Doh.
OK, here's a more detailed ADS-B track for ACA865:
HH MM SS Alt Latitude Longitude IAS TAS GS
13:34:43 675 51.464941 -0.489502 --- --- ---
13:34:45 775 51.464895 -0.492706 --- --- ---
13:34:46 825 51.464895 -0.494232 --- --- ---
13:34:47 875 --------- --------- --- --- ---
13:34:47 900 --------- --------- --- 190 172
13:34:48 950 51.464895 -0.496368 --- --- ---
13:34:49 1025 51.464859 -0.497799 --- --- ---
13:34:49 1025 --------- --------- --- --- ---
13:34:51 1125 51.464859 -0.499729 --- --- ---
13:34:52 1175 --------- --------- --- --- ---
13:34:52 1175 --------- --------- --- 192 168
13:34:52 1175 --------- --------- --- --- ---
13:34:52 1175 51.464859 -0.501585 --- --- ---
13:34:53 1250 51.464802 -0.503082 --- --- ---
13:34:54 1300 51.464802 -0.503921 --- --- ---
13:34:55 1325 51.464813 -0.504480 --- --- ---
13:34:55 1350 --------- --------- --- --- ---
13:34:55 1350 51.464802 -0.505066 --- --- ---
13:34:55 1350 --------- --------- --- --- ---
13:34:56 1400 51.464767 -0.506187 --- --- ---
13:34:57 1450 --------- --------- --- --- ---
13:34:57 1450 --------- --------- --- 184 164
13:34:57 1450 51.464767 -0.507375 --- --- ---
13:34:57 1475 --------- --------- --- --- ---
13:35:00 1650 51.464675 -0.511161 --- --- ---
13:35:01 1675 --------- --------- --- 190 160
13:35:01 1675 --------- --------- --- --- ---
13:35:01 1700 --------- --------- --- --- ---
13:35:02 1750 --------- --------- 187 --- ---
13:35:02 1750 --------- --------- --- 190 160
13:35:02 1750 51.464662 -0.513458 --- --- ---
13:35:03 1800 51.464630 -0.514353 --- --- ---
13:35:04 1850 51.464630 -0.515392 --- --- ---
13:35:04 1875 51.464616 -0.515976 --- --- ---
13:35:05 1900 --------- --------- --- --- ---
13:35:05 1900 51.464584 -0.516580 --- --- ---
13:35:05 1950 --------- --------- --- --- ---
13:35:07 2025 51.464584 -0.517842 --- --- ---
13:35:07 2025 --------- --------- 186 --- ---
13:35:07 2025 --------- --------- --- --- ---
13:35:07 2025 --------- --------- 186 --- ---
13:35:07 2025 --------- --------- --- --- ---
13:35:07 2025 --------- --------- --- 190 156
13:35:07 2025 --------- --------- --- --- ---
13:35:07 2050 51.464569 -0.518646 --- --- ---
13:35:07 2050 --------- --------- --- --- ---
13:35:07 2075 --------- --------- --- --- ---
13:35:08 2075 51.464523 -0.519409 --- --- ---
13:35:08 2125 51.464492 -0.520811 --- --- ---
13:35:09 2150 --------- --------- --- --- ---
13:35:09 2175 --------- --------- --- --- ---
13:35:09 2175 51.464492 -0.521924 --- --- ---
13:35:10 2200 51.464476 -0.522461 --- --- ---
13:35:10 2225 51.464476 -0.522842 --- --- ---
13:35:11 2250 51.464476 -0.523300 --- --- ---
13:35:11 2275 --------- --------- --- --- ---
13:35:11 2275 51.464476 -0.523910 --- --- ---
13:35:12 2300 --------- --------- --- --- ---
13:35:12 2300 --------- --------- --- 188 150
13:35:12 2300 51.464476 -0.524597 --- --- ---
13:35:12 2325 51.464446 -0.525191 --- --- ---
13:35:13 2375 --------- --------- --- --- ---
13:35:13 2375 --------- --------- 184 --- ---
13:35:13 2375 --------- --------- --- 190 148
13:35:13 2375 51.464429 -0.525665 --- --- ---
13:35:14 2400 --------- --------- 184 --- ---
13:35:14 2425 51.464429 -0.527038 --- --- ---
13:35:15 2450 51.464446 -0.527566 --- --- ---
13:35:15 2475 51.464429 -0.527572 --- --- ---
13:35:15 2500 --------- --------- --- --- ---
13:35:16 2500 51.464446 -0.527789 --- --- ---
13:35:17 2575 --------- --------- 179 --- ---
13:35:17 2575 --------- --------- --- --- ---
13:35:17 2575 --------- --------- --- 184 144
13:35:17 2575 --------- --------- --- --- ---
13:35:17 2600 --------- --------- --- --- ---
13:35:18 2600 51.464383 -0.530853 --- --- ---
13:35:19 2650 51.464383 -0.531768 --- --- ---
13:35:19 2675 --------- --------- --- 182 140
13:35:19 2675 --------- --------- --- --- ---
13:35:20 2700 51.464401 -0.532762 --- --- ---
13:35:20 2725 --------- --------- --- --- ---
13:35:20 2725 --------- --------- --- 180 140
13:35:20 2725 51.464383 -0.533218 --- --- ---
13:35:21 2750 51.464383 -0.533905 --- --- ---
13:35:21 2750 --------- --------- --- --- ---
13:35:21 2775 51.464355 -0.534395 --- --- ---
13:35:21 2800 --------- --------- --- --- ---
13:35:22 2800 51.464383 -0.534896 --- --- ---
13:35:22 2800 --------- --------- 172 --- ---
13:35:22 2800 --------- --------- --- 178 138
13:35:23 2850 51.464355 -0.535063 --- --- ---
13:35:23 2875 --------- --------- --- --- ---
13:35:25 2950 --------- --------- --- --- ---
13:35:25 2975 --------- --------- --- --- ---
13:35:26 3000 51.464309 -0.539146 --- --- ---
13:35:26 3000 --------- --------- --- --- ---
13:35:27 3025 51.464290 -0.539550 --- --- ---
13:35:27 3025 --------- --------- 164 --- ---
13:35:27 3025 --------- --------- --- --- ---
13:35:27 3025 --------- --------- --- 170 130
13:35:27 3025 51.464290 -0.539932 --- --- ---
13:35:27 3050 51.464290 -0.540542 --- --- ---
13:35:28 3075 51.464263 -0.541002 --- --- ---
13:35:29 3100 --------- --------- --- --- ---
13:35:29 3100 --------- --------- --- --- ---
13:35:29 3125 --------- --------- --- --- ---
13:35:30 3125 51.464218 -0.542487 --- --- ---
13:35:31 3150 51.464197 -0.543518 --- --- ---
13:35:31 3175 --------- --------- 162 --- ---
13:35:32 3175 --------- --------- 162 --- ---
13:35:32 3175 --------- --------- --- --- ---
13:35:32 3200 --------- --------- 162 --- ---
13:35:33 3200 --------- --------- --- --- ---
13:35:33 3200 --------- --------- --- --- ---
13:35:33 3200 51.464172 -0.545975 --- --- ---
13:35:33 3225 --------- --------- --- --- ---
13:35:34 3225 51.464126 -0.547089 --- --- ---
13:35:35 3250 --------- --------- --- --- ---
13:35:37 3275 --------- --------- --- 168 128
13:35:37 3275 --------- --------- --- --- ---
13:35:37 3275 51.464104 -0.549240 --- --- ---
13:35:37 3275 --------- --------- --- --- ---
13:35:37 3300 51.464080 -0.549687 --- --- ---
13:35:37 3300 --------- --------- --- --- ---
13:35:37 3300 --------- --------- 162 --- ---
13:35:37 3300 --------- --------- --- 168 128
13:35:38 3300 --------- --------- 163 --- ---
13:35:38 3300 51.464080 -0.550281 --- --- ---
13:35:38 3300 51.464057 -0.550308 --- --- ---
13:35:38 3300 --------- --------- 163 --- ---
13:35:38 3300 --------- --------- --- --- ---
13:35:38 3300 --------- --------- --- 170 128
13:35:39 3300 51.464080 -0.550801 --- --- ---
13:35:39 3325 51.464057 -0.551300 --- --- ---
13:35:40 3325 51.464035 -0.552879 --- --- ---
13:35:41 3325 --------- --------- --- --- ---
13:35:41 3325 51.464010 -0.553970 --- --- ---
13:35:42 3325 --------- --------- 165 --- ---
13:35:42 3325 --------- --------- --- --- ---
13:35:42 3325 --------- --------- --- 172 132
13:35:42 3350 51.464010 -0.554351 --- --- ---
13:35:43 3350 51.464010 -0.554809 --- --- ---
13:35:43 3350 51.463964 -0.555267 --- --- ---
13:35:43 3350 --------- --------- --- --- ---
13:35:43 3350 51.463964 -0.555801 --- --- ---
13:35:44 3350 --------- --------- --- --- ---
13:35:44 3350 51.463943 -0.556368 --- --- ---
13:35:45 3350 51.463964 -0.556869 --- --- ---
13:35:45 3350 --------- --------- --- --- ---
13:35:45 3350 --------- --------- --- --- ---
13:35:45 3375 --------- --------- --- --- ---
13:35:45 3375 --------- --------- 168 --- ---
13:35:45 3375 --------- --------- --- 176 136
13:35:46 3375 51.463943 -0.557927 --- --- ---
13:35:46 3375 51.463943 -0.558372 --- --- ---
13:35:46 3375 51.463917 -0.558853 --- --- ---
13:35:47 3375 --------- --------- 169 --- ---
13:35:47 3375 --------- --------- --- --- ---
13:35:47 3375 --------- --------- --- 176 136
13:35:47 3375 --------- --------- --- --- ---
13:35:48 3400 51.463897 -0.560525 --- --- ---
13:35:49 3400 --------- --------- --- --- ---
13:35:49 3400 --------- --------- --- --- ---
13:35:50 3400 51.463871 -0.562133 --- --- ---
13:35:50 3400 --------- --------- 172 --- ---
13:35:50 3400 --------- --------- --- --- ---
13:35:50 3400 51.463851 -0.562678 --- --- ---
13:35:50 3425 51.463871 -0.563125 --- --- ---
13:35:51 3425 51.463851 -0.563494 --- --- ---
13:35:52 3425 --------- --------- 173 --- ---
13:35:52 3425 --------- --------- --- 180 140
13:35:52 3425 51.463851 -0.564088 --- --- ---
13:35:52 3425 51.463824 -0.564575 --- --- ---
13:35:53 3425 --------- --------- --- --- ---
13:35:53 3425 51.463851 -0.565127 --- --- ---
13:35:53 3425 --------- --------- --- --- ---
13:35:53 3450 51.463824 -0.565719 --- --- ---
13:35:53 3450 --------- --------- 174 --- ---
13:35:53 3450 --------- --------- --- --- ---
13:35:53 3450 --------- --------- 174 --- ---
13:35:53 3450 --------- --------- --- --- ---
13:35:53 3450 --------- --------- 174 --- ---
13:35:53 3450 --------- --------- --- --- ---
13:35:54 3450 51.463824 -0.566330 --- --- ---
13:35:55 3450 51.463824 -0.566558 --- --- ---
13:35:55 3475 --------- --------- --- --- ---
13:35:56 3475 51.463778 -0.568313 --- --- ---
13:35:56 3475 51.463778 -0.568924 --- --- ---
13:35:57 3475 --------- --------- 177 --- ---
13:35:57 3475 --------- --------- --- --- ---
13:35:57 3475 --------- --------- --- 184 144
13:35:57 3475 51.463760 -0.569581 --- --- ---
13:35:57 3475 --------- --------- --- --- ---
13:35:57 3475 --------- --------- 177 --- ---
13:35:57 3475 --------- --------- --- --- ---
13:35:58 3475 51.463714 -0.571363 --- --- ---
13:35:59 3500 51.463714 -0.572031 --- --- ---
13:35:59 3500 --------- --------- --- --- ---
13:36:00 3500 51.463714 -0.572699 --- --- ---
13:36:00 3500 51.463685 -0.573272 --- --- ---
13:36:00 3500 --------- --------- --- --- ---
13:36:01 3500 51.463685 -0.573654 --- --- ---
13:36:01 3500 --------- --------- --- --- ---
13:36:01 3500 51.463668 -0.574184 --- --- ---
13:36:01 3500 --------- --------- --- --- ---
13:36:02 3500 --------- --------- 182 --- ---
13:36:02 3500 --------- --------- --- --- ---
13:36:02 3500 --------- --------- --- 190 150
13:36:02 3525 --------- --------- 182 --- ---
13:36:02 3525 --------- --------- --- --- ---
13:36:02 3525 --------- --------- --- 190 150
13:36:02 3525 51.463668 -0.575817 --- --- ---
13:36:03 3525 51.463638 -0.576400 --- --- ---
13:36:03 3525 --------- --------- --- --- ---
13:36:03 3525 51.463668 -0.576262 --- --- ---
13:36:04 3525 51.463638 -0.576858 --- --- ---
13:36:04 3525 51.463623 -0.577747 --- --- ---
13:36:05 3550 --------- --------- --- --- ---
13:36:05 3550 51.463577 -0.579306 --- --- ---
13:36:06 3550 51.463591 -0.580597 --- --- ---
13:36:07 3550 --------- --------- --- 194 154
13:36:07 3550 51.463577 -0.581458 --- --- ---
13:36:08 3575 51.463531 -0.582052 --- --- ---
13:36:08 3575 --------- --------- --- --- ---
13:36:08 3575 --------- --------- 186 --- ---
13:36:09 3575 --------- --------- --- 194 156
13:36:09 3575 --------- --------- --- --- ---
13:36:09 3575 51.463498 -0.583648 --- --- ---
13:36:09 3575 --------- --------- 188 --- ---
13:36:10 3575 51.463498 -0.584106 --- --- ---
13:36:11 3600 --------- --------- --- --- ---
13:36:11 3600 --------- --------- 190 --- ---
13:36:11 3600 --------- --------- --- --- ---
13:36:11 3600 --------- --------- --- 198 158
13:36:12 3625 51.463452 -0.587234 --- --- ---
13:36:12 3625 --------- --------- --- --- ---
13:36:13 3625 --------- --------- --- --- ---
13:36:14 3625 51.463439 -0.588807 --- --- ---
13:36:14 3625 51.463394 -0.589179 --- --- ---
13:36:14 3650 51.463405 -0.589752 --- --- ---
13:36:15 3650 --------- --------- 193 --- ---
13:36:15 3650 51.463394 -0.590366 --- --- ---
13:36:16 3650 --------- --------- --- 202 162
13:36:16 3650 51.463348 -0.591554 --- --- ---
13:36:16 3675 --------- --------- 193 --- ---
13:36:16 3675 --------- --------- --- 202 162
13:36:17 3675 51.463348 -0.592296 --- --- ---
13:36:17 3675 --------- --------- --- --- ---
13:36:17 3675 51.463348 -0.592742 --- --- ---
13:36:17 3675 --------- --------- --- --- ---
13:36:17 3675 --------- --------- --- 204 162
13:36:18 3675 51.463312 -0.593338 --- --- ---
13:36:19 3675 51.463312 -0.594635 --- --- ---
13:36:19 3675 51.463312 -0.595092 --- --- ---
13:36:19 3700 --------- --------- --- --- ---
13:36:20 3700 51.463256 -0.595711 --- --- ---
13:36:20 3700 --------- --------- --- --- ---
13:36:21 3700 --------- --------- --- --- ---
13:36:21 3700 --------- --------- 198 --- ---
13:36:21 3700 --------- --------- --- 208 166
13:36:22 3700 51.463219 -0.598526 --- --- ---
13:36:22 3700 --------- --------- 198 --- ---
13:36:22 3725 51.463219 -0.599289 --- --- ---
13:36:22 3725 51.463219 -0.599670 --- --- ---
13:36:23 3725 51.463172 -0.600128 --- --- ---
13:36:23 3725 --------- --------- --- --- ---
13:36:24 3725 51.463172 -0.601196 --- --- ---
13:36:24 3750 --------- --------- --- --- ---
13:36:25 3750 51.463172 -0.601959 --- --- ---
13:36:25 3750 51.463126 -0.602493 --- --- ---
13:36:25 3750 --------- --------- 201 --- ---
13:36:25 3750 --------- --------- --- --- ---
13:36:25 3750 51.463119 -0.603134 --- --- ---
13:36:26 3750 51.463126 -0.603790 --- --- ---
13:36:26 3750 --------- --------- --- --- ---
13:36:26 3750 --------- --------- --- 212 170
13:36:27 3750 51.463126 -0.604400 --- --- ---
13:36:27 3775 --------- --------- --- 212 172
13:36:27 3775 51.463079 -0.604934 --- --- ---
13:36:28 3775 --------- --------- --- 214 172
13:36:29 3775 --------- --------- --- --- ---
13:36:29 3775 51.463033 -0.608368 --- --- ---
13:36:29 3775 --------- --------- --- --- ---
13:36:30 3775 51.463027 -0.608850 --- --- ---
13:36:31 3775 51.462982 -0.610631 --- --- ---
13:36:31 3775 --------- --------- 208 --- ---
13:36:31 3775 --------- --------- --- --- ---
13:36:31 3775 --------- --------- --- 218 178
13:36:32 3800 51.462986 -0.611267 --- --- ---
13:36:32 3800 51.462940 -0.611801 --- --- ---
13:36:32 3800 --------- --------- --- --- ---
13:36:33 3800 --------- --------- --- --- ---
13:36:33 3800 --------- --------- --- 220 178
13:36:33 3800 --------- --------- 210 --- ---
13:36:33 3800 --------- --------- --- 220 178
13:36:33 3800 --------- --------- --- --- ---
13:36:34 3800 51.462940 -0.613632 --- --- ---
13:36:34 3825 --------- --------- --- --- ---
13:36:35 3825 --------- --------- --- --- ---
13:36:36 3825 51.462893 -0.615463 --- --- ---
13:36:36 3850 --------- --------- --- --- ---
13:36:36 3850 --------- --------- 214 --- ---
13:36:37 3850 51.462844 -0.617535 --- --- ---
13:36:37 3850 --------- --------- --- --- ---
13:36:38 3875 51.462754 -0.620193 --- --- ---
13:36:39 3875 51.462753 -0.620727 --- --- ---
13:36:39 3900 --------- --------- 216 --- ---
13:36:40 3900 --------- --------- --- --- ---
13:36:40 3900 51.462660 -0.622558 --- --- ---
13:36:40 3900 --------- --------- 217 --- ---
13:36:40 3925 --------- --------- --- --- ---
13:36:40 3925 --------- --------- --- 228 186
13:36:41 3925 51.462615 -0.623325 --- --- ---
13:36:41 3925 51.462615 -0.623845 --- --- ---
13:36:41 3925 --------- --------- 218 --- ---
13:36:41 3925 --------- --------- --- --- ---
13:36:41 3925 --------- --------- --- 228 186
13:36:41 3925 --------- --------- --- --- ---
13:36:41 3925 --------- --------- --- 230 186
13:36:41 3925 --------- --------- --- --- ---
13:36:42 3925 51.462567 -0.624542 --- --- ---
13:36:43 3975 51.462428 -0.626373 --- --- ---
It looks pretty typical to me - your problem is that you are misinterpreting the data from FlightAware/FR24:
Originally Posted by
ImageGear
That seems to me like a very steep climb to 3500' with an equally large drop in corresponding airspeed/VSI. (162 down to 131)
It's the
groundspeed that's dropping, not the
airspeed, and the reason is pretty straightforward. Surface wind at LHR this afternoon was about 15 kts westerly, but by the time the A333 had climbed to 3,500 ft, it was flying into a headwind component of about 40 kts.
I hope that makes sense.