The aviation authority is investigating a runway incident at Hong Kong International Airport where a cargo jet had to pull back from landing to avoid a potential collision with a commercial airliner with no passengers that was still taking off.The Civil Aviation Department (CAD) said in a statement on Saturday that the two aircraft were more than 1.7 kilometres apart, adding no one was injured and airport operations were unaffected from Friday’s incident, which came even with the huge slump in…