Human Factors NTSB Case Studies

Technologically Advanced Aircraft and Risk Compensation: Risk compensation is an effect whereby individual people may tend to adjust their behavior in response to perceived changes in risk. Individuals will behave less cautiously in situations where they feel "safer" or more protected.

The airplane, while operating under an instrument flight rules (IFR) flight plan, departed from controlled flight after encountering icing conditions, entered an uncontrolled descent, and collided with the ground. The airplane was equipped with an Ice Protection System that when activated supplied deicing fluid to the wings, tail, and propeller. The aircraft was not certified for flight into known icing and the Pilot Operating Handbook reads that, "Flight into known icing conditions is prohibited." The last transmission from the pilot was at 1817:42, again indicating that he was icing up and coming down. According to investigators from Ballistic Recovery Systems (BRS), following the examination of the ballistic parachute system, they determined the system was deployed outside of the operating envelope of the system, which is 133 knots indicated airspeed. Full Narrative

Perceptual Blindness is the phenomenon of not being able to perceive things that are in plain sight. It is caused by an absence of attention to the unseen object and is clear evidence of the importance of attention for perceiving

The Pilatus P3-05 was holding for takeoff while the North American AT-6A was taxiing for takeoff. According to the pilot of the Pilatus, prior to his departure he obtained fuel and taxied to a clear area for about 1-2 minutes because of other airplanes entering the fueling area. While holding in this area, a North American taxied from behind the Pilatus and struck it. The North American pilot stated that he was in the process of loading and unloading passengers for rides with the engine running when the Pilatus stopped in front of him. The Pilatus sustained substantial damage, which included two damaged ribs within the left wing; the North American sustained minor damage to its right main landing gear door. The NTSB determines the probable cause(s) of this accident as follows: The North American pilot's failure to maintain adequate visual lookout, which resulted in an on-ground collision with the Pilatus. Full Narrative

Controlled Flight Into Terrain: An occurence in which an aircraft, under the control of the crew, is flown into terrain, water, or an obstacle with no prior awareness on part of the crew of the impending disaster.

The airplane collided with rising mountainous terrain during climb to cruise about 21 nm southwest of the departure airport. The accident occurred during dark night, visual meteorological conditions, about 13 minutes into the night cross-country flight. Over the last 6 minutes of the flight, recorded radar data indicated the airplane's average groundspeed was 100 knots and its average rate of climb was 406 fpm; an average rate of climb of 600 fpm was required to clear terrain along the flight path. An examination of the accident site indicated that the airplane impacted rapidly rising terrain in a near level flight attitude before descending and coming to rest in a rock outcropping. The airplane was equipped with a Garmin G1000 Integrated Cockpit System, which incorporates a multifunction color display that is capable of displaying terrain elevation information when selected to the Terrain Proximity page. Records indicate that the pilot had received G1000 training.The airplane's course remained constant as he approached and impacted the mountain during the dark nighttime flight. Full Narrative

Dirty Dozen: The twelve most common Aviation Maintenance-related, Human Factors causes of errors: Lack of Communication, Complacency, Lack of Knowledge, Distraction, Lack of Teamwork, Fatigue, Lack of Resources, Pressure, Lack of Assertiveness, Stress, Lack of Awareness, and Norms.

The helicopter's engine suddenly lost power during initial climb on an instructional flight. The certified flight instructor (CFI) took the controls and autorotated to a hard touchdown in a gravel pit. After securing the helicopter, the CFI inspected the throttle linkage. He reported that something appeared disconnected behind the firewall. "When rotating the throttle from full open to full close, the push/pull tube that connects to the carburetor does not move." The subsequent examination of the helicopter's throttle spring assembly revealed that on a previous occasion improper maintenance had been performed. The helicopter's maintenance records did not reflect maintenance in this area. The inspection revealed that the upper rod end bearing was disconnected from the lower portion of the rod because it had not been safety wired as required. This maintenance error resulted in a total loss of throttle control. The NTSB determines the probable cause(s) of this accident as follows: Disconnection of the throttle control linkage due to improper maintenance, which resulted in a loss of engine power during initial climb. Full Narrative 

Loss of Situational Awareness: Situational Awerness is the perception of elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status into the near future.

Radar data showed the airplane proceeding outbound for the procedure turn. The pilot reported that they were having trouble extending the landing gear and stated, " ... we’re trying to turn back in and do our gear here all at the same time, Radar data indicated the airplane crossed the localizer at almost a 90-degree angle and continued turning right until it started to intercept the localizer. The data then indicated that the airplane made a left turn away from the localizer that continued and terminated near the accident site. The turn was captured by six plots. The first plot showed the airplane had descended from 9,400 feet to 9,200 feet and its ground speed had increased from 85 knots to 152 knots. The second plot showed the altitude had increased to 9,700 feet and ground speed had decreased to 132 knots. The third plot showed the altitude had increased further to 10,200 feet and ground speed had dropped to 76 knots. The fourth plot showed the airplane had made almost a 180-degree turn and was at 8,900 feet and at a ground speed of 120 knots. The fifth plot showed the airplane was at 8,700 feet and 20 knots. The sixth and final plot showed the airplane at 8,400 feet and 38 knots. The pilot's loss of situational awareness while maneuvering in adverse weather conditions, resulting in spatial disorientation. Full Narrative