CEN23FA084

The pilot’s spatial disorientation during a missed approach in instrument meteorological conditions, which led to an exceedance of the airplane’s critical angle of attack and a subsequent aerodynamic stall.

A review of air traffic control (ATC) data showed that the airplane departed with an instrument flight rules (IFR) clearance for the destination airport. The pilot requested and was cleared for an RNAV (GPS) approach into the destination airport. When the airplane was descending through 3,500 ft msl , the controller instructed the pilot to report cancelling the IFR clearance and approved a radio frequency change. There was no further communication from the pilot; the ATC facility reported that radar contact was lost when the airplane reached 2,000 ft msl, which was normal for the approach. The sole surviving passenger reported the airplane was off course during the approach, and the pilot was struggling with the airplane to get it back on course. The passenger remembered hearing a warning alarm several times and the airplane “aggressively pitching up” with more warning alarms and then “aggressively pitching down.” He observed the pilot pulling hard on the yoke and he believed he heard the copilot calling for the pilot to try and get the nose of the airplane up and straightened out. He said that he couldn’t see anything out of the windows due to the clouds and fog until right before the airplane impacted the ground. The airplane came to rest in an open pasture about 1.5 miles from the destination airport. Low IFR (LIFR) conditions were forecast for the area of the accident site and the destination airport. The National Weather Service (NWS) forecasts were consistent with the weather conditions encountered by the pilot on the approach. Data recovered from the airplane’s autopilot indicate that the pilot began the approach with the autopilot engaged. When the airplane was about 1 mile from the runway and 500 ft above the airport elevation, the pilot initiated a right climbing turn and disconnected the autopilot. This action was consistent with the initiation of the missed approach procedure. Autopilot data indicate that the airplane’s pitch then increased as high as +20° and roll to +47° (right) during the climbing right turn. These angles suggest that the pilot likely had difficulty controlling the airplane. The pilot then engaged the autopilot’s unusual attitude recovery mode. The autopilot made inputs to return to a level flight attitude; however, autopilot data indicate that the pilot made conflicting flight control inputs. As a result, the airplane entered a brief descent, followed by a rapid climb. Indicated airspeed at the top of the climb was 16 knots, well below the airplane’s stall speed for any flap configuration. Thus, the airplane likely entered an aerodynamic stall followed by a rapid descent to impact with the terrain. The airplane impacted an open field at a shallow pitch angle, which suggests that the pilot may have attempted a stall recovery maneuver. However, altitude was insufficient for a full recovery. Postaccident examination revealed no anomalies with the airframe, engine, or autopilot. Toxicology testing showed trace levels of pheniramine, naltrexone, naltrexol, and CBD in the pilot’s system. Although postmortem toxicological testing indicates that the pilot had used these substances, his performance was not likely impaired by effects of those substances at the time of the accident. Based on the level of meclizine detected in the copilot’s heart blood, it is reasonably likely he was experiencing some effects of this medication at the time of the accident. However, whether such effects impaired his performance in a way that contributed to the accident is unknown, particularly considering his uncertain role on the flight and the presence of the other pilot. The copilot’s toxicology testing also indicated he had used cetirizine, but this medication was not detected in his blood, so it was not likely causing impairing effects at the time of the accident. The pilot’s difficulty in controlling the airplane when initiating the climbing turn in instrument conditions, along with the activation of the autopilot’s unusual attitude recovery mode, and his continued inappropriate control inputs suggest that pilot was experiencing spatial disorientation during the missed approach procedure.

The weather forecast information applicable for the accident time indicated that a Center Weather Advisory (CWA) and both the text NWS Airmen’s Meteorological Information (AIRMET) and the Graphical AIRMET (G-AIRMET) were both valid for the accident site and the destination airport for low IFR and IFR conditions through 1200. A search of archived information indicated that the pilot did not request weather information from Leidos Flight Service. The pilot did request and receive a weather briefing package from ForeFlight at 0705, and the weather briefing package at 0705 contained all the standard weather forecast information valid at that time, including CWA 102 and the text AIRMET and G-AIRMETs. The pilot did not view any weather imagery information on the ForeFlight App before the flight. It is unknown what additional weather information, if any, the pilot checked or received during the accident flight. The landowner where the airplane came to rest stated that shortly after the accident occurred, he noticed a lot of fog at the accident site with a calm wind. In addition, an air medical helicopter dispatched from Victoria, Texas, to fly to the accident site cancelled its flight due to the heavy fog in the area around 1100. The closest meteorological reporting station to T85 was the Roger M. Dreyer Memorial Airport (T20), Gonzales, Texas. The T20 Automated Weather Observing System (AWOS) was located about 23 miles northwest of the accident site. In addition, the Victoria Regional Airport (VCT), Victoria, Texas, was located about 29 miles south-southwest of the accident site. Cloud tops were noted around 1,800 to 2,300 ft based on the High-Resolution Rapid Refresh (commonly called HRRR) sounding data and pilot reports (commonly called PIREPs). As the low clouds and fog formed during the early morning hours and passed over VCT and T20, the lowest cloud ceilings were noted at 100 to 300 ft above ground level with visibilities down to 1.5 miles. CWA 102 was valid from 0658 and until 0900. CWA 102 called for LIFR conditions for the area, which included the accident location. CWA 102 was later updated by CWA 103, which also called for LIFR. CWA 103 was issued at 0859 and valid until 1100. A review of ATC services provided by the Houston Air Route Traffic Control Center was conducted by the National Transportation Safety Board. The review found that the controller failed to disseminate CWA 103 to the pilot. The review also found that the weather conditions reported by the pilot were not entered as a PIREP, as required. Pilot According to the pilot’s wife, the pilot would sometimes fly the airplane for business reasons from his home in Tennessee to the manufacturing facility in Yoakum. The pilot’s son-in-law, who works as a commercial airline pilot, had flown with the pilot about 50 times over the last several years. The son-in-law described his father-in-law as a very competent pilot. According to the surviving passenger, he had flown with the pilot several times in the past and he felt the pilot was very organized and competent. The pilot’s final logbook entry was dated January 10, 2021, and the investigation was unable to determine the pilot’s recent flight experience. Copilot According to the copilot’s wife, the copilot used to fly daily, but more recently, he would only fly a few times a year. The copilot’s logbook was not available for review. According to FAA registration records, the pilot purchased the airplane on December 31, 2020. A review of the airframe maintenance records showed the airplane was modified on February 11, 2020, via FAA supplemental type certificate ST00541SE, as a JetProp DLX model. The airplane was equipped with a stall warning system that is activated between five and ten knots above the stall speed, with mild airframe buffeting and pitching preceding the stall. When the landing gear and the flaps are both retracted, the stall speed is 69 knots (indicated airspeed). The airplane was also equipped with a suite of advanced avionics including an Electronics International MVP-50T engine monitoring system, an Avidyne multi-function display, an Avidyne primary function display, an Avidyne DFC-90 autopilot system, and a Honeywell KMH 820 enhanced ground proximity warning system (EGPWS). A review of the laminated checklist booklet found in the wreckage, for the approach and landing sections, displayed several variations from the checklist published in the JetProp DLX Pilot’s Operating Handbook and FAA-approved Airplane Flight Manual. The FAA has published Safety Alert For Operators 17006 Safety Concerns with Using Commercial Off-the-Shelf (COTS) or Personally Developed Checklists. This document states in part: Pilots and operators, other than those operating an aircraft under 14 CFR Part 121 or 135 that choose to use COTS or personally developed checklists should meticulously compare them to the manufacturer’s checklist and placards contained in the POH/AFM to confirm they are consistent. This action will ensure the pilot has all pertinent manufacturer’s information during aircraft flight operations. Pilot The Fort Bend County Medical Examiner Office performed the pilot’s autopsy. According to the pilot’s autopsy report, his cause of death was multiple blunt force trauma. His autopsy did not identify significant natural disease. The FAA Forensic Sciences Laboratory performed toxicological testing of postmortem specimens from the pilot. Pheniramine was detected at a trace level in femoral blood and was also detected in liver tissue. Naltrexone was detected in liver tissue; naltrexone was not detected in heart blood. The naltrexone metabolite 6-beta-naltrexol was detected at a trace level in heart blood and was also detected in liver tissue. Cannabidiol (commonly known as CBD) was detected in heart blood and liver tissue. Copilot The Fort Bend County Medical Examiner Office performed the copilot’s autopsy. According to the copilot’s autopsy report, his cause of death was multiple blunt force trauma. His autopsy did not identify significant natural disease. The FAA Forensic Sciences Laboratory performed toxicological testing of postmortem specimens from the copilot. Meclizine was detected in heart blood at 36.5 ng/mL; meclizine was not detected in urine. Cetirizine was detected in urine; cetirizine was not detected in heart blood. The airplane came to rest upright near a barbed wire fence, and both wings were separated from the fuselage. The cockpit area sustained impact damage, while the cabin and empennage were attached and remained mostly intact. The nose wheel was found separated. The airplane sustained substantial damage to both wings and the fuselage. The main landing gear was found extended. The landing gear handle was in the extended (gear down position). The flap handle and flap indicator showed the flaps were retracted. Flight control continuity was established for the airframe. A download and review of the Avidyne DFC-90 autopilot system data showed that there were no mechanical anomalies with the autopilot system. During the approach, the autopilot was engaged; it was then disconnected when the airplane entered a climbing right turn. Autopilot data indicate that pitch increased as high as +20° and roll to +47° (right) during the climbing right turn. The autopilot was then re-engaged via the unusual attitude recovery (commonly called the UAR) button during the climbing right turn. The UAR mode was disabled by the pilot shortly after being enabled, before the impact with terrain. A download and review of the Honeywell KMH 820 EGPWS data showed that once the airplane entered a climbing right turn, a “sink rate” caution alert occurred and then shortly after a “pull up” warning alert occurred. Examination of the seats and restraint systems did not reveal any mechanical anomalies. The engine, which sustained some impact damage, was found attached to the air