The medical transport flight was en route to pick up a patient on a neighboring island on an instrument flight rules (IFR) flight plan in dark night conditions over the ocean. About 13 minutes after departure, at 13,000 ft mean sea level (msl), the airplane’s vertical gyro failed, which subsequently failed the pilot’s Electric Attitude Director Indicator (EADI), which also caused the autopilot to disconnect. The failure of the EADI and autopilot disconnect required the pilot to manually fly the airplane using the copilot’s attitude gyro for his horizon information (bank angle and pitch attitude) for the duration of the flight. The pilot did not declare an emergency, nor did he inform air traffic control (ATC) that his electric attitude indicator had failed and that his autopilot had disengaged.  After the instrumentation failure and autopilot disconnect, the airplane entered a series of right banks before being brought back to level, followed by a left turn, and then subsequent right banks. ATC asked the pilot to change course and the pilot agreed. The copilot attitude indicator indicated that the airplane entered a descending, steep right bank turn. Over the next 5 minutes, ATC issued varying instructions to the pilot. During this time, the airplane entered several right- and left-hand banks and rolls and descended 1,000 ft per minute (fpm), which increased to -3,500 fpm as the airplane’s airspeed increased. About 7 minutes after the instrumentation failure, the airplane was in a 65° bank angle when ATC asked the pilot to verify his heading. As the pilot responded, the airplane bank angle increased to 90° and the airspeed exceeded 260 knots. The bank angle and airspeed continued to increase; a loud metallic bang was recorded that was consistent with an in-flight separation of the empennage from the fuselage before impacting with the water. Page 2 of 32 ANC23FA008After an extensive underwater search, the main wreckage was located on the seabed at a depth of about 6,420 ft. The wreckage was recovered and transported to a facility for examination. A postaccident examination of the engines and airframe revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The engines exhibited contact signatures consistent with the engines developing power at the time of impact.The examination of the vertical gyro was unable to determine the reason for its failure due to the damage incurred by the unit during the accident sequence and the subsequent saltwater contamination.The operator had installed an Appareo Vision 1000 airborne image recording system (AIRS) in the airplane in 2018. The camera was mounted in a position that captured the entire instrumentation for both the left and right seats, as well as the center pedestal and overhead panel. During the accident flight, the Appareo video recording showed the pilot using his cell phone to listen to music shortly after takeoff, and the pilot talking to and passing money back to a medical flight crewmember as the airplane climbed through 1,400 ft msl. Both of these actions took place during a critical phase of flight and were in direct conflict with Guardian Flight’s Standard Operating Procedures. The Appareo video recording revealed that the airplane’s Collins multi-function display (MFD) was inoperative for the duration of the flight, and on the last four flights of recorded video. It also captured the EADI on the captain’s side (or left side), going black, or inoperative, approximately 13 minutes into the flight. Additionally, the video recording captured audible sounds including the autopilot disconnect, master caution warning, altitude alert tones, and the sound of a loud metallic bang shortly before water impact.Although this flight was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 flight, upon landing and loading the patient for transport to Honolulu the flight at that point would be operated under 14 CFR Part 135. Guardian Flight was allowed in their Operation Specifications to operate the Part 135 flight with a single pilot; however, those flights with only one pilot were required to have an operating autopilot. Therefore, in the airplane’s condition, with the autopilot and EADI inoperative due to the vertical gyro failure, they would not have been able to transport the patient according to their Operation Specifications.A review of the pilot’s certification history before he was employed by Hawaii Life Flight revealed that he had six Notice of Disapproval entries in his Federal Aviation Administration (FAA) records. Of those six notices, three were in rotorcraft and three were in fixed-wing aircraft, each one the culmination of multiple unsatisfactory training events. The records detailed consistent deficiencies in the use of navigational systems, instruments, and multiengine aircraft maneuvering. A review of the pilot’s training record at Hawaii Life Flight indicated that during initial Advanced Aviation Training Devices (AATD) training, which consisted of 6 training sessions during Page 3 of 32 ANC23FA008December 2019, he had five unsatisfactory ratings. Of those, two were on the last training event. The pilot was given two additional training sessions in January 2020 and all training areas indicated “satisfactory.”The pilot had been employed by Hawaii Life Flight for three years and had six mandatory checking events. He failed three checkrides on the first attempt. Training records indicated that following each unsatisfactory training event, the accident pilot was given additional training, and subsequently reevaluated. The second evaluations were marked as “satisfactory.”  It is the responsibility of the operator to ensure their crews have the training, skills, competency, and proficiency to operate in their target environment. Guardian’s flight standards manual states that following multiple consecutive training or checking failures, the pilot should have been placed in remedial training and on an improvement plan. It was unclear if a formal plan was developed to address the issue. At no time did the pilot go to Guardian headquarters to facilitate retraining initiatives. Both the assistant chief pilot (ACP) and chief pilot (CP) stated the pilot was “retrained to proficiency.”Guardian Flight was not required to have a flight operations quality assurance (FOQA) program. However, with the airplane equipped with a cockpit voice recorder (CVR), ADS-B, the Appareo cockpit imaging system, and the SkyTrac ISAT-100A satellite communication transceiver, they had the tools installed and in place to have a FOQA program. But Guardian Flight did not acquire the mechanism or means to manage or download the data from these systems. Guardian Flight’s failure to monitor operations likely contributed to this pilot’s non-compliance with the operating procedures. With a lack of appropriate infrastructure to monitor the flights, Guardian Flight did not have any way to determine this pilot’s nor any other pilot’s, compliance.The pilot likely experienced spatial disorientation as result of the failed EADI and the autopilot disconnect. Spatial disorientation can affect even the most skilled pilots, but the phenomenon is more likely to occur with a pilot who has inexperience with or a history of deficiencies using navigational and instrument systems, such as exhibited by the accident pilot. Additionally, the pilot did not declare an emergency or communicate the loss of his attitude indicator or autopilot. Notifying ATC would have made them aware that they should limit communications to only what was necessary. Unaware of the issue, ATC continued to issue several instructions to which the pilot then tried to respond and adhere, diverting his attention away from manually flying the aircraft and maintaining spatial orientation. The loss of the EADI and autopilot disconnect in dark, overwater conditions, required the pilot to fly with a partial instrument panel and rely on the copilot’s attitude indicator, which likely resulted in the pilot’s spatial disorientation and loss of control. The pilot’s recurrent difficulties in aircraft maneuvering, systems management, and use of navigational instruments likely led to his inability to maintain positive control and spatial awareness once the EADI went inoperative and the autopilot ceased to function.Page 4 of 32 ANC23FA008