History of Flight
On December 9, 2019, about 2017 central standard time, a Cessna 208B airplane, registration N4602B, was destroyed in an accident near Victoria, Texas. The airline transport pilot was fatally injured. The airplane was operating as a Title 14 Code of Federal Regulations Part 135 cargo flight, planned from Victoria Regional Airport (VCT) to George Bush Intercontinental Airport (IAH) in Houston, Texas, under instrument flight rules. The airplane carried 752 pounds of non-hazardous cargo. The pilot, unfamiliar with VCT, initially taxied to the wrong runway before being corrected by the controller.
Departure occurred about 2004, with clearance to 3,000 feet mean sea level. As the airplane climbed through 1,900 feet, air traffic control data showed a series of fifteen course changes, each involving heading changes exceeding 90 degrees, alternating left and right. The controller queried the pilot about the erratic movements and assigned a heading of 035 degrees toward the GMANN fix. The pilot continued making large turns with erratic altitude and airspeed changes, and his radio transmissions became unintelligible.
About 2011, the pilot stated he had "some instrument problems." The controller suggested returning to VCT, and the pilot agreed. Initially cleared for a visual approach, the controller later advised radar vectors after another pilot reported "really hazy" conditions. The pilot acknowledged but the airplane made more large turns, entered a rapid descent, and radar contact was lost.
Personnel Information
The pilot was hired by Martinaire Aviation in November 2017. Training records noted challenges with situational awareness and procedural knowledge. After striking a taxiway sign in January 2018, he received remedial ground training. In September 2018, he left to work for a passenger-carrying Part 135 operator in Hawaii, but was released during initial training due to weak instrument flying skills, language difficulties, and poor systems knowledge. He returned to Martinaire in February 2019. On his last checkride (August 23, 2019), flown in an inverter-equipped airplane, he required instruction on the inverter system. The accident flight was his third in an inverter-equipped airplane.
Aircraft Information
The accident airplane was one of two in the fleet equipped with two inverters powering the pilot's side flight instruments. The inverter selector switch had positions labeled "1", "OFF", and "2". An "INVERTER INOP" annunciator light illuminated if neither inverter powered the system. Without inverter power, "ATTITUDE" and "COMPUTER" flags appeared over the attitude indicator, and "NAV" and "COMPASS" flags over the horizontal situation indicator. During ground operations, after the gyros were powered for about two minutes, the flags would retract.
Meteorological Information
Several weather facilities reported restricted visibility due to mist and haze. A pilot in the vicinity described conditions as "really hazy." At the accident time, the sun was 35 degrees below the horizon and the moon was 54 degrees above.
Wreckage and Impact Information
The airplane impacted a rural area on a southwesterly heading in a nearly vertical attitude. The propeller hub was buried about 5 feet deep in clay soil, and the airplane was heavily fragmented, with fuel tank and engine tubing remnants located 225 feet from the main wreckage. All three propeller blades separated from the hub, two found with the main wreckage and one about 160 feet away. Flight control continuity was confirmed to the extent possible. Flaps were retracted; fuel tanks were impact-damaged and empty. Engine disassembly showed rotational damage consistent with power at impact.
Examination of the vacuum-driven gyros (copilot side) showed rotational scoring; the electrically-powered attitude gyro (pilot side) did not. The inverter select switch position could not be determined due to damage. The annunciator panel's "INVERTER INOP" light showed hot filament stretch, consistent with being illuminated at impact.
Communications
The filed flight plan indicated conventional navigation only, but the pilot accepted an IFR routing including the RNAV fix GMANN. After departure, he could not maintain a straight course and was assigned a heading. Following the accident, the FAA adjusted routing protocols near VCT to avoid assigning RNAV fixes to conventionally-equipped aircraft. When the pilot reported instrument problems and agreed to return, the controller asked if he had the airport in sight; the pilot replied he was "looking." The controller issued a visual approach clearance before the pilot confirmed visual acquisition, contrary to FAA directives. After another pilot reported haze, the controller provided radar vectors.
Medical and Pathological Information
Toxicology tests by the FAA identified ethanol at 0.010 gm/hg in brain tissue and 0.017 gm/hg in muscle tissue. Morphine was found at 32 ng/hg in liver but not in muscle; no blood was available. Ethanol may be produced postmortem. Morphine is an opioid pain medication. The pilot had dental surgery in South Korea weeks before the accident; no information on prescribed medications was available.
Organizational Information
The operator's training material covered the annunciator panel and inverter system. The engine start checklist required an inverter to be selected; the taxi checklist required it checked; and the before-takeoff checklist required all annunciator lights extinguished.