1
T00088: ARC-SIRIL
1
T00088: ARC-SIRIL
2
Aviation Regulation Conformal - Surface Intensity Reduced Intelligent Lighting
1
1
3
4
Lighting concept for the proper observance and optimization of safety relevant requirements of
5
an identification of obstructions to aviation at wind power plants at night
6
7
8
9
10
11
12
13
14
15
16
We are specially grateful to Ferdinand Behrend (TU-Berlin), Florian Holzapfel (TU-Munich) and Jörn
17
Jakobi (DLR) for their professional support.
18
19
20
21
31.03.2015 - Version 1.7
22
Lanthan Gesellschaft for technische Entwicklungen mbH & Co. KG
23
D 28195 Bremen – [email protected]
24
T00088 _ARC-SIRIL 20150331-en
T00088: ARC-SIRIL
2
2
2
25
Table of Contents
26
List of abbreviations ................................................................................................................................. 4
27
1
Summary ......................................................................................................................................... 5
28
2
Technical Definition of the Lights..................................................................................................... 7
29
2.1
Light A ...................................................................................................................................... 7
30
2.2
Light B ...................................................................................................................................... 9
31
2.3
Light C (IR light) ..................................................................................................................... 10
32
2.4
Light D (IR light) ..................................................................................................................... 11
33
2.5
Ranges of the Lights .............................................................................................................. 12
34
2.5.1
Light W, red (actual AVV) Threshold Light Intensity 1E-6 Lux ...................................... 14
35
2.5.2
Light W, red (actual AVV) for Threshold Light Intensity 2E-7 Lux ................................. 14
36
2.5.3
Light A (Substitute Light W, red) Threshold Light Intensity 1E-6 Lux ............................ 15
37
2.5.4
Light A (Substitute Light W, red) Threshold Light Intensity 2E-7 Lux ............................ 15
38
2.5.5
Obstacle light (actual AVV) Threshold Light Intensity 1E-6 Lux .................................... 16
39
2.5.6
Obstacle light (actual AVV) Threshold Light Intensity 2E-7 Lux .................................... 16
40
2.5.7
Light B (Substitute for obstacle light) Threshold Light Intensity 1E-6 Lux ..................... 16
41
2.5.8
Light B (Substitute for obstacle light) Threshold Light Intensity 2E-7 Lux ..................... 16
42
3
Lighting Concept Light A / Light B ................................................................................................ 17
3.1
43
General Rules ........................................................................................................................ 17
44
3.1.1
Weather Minima............................................................................................................. 17
45
3.1.2
Minimum Safety Height.................................................................................................. 18
3.2
46
Operative Safety Concept ..................................................................................................... 19
47
3.2.1
Light Effect above 0° ..................................................................................................... 26
48
3.2.2
Light Effect below 0° ...................................................................................................... 29
49
4
IR-Light Lighting Concept .............................................................................................................. 30
50
4.1
Test Array .............................................................................................................................. 30
51
4.2
Technical IR Light Specification ............................................................................................ 32
52
4.2.1
Light 1 ............................................................................................................................ 32
53
4.2.2
Light 2 ............................................................................................................................ 33
54
4.2.3
Light 3 ............................................................................................................................ 34
55
4.3
System Settings ..................................................................................................................... 35
56
4.3.1
Intensity ......................................................................................................................... 35
57
4.3.2
Flashing Cycle ............................................................................................................... 35
58
4.3.3
Web-Interface ................................................................................................................ 35
59
60
61
4.4
Preliminary Results ................................................................................................................ 35
3
T00088: ARC-SIRIL
3
3
62
List of figures
63
Figure 1-1:
Alternative lighting concept .............................................................................................. 7
64
Figure 2-1:
Limits of the photometrical light intensities of the light A and the light W, red (ES) ........ 8
65
Figure 2-2: Limits of the photometrical light intensities of light B and of the obstacle light (ES) ............. 9
66
Figure 2-3: Limits of the IR intensities of light C .................................................................................... 10
67
Figure 2-4: Minimum of the IR intensities of the light D ........................................................................ 12
68
Figure 3-1:
69
meteorological visibility of 10000 m ....................................................................................................... 23
70
Figure 3-2:
71
meteorological visibility of 5000 m ......................................................................................................... 24
72
Figure 3-3:
73
meteorological visibility of 800 m ........................................................................................................... 25
74
Figure 3-4: Radiation above 0° .............................................................................................................. 27
75
Figure 3-5: Radiation above 0° .............................................................................................................. 28
76
Figure 3-6:
77
Figure 4-1: Location of the test equipment ............................................................................................ 31
78
Figure 4-2: Light MB20-IR ..................................................................................................................... 32
79
Figure 4-3: IR-Intensity [mW/sr] of the MB20-IR ................................................................................... 32
80
Figure 4-4: MB17UK-IR ......................................................................................................................... 33
81
Figure 4-5: IR-Intensity [mW/sr] of the MB17UK-IR .............................................................................. 33
82
Figure 4-6: Low-Intensity IR light ........................................................................................................... 34
83
Figure 4-7: IR-Intensity [mW/sr] of the modified HF102 ........................................................................ 34
84
85
Comparison of the ranges of light A and B with light W, red, and the Obstacle light at a
Comparison of the ranges of light A and B with light W, red, and the obstacle light at a
Comparison of the ranges of light A and B with light W, red, and the obstacle light at a
Ranges below 0°............................................................................................................ 29
4
T00088: ARC-SIRIL
86
List of abbreviations
87
AVV ............................................General Administrative Regulation
88
BNK ...........................................Proper Night Identification
89
ES ..............................................Extended Specification
90
ICAO ..........................................International Civil Aviation Authority
91
IR ...............................................Infrared Light
92
LuftVO........................................Air Traffic Regulations
93
MOD ..........................................Ministry of Defence
94
LFZ ............................................Aircraft
95
SAR ...........................................Search and Rescue
96
WEA...........................................Wind power plant
4
4
5
T00088: ARC-SIRIL
5
5
97
1
Summary
98
This document presents two extensions and supplements to the existing systems for the identification
99
of obstructions to aviation of wind power plants (WEA) at night.
100
The system for night identification currently applicable is defined in the currently valid General
101
Administrative Regulation for the Identification of Obstructions to Aviation“ (AVV). According to §26 of
102
the AVV there exists the possibility to deviate from the prescribed identification by a special regulation
103
of the Federal Ministry for Transport und Digital Infrastructure (BMVI) and to use an alternative
104
concept. Such a special regulation is envisaged for the alternative lighting concept described in the
105
present document.
106
The first system is an alternative to the previous configuration and is a proposal for the substitution of
107
the previous light W, red, and obstacle light. The second system is composed of infrared lights and is
108
presented as non-binding supplement to the previous system or the herein presented substitute
109
system.
110
The alternative system presents improved properties with regard to light emission and the thereby
111
resulting acceptance by the residents. The latter up to now is strongly influenced by the high light
112
emission of the equipment at night. In Particular WEA plants with a total height above 100 m include
113
various light elements (light W, red / obstacle light) which are considered by the affected residents as
114
intrusive. The reason for which the Federal Ministry for Transport and Infrastructure at present is about
115
to revise the General Administrative Regulation for the Identification of Obstructions to Aviation (AVV)
116
to provide possibilities for a needs-oriented lighting This revision, however, will not be affected by this
117
concept. A technically realized radiation limitation of the previous lighting elements from the horizontal
118
level downwards shall significantly reduce the light emission close to ground level. An analysis of the
119
valid regulations regarding the operative realization of air traffic within the range of WEA and a
120
corresponding technical design of the lighting elements is not expected to decrease the existing level
121
of safety. By the technical improvement of the lighting effect in positive vertical direction. an increase
122
of the actually applied maximum not illuminated range of 65 m above the light W, red, will be possible.
123
This concept shall demonstrate that the safety lev el will not be impaired by the herein proposed
124
modifications, but rather be improved in many cases. Besides that it will allow for an enormous
125
increase of the acceptance of the further extension (and also the refurbishment of existing wind farms)
126
of the wind power, at a relatively small expenditure. With the options provided the air traffic can be
127
increased with regard to visibility above the wind farm and the visibility below the wind power plant
128
gondola with residual light amplifying visibility systems
129
Additional infrared (IR) lights not visible by the human eye may be used as supplement to the existing
130
system and will increase the visibility of the WEA, e.g. for the operational traffic of the federal police
131
and Search and Rescue (SAR) units. These normally are equipped with night vision equipment and
132
thus can detect the used IR lights. This will permit a substantial improvement of the affected air traffic.
6
T00088: ARC-SIRIL
6
6
133
Traffic analyses have shown that these traffic types represent the major part of aviation traffic at night
134
at low flight height (federal police, SAR, military low altitude flights).
135
Both systems work independently on the proper night identification and are permanently active at night
136
(BNK), therefore this concept does not affect the amendment of the AVV.
137
As previously the lighting elements will be attached to the tower and to the gondola. Figure 1-1 shows
138
the night lighting concept by the example of an E-126 WEA of Messrs. Enercon. As tower identification
139
four modified obstacle lights (light B) and four additional low-intensity-Infrared lights (light D) are
140
active. To the gondola two infrared lights (light C) and two modified lights W, red (light A) are mounted.
141
From the beginning of April 2014, on request of the BMIV, together with the federal police a field test is
142
being carried out regarding the use of IR lighting elements on WEA. The first results are presented in
143
4.4.
144
The lighting systems are designed for the whole aviation traffic – independently on its purpose or
145
equipment – taking place in the neighbourhood of a WEA. The herein presented systems are no
146
demand driven night identification (BNK). Contrary to the BNK, these systems are permanently active
147
at night. Both systems work independently from each other and thus can be used separately.
T00088: ARC-SIRIL
7
7
7
148
149
Figure 1-1:
Alternative lighting concept
150
2
151
The following section deals with the technical description of the corresponding lighting elements, in
152
particular with the modified radiation angles of the alternative lighting concept. A comparison of the
153
previous and of the new lighting elements will be made by tables and graphs.
154
2.1
155
The light A is a modified light W, red (ES) and shall be used as substitute for the actually used light
156
W, red.
157
The light has been modified with regard to its visible radiation in the angle range downwards (see also
158
Figure 2-1). In the graph the blue curves show the minimum and the maximum photometrical light
Technical Definition of the Lights
Light A
8
8
T00088: ARC-SIRIL
8
159
intensity of the actually used light W, red (extended specification, ES). The red curves show the
160
minimum and the maximum photometrical light intensity of the new light A.
161
The light A works like the light W, red, range controlled, i.e. the intensity will be adapted as function of
162
their actual horizontal visibility. The corresponding parameters applied are identical to those of the light
163
W, red.
photometrical radiation value in [cd]
300
Feuer A min.
Feuer A max.
Feuer W, rot min.
Feuer W, rot max.
250
200
150
100
50
0
-20
-15
-10
164
-5
0
5
vertical radiation angle
10
15
20
165
Figure 2-1:
166
The colour of the light corresponds to the requirements of the ICAO annex 14 volume I enclosure 1
167
item 2.1 Colours for aviation ground lights.
168
The light intensity must be referred to the horizontal line in the below indicated vertical angle ranges
169
and reach for each horizontal direction (0° < Φ < 360°) the corresponding required minimum values.
170
Light A will be operated with analogous cycles to Light W, red. The cycle sequence will be: 1 s bright –
171
0.5 s dark - 1 s bright – 1.5 s dark
172
If the light, in new condition, can be set to permanent operation, e.g. for photometrical purposes, an
173
estimate between photometrical light intensity Iphoto and effective operating light intensity IBetrieb will
174
result.
175
Limits of the photometrical light intensities of the light A and the light W, red (ES)
IBetrieb in cd
Iphoto in cd
100
170
20
34
2
3,4
9
9
T00088: ARC-SIRIL
9
176
Basically the light A will correspond to the requirements of the previously used light W, red, with a
177
radiation angle reduced by 10° to the ground (see also Figure 2-1).
178
2.2
Light B
180
The light B is a modified obstacle light. Like the light A, the light B will have a vertical radiation angle
181
limited towards the ground. It shall serve as complete substitute for the previously used obstacle light
182
for mast identification.
183
The light B corresponds to the ICAO recommendations for Low Intensity Light type A without any
184
limitations.
185
Figure 2-2 shows by the red curves of the minimum and of the maximum intensity of the new light B.
186
The blue curves show the minimum and the maximum intensity of the previous obstacle light (ES) acc.
187
to AVV (the maximum curve is a proposal for the actual AVV draft).
photometrical light intensity in [cd]
179
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Feuer B min.
Feuer B max.
Hindernisfeuer min.
Hindernisfeuer max.
-30
-25
-20
-15
188
-10
-5
0
5
10
vertical radiation angle in [°]
15
20
25
30
189
Figure 2-2: Limits of the photometrical light intensities of light B and of the obstacle light (ES)
190
The minimum light intensity, referred to the horizontal line within a vertical angle range of +6° to +10°,
191
for each horizontal direction (0° < Φ < 360°), shall amount to 10 cd. At the vertical angles of +4° and
192
+14°, the minimum light intensity, referred to the horizontal line, shall amount for each horizontal
193
direction (0° < Φ < 360°) to 5 cd.
194
The maximum light intensity may, referred to the horizontal line, in each horizontal direction (0° m Φ <
195
360°), amount to the following values (see also Figure 2-2):
196
•
In a vertical angle range of -30° to -2° = 2 cd
•
197
10
10
T00088: ARC-SIRIL
10
In a vertical angle range of -2° to +7° in accordance with a linearly increasing development of
the light intensity from 2 cd at -2° to 25 cd at +7°
198
•
199
In a vertical angle range of +7° to +30° = 25 cd
200
2.3
202
The light C is an IR light and will be mounted in addition in the position of the light W, red, (see also
203
figure 1-1). These lights shall be used, as already mentioned in the beginning, as complementary but not
204
mandatory light elements. They can be seen at night by aircraft commanders equipped with
205
corresponding night vision equipment for performing their special flight task (e.g. patrolling flights of the
206
federal police, military low-altitude flights at night). Thus they serve as additional aid for the identification
207
of a WEA plant as relevant aviation obstruction and may contribute considerably to increase of the
208
situation awareness.
209
In the wind energy park of Wiemersdorf two alternative models have been installed for this light for the
210
evaluation by the Federal Police Aviation Squadron of Fuhlendorf. Section 4 includes a short description
211
of the previous experience based on the test operation.
IR-Intensity [mW/sr]
201
Light C (IR light)
2100
2000
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
100 %
75 %
50 %
25 %
MOD-Maximum
MOD-Minimum
-20
212
213
-15
-10
-5
0
5
10
15
vertical radiation asngle in [°]
Figure 2-3: Limits of the IR intensities of light C
20
25
30
35
11
T00088: ARC-SIRIL
11
11
214
The red curves in figure 2-3 show the limits of the IR light model 1 which comply with the specifications
215
already being used of the British Ministry of Defence (MOD) by the Royal Air Force in Great Britain.
216
The four further colored curves identified by 25 %, 50 %, 75 % and 100 %, represent the properties of
217
an alternative to model 1 (model 2). Light C model 2 is a modified light W, where the red LED’s have
218
been exchanged against IR LED’s. The radiation range of this version corresponds to the radiation
219
range of the light W, red. This light has been equipped in the field test with 4 dimming levels.
220
2.4
221
The light D is an IR light. These lights, analogously to light C, shall be used as supplementary – not
222
mandatory – lighting elements. The use of the lights D is provided as tower lights. They serve aircraft
223
commanders equipped with corresponding equipment (night vision equipment) as additional aid for
224
identification of a WEA as relevant aviation obstruction. Thus they can contribute considerably to the
225
increase of the situation awareness regarding the special flight task (e.g. military low altitude flights).
226
In the wind energy park of Wiemersdorf this array has been installed for this light for the evaluation by
227
the Federal Police Aviation Squadron of Fuhlendorf. Section 4 includes a short description of the
228
previous experience based on the test operation
229
Figure 2-4 shows the vertical radiation angle regarding the minimum intensities of the light D. The light
230
C (both used models) will reach by its large vertical radiation angle the surface of the Earth at a
231
distance of 3.7 times the light height of the wind power plant.
Light D (IR light)
12
12
T00088: ARC-SIRIL
12
160
140
120
IR-Intensity [mW/sr]
100
80
60
40
20
0
-60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5
0
5 10 15 20 25 30 35 40 45 50 55 60
vertical radiation angle in [°]
232
233
Figure 2-4: Minimum of the IR intensities of the light D
234
235
2.5
Ranges of the Lights
236
The following tables will show the ranges as function of the radiation angle of the previously used
237
standard lights on wind power plants - light W, red, and the obstacle light - and the modified light A
238
and B, used herein as newly designed.
239
The intensity of the lights W, red, will be controlled as function of the meteorological visibility. At good
240
visibility, the light intensity of the lights, red, will be controlled as function of the meteorological
241
visibility. At good visibility, the light intensity will be reduced to 10 %.
242
The following tables will consider moreover the threshold light intensity. For evaluating the visibility of
243
a light at night, in the Waterways and Shipping Administration two different threshold light Intensities
244
are used.
245
(a) 2*10-7 lx (Lux)
246
This light intensity in general is used for all equipment at sea and at land.
247
(b) 1*10-6 lx
13
T00088: ARC-SIRIL
13
13
248
According to the administrative regulations, this light intensity has to be used for the “guide light” type
249
of lighting. The threshold Light Intensity is that light intensity that must reach from the light signal the
250
eye of the corresponding observer in order that it is considered as definitively detected. It depends on
251
the ambient brightness and must be chosen differently for day and night.
252
In practice the value of 2*10-7 Lux is used for areas without big background lightening and the value
253
of 1*10-6 Lux for areas with background lightening (e.g. light in front of cities or shipyards).
254
For safety reasons the higher threshold Light Intensity of 1*10-6 Lux has been used for the design of
255
the light W, red.
256
14
14
14
T00088: ARC-SIRIL
257
2.5.1
Light W, red (actual AVV) Threshold Light Intensity 1E-6 Lux
258
Meteorological visibility of 800 m
Intensity
Angle
Range of the light [m]
100 cd
-5° to + 5°
1153
20 cd
-10° and + 10°
873
2 cd
-15° and + 15°
530
Intensity
Angle
Range of the light [m]
30 cd
-5° to + 5°
2550
6 cd
-10° and + 10°
1540
0.6 cd
-15° and + 15°
650
Intensity
Angle
Range of the light [m]
10 cd
-5° to + 5°
2257
2 cd
-10° and + 10°
1180
0.2 cd
-15° and + 15°
400
264
2.5.2
Light W, red (actual AVV) for Threshold Light Intensity 2E-7 Lux
265
Meteorological visibility 800 m
259
260
Meteorological visibility 5000 m
261
262
Meteorological visibility 10000 m
263
Intensity
Angle
Range of the light [m]
100 cd
-5° to + 5°
1458
20 cd
-10° and + 10°
1153
2 cd
-15° and + 15°
760
Intensity
Angle
Range of the light [m]
30 cd
-5° to + 5°
3858
6 cd
-10° and + 10°
2550
0.6 cd
-15° and + 15°
1200
Intensity
Angle
Range of the light [m]
10 cd
-5° to + 5°
3930
2 cd
-10° and + 10°
2250
0.2 cd
-15° and + 15°
800
266
267
Meteorological visibility 5000 m
268
269
270
Meteorological visibility 10000 m
15
15
15
T00088: ARC-SIRIL
271
2.5.3
Light A (Substitute Light W, red) Threshold Light Intensity 1E-6 Lux
272
Meteorological visibility 800 m
Intensity
Angle
Range of the light [m]
106 cd
4° to 6°
1164
12 cd
-2° and 12°
790
2 cd
-5° and 15°
527
Intensity
Angle
Range of the light [m]
32 cd
4° to 6°
2598
3,6 cd
-2° and 12°
1289
0.6 cd
-5° and 15°
640
Intensity
Angle
Range of the light [m]
10,6 cd
4° to 6°
2305
1,2 cd
-2° and 12°
950
0.2 cd
-5° and 15°
420
273
274
Meteorological visibility 5000 m
275
276
Meteorological visibility 10000 m
277
278
2.5.4
Light A (Substitute Light W, red) Threshold Light Intensity 2E-7 Lux
279
Meteorological visibility 800 m
Intensity
Angle
Range of the light [m]
106 cd
4° to 6°
1470
12 cd
-2° and 12°
1062
2 cd
-5° and 15°
761
Intensity
Angle
Range of the light [m]
32 cd
4° to 6°
3915
3,6 cd
-2° and 12°
2197
0.6 cd
-5° and 15°
1207
Intensity
Angle
Range of the light [m]
10.6 cd
4° to 6°
3999
1.2 cd
-2° and 12°
1855
0.2 cd
-5° and 15°
876
280
281
Meteorological visibility 5000 m
282
283
284
Meteorological visibility 10000 m
16
285
2.5.5
16
16
T00088: ARC-SIRIL
Obstacle light (actual AVV) Threshold Light Intensity 1E-6 Lux
Meteorological
Intensity
Angle
Range of the light [m]
800
10 cd
-2° to + 10°
761
5000
10 cd
-2° to + 10°
1830
10000
10 cd
-2° to + 10°
2255
visibility [m]
286
287
2.5.6
Obstacle light (actual AVV) Threshold Light Intensity 2E-7 Lux
Meteorological
Intensity
Angle
Range of the light [m]
800
10 cd
-2° to + 10°
1030
5000
10 cd
-2° to + 10°
2935
10000
10 cd
-2° to + 10°
3930
visibility [m]
288
289
2.5.7
Light B (Substitute for obstacle light) Threshold Light Intensity 1E-6 Lux
Meteorological
Intensity
Angle
Range of the light [m]
800
10 cd
+6° to +10°
761
5000
10 cd
+6° to +10°
1830
10000
10 cd
+6° to +10°
2255
800
5 cd
+4° and +14°
655
5000
5 cd
+4° and +14°
1450
10000
5 cd
+4° and +14°
1730
visibility [m]
290
291
2.5.8
Light B (Substitute for obstacle light) Threshold Light Intensity 2E-7 Lux
Meteorological
Intensity
Angle
Range of the light [m]
800
10 cd
+6° to +10°
1030
5000
10 cd
+6° to +10°
2935
10000
10 cd
+6° to +10°
3930
800
5 cd
+4° and +14°
910
5000
5 cd
+4° and +14°
2420
10000
5 cd
+4° and +14°
3130
visibility [m]
292
293
T00088: ARC-SIRIL
17
17
17
294
3
Lighting Concept Light A / Light B
295
The present lighting concept acc. to AVV for the identification at night may constitute an obstacle for
296
the further development of the wind energy. The high light emission of the night identification of WEA
297
plants is felt by the population as molesting. As a matter of fact, identifying aviation obstructions, they
298
should not be visible from the ground but only by affected aircrafts (LFZ) in their neighbourhood in
299
order to increase the corresponding situation awareness. In the meantime WEA plants reach tower
300
heights above 150 m, thus still remaining below the operative altitude of LFZ of any kind, except of
301
those which operate due to their special flight task (e.g. military night flights or patrolling flights of the
302
federal police) at low altitude.
303
The lighting concept herein described is adjusted to the operative aviation requirements without
304
changing the present safety level and reduces light emission in ground level viewing direction which
305
are considered to be disturbing.
306
3.1
307
Different rules in the airspace of the Federal Republic of Germany, when being observed properly,
308
take care of avoiding dangerous approaches between LFZ and obstructions. Clearly defined weather
309
minima as function of the airspace class and minimum safety altitudes provide for a natural separation
310
between LFZ and aviation relevant obstructions. Only violating these rules will cause a possibility of a
311
dangerous approach of an LFZ to a WEA. In this case the corresponding lighting elements shall
312
contribute to the increase of the situation awareness and the identification of the WEA as relevant
313
obstruction and prevent a possible collision.
314
3.1.1
315
Wind power plants essentially are located in the airspace G (Golf) which is an uncontrolled airspace.
316
The vertical extension always is defined above ground, namely graded from 1000 ft (305 m) to 1700 ft
317
(518 m) and 2500ft (762 m) over ground, with increasing distance to a controlled area of an airport
318
controlled by the air traffic control.
319
In the uncontrolled airspace basically only LFZ may stay which are operating according to visual flight
320
rules (VFR). The aircraft commander himself will be responsible for avoiding any collision with other
321
airspace participants or obstructions, he will not be subject to the control of the air traffic control.
322
Accordingly he must observe certain meteorological requirements in order to cope with this
323
responsibility.
324
The requirements in the airspace G are:
General Rules
Weather Minima
325
•
Horizontal sight of 1500 m or 800 m for rotary wing aircrafts (among others, helicopters)
326
•
Ground sight always must exist
327
•
The LFZ must be clear of clouds
328
According to the air traffic regulations (LuftVO) §3a, the aircraft commander shall provide for a
329
corresponding flight preparation. The latter also includes a detailed weather analysis by collecting
330
weather information in order to guarantee the required values during the whole planned flight
T00088: ARC-SIRIL
18
18
18
331
progress. Nevertheless this information is based on forecasts which include a certain inaccuracy.
332
During the whole flight the aircraft commander shall observe the weather and abort the flight or choose
333
another flight route if the required minimum values are not reached.
334
Basically it can be assumed that no air traffic will take place in the neighbourhood of a WEA in case of
335
weather conditions below the indicated minima. However there exist corresponding special regulations
336
– so lower minima apply e.g. to the operative traffic of the Search and Rescue SAR units in order to
337
guarantee their operativeness even at bad visibility conditions. These units do receive however a
338
special training as well as a corresponding flight preparation in order to dispose of a corresponding
339
situation awareness with regard to aviation obstruction at low altitude.
340
341
3.1.2
Minimum Safety Height
342
Based on the aviation regulations LuftVO §6, the aircraft commander shall observe certain minimum
343
safety heights for his flight under VFR conditions. These are the following:
344
(1) Above cities, other highly populated areas, industrial plants, human gatherings, locations of
345
accidents as well as disaster areas the minimum safety height is 300 m (1.000 ft) above the
346
highest obstruction within a radius of 600 meters, in all other cases 150 m (500 ft) above
347
ground or water.
348
349
(2) Bridges and similar constructions as well as overhead lines and antennae must not be passed
below.
350
(3) Cross-country flights subject to visual flight regulations with motor driven LFZ shall be
351
performed at a minimum height of 600 m (2.000 ft) above ground or water, unless a major
352
height has to be observed for safety reasons as per paragraph 1, sentence 2 and 3.
353
WEA reach at present total heights up to 200 m with a hub height of abt. 150 m. Therefore it has to be
354
assumed that a LFZ at a cross-country flight subject to visual flight rules is travelling in the airspace G
355
above a WEA. A decrease of the minimum safety height for cross-country flights only will be
356
admissible based on certain special permits after thorough examination by the corresponding regional
357
aviation authority. Even with application of the lowest minimum safety height of 500 ft, the LFZ still will
358
not violate the hub height of the highest WEA plants. Therefore the area below 500 ft under normal
359
conditions will not be relevant for a LFZ. This also is reflected by the valid AVV as far as the
360
identification of WEA plants is concerned. WEA plants only must be illuminated from a total height of
361
100 m (abt. 300 ft). WEA plants with a total height below 100 m need not to be identified at night, i.e.
362
in this case an aircraft commander cannot rely on a corresponding lighting.
363
Exceptions are created by military low altitude flights and flights of the federal police, the civil
364
protection and desaster prevention, SAR and state police. They may be performed due to their special
365
flight task also below 500 ft above ground. In these cases, however, as already mentioned a special
366
flight preparation will take place so that there will exist an increased situation awareness for aviation
19
19
19
T00088: ARC-SIRIL
367
obstructions. Besides that the aircraft commanders will be equipped with corresponding night vision
368
gear in order to allow for a better visual identification of obstructions.
369
370
3.2
Operative Safety Concept
371
The lighting elements of a WEA shall contribute to increase the situation awareness of an aircraft
372
commander with regard to corresponding aviation obstructions. Independently of the lighting elements,
373
already the flight preparation prescribed by law (among other things, the analysis of aeronautical
374
charts with obstructions, weather) and the observance of the minimum safety heights will contribute to
375
avoid a dangerous approach. Only in determined circumstances the aircraft commander will reach a
376
situation where he has to avoid a WEA plant. Then specially at night the lighting elements will provide
377
a good orientation for determining the positon of the WEA.
378
As described in 3.1.2, a LFZ in regular conditions will not be found below the gondola of a WEA plant.
379
Only a FLZ in a real emergency situation in the air – in particular with an engine failure at a single
380
engine aircraft – can cause the FLZ to approach the WEA in gliding condition. In the following figures
381
the ranges of the previous lighting concept (Light W, red and obstacle light) are opposed to the
382
alternative concept (light A and B).
383
The red area is the range of the light W, red, or of the light A respectively, the yellow area is the range
384
of the obstacle lights or of the light B respectively. The black line represents the LFZ in gliding
385
condition without engine power. The glide ratio assumed in this case (ratio between vertical descent
386
vs. horizontally covered distance) of 1:20 is a rather conservative value chosen, i.e. a better gliding as
387
presumably can be expected is assumed. A high-performance glider presents glide ratios of up to
388
1:60, a modern airliner (e.g. Airbus A320) a glide ratio of 1:20 and a Cessna 172, a typical LFZ of the
389
general aviation staying in the airspace G, a glide ratio of 1:10. The lower the glide ratio, the flatter the
390
vertical approach in the direction of the WEA plant will result.
391
The graph is given for all three light intensities controlled as function of the meteorological visibilities.
Meteorological visibility
Intensity [%]
800 m
100
1.500 m
30
10.000 m
10
392
Table: Intensity as function of the visibility
393
The comparison demonstrates clearly that the alternative lighting concept, for all visibility dependent
394
light intensities and different threshold light intensities, is at least equivalent to the previous concept
395
with light W, red, and obstacle light. All areas relevant for FLZ will be reached by the light A and B. In
396
the area above the hub, an improvement compared with the previous light W, red, and obstacle light
397
by the increase of the photometrical light intensity can be expected (see also. 3.2.1). If the unlikely
398
case would occur that the FLZ should stay on the level of the hub or even in gliding condition below
20
T00088: ARC-SIRIL
20
20
399
this level due to an engine failure, the WEA plant still will be identified with the aid of the alternative
400
lighting concept (see also 3.2.2).
401
Finally it has to be said that the existing safety level will not be altered by the alternative lighting
402
concept. The use of new technical knowledge offers the possibility of still improving the existing safety
403
level (see also 3.2.1).
404
(Source WSV, FVT):
405
The visibility as well as the prominence of a light will be examined below by the light technology
406
criteria:
407
- Preconditions for the acknowledgement of coloured light signs, Gerdes, Ortung und Navigation 3/82
408
[1]
409
- VV-WSV 2405 Ranges and light intensities pf lights and signal lights [2]
410
- VV-WSV 2401 Leading lights [3]
411
- Lighting manual [4]
412
(VV-WSV: Administrative regulation of the Federal Waterways and Shipping Administration)
413
414
Threshold light intensity
415
Two different threshold light intensities are used for the evaluation of the visibility of a light at night by
416
the Waterways and Shipping Administration
417
(a) 2*10-7 lx (Lux)
418
This light intensity in general is used for any equipment at sea and in the interior
419
(b) 1*10-6 lx
420
According to the Administrative Regulations this light intensity has to be used for the light type “leading
421
light”
422
The threshold light intensity is the light intensity that must reach the eye of the observer from the slight
423
signal in order to be safely acknowledged. It depends on the ambient brightness and must be chosen
424
differently for day and night.
425
The use of different threshold light intensities for the operation at night in addition makes sense as for
426
adapting the determined required light intensity to the ambient light of the object.
427
As in the last decades the artificial lighting has increased significantly, in the area of navigation signs
428
often exists the request for the use of the higher threshold light intensity (b). Thereby the light intensity
21
21
21
T00088: ARC-SIRIL
429
is increased by the factor 5 than at the use of (a), so that the light signal prevails with regard to the
430
competing lights.
431
Therefore, for practical purposes, the value of 2*10-7 Lux is used for areas without important
432
background lighting and 1*10-6 Lux for areas with background lighting (e.g. lights ahead of towns or
433
shipyards).
434
However, there does not exist a precise differentiation between these areas. The notion of range
435
describes the distance at which a light is safely acknowledged. The light irradiated by the light will
436
merely reach at this distance the threshold light intensity at the observer. The range depends on the
437
light intensity of the light and on the opacity of the atmosphere.
438
The predominance of the light can be expressed by the ratio between the light intensity arriving at the
439
Ereal and the threshold light intensity Ethreshold
440
A = Ereal / Ethreshold. 477
441
The following tables indicate the ratio A between the light intensity arriving at the observer and the
442
required threshold light intensity. With A = 1 the light is considered to be safely acknowledgeable, the
443
greater A, the more predominant the light will become. The visibility ranges are indicated as practical
444
al meteorological visibility (V0,05)
445
446
Formulas and calculations
447
Illumination intensity E as function of light intensity I0, distance r und constant z.
448
𝐸𝐸(𝑟𝑟) = 𝐼𝐼0 ∗
449
450
451
𝑒𝑒 −𝑧𝑧∗𝑟𝑟
from [1]
𝑟𝑟 2
Ratio between constant z, visibility σ, transmission factor q and practical meteorological visibility
V0,05.
452
ln(𝑞𝑞)
454
𝑞𝑞 = 𝑒𝑒 −𝑧𝑧∗1000𝑚𝑚
455
Ratio between visibility σ and transmission factor q
456
ln(σ) = 1,852 * ln(q)
453
⇒
−𝑧𝑧 =
1000𝑚𝑚
⇒
𝐸𝐸(𝑟𝑟) = 𝐼𝐼0 ∗
ln(𝑞𝑞)∗𝑟𝑟
𝑒𝑒 1000𝑚𝑚
𝑟𝑟 2
457
458
459
Ratio between transmission factor q and practical meteorological visibility V0,05
𝑉𝑉0,05 =
460
22
22
T00088: ARC-SIRIL
22
1300𝑚𝑚
1
ln � �
𝑞𝑞
Examined practical meteorological visibilities
461
V0,05 in km
σ (visibility value)
q (transmission factor)
0,8
5
7
10
0,000972
0,3296
0,442
0,5741
0,02363
0,5492
0,6435
0,7411
462
463
Source end
464
In the following diagrams the predominance of the lights is marked by colours. Within these ranges the
465
light is considered to be safely acknowledgeable. Outside these ranges, the light effect pf the lights is
466
not equal to zero, only the predominance will decrease. This type of recognition is difficult to
467
demonstrate, one may start from the comparison of the different predominance areas resulting from
468
different threshold light intensities.
469
With regard to the gliding of an aircraft in the procedure of emergency landing, tit has to be noted that
470
the aircraft will pass at any rate the range of assured predominance even with the pessimistic
471
assumption of a gliding index of 1:20. This case. However, will remain hypothetical as at practical
472
conditions a straight forward emergency landing will be quite impractical, the aircraft commander at
473
night always will try to find an emergency landing area below the aircraft and to make an U-turn on his
474
gliding flight continuing.
475
Of relevance will remain in the airspace below the lights, operations of the Federal Police, SAR
476
operations and similar operations. Particularly with regard to this air traffic, the use of IR lights
477
achieves a particular importance, the more as with the night-vision devices used in Germany the
478
currently red lights cannot be recognized
479
On the following pages the ranges of the various lights will be represented as room sections inside of
480
which the light by definition is safely acknowledgeable. The red areas are caused by the gondola lights
481
and the yellow ones by the tower lights. As variations, besides the various types of light, the threshold
482
light intensity and the meteorological visibility will be represented on the following pages.
483
23
23
23
T00088: ARC-SIRIL
484
485
486
487
488
489
490
Figure 3-1:
Comparison of the ranges of light A and B with light W, red, and the Obstacle light at a
meteorological visibility of 10000 m
24
24
24
T00088: ARC-SIRIL
491
492
493
494
495
496
497
Figure 3-2:
Comparison of the ranges of light A and B with light W, red, and the obstacle light at a
meteorological visibility of 5000 m
25
25
25
T00088: ARC-SIRIL
498
499
500
501
502
503
504
Figure 3-3:
Comparison of the ranges of light A and B with light W, red, and the obstacle light at a
meteorological visibility of 800 m
26
T00088: ARC-SIRIL
26
26
505
3.2.1
Light Effect above 0°
506
The area relevant for LFZ above the WEA plant, measured from the height of the hub, will be reached
507
by the alternative concept, with the light A and B being improved to the present condition. A better
508
visibility will be obtained for positions above the WEA plant by the increase of the photometrical light
509
intensity of the light A in the positive vertical radiation angle (downwards).
510
At the lowest accepted meteorological visibility of 800m the light A will have an extension in height of
511
164 m with a threshold Light Intensity of 1*10-6 lx or 220 m with a threshold Light Intensity of 2*10-7
512
lx. Thus a FLZ will recognize at least from 164 m vertical above the position of the light A the gondola
513
of the WEA plant where, as previously, the light W, red, will be located (see also figure 3-5). Thus a
514
clear identification of the WEA as obstruction and the observance of the corresponding safety distance
515
will be guaranteed.
516
An extension of the unlighted area above the hub may be achievable by the improved visibility. This
517
value, acc. to the valid AVV, is of 65 m, which could be extended however by the use of the alternative
518
lighting concept light A and B in accordance with the values indicated in figure 3-4.
27
27
27
T00088: ARC-SIRIL
519
520
Ranges of the lights A and B with a meteorological visibility of 10.000 m
521
522
Ranges of the lights A and B with a meteorological visibility of 5.000 m
523
524
525
Ranges of the lights A and B with a meteorological visibility of 800 m
Figure 3-4: Radiation above 0°
28
28
28
T00088: ARC-SIRIL
526
527
528
Ranges of the lights A and B with a meteorological visibility of 10,000 m
529
530
Ranges of the lights A and B with a meteorological visibility of 5,000 m
531
532
533
534
Ranges of the lights A and B with a meteorological visibility of 800 m
Figure 3-5: Radiation above 0°
29
29
29
T00088: ARC-SIRIL
535
3.2.2
Light Effect below 0°
536
The light effect below 0°, thus the area perceived by the residents in the neighbourhood of the wind
537
farm and where they feel molested, has been determined by measurement of the light A prototype and
538
calculation of the range as function of the meteorological visibility. Figure 3-6 shows clearly that no
539
light emissions have to be expected on the ground by the alternative lighting concept light A and B.
540
Aircraft commanders who operate due to their special flight task below the visible area of the lighting
541
(e.g. military exercise traffic, federal police) will dispose by special flight preparations of a
542
corresponding situation awareness so that they are familiar with all aviation relevant obstructions in
543
their neighbourhood.
544
In this context it has to be noticed that WEA plants with a total height below 100m according to the
545
actual AVV did not have to be lighted. Thus a reduction of the light effect of lighting systems for WEA
546
with a total height above 100m may not have any effect on the existing safety level.
547
The following two diagrams show that the lights, in favour of a higher acceptance by the residents, are
548
visible as a bright spot up to 143 m or 74 m below the light respectively .
549
550
551
552
553
554
555
Figure 3-6:
Ranges below 0°
30
T00088: ARC-SIRIL
30
30
556
4
IR-Light Lighting Concept
557
IR lights serve the better perceptibility of WEA plants at night by traffic of the federal police and other
558
air traffic operating due to its specific flight tasks at low altitude at night in the neighbourhood of WEA
559
plants and equipped with image intensifier equipment (e.g. SAR air traffic or military flights at low
560
altitude). Aircraft commanders with image intensifier goggles or night vision devices complain about a
561
bad visibility of the previous lighting elements at night. Thus IR lights could contribute much to an
562
improvement of the situation awareness of the concerned aircraft commanders as they are perceived
563
much better with the aid of the above mentioned vision devices.
564
The IR lights light C and light D shall serve as complementary to the previous lighting concept light W,
565
red, and obstacle light or light A and light B respectively. An exclusive use has not been considered if
566
a lighting according to the actually valid AVV has been provided due to the height of the WEA.
567
On the occasion of a meeting with the BMVi at Bonn on 30-07-2013, a field test was proposed to the
568
BMVi and the BPol on the subject of IR lights. On 11-02-2014 the Federal Police Aviation Squadron
569
Fuhlendorf was designated as contact. The field test shall deal with the evaluation of the perceptibility
570
of various infrared obstacle lights with image intensifier goggles at night. The test is under way since
571
03-04-2014 and has no limit in time.
572
4.1
573
At present 3 different IR lights are being tested at a wind energy power plant by means of a test array
574
for evaluating the perceptibility of various infrared obstacle lights at night with the aid of image
575
intensifier goggles.
576
These lights are remotely controlled by means of a web interface. The remote control concerns the
577
selection of the lights (only one of the different lights at a time), the light intensity and the flashing
578
cycle. The lights are installed at the Enercon wind power plant no. 4 of the Wiemersdorf. All aircraft
579
commanders of the Federal Police Aviation Squadron Fuhlendorf who are on duty at night and operate
580
close to the WEA with the test array are requested to provide a corresponding quality assessment of
581
the IR lights.
Test Array
31
T00088: ARC-SIRIL
582
583
584
585
Figure 4-1: Location of the test equipment
31
31
32
32
32
T00088: ARC-SIRIL
586
4.2
Technical IR Light Specification
587
Below the three different IR lights used at the field test are described.
588
4.2.1
Light 1
589
The light 1 is the light MB20-IR of the manufacturer TWE. This
590
light is a modified light W, red, as being used up to now
591
already at wind energy power plants for identification at night.
592
593
594
595
596
597
598
599
Figure 4-2: Light MB20-IR
600
601
602
Figure 4-3: IR-Intensity [mW/sr] of the MB20-IR
33
603
4.2.2
33
33
T00088: ARC-SIRIL
Light 2
604
The light 2 is the light MB17UK-IR of the manufacturer TWE. This
605
light complies with the MOD specification for IR lights of the Royal
606
Air Force for IR and low intensity red vertical obstacle lighting.
607
608
609
610
611
612
613
614
Figure 4-4: MB17UK-IR
615
616
617
Figure 4-5: IR-Intensity [mW/sr] of the MB17UK-IR
34
34
34
T00088: ARC-SIRIL
618
4.2.3
Light 3
619
The light 3 is a modified low intensity type B obstacle light (10 Candela) of the manufacturer Lanthan.
620
621
Figure 4-6: Low-Intensity IR light
Modified vertical beam spread HF102
250
IR Intensity [mW/sr]
200
150
100
50
0
-90 -80 -70 -60 -50 -40 -30 -20 -10
0
10
20
30
vertical radiation angle [degrees]
622
623
624
625
626
Figure 4-7: IR-Intensity [mW/sr] of the modified HF102
40
50
60
70
80
90
T00088: ARC-SIRIL
35
35
35
627
4.3
System Settings
628
4.3.1
629
For the lights 1 and 2 a choice of the intensity between 25%, 50%, 75% and 100% will be possible.
630
The light 3 exclusively will be operated at an intensity of 100%. During the field test all different
631
intensities will be operated and evaluated thereafter by the involved aircraft commanders.
632
4.3.2
633
For all 3 lights a choice between the following flashing cycles will be possible:
Intensity
Flashing Cycle
634
•
W, red, cycle: 1 s hell – 0.5 s dark - 1 s bright- 1.5 s dark
635
•
MOD cycle: 0.25 ms bright – 0.75 s dark
636
•
Permanently switched on
637
4.3.3
638
The choice of the lights, the intensity and the flashing cycle can be set by a Web-Interface on a
639
computer or by a smart-phone. The Web-Interface will be queried any 5 minutes by the wind power
640
plant 4. In case of a setting change the query will take place for a period of 15 minutes twice per
641
minute.
642
4.4
643
The test array at the WEA of the Wiemersdorf/Fuhlendorf wind farm is undergoing a test operation
644
since March 12, 2014. The evaluation of the federal police up to the current date has resulted in the
645
following findings for the up to date most suitable configuration:
Web-Interface
Preliminary Results
646
•
Light 1 with intensity of25%
647
•
Light 3
648
•
Flashing cycle corresponding to light W, red
649
The light intensities of the light types 1 and 2 are perceived as too bright and dazzling and at short
650
distance even have a negative effect on the general visibility. The flashing cycle according to the MOD
651
specification (fast frequent flashing) is rather considered as intrusive. At present the flashing cycle of
652
the known light W, red, is preferred. Similar results also have to be expected from the aircraft
653
commanders of the armed forces, ADAC and SAR as they use the same type of night vision devices
654
or image intensifiers respectively.
655
At present the field test continues in order to confirm the findings made up to date regarding light type
656
and configuration or setting of the light.