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Helicopter Noise Propagation Studies for Air Installation Compatible
Use Zoning»
Philip Dickinson
Bickerdike,A l l e n ,Partners*
With the helicopter, noise undoubtedly is the environmental pol­
lutant which causes the greatest concern from the point of view of
the general public and social acceptability (1),
The noise radiated
from a helicopter is very complex, composed of sound produced by
several different sources, each of which generates acoustic energy by
more than one mechanism.
and 'Blade Slap's
These include noise from engines, tail rotor
The former is adequately described in terms of dBA.
Certainly the other two are not.
Externally, the noise is controlled largely by the noise component
from the rotors, although high frequency compressor
'whine5 is subjectively
significant at relatively short distances from the helicoptcr.
subjective considerations,
slap and tail rotor noise»
From
the two most important sources are the bladeBlade-slap is a loud impact noise which
occurs at the blade passing frequency - typically 15 to 20 Hz - and when
it occurs it can cause extreme annoyance.
It is usually associated
with tandem rotor helicopters and those helicopters with a two blade
single rotor, although it can be generated to some extent on practically
all helicopters (1).
Opinions differ as to the exact cause, but the most
likely hypothesis (2) is that it is caused by a blade/vortex interaction
mechanism.
The methodology for predicting helicopter noise in the far field
is similarly very complex also;
the initial process being one of pseudo­
convection with the directivity of the advancing blade, resulting in
many cases in an epicentric curling of vortices predominantly along one
side of the flight track.
In the mid-field, often these ride over on­
coming low level wind; producing increased noise levels upwind,
i.e.,
the converse of noise from conventional take-off and land aircraft, with
the exception sometimes of some turbo-propeller varieties - as discovered
by researchers during the design considerations for the Schiphol and
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14
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Saltholm Airports in the Tîethorlandc (3)»
This lasts until tho individual
vortices expend all their energy as sound and heat, at which point the
pulse propagates in a more conventional manner.
But this too is complic­
ated by the nature of the pulse and the directivity it has gained by the
air movement*
Hence the pulse itself - basically one of a narrow band
signal in the 250 Hz range, on a carrier wave of about 20 Hz - is not
exactly conventional and the polar spread, air attenuation and ground
absorption properties differ considerably from conventional aircraft
spectra.
One of the greatest problems is in determining the lateral propagation,
i.e., the noise propagation at right angles to the helicopter track.
Hoine
levels in the mid-field - up to 2000 feet or so - do not continuously
decrease with distance.
Nor is the noise from a single event symmetrical
about the flight track, except for a few helicopters at fairly high
altitude.
The shape of the noise footprint also differs from one heli­
copter variant to another of the same model.
ouch considerations make
the computation process very difficult and time consuming.
The effect of the topography and general climate of the area under
consideration is critical and, in all helicopter noise prediction work,
raw base data, within tho particular geographical confines of the area
under consideration, must be obtained.
The noise exposure contours for
a certain group of helicopters in, say, Nova Scotia will be quite differ­
ent from the noise exposure contours for the same helicopters doing
exactly tho same operations in, say, Alberta or evon another part of
Nova Scotia!
Sub.jective Considerations
Subjectively, blade-slap is perhaps the most important noise source
on helicopters in certain flight regions.
It is fairly clear that conven­
tional use of PNL or dBA rating methods do not adequately account for tho
subjective effects or intrusiveness of helicopter noise when it is
dominated by blade-slap.
This has been shown clearly by a number of
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15
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investigations (4? 5)®
However, few studies have been carried out to
develop a suitable method for differentiating between slapping and
non-slapping helicopters or to determine the subjective penalty.
The most comprehensive study has been by John Leverton - considered
the world authority on helicopter noise - and his acoustics group at
Westland Helicopters (6).
From a comprehensive series of subjective
tests of noise from slapping and non-slapping helicopters, they found
that a simple add-on type of correction for impulsive helicopter noise
v/as possible, the correction factor being directly related to the Crest
Factor of the noise in the 250 Hz octave band i.e., (Peak Linear - Slow
Response) in the frequency range from about 200 to 400 Hz,
Munch and King of Sikorsky Helicopters (7) undertook a study for
N.A.S.A.
on the Community Acceptance of Helicopters and came to a very
similar conclusion*
Figure 1 shows the findings in graph form°(8).
Considering the two studies had no inter-relationship and were separated
by some thousands of miles and subjects were of different types, the
results are remarkably alike*
When suitable instrumentation is not
available, the F.A.A. has suggested (9) a. +7 dB correction to meter
readings when blade-slap is present, i.e., as a rough guide, impulsive
helicopter noise is subjectively the same as that from a jet aircraft
that is 7 dB noisier.
The helicopters we find most common in military circles are derivatives
of the Bell model 209 (AH1), the Bell model 204 (UH1), the Boeing Vertol
model 107 (CH46) and the Sikorsky S61
(CH53)«
On the occasions that
blade-slap occurs, the envelope of propagation is in the forward direction
only.
The blade-slap for small single rotor helicopters, such as the AH1J
and the UH1N, we believe follows that of a cone of half angle 10° centred
about the forward axis of flight.
Measurements on the twin rotor CH46
lead us to believe that the blade-slap, although still in a forward
direction only, is not symmetrical but follows -that of a skewed cone
Cf
where on the left hand side of the craft the half angle is about 10 but
0
on the right hand side the half angle approaches 4 4 s with a sharp trans-
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16
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ition on the
flight track,
difficult
to m e a s u r e
have u s e d
are pr ec ise.
if there
and we are by no m e a n s
But,
a few d e g r e e s er ro r is not
As
the p r o p a g a t i o n
correction
history
c e r t a i n that
2).
a straight
The net
inte rv al s.
eff ec t
effects.
is m o r e
The
an in cr eas e
in
c o r r e c t i o n is a p p l i e d
To b r i n g this c o m p u t a t i o n
pe ak l e v e l of the time his to ry ,
the curve
and
i ni ti al
the A w e i g h t e d so u nd p r e s s u r e
within
bounds,
this
10 d B d o w n point and the
extrapolated
le v e l + the
back to the
subjective
correction
10 d B b e l o w the p e a k level®
We b e l i e v e
riate e x t a n t
procedure
this W e s t l a n d
im p u l s i v e
for this type of noise.
is n o w u n d e r d e l i b e r a t i o n
Organisation
correction
to be the m o s t
It is u n d e r s t o o d
by the
for a s t a n d a r d on h e l i c o p t e r n o i s e - to be
to a noi se d e s c r i p t o r ,
and s h o u l d t h e r e f o r e
of a n o i s e
equivalent
c h ang e
le ve l
a ni g h t w e i g h t e d e q u i v a l e n t
ge n e r a l use®
States,
the n a t u r e
the na me as well.
c o r r e c t i o n of any
of that d e s c r i p t o r
is g a i n i n g ac cept a n c e .
level - the D a y / N i g h t
In the U n i t e d Sta tes ,
Level
impa ct
correction,
Imp act W e i g h t e d D a y / N i g h t L e v e l
In an Air I n s t a l l a t i o n
nois e
issu ed shortly .
- is in
in the U n i t e d
r a t h e r th an to
the na me of the no is e d e s c r i p t o r we have,
u s e d the term
assessment
C o m p a t i b l e Use
Z o n i n g st u d y
e mp loys only a few spot
the c o n t o u r s b e i n g p r e d i c t e d
this c o r r e c t i o n
I n t e r n a t i o n a l l y , the use
For our s t u d i e s of h e l i c o p t e r no is e
oojnpletely change
aircraft
one ch a n g e s
ba sed on this unit w i t h a s u b j e c t i v e
c o n fusio n,
that
approp­
International Standards
It m u s t be s t r e s s e d that by u s i n g a s u b j e c t i v e
sort
the s u b j e c t i v e
a d d i t i o n to the p e a k le v e l as in other
the
wa s
factors p re s e n t ,
can be a p p l i e d on ly on the rise of the time-
was a p p l i e d to the i n t e r v a l b etwe en
point wh e r e
is v e r y
the fi g u r e s we
fo rw ard d i r e c t i o n only,
to q u a l i f y the s u b j e c t i v e
at h a l f - s e c o n d
angle
sign if ica nt .
(as shown in F i g u r e
at t e m p t s
Th is
w i t h all the e n v i r o n m e n t a l
is in the
for b l a d e - s l a p
d u r a t i o n and not
is no wind.
to save
IL^,.
(AICUZ)
usually
c h oc ks of noi s e
level;
s o l e l y by the use of a c o m p u t e r progr am.
-
17
-
the
Thi s inc orp or at es a comprehen sive
file of sourcer-noise reference data
on the usual aircraft types - by cate gory only - that are encountered at
m il i ta r y airfields.
er abl y less.
aircraft,
Ra r e ly arc more than 9 categories used, often con s i d ­
Also,
this reference data is ex clusivel y for fixed wi ng
there being rea lly no comparable noise data for rotorcraft.
Indeed few pr og ra ms can include rotorcraft except
pro pag at io n applies.
by assum in g conventional
Wi th only one or, maybe, two exceptions,
cannot acc omp l is h pre dictions in, and are not intended for,
he licopters
cases where
form a sign ificant part of the total traffic.
B i c k e r d i k e ,Allen was,
N a vy to pro du ce noise
Of course,
the programs
a short while ago,
commissioned by the U.S.
contours for bases where hel ic opters predominate.
in order to get a true idea of the base data,
m e asur em en t study should be undertaken.
a four season
Rut, all programme s - p a r t i cu l ­
arly for the M i l i t a r y - have time lim it ations and so me as ur em en ts have
to be confined to a short period only.
become Apri l or May,
Inevitably this has,
when it has been supposed that rea so na bl y average
sort of con di ti on s for the year occur.
Corps Air St a t i o n
in the past,
(Helicopter)
One such study was for the Ma r i n e
at New River North Carolina,
and its o u t l y i n g
fields of Oak Grove and Camp Davis.
The Ma ri ne
Pl an ni ng Zone
Corps Air Station is loc ated in the de signated West
in the northw est area of Camp Lejeune.
occupies about Z*700 acres
North Carolina,
Base
The air station
to the south and east of the city of Jacksonville ,
with two out ly in g fields in the nearby "Boondocks" - a
word actually o r ig in at in g in Camp Lejeune
from marine operati ons in
the
Philippines.
For d a t a acquisition at various locations,
consisted of a pair of Genrad
our main me as u r i ng systems
1933 Pr ecision Sound Level Mete rs each
ing one channel of a Uhe r CR134 stereo recorder,
Esterl ine
Angus Min ise rv or ec or de r.
the slow mode rec o r d in g in
and,
in the dc mode,
feed­
an
One of the sound level meters was in
'A' wei ghted deciBels,
the other in the impact
mode was spe c i al l y converted to accept a 50 micro-sec on d
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18
-
rise
time held
to
a 50 milli-second decay time operating in the 250 Hz octave band.
The
Uher recorder was also specially prepared so that with Maxell UD tape it
was capable of capturing a 70 micro-second rise time in the frequency
range 18 to 15,000 Hz.
This type of system enabled an immediate determin­
ation to be made of the crest factor for each event at that location,
related to dBA slow response, as well as providing recorded material for
later analysis.
Hindsight, however, showed that if a system is working
the benefits of immediate
'viewing'
that the system is working.
are marginal - except of course to show
A system comprising a Castle CS 1 92B Precision
Sound Level Meter feeding the Uher recorder was found much more convenient
and probably more accurate.
Calibration was carefully maintained, of
course, and a continual check of compatibility between the several systems
used made by recording some events at each location with
a
Bruel and
Kjaer 2209 and Nagra ifS recorder, and comparing the results in the slow
mode - the Nagra and its Ampex tape had not been specially prepared to
accept the 70 micro-second rise time.
In addition to noise recording, meteorological conditions at each
location were measured - wind, temperature, humidity etc., - and this
data used in conjunction with the macro data from the local meteorological
station.
Polaroid photography was used to determine the altitude of
each helicopter, and radio contact maintained for details of speed and
power setting.
Also for future use, rough estimates of the ground
impedance were made by the 'Free Field Method'
(11).
In the laboratory, real time analysis was not possible, and the
data analysis was accomplished using Bruel and Kjaer 2120, 2113 and 2209
+ 1616 frequency analysing systems recording on B & K type 2305 level
recorders.
An oscillograph was used to check the crest factor determin­
ations.
The primary aim of the measurement programme was to accumulate
sufficient noise data on each of the various types of aircraft under
each operational mode sequence, to allow typical noise event levels to
be predicted within a reasonable confidence level at any position for
-
19
-
any operational activity.
For maximum accuracy and sensitivity the
majority of recordings were made in relatively close proximity to the
source aircraft, and this meant most were in the air base confines* . A
second purpose was to measure actual events encountered in adjacent areas
and on cross-country routes to act as corroborative tests of the. levels
predicted for such areas*
Since it was quite impracticable to obtain data on all the types of
aircraft in use at these bases, the k main types comprising 8k% of all
helicopter'movements were selected*
Lateral and longitudinal traverses
were made of the initial part of the flight envelope, as well as a com­
plete traverse of the base itself to obtain the effects of engine
testing and maintenance operations and to delimit the effects of the
various barrier buildings and obstacles on base.
A large number of
measurements were made in the nearby city, but at no time was the heli­
copter noise in the same order as that from the surface transportation.
Observations.
The directionality of the impulsive blade-slap and the overall
strange propagation was very noticeable.
In particular, this region has
many small drainage ditches and inevitably the noise recorded on the far
side v/ould be greater than that on the near side.
ation for this.
We can give no explan­
Also, on base for low altitudes of rotorcraft (50 feat
or so) noise levels at 800 feet laterally were often well in excess of
those at 200 feet and 400 feet.
This can perhaps be explained by the
directionality of the pulse and the effects of fuselage shielding.
a helicopter
bearing towards, but a few degrees off, the wind direction
the main noise event may be completely to one side of the track.
with no wind,
With
by
Howe v e r ,
taking into account the directionality of pulse and
the shielding, it has been found that a reasonable prediction can be m a d e <
A derivative of the British Noise Model has been adapted to utilise this
data and performs well provided the wind can be assumed zero.
little wind and things are not so good at all.
-
20
-
Just a
The contours produced for New IRiver arid shown in Figures 3 and
being the true L ^ T and the Impact corrected
respectively.
Where
barriers occurred on the base, much weight was given to interpolation
of measured values rather than predictions for no satisfactory theory
for the passage of such a noise over a barrier has yet been devised
(we believe).
Figure 5 shows the contour for Camp Davis.
It is interesting to
note that at one point this contour is actually outside the track.
This
is due to the large majority of flights by the CH^+6, which in a bank
produces an extremely lop-sided impact noise footprint.
A selection of some of the data recorded is given in tables 1-1
l-*f.
This work was supported by the United States Navy Southern
Division under contract No. N62^67-76-C-0860.
Their permission
to present this paper is acknowledged.
This paper was presented at the Annual Meeting of the CAA, Halifax, Nova
Scotia, November 1978.
-
21
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to
References:
1
Southwood B.J. et al. Acoustics Note 1162.
Westland Helicopters
Institute of Acoustics Spring Conference U.K. 1976.
2
Leverton J.W.
Helicopter Noise Assessment. Westland Helicopters 1976.
3
Ingerslev F . , and Svane C., Lydteknisk Laboratorium, Selvejende Institution
Tilknyttet, Akademiet for de Tekniske Videnskaber.
k
Leverton J.W. "Helicopter Noise:
Can it be Adequately Rated?" Proceedings
of Symposium on Noise in Transportation. 8th I.C.A. Southampton 1976.
5
Southwood B.J. "The 'Rating and Subjective Assessment of Helicopter BladeSlap" Institute of Acoustics April 1976.
6
Leverton J.W. et al. "The Rating and Assessment of Helicopter Noise"
Applied Acoustics Note 11^-7* Westland Helicopters 1976.
7
Munch C.L. and King R.J. "Community Acceptance of Helicopters, Noise:
Criteria and Application" NASA CR-132^30 June 197^+ •
8
Extracted from references 2, 6, and 7.
9
Federal Register Vol 42 No. 2. Title 32 National Defense Part 256.10
USA.
10 Air Installation Compatible Use Zone Study. MCAS(II) New River. Southern
Division Naval Facilities Engineering Command, U.S. Navy.
1978.
11 Dickinson P.J. "Free Field Measurement of the Acoustic Impedance of
Ground Surfaces."
Institute of Sound and Vibration Research 1969 .
-
22
-
Impulse
Correction
dBA
BLADE-SLAP IMPULSE CORRECTION
Crest Factor
T"
11
'
S
( Peak 2 0 0 “ 4 0 0 H z ) “ dBA Slow
I
I
12
13
14
Crest Factor ( P e a k - S l o w )
I
15
2 00 — 400Hz
FIGURE 1
-
23
-
EXAMPLE OF IMPACT CORRECTED dBA
TIME HISTORY FOR A HELICOPTER OVERFLIGHT
dBA rms
slow
impact corrected
\
\
10dB
\
x
x
X.
T------ I------ I------ I”
T
T™™™r™T
Time
1—
T—
10
S
in seconds
FIGURE 2
-
24
-
T— T
t------ r
15
New River Marine Cortis Air Station,
True_LDN__l2Z2
^A C K S pN V Æ LE
GwJgM of n f
M'qfit S«h»a»
W ils o n I
| i r w i 47i
W ilson
B ay
[
^
R<V«»> D«y
4
^ M u rti fo r< j P o il
h'
bfan 51
P@int
V a Traiter pïrfcT
fro < < p « » P o in t
Scalo
1^50,000
?
Figure 3
-
25
-
New River Marine Corps Air Station (Helicopter)
at k '6"
Impact weighted
1977
'Sf: vM j ^<JACKSDNVIT-,T.F
J1
ltfWl47
W ils o n
M o i USl
Ba\f_
CnveintnitafeKffi*
LTtfrcr pâfîr'
r«v Oa/WâVh <3
f4
Tu'i ;. I SMC4È
Rsgg©d Point
^Rafgfld
]
[Tfgilef pùiC
tfo U riés P o in t
LüttUjRag jed
L>|M U
0
1
Scale 1:50 000
1
»
2
«
3
4 8 6 7 8 9
10
«-._1— 1 — 1 — 1 — s.— i - _ i
thousands of feet
Figure /+
-
26
-
Noise Contour Map
Impact Weighted
3
—
..V SV M .W
0
t—
1977
Zone 2 ( 6 5 - 7 5 L DN)
Station Boundary
Figure 5
Exhibit 9B
HOLF CAMP DAVIS, NC
-
27
-
7.000
,
4 CX»
Table 1-1
Representative Single Event Noise Levels. dBA
Maneuver: Level Flight
Temperature ®F
R.H.
Wind
Ground Imped, estim®
3 - 9i
ground
500 ft
Roughness length esti®. .005m
66
77
Not signif
55%
Skies:
Clear
Aircraft Hor.dist Slant ht Track Bearing Speed Crest
SEL
selt
Imp
CH46
0
500
230
20+
240
94.6
98®8
800
950
230
320
ft/s
20+
90.9
95.4
1600
1690
230
320
240
20+
85.4
90.5
0
1000
230
240
20+
90.6
95.2
800
1300
230
320
240
20+
89.2
94.2
1600
1900
230
320
240
20+
92*2
86.9
400
640
CH53
230
HO
11
250
92.3
92.3
800
950
230
320
11
250
89.6
89.6
1600
1700
230
320
11
250
83.4
83.4
400
1080
230
11
HO
250
88.7
88.7
1600
1900
230
320
11250
84.8
84.8
UH1N
0
500
230
180
20+
95.6
100.4
800
940
230
320
180
20+
92.7
97,8
1600
1670
230
320
180
20+
87.8
93.1
AH1J
400
570
230
HO
300
20+
93.0
97.7
800
230
895
300
HO
20+
95.6
90.3
800
940
230
320
300
20+
95.2
89.9
3200
3240
230
320
300
20+
78.1
83.5
0V10
0
500
180
290
92.0
92.0
800
950
180
090
290
88.5
88.5
1600
1680
180
090
290
82.3
82.3
0
1000
180
090
290
87.8
87.8
800
1280
180
090
290
85.6
85.6
1600
1 890
180
090
290
81.8
81.8
«
-
—
—
—
—
«
I
■p
I
-p
o
CQ
n
o
+>
<
-
28
-
Table 1-2
Maneuver:
Representative Single Event Noise Levels. dBA.
Level Flight
Temperature *F
ground
5 0 0 ft
80
66
R.H.
Wind
58%
Not signif
Ground Imped.estim.
4 - Hi
Roughness length estim. .00005m
Skies: Clear
Aircraft Hor.dist Slant ht Track Bearing Speed
0
CH/+6
CH53
AH1 J
CH46
CH53
97.4
95.8
93.6
101 .5
100.1
98.1
360
360
250
250
250
111 111-
96.5
94.8
92.1
96.5
9*4.8
92.1
270
270
270
360
360
300
300
300
20+
20+
20+
96.2
94.7
92.3
100.3
99.5
97.7
090
090
090
090
360
360
360
360
240
240
240
240
20+
20+
20+
20+
95.3
93.0
92.7
91 .8
99.7
97.6
97.5
96.9
090
090
360
360
250
250
1111-
9 1 .5
91 *5
90.2
9 0 .2
800
0
400
800
500
640
940
270
270
270
0
400
800
490
650
950
400
800
400
800
640
940
1100
1300
400
800
1100
+>
«
©
«M
SELt
Imp
20+
20+
20+
270
270
270
1300
SEL
240
ft/s
240
490
630
930
400
Crest
«
360
360
«.
-P
a>
e>
<1-1
£
o
■n
CQ
T3
O
-P
<
-
29
-
Table 1-3
Maneuver:
Representative Single Event Noise Levels. dBA.
Climbing turn
Temperature *F
ground
500 ft
77
66
R.H.
55%
55%
Wind
Ground Imped.estim.
3 - 9i
Roughness length estim. .005m
Skies: Clear
Not signif
Aircraft Hor.dist Slant ht Track Bearing Speed
CH46
CH53
UH1N
AH1 J
.
0
400
800
400
800
800
800
800
800
300
0
400
800
400
800
800
800
300
500
850
500
850
900
900
left
turn
0
400
800
400
800
800
800
290
500
850
500
850
900
900
left
turn
0
400
800
400
800
800
800
800
800
300
490
850
510
850
left
turn
900
900
inside
outside
right inside
turn outside
510
850
490
850
900
900
850
850
850
850
inside
turn
outside
turn
inside
outside
right inside
turn outside
left
turn
—
Crest
SEL
SEL,
Imp
20+
20+
20+
20+
20 +
20+
20+
20+
20+
11
97.6
95.6
91.4
94.6
90.0
92.0
90.8
93.0
90.4
11 —
11—
11 —
11 —
11-
97.6
95.0
90.2
94.0
88.8
90.8
89.7
102.6
100.5
96.4
99.5
95.2
97.3
95.9
98.7
95.3
97.6
95.0
90.2
94.0
88.8
90.8
89.7
11 —
11 —
11 —
11 —
11
11
11
97.9
96.2
93.0
95.6
91.7
93.8
92.6
97.9
96.2
93.0
95.6
91.7
93.8
92.6
11
11
1111
11—
1111
11
11-
96.8
94.7
90.4
93.7
89.4
91.1
96.8
94.7
90.4
93.7
89.4
91.1
90.0
89.9
89.1
—
inside
ee
outside
9*
inside
outside
**
inside
as
outside
CO
CO
0)
8S
CO
CO
cfl
inside
outside
-p
o
35
inside
—
—
-
—
—
09
outside
—
90
—
—
+•>
<
-
30
-
90.0
89.9
89.1
Table 1 -if Representative Single Event Noise Levels. dBA
Maneuver:
Approach
Wind
ReH®
Temperature *F
ground
500 ft
Not signif
66
77
55%
Aircraft Hor.dist Slant ht Track Bearing
CH46
CH53
UK1 N
0
400
1600
400
1600
0
400
800
400
800
0
400
1600
0
400
1600
0
400
800
0
400
800
AH1 J
0V10
400
570
1650
570
1650
200
450
825
450
825
400
570
1650
200
450
1610
050
400
560
890
200
450
820
050
050
050
050
050
050
400
570
050
050
050
050
050
050
050
050
050
050
050
050
050
050
050
0
400
800
0
400
800
200
450
820
050
050
050
050
050
050
0
800
0
800
400
890
200
820
180
180
180
180
900
Ground Imped.estim®
3 - 9i
Roughness length estim. .005»
Skies: Clear
SELtImp
Speed Crest
SEL
140
140
320
320
-
140
140
320
320
a»
140
320
140
140
320
-»
140
320
T3
At
UJ
CO
CO
—
CO
CO
140
320
si
•p
o
»
z
140
320
—
140
320
20+
20+
20+
20+
20+
20+
20+
20+
20+
20+
111111111111-
95.9
93.9
85.0
93.8
85.1
100.0
95.3
90.0
95.1
90.0
101 .1
99.6
91.0
99.7
91.4
105.0
100.8
95.8
100.8
96.0
95.6
93.2
83.1
100.4
94.8
82.2
95.6
93.2
83.1
100.4
94.8
82.2
13
14
14
16
17
17
96.1
95.0
92.9
99.7
96.1
91. 6
97.6
96.8
94.9
103.3
100.0
95.8
13
14
15
16
18
18
94.4
93.0
90.3
99.2
94.4
89.0
96.2
95.0
92.5
103.0
98.5
93.3
92.0
86.3
97.8
87.0
92.0
86.3
97.8
87.0
»
270
270
g
o
T3
4 ->
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31
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