Among fatal plane crashes that occurred during the past 70 years, 581 were due to pilot error, 56 were due to other human error, 579 were due to weather, 555 were due to mechanical problems, and 526 were due to sabotage. Construct the relative frequency distribution. What is the most serious threat to aviation safety, and can anything be done about it? Complete the relative frequency distribution below. Cause Relative Frequency Pilot error nothing% Other human error nothing% Weather nothing% Mechanical problems nothing% Sabotage nothing%