
34.6
37.8
40.9
44.1
47.3
50.4
53.6
56.7
59.9
63.1
66.2
69.4
73.2
45%
190
73
76
79
82
85
88
90.7
52%
22
25
28
31
34
37
40
43
46
49
52
55
58
61
64
67
70.6
39%
200
70.6
73.4
76.3
79.1
82
84.9
87.4
47%
22
24.9
27.7
30.6
33.4
36.3
39.1
42
44.9
47.7
50.6
53.4
56.3
59.1
62
64.9
68.3
33%
210
68.4
71.1
73.8
76.5
79.3
82
84.5
42%
22
24.7
27.5
30.2
32.9
35.6
38.4
41.1
43.8
46.5
49.3
52
54.7
57.5
60.2
62.9
66.2
26%
220
66.3
69
71.6
74.2
76.8
79.4
81.7
36%
22
24.6
27.2
29.8
32.4
35
37.7
40.3
42.9
45.5
48.1
50.7
53.3
55.9
58.5
61.1
64.3
19%
230
64.5
67
69.5
72
74.5
77
79.3
31%
22
24.5
27
29.5
32
34.5
37
39.5
42
44.5
47
49.5
52
54.5
57
59.5
62.5
12%
240
62.8
65.2
67.6
70
72.4
74.8
77
25%
22
24.4
26.8
29.2
31.6
34
36.4
38.8
41.2
43.6
46
48.4
50.8
53.2
55.6
58
60.9
4%
250
Aircraft Ground Speed in Knots (Nautical Miles/Hour)
Distance, Speed, Delay vs. Transport Time
X-axis = Aircraft ground speed; Y-axis = Total distance traveled from evacuation site to injury site to surgical site. Table values = Time in minutes.
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
162
Approximate Percentage
Uncovered, Circle
170
180
190
200
210
220
229
Approximate Percentage
Uncovered, Square
Distance to Patient
Then to Facility
(Nautical Miles)
TABLE CI.
260
61.2
63.5
65.8
68.2
70.5
72.8
74.8
19%
22
24.3
26.6
28.9
31.2
33.5
35.8
38.2
40.5
42.8
45.1
47.4
49.7
52
54.3
56.6
59.4
0%
270
59.8
62
64.2
66.4
68.7
70.9
72.9
15%
22
24.2
26.4
28.7
30.9
33.1
35.3
37.6
39.8
42
44.2
46.4
48.7
50.9
53.1
55.3
58
280
58.4
60.6
62.7
64.9
67
69.1
71.1
12%
22
24.1
26.3
28.4
30.6
32.7
34.9
37
39.1
41.3
43.4
45.6
47.7
49.9
52
54.1
56.7
290
57.2
59.2
61.3
63.4
65.4
67.5
69.4
9%
22
24.1
26.1
28.2
30.3
32.3
34.4
36.5
38.6
40.6
42.7
44.8
46.8
48.9
51
53
55.5
300
56
58
60
62
64
66
67.8
6%
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54.4
310
54.9
56.8
58.8
60.7
62.6
64.6
66.3
4%
22
23.9
25.9
27.8
29.7
31.7
33.6
35.5
37.5
39.4
41.4
43.3
45.2
47.2
49.1
51
53.4
320
53.9
55.8
57.6
59.5
61.4
63.3
64.9
3%
22
23.9
25.8
27.6
29.5
31.4
33.3
35.1
37
38.9
40.8
42.6
44.5
46.4
48.3
50.1
52.4
330
52.9
54.7
56.5
58.4
60.2
62
63.6
2%
22
23.8
25.6
27.5
29.3
31.1
32.9
34.7
36.5
38.4
40.2
42
43.8
45.6
47.5
49.3
51.5
340
52
53.8
55.5
57.3
59.1
60.8
62.4
1%
22
23.8
25.5
27.3
29.1
30.8
32.6
34.4
36.1
37.9
39.6
41.4
43.2
44.9
46.7
48.5
50.6
350
51.1
52.9
54.6
56.3
58
59.7
61.3
0%
22
23.7
25.4
27.1
28.9
30.6
32.3
34
35.7
37.4
39.1
40.9
42.6
44.3
46
47.7
49.8
Initial Insights From the Future of Vertical Lift Study
operation. Any coverage exceeding the brigade circular area is represented by Equation 8.
The location of the “surgical-evacuation” team in Equation 7 assumes inscription inside
the brigade circle. Equation 8 assumes superscription, regardless of team location.
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