Why these risks aren't reflected in accident statistics boils down to technology. The air transport industry has been revolutionized by technology, nowhere more profoundly than in the area of safety. Improvements in propulsion mechanics have helped reduce the rate of in-flight engine failures, and engineering advances have ensured that airframe corrosion does not necessarily render an aircraft inoperable like it did in years prior. Technology has also made human error more tolerable. For example, the "ground proximity warning system" generates an auditory alert if the aircraft is in danger of colliding with the ground. That's good news for weary budget pilots who, by virtue of flying more every day, face these risks more regularly. Similarly, the "engine indicating and crew alerting system" provides a visual message to pilots if ground staff, rushed to get a flight out on time, improperly shut a cargo door.