Warning systems failed on Qantas planes involved in near miss The two planes came within about 200 metres of each other west of Adelaide. Picture: News Corp Source: News Limited PILOTS on one of two Qantas passenger aircraft that came within seconds of colliding near Adelaide last month received no warning from their plane's onboard systems, an investigation has found. The two planes came within about 200 metres of each other west of Adelaide as one travelling from Sydney to Perth was cleared to climb from 38,000 to 40,000 feet, bringing it too close to the other aircraft travelling from Perth to Sydney. Warning systems on the second plane were triggered but the Australian Transport Safety Bureau (ATSB) says crews on the first plane were not alerted by their Traffic Collision Avoidance System (TCAS). The ATSB says the crew of the Sydney to Perth flight later indicated they could not "see" other aircraft on their TCAS display during the rest of the flight in situations where other planes could see them. "They had been able to see other aircraft on departure from Sydney and there was no indication of a TCAS failure prior to the loss of separation event," the ATSB said in an interim report on Thursday. A test of the plane's TCAS later identified a fault and the unit was replaced. The ATSB says there are occasions when safety-critical personnel make errors and in those instances systems are in place to detect the mistakes or mitigate the consequences. "In this occurrence one of those detection and recovery controls did not work effectively," it said. At the time of the incident Qantas said the pilots on both its Airbus A330 aircraft had followed standard operating procedures. The ATSB said its investigation was continuing and would include further analysis of radar and audio data, an examination of the air traffic controller's actions and a review of the reliability of the TCAS.