The takeoff and departure flight phase can be one of the more risky among instrument procedures, especially at night in IMC aviation. On one hand, the pilot is abruptly transitioning from a presumably well-lit runway and airport environment to flying on instruments near terrain. On another hand, the airplane may not be up to the task, due to mechanical issues or misconfiguration by the pilot. And there’s also the immediate need to comply with whatever departure procedure is in use and join the en route airspace structure.
These challenges can confront a pilot simultaneously, and to ensure success, he or she needs to have solid instrument skills and a firm understanding of the airplane’s systems, along with Air Traffic Control’s expectations. Much of this can be easier with a multiple-pilot crew; single-pilot IFR departure operations demand almost error-free airmanship. When pilots lack the cockpit skills, systems knowledge, situational awareness or simple checklist discipline, the potential for a bad outcome rises dramatically. When all these factors combine to varying degrees, a good outcome is improbable.
On December 9, 2019, at about 2017 Central time, a Cessna 208B Grand Caravan was destroyed when it was involved in an accident near Victoria, Texas. The solo airline transport pilot was fatally injured. Although the departure airport’s weather was reported to be marginal visual conditions, it was a dark night, with an overcast, and other nearby weather observing stations—plus at least one other pilot—reporting hazy conditions. An IFR flight plan was filed for the FAR Part 135 cargo operation.
The pilot was unfamiliar with the departure airport and incorrectly taxied to Runway 31L. After Air Traffic Control corrected him, the airplane departed Runway 13L at about 2004 with a clearance to 3000 feet msl, about 2900 feet agl. As the airplane climbed through 1900 feet msl, Air Traffic Control data showed the airplane beginning a series of 15 course deviations that continued for the remainder of the flight, alternating between left and right turns, and involving heading changes of more than 90 degrees, prompting controllers to assign a heading.
The pilot continued to make large turns with erratic altitude and airspeed changes, and the pilot often responded to the controller with unintelligible transmissions. At about 2011, the pilot stated he had “some instrument problems.” The controller suggested returning for a landing and the pilot concurred. The pilot was initially cleared for a visual approach but when the other pilot reported “really hazy” conditions near the airport, the controller notified the accident pilot he would be given radar vectors and to maintain 3000 feet. The pilot acknowledged the clearance but the airplane continued to make large turns, subsequently entering a rapid descent, during which radar contact was lost.
The FAA’s Airplane Flying Handbook (FAA-H-8083-3B) describes some of the hazards associated with flying when the ground or horizon are obscured: “The vestibular sense (motion sensing by the inner ear) in particular can and will confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in airplane attitude, nor can they accurately sense attitude changes that occur at a uniform rate over a period of time. On the other hand, false sensations are often generated, leading the pilot to believe the attitude of the airplane”
The FAA’s Instrument Flying Handbook (FAA-H-8083-15B), meanwhile, has the following advice for coping with spatial disorientation: “The sensations that lead to illusions during instrument flight conditions are normal perceptions experienced by pilots. These undesirable sensations cannot be completely prevented, but through training and awareness, pilots can ignore or suppress them by developing absolute reliance on the flight instruments.”
The airplane impacted terrain in a nearly vertical attitude. The propeller hub was buried about five feet deep into clay soil; the airplane was highly fragmented, with remnants of a fuel tank and engine tubing located 225 feet from the main wreckage. All three propeller blades were separated from the hub about a foot from the shank. Two of the blades were found with the main wreckage, with the third blade about 160 feet away.
All primary and secondary flight controls were attached to the airframe and flight control continuity was confirmed to the extent allowed by impact damage. The wing flaps were retracted. The fuel tanks were impact damaged and no fuel was recovered. Internal examination of the engine revealed rotational damage consistent with the engine producing power at impact. Examination of the vacuum-driven co-pilot’s attitude, direction and turn-and-bank instruments showed evidence of rotational scoring. The pilot’s electrically powered attitude gyro did not show evidence of rotational scoring. Impact damage precluded ascertaining the position of the inverter select switch, or even testing it and the two inverters. The INVERTER INOP annunciator light demonstrated hot filament stretch, which is consistent with being illuminated at impact.
The pilot’s initial training records revealed situational awareness and procedural knowledge challenges. After the pilot struck a taxiway sign while exiting a runway on January 1, 2018, he received remedial ground training. In September 2018, the pilot moved to another company, but was released during initial training due to weak instrument flying skills, language difficulties and poor systems knowledge. After returning to the accident aircraft operator and during his last checkride, flown in an inverter-equipped airplane, the pilot required instruction for the inverter system, including the need to select one of the two inverters during the engine-start checklist. The accident flight was the pilot’s third in an inverter-equipped airplane.
The NTSB determined the probable cause(s) of this accident to include: “The pilot’s loss of control due to spatial disorientation. Contributing to the accident were the inoperative attitude indicator and horizontal situation indicator on the pilot’s side of the cockpit, and the pilot’s failure to reference the flight instruments that were operative.”
According to the NTSB, “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 in aviation, and the airplane’s extensive fragmentation indicative of a high-energy impact was consistent with the known effects of spatial disorientation.”
Also according to the NTSB, “The airplane’s engine start checklist required an inverter be selected on and the taxi checklist required an inverter be checked on. The before takeoff checklist required the annunciator panel be checked for all lights extinguished.”
From his training and operational records, it’s clear the pilot wasn’t at the top of his class. Still, he had earned ATP certification and, presumably, had gotten through multiple checkrides over his career. While most of his Caravan experience may have been in airframes without an inverter, paying attention to the checklist should have resolved that problem. Instead, the night got off to a bad start when he taxied to the wrong runway, and it never got better.
Pardon my ignorance, but what is the inverter and what function does it perform?
An Inverter is a device that converts DC current to AC
Professor Google is your friend….look it up!