When did the accident occur that the 2017 Joan Gamper Trophy held a tribute for?
2017 Joan Gamper Trophy:  This marked Chapecoense's first ever appearance in the Joan Gamper Trophy, as a tribute to the 71 Chapecoense players and staff who lost their lives after the LaMia Flight 2933 tragedy in La Unión, Colombia, on 28 November 2016. LaMia Flight 2933: LaMia Flight 2933 (LMI2933) was a charter flight of an Avro RJ85, operated by LaMia, which crashed in Colombia at 21:58 on 28 November 2016 killing 71 of 77 people on board.
i don't know