Houston-George Bush-Intercontinental

A Cessna 208B airplane collided with a powered paraglider during cruise flight at 5,000 feet mean sea level (msl) in Class E airspace. Based on video evidence, the powered paraglider operator impacted the Cessna’s right wing leading edge, outboard of the lift strut attachment point. The outboard 10 ft of the Cessna’s right wing separated during the collision. The Cessna impacted terrain at high vertical speed in a steep nose-down and inverted attitude. The powered paraglider operator was found separated from his seat style harness. The paraglider wing, harness, and emergency parachute were located about 3.9 miles south of the Cessna’s main wreckage site. Based on video evidence and automatic dependent surveillance-broadcast (ADS-B) data, the Cessna and the powered paraglider converged with a 90° collision angle and a closing speed of about 164 knots. About 8 seconds before the collision, the powered paraglider operator suddenly turned his head to the right and about 6 seconds before the collision, the powered paraglider maneuvered in a manner consistent with an attempt to avoid a collision with the converging Cessna. Research indicates that about 12.5 seconds can be expected to elapse between the time that a pilot sees a conflicting aircraft and the time an avoidance maneuver begins. Additionally, research suggests that general aviation pilots may only spend 30-50% of their time scanning outside the cockpit. About 8 seconds before the collision (when the powered paraglider operator’s head suddenly turned to the right), the Cessna would have appeared in the powered paraglider operator’s peripheral view, where research has demonstrated visual acuity is very poor. Additionally, there would have been little apparent motion because the Cessna and the powered paraglider were on a collision course. Under optimal viewing conditions, the powered paraglider may have been recognizable to the Cessna pilot about 17.5 seconds before the collision. However, despite the powered paraglider’s position near the center of his field of view, the Cessna pilot did not attempt to maneuver his airplane to avoid a collision. Further review of the video evidence revealed that the powered paraglider was superimposed on a horizon containing terrain features creating a complex background. Research suggests that the powered paraglider in a complex background may have been recognizable about 7.4 seconds before the collision. However, the limited visual contrast of the powered paraglider and its occupant against the background may have further reduced visual detection to 2-3 seconds before the collision. Thus, after considering all the known variables, it is likely that the Cessna pilot did not see the powered paraglider with sufficient time to avoid the collision. The Cessna was equipped with a transponder and an ADS-B OUT transmitter, which made the airplane visible to the air traffic control system. The operation of the powered paraglider in Class E airspace did not require two-way radio communication with air traffic control, the use of a transponder, or an ADS-B OUT transmitter and therefore was not visible to air traffic control. Neither the Cessna nor the powered paraglider were equipped with ADS-B IN technology, cockpit display of traffic information, or a traffic alerting system. Postmortem toxicological testing detected the prescription antipsychotic medication quetiapine, which is not approved by the Federal Aviation Administration (FAA), in the Cessna pilot’s muscle specimen but the test results did not provide sufficient basis for determining whether he was drowsy or otherwise impaired at the time of the collision (especially in the absence of any supporting details to suggest quetiapine use). Testing also detected ethanol at a low level (0.022 g/dL) in the Cessna pilot’s muscle specimen, but ethanol was not detected (less than 0.01 g/dL) in another muscle specimen. Based on the available results, some, or all of the small amount of detected ethanol may have been from postmortem production, and it is unlikely that ethanol effects contributed to the accident. The Cessna pilot likely did not have sufficient time to see and avoid the powered paraglider (regardless of whether he was impaired by the quetiapine) and, thus, it is unlikely the effects of quetiapine or an associated medical condition contributed to the accident.

The airline transport pilot departed on a night cargo flight into conditions that included an overcast cloud ceiling and “hazy” visibility, as reported by another pilot. About one minute after takeoff, the pilot made a series of course changes and large altitude and airspeed deviations. Following several queries from the air traffic controller concerning the airplane’s erratic flight path, the pilot responded that he had “some instrument problems.” The pilot attempted to return to land at the departure airport, but the airplane impacted terrain after entering a near-vertical dive. The airplane was one of two in the operator’s fleet equipped with an inverter system that electrically powered the pilot’s (left side) flight instruments. Examination of the annunciator panel lighting filaments revealed that the inverter system was not powered when the airplane impacted the ground. Without electrical power from an inverter, the pilot’s side attitude indicator and horizontal situation indicator (HSI) would have been inoperative and warning flags would have been displayed over the respective instruments. The pilot had a history of poor procedural knowledge and weak flying skills. It is possible that he either failed to turn on an inverter during ground operations and did not respond to the accompanying warning flags, or he did not switch to the other inverter in the event that an inverter failed inflight. Due to impact damage, the operational status of the two inverters installed in the airplane could not be confirmed. However, the vacuum-powered flight instruments on the copilot’s (right side) were operational, and the pilot could have referenced these instruments to maintain orientation. Based on the available information, the pilot likely lost control of the airplane after experiencing spatial disorientation. The night marginal visual flight rules conditions and instrumentation problems would have been conducive to the development of spatial disorientation, and the airplane’s extensive fragmentation indicative of a high-energy impact was consistent with the known effects of spatial disorientation. Ethanol identified during toxicology testing may have come from postmortem production and based on the low levels recorded, was unlikely to have contributed to this accident. Morphine identified in the pilot’s liver could not be used to extrapolate to antemortem blood levels; therefore, whether or to what extent the pilot’s use of morphine contributed to the accident could not be determined.

On February 23, 2019, at 1239 central standard time, Atlas Air Inc. (Atlas) flight 3591, a Boeing 767-375BCF, N1217A, was destroyed after it rapidly descended from an altitude of about 6,000 ft mean sea level (msl) and crashed into a shallow, muddy marsh area of Trinity Bay, Texas, about 41 miles east-southeast of George Bush Intercontinental/Houston Airport (IAH), Houston, Texas. The captain, first officer (FO), and a nonrevenue pilot riding in the jumpseat died. Atlas operated the airplane as a Title 14 Code of Federal Regulations Part 121 domestic cargo flight for Amazon.com Services LLC, and an instrument flight rules flight plan was filed. The flight departed from Miami International Airport (MIA), Miami, Florida, about 1033 (1133 eastern standard time) and was destined for IAH. The accident flight’s departure from MIA, en route cruise, and initial descent toward IAH were uneventful. As the flight descended toward the airport, the flight crew extended the speedbrakes, lowered the slats, and began setting up the flight management computer for the approach. The FO was the pilot flying, the captain was the pilot monitoring, and the autopilot and autothrottle were engaged and remained engaged for the remainder of the flight. Analysis of the available weather information determined that, about 1238:25, the airplane was beginning to penetrate the leading edge of a cold front, within which associated windshear and instrument meteorological conditions (as the flight continued) were likely. Flight data recorder data indicated that, during the time, aircraft load factors consistent with the airplane encountering light turbulence were recorded and, at 1238:31, the airplane’s go-around mode was activated. At the time, the accident flight was about 40 miles from IAH and descending through about 6,300 ft msl toward the target altitude of 3,000 ft msl. This location and phase of flight were inconsistent with any scenario in which a pilot would intentionally select go-around mode, and neither pilot made a go-around callout to indicate intentional activation. Within seconds of go-around mode activation, manual elevator control inputs overrode the autopilot and eventually forced the airplane into a steep dive from which the crew did not recover. Only 32 seconds elapsed between the go-around mode activation and the airplane’s ground impact.

The pilots reported that the cargo airplane was about 60 pounds over its maximum takeoff weight. Because their taxi to the assigned runway was long, they decided to reduce weight by using higher-than-normal engine power settings to burn fuel before takeoff while using the wheel brakes to control the airplane’s speed while taxiing. During the taxi, a fire ignited in the right wheel housing. The pilots brought the airplane to a stop on the taxiway, evacuated, and attempted to extinguish the fire with two handheld fire extinguishers. Airport firefighting personnel arrived on scene and extinguished the fire using foam suppressant. Although the fire damage was extensive, postaccident examination of the airplane did not show evidence of mechanical malfunctions or failures with the wheel and brake system that could have caused the fire. The right and left main landing gear tires deflated when the fusible plugs in the wheels blew due to overheating. The fusible plugs are designed to “fail” if the wheels overheat, and those plugs functioned as designed. The pilots stated that they had been trained to not ride the brakes while taxiing. However, the captain stated that he did not realize that he was in danger of blowing the tires much less causing a fire, otherwise he would not have attempted to bum off excess fuel while taxiing.

On December 20, 2008, about 1818 mountain standard time, Continental Airlines flight 1404, a Boeing 737-500, N18611, departed the left side of runway 34R during takeoff from Denver International Airport (DEN), Denver, Colorado. A postcrash fire ensued. The captain and 5 of the 110 passengers were seriously injured; the first officer, 2 cabin crewmembers, and 38 passengers received minor injuries; and 1 cabin crewmember and 67 passengers (3 of whom were lap-held children) were uninjured. The airplane was substantially damaged. The scheduled, domestic passenger flight, operated under the provisions of 14 Code of Federal Regulations Part 121, was departing DEN and was destined for George Bush Intercontinental Airport, Houston, Texas. At the time of the accident, visual meteorological conditions prevailed, with strong and gusty winds out of the west. The flight operated on an instrument flight rules flight plan.

After an asymmetrical deployment of the thrust reversers during landing rollout deceleration, the captain failed to maintain directional control of the airplane and it veered off the runway, collapsing the nose gear and damaging the forward fuselage. Several days before the flight the #1 thrust reverser had been rendered inoperative and mechanically locked in the stowed position by maintenance personnel. In accordance with approved minimum equipment list (MEL) procedures, the airplane was allowed to continue in service with a conspicuous placard noting the inoperative status of the #1 reverser placed next to the engine's thrust lever. When this crew picked up the airplane at the departure airport, the inbound crew briefed the captain on the status of the #1 thrust reverser. The captain was the flying pilot for this leg of the flight and the airplane touched down on the centerline of the runway about 1,200 feet beyond its threshold. The captain moved both thrust levers into the reverse position and the airplane began yawing right. In an effort at maintaining directional control, the captain then moved the #1 thrust lever out of reverse and inadvertently moved it to the Take-Off/Go-Around (TOGA) position, while leaving the #2 thrust lever in the full reverse position. The thrust asymmetry created by the left engine at TOGA power with the right engine in full reverse greatly increased the right yaw forces, and they were not adequately compensated for by the crew's application of rudder and brake inputs. Upon veering off the side of the runway onto the dirt infield, the nose gear strut collapsed. The airplane slid to a stop in a nose down pitch attitude, about 7,650 feet from the threshold. There was no fire. Company procedures required the flying pilot (the captain) to give an approach and landing briefing to the non flying pilot (first officer). The captain did not brief the first officer regarding the thrust reverser's MEL'd status, nor was he specifically required to do so by the company operations manual. Also, the first officer did not remind the captain of its status, nor was there a specific requirement to do so. The operations manual did state that the approach briefing should include, among other things, "the landing flap setting...target airspeed...autobrake level (if desired) consistent with runway length, desired stopping distance, and any special problems." The airline's crew resource management procedures tasked the non flying pilot to be supportive of the flying pilot and backup his performance if pertinent items were omitted from the approach briefing. The maintenance, repair history, and functionality of various components associated with the airplane's directional control systems were evaluated, including the brake system, the nose landing gear strut and wheels, the brakes, the antiskid system, the thrust levers and reversers, and the throttle control unit. No discrepancies were found regarding these components.