Among fatal plane crashes that occurred during the past 50 years, 403 were due to pilot error, 88 were due to other human error, 287 were due to weather, 210 were due to mechanical problems, and 447 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. Relative Cause Frequency Pilot error Other human error Weather Mechanical problems Sabotage (Round to one decimal place as needed.) What is the most serious threat to aviation safety, and can anything be done about it? A. Pilot error is the most serious threat to aviation safety. Pilots could be better trained. O B. Sabotage is the most serious threat to aviation safety. Airport security could be increased. OC. Weather is the most serious threat to aviation safety. Weather monitoring systems could be improved. O D. Mechanical problems are the most serious threat to aviation safety. New planes could be better engineered