Three people who were killed in a plane crash on Thursday have been identified as part of the South African Civil Aviation Authority's (Sacaa) flight inspection unit, it was revealed on Friday."On board the aircraft there were three professionals, all employees of the Sacaa. It is with deep regret and devastation to announce that these esteemed colleagues were all fatally injured during the aircraft incident," director of civil aviation, Poppy Khoza, said in a briefing on Friday.The deceased, Captain Thabiso Tolo (49), first officer Caroline Lekalakala (33) and flight inspector Gugu Mnguni (36), were on a plane during a calibration mission that took off from George Airport and crashed into mountainous terrain near Mossel Bay on Thursday.Tolo, who qualified in 2013 and had approximately 4 959 hours of flying to his name, was the first black captain of the Sacaa's flight inspection unit.Fears for three crew members as plane goes missing near George | @gerbjan https://t.co/HNWAIXjTp5 pic.twitter.com/yECP6ZFMH1— News24 (@News24) January 23, 2020 Lekalakala had approximately 1 050 hours of flying to her credit and Mnguni had 1 300 hours of flying under his belt.The function of flight calibration is essential to the safety of air navigation and is carried out by the flight inspection unit. There were no passengers on the flight when it crashed at 11:30 on Thursday.News24 reported that the wreckage, however, was only discovered at 14:05, according to Western Cape Emergency Medical Services (EMS).No contact 10 minutes after take-offSacaa said in a statement on Thursday that its air traffic control tower could not make contact with the aircraft 10 minutes after take-off.The regulatory body added that it was not clear what caused the accident."At this stage we have no details [on] what caused the accident, hence we call on everyone to avoid speculation...We do hope that the investigation will provide us with answers," Khoza said.The investigation unit that will probe the incident reports directly to the Department of Transport.The families of the deceased have since been informed of the tragedy.Questions and allegations emerged during the briefing regarding the competency of the crew, particularly Captain Tolo who was allegedly fired from a South African airline prior to his post at the Sacaa.'He was competent'"I cannot get into the issues at SAA, but I know he was hired on his competence and qualifications at the Sacaa."He has been flying in the inspection unit for eight years without an accident. He was competent and we have no doubt that he did his work with diligence," Khoza responded.The preliminary report is expected to be ready within 30 days.Transport Minister Fikile Mbalula has expressed sadness over the three employees' death."My sincere condolences to the families and friends of the deceased. We wish to thank Sacaa for their swift response to this tragedy and we offer our support in their endeavours to get to the bottom of what transpired," Mbalula said.He plans to visit the families of the deceased soon.