I'm writing this thread to share my experience purpose and add data point for DJI Mavic Mini crash event.
Background:
- My aircraft purchased on 2019 Oct and flew less than 3 hour
- Properly stored in a protected camera case and no fly at all.
- Success flew on 2020 Dec about 1 hour
- 14months old when it crashed. both warranty and insurance is expired.
When crash:
- Temp. = -4 C
- Wind <= 1m/s
- C-mode (smooth)
- Battery pre-heated in my pocket and 100% when take-off.
- AC have > 2m clearnce around.
After crash:
- LED green & red flash every 2 sec
- RC cannot found AC
- Mobile App could connect with RC but also could not found AC
- Hold 4 sec power button on AC won't goes to pairing mode (no change on LED status)
- With / without SD card perform same behaviour
- Swapped different SD card
I read all RC&AC connect/pairing thread in this form seems the solution there is not working in my case.
So technically my AC was dead at this moment.
----------Edited and added following analysis----------
By looking into the RCLOG which export from my DJI app, I figure out the root cause of crash event is highly related to the RF interference, see the highlighted log following:
12-13 10:51:03.435:mem_use = 48%, cpu_use = 35%
12-13 10:51:03.465:[GND_wifi0_stats] rx_pkts: 390, rx_errs: 0, tx_pkts: 54, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 0,rssi: -49, rx_rate: 36Mbps, osd 10, stream 350
12-13 10:51:05.856:[2020-12-13 10:51:05]: second 530, USB IOS, bat 96, uart 6986,80480
12-13 10:51:06.486:[GND_wifi0_stats] rx_pkts: 361, rx_errs: 0, tx_pkts: 51, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 1,rssi: -49, rx_rate: 36Mbps, osd 10, stream 322
12-13 10:51:08.450:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:6M txpower:20, link:1 phone:1 sw:2057kbps video:2057kbps rc>>105kbps >>rc1888bps
beacon[rx_all:4402 rx:4401 tx:8 tx_miss:0], probe[req:0 resp_all:0 resp:0] rxint:1745639 txint:87621
12-13 10:51:08.451:mem_use = 48%, cpu_use = 30%
12-13 10:51:09.533:[GND_wifi0_stats] rx_pkts: 341, rx_errs: 0, tx_pkts: 56, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 0,rssi: -52, rx_rate: 36Mbps, osd 11, stream 301
12-13 10:51:10.876:[2020-12-13 10:51:10]: second 535, USB IOS, bat 96, uart 7065,81248
12-13 10:51:12.532:[GND_wifi0_stats] rx_pkts: 289, rx_errs: 0, tx_pkts: 55, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 1,rssi: -47, rx_rate: 36Mbps, osd 10, stream 252
12-13 10:51:13.546:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:6M txpower:20, link:1 phone:1 sw:2348kbps video:2348kbps rc>>113kbps >>rc2384bps
beacon[rx_all:4451 rx:4450 tx:8 tx_miss:0], probe[req:0 resp_all:0 resp:0] rxint:1762487 txint:88576
12-13 10:51:13.547:mem_use = 48%, cpu_use = 27%
12-13 10:51:15.667:[GND_wifi0_stats] rx_pkts: 353, rx_errs: 0, tx_pkts: 55, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 9,rssi: -52, rx_rate: 36Mbps, osd 10, stream 321
12-13 10:51:15.896:[2020-12-13 10:51:15]: second 540, USB IOS, bat 96, uart 7140,82034
12-13 10:51:18.678:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:6M txpower:20, link:1 phone:1 sw:2603kbps video:2603kbps rc>>119kbps >>rc2024bps
beacon[rx_all:4499 rx:4498 tx:8 tx_miss:0], probe[req:0 resp_all:0 resp:0] rxint:1779318 txint:89536
12-13 10:51:18.679:mem_use = 48%, cpu_use = 31%
12-13 10:51:18.709:[GND_wifi0_stats] rx_pkts: 378, rx_errs: 0, tx_pkts: 55, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 8,rssi: -55, rx_rate: 36Mbps, osd 10, stream 338
12-13 10:51:20.916:[2020-12-13 10:51:20]: second 545, USB IOS, bat 96, uart 7215,82817
12-13 10:51:21.850:[GND_wifi0_stats] rx_pkts: 392, rx_errs: 0, tx_pkts: 55, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 1,rssi: -50, rx_rate: 36Mbps, osd 11, stream 353
12-13 10:51:23.865:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:6M txpower:20, link:1 phone:1 sw:3125kbps video:3125kbps rc>>109kbps >>rc2520bps
beacon[rx_all:4549 rx:4548 tx:8 tx_miss:0], probe[req:0 resp_all:0 resp:0] rxint:1796427 txint:90511
12-13 10:51:23.866:mem_use = 48%, cpu_use = 33%
12-13 10:51:24.910:[GND_wifi0_stats] rx_pkts: 397, rx_errs: 0, tx_pkts: 64, tx_retries: 0, tx_fails: 0, tx_per: 0, ac_tx_per: 2,rssi: -50, rx_rate: 36Mbps, osd 10, stream 361
12-13 10:51:25.936:[2020-12-13 10:51:25]: second 550, USB IOS, bat 96, uart 7290,83591
12-13 10:51:27.974:[GND_wifi0_stats] rx_pkts: 295, rx_errs: 0, tx_pkts: 58, tx_retries: 2, tx_fails: 2, tx_per: 6, ac_tx_per: 30,rssi: -60, rx_rate: 36Mbps, osd 10, stream 242
12-13 10:51:28.941:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:6M txpower:20, link:1 phone:1 sw:1122kbps video:1122kbps rc>>189kbps >>rc1992bps
beacon[rx_all:4596 rx:4595 tx:8 tx_miss:0], probe[req:0 resp_all:0 resp:0] rxint:1813095 txint:91470
12-13 10:51:28.942:mem_use = 48%, cpu_use = 22%
12-13 10:51:29.983:strong interference: tx_per: 64, rssi: -49
12-13 10:51:30.956:[2020-12-13 10:51:30]: second 555, USB IOS, bat 96, uart 7350,84365
12-13 10:51:30.998:strong interference: tx_per: 100, rssi: -49
12-13 10:51:30.998:[GND_wifi0_stats] rx_pkts: 0, rx_errs: 0, tx_pkts: 51, tx_retries: 52, tx_fails: 52, tx_per: 100, ac_tx_per: 8,rssi: -49, rx_rate: 36Mbps, osd 0, stream 0
12-13 10:51:32.006:strong interference: tx_per: 98, rssi: -49
12-13 10:51:33.016:strong interference: tx_per: 100, rssi: -49
12-13 10:51:33.623:plane disconnect
12-13 10:51:34.011:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:6M txpower:20, link:0 phone:1 sw:0kbps video:0kbps rc>>6kbps >>rc8160bps
beacon[rx_all:4602 rx:4601 tx:8 tx_miss:0], probe[req:1 resp_all:0 resp:0] rxint:1829727 txint:91679
12-13 10:51:34.013:mem_use = 46%, cpu_use = 14%
12-13 10:51:34.846:try scan flush
12-13 10:51:35.976:[2020-12-13 10:51:35]: second 560, USB IOS, bat 96, uart 7372,85109
12-13 10:51:37.579:check ibss connection, find peer:64:60:1f:e8:87:f0, run ibss rejoin, freq:5745
12-13 10:51:39.087:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:NA txpower:20, link:0 phone:1 sw:0kbps video:0kbps rc>>4kbps >>rc1800bps
beacon[rx_all:4602 rx:4601 tx:13 tx_miss:0], probe[req:11 resp_all:0 resp:0] rxint:1846429 txint:91728
12-13 10:51:39.088:mem_use = 46%, cpu_use = 47%
12-13 10:51:41.030:[2020-12-13 10:51:41]: second 566, USB IOS, bat 96, uart 7382,85796
12-13 10:51:41.691:check ibss connection, find peer:64:60:1f:e8:87:f0, run ibss rejoin, freq:5745
12-13 10:51:44.214:[GND] CC:CN FCC Cal:0, freq:5745 bw:5MHz rate:NA txpower:20, link:0 phone:1 sw:0kbps video:0kbps rc>>4kbps >>rc1760bps
beacon[rx_all:4602 rx:4601 tx:18 tx_miss:0], probe[req:21 resp_all:0 resp:0] rxint:1863197 txint:91773
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