ERA16FA279

The pilot's loss of control due to spatial disorientation shortly after takeoff, while maneuvering over water during dark night conditions.

The instrument-rated commercial pilot departed from an airport adjacent to the Gulf of Mexico with an instrument flight rules clearance for a cross-country flight in dark night, visual meteorological conditions. The flight continued in a south-southwesterly direction, climbing to about 900 ft over the gulf, where it entered a steep right turn. The airplane then descended at a steep rate and impacted the water in a nose-low attitude. Postaccident examination of the recovered wreckage, including flight controls, engines, and propellers revealed no evidence of preimpact failure or malfunction. While the outlet fuel line from the left auxiliary fuel pump was found separated and there was evidence that the B-nut was loose and had been only secured by the first 2 threads, recorded data from the engine monitor for the flight revealed no loss of power from either engine. Therefore, the final separation likely occurred during the impact sequence. Although the accident pilot was instrument rated and had recently completed instrument currency training, the dark night conditions present at the time of the accident combined with a further lack of visual references due to the airplane's location over a large body of water, presented a situation conducive to the development of spatial disorientation. The pilot had been instructed by air traffic control to turn southwest after takeoff; however, the continuation of the turn past the intended course and the airplane's steep bank angle and excessive rate of descent are consistent with a loss of control due to spatial disorientation.

DTS was located 1 mile east of Destin, Florida, at an elevation about 22 ft msl. It was equipped with a single asphalt runway designated 14/32, which was 5,001 ft long and 100 ft wide. Published NOTAM (12/003) specified an obstruction (320-ft-tall crane) located 1.5 nautical miles southeast of the airport. Further plotting of the location indicated it was located about .8 nautical mile and 142° from the departure end of runway 14. The effective date of the NOTAM was December 5, 2015 and it was in effect on the accident date. According to the building superintendent associated with the crane, it was lowered and the boom was pointed to the southeast corner of the building at the end of every work day, but remained over the building. He reported that procedure was followed at the end of the day on August 2nd. Postaccident examination of the crane at night 2 days after the accident revealed an operating single red flashing light. No debris associated with the airplane was observed around the crane or reported by the superintendent. Nonvolatile Memory The airplane was equipped with a portable Garmin GPS receiver, a Shadin Avionics fuel flow indicator, and a J.P. Instruments EDM 760 engine monitor. These components were retained for download by the NTSB's Vehicle Recorder Division. Although the GPS did record and retain flights, the accident flight was not recorded. No data was recovered from the fuel flow indicator. According to the NTSB specialist's factual report concerning the EDM 760, the device was set to record, in part, exhaust gas temperature (EGT), cylinder head temperature (CHT), and total inlet temperature (TIT) for both engines. The data was sampled every 6 seconds, and data associated with the accident flight contained 115 points of data covering the entire flight (11 minutes, 24 seconds). Due to the loss of functionality of the unit's internal clock, the data could not be correlated to real time. The data indicated that from 6 minutes 48 seconds elapsed recorded time until the end of recorded data at 11 minutes 24 seconds elapsed time, all CHT and EGT readings for both engines were consistent with normal parameters. Auxiliary Fuel Pump Outlet Line and Fitting Metallurgical examination of the separated hard aluminum fuel line and fitting revealed about 90° arc of the partial first thread of the fitting was fractured consistent with overstress shearing toward the tube. Close examination of the second thread of the fitting revealed fretting wear scars to the flare side flank of the thread. The fretting wear damage completely penetrated the blue anodized coating over an approximate 90° arc. The flare portion of the fitting exhibited features consistent with fretting wear. Examination of the internal portion of the flare of the tube revealed fretting wear, which matched the general shape of the fretting on the fitting. Additionally, the first threads of the B-nut for the tube revealed crest damage around about 270°. The thread was sheared in overstress toward the union in that location. The outward facing flank of the second thread had fretting wear damaged in two locations, which approximates the location of fretting wear scars noted on the threads of the fitting. Annunciator Panel Bulb Filaments The annunciator panel was sent to the NTSB Materials Laboratory to determine whether any of the bulb filaments exhibited stretching. X-ray examination revealed that none of the bulb filaments was stretched. Spatial Disorientation According to FAA Safety Team literature, pilots flying under both instrument and visual flight rules are subject to spatial disorientation and optical illusions that may cause a loss of aircraft control. Sight, supported by other senses, allows a pilot to maintain orientation while flying. However, when visibility is restricted (i.e., no visual reference to the horizon or surface detected) the body's supporting senses can conflict with what is seen. When this spatial disorientation occurs, sensory conflicts and optical illusions often make it difficult for a pilot to tell which way is up. Contributing to these phenomena are the various types of sensory stimuli: visual, vestibular (organs of equilibrium located in the inner ear), and proprioceptive (receptors located in the skin, muscles, tendons and joints). Changes in linear acceleration, angular acceleration, and gravity are detected by the vestibular system and the proprioceptive receptors, and then compared in the brain with visual information. In a flight environment, these stimuli can vary in magnitude, direction, and frequency, resulting in a sensory mismatch that can produce illusions and lead to spatial disorientation. The 1953 automated surface observation at DTS reported wind from 330° at 5 knots, 10 miles visibility, and clear skies. The temperature and dew point were 29°C and 25°C, respectively, and the altimeter was 30.03 inches of mercury. Data from the GOES-13 infrared image at 2030 indicated scattered low to midlevel stratiform clouds. The radiative cloud top temperature corresponded to cloud tops near 5,000 ft. According to data from the US Naval Observatory for the accident site area, the end of civil twilight was 2005, and, at the time of the accident, the sun was 10.9° below the horizon at an azimuth of 298°. The moon set at 1931 and was more than 15° below the horizon with no illumination; dark nighttime conditions prevailed at the time of the accident. The District One Medical Examiner's Office, Fort Walton Beach, Florida, performed a postmortem examination of the pilot. According to the autopsy report, the cause of death was drowning, with a contributory cause of blunt impact of head and chest. The FAA Bioaeronautical Sciences Research Laboratory (FAA), Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. The toxicology report indicated negative results for carbon monoxide and volatiles; 319.5 ug/ml acetaminophen was detected in the urine, and an unquantified amount of the same drug was detected in the submitted blood specimen. The pilot, age 63, held a commercial pilot certificate with ratings for airplane single-engine land and sea, airplane multiengine land, and instrument airplane. His most recent time-limited Special Issuance Federal Aviation Administration (FAA) second-class medical certificate with a limitation to wear corrective lenses was issued on August 18, 2014; it was not valid for any class after December 31, 2015. The pilot was not issued a subsequent medical certificate. Family members reported that the pilot had over 15,000 total hours of flight experience, was in good health, and to their knowledge, was not taking any medication. They indicated he was in the process of obtaining a new medical certificate. He was a pilot for the co-owners of the airplane. According to records provided by SimCom, during a three-day period between July 22 and 24, 2016, the pilot obtained recurrent training at their Orlando, Florida facility. The training consisted of 2 hours each day in a multiengine simulator appropriate for a Cessna 421C, and differences training in the same simulator for the Cessna 414A. The ground training was scheduled for 3 hours each day and covered aircraft systems, including differences training for the Cessna 414A. During this period, the pilot also completed training in instrument flight procedures in the simulator, including two unusual attitude recoveries while in a descending Vne (velocity never exceed speed) condition, and two unusual attitude recoveries while in an ascending stall speed condition. He satisfactorily completed all training and was issued a completion certificate. The low-wing, retractable-gear Cessna 414A airplane, serial number 414A0463, was manufactured in 1980. It was originally equipped with two 310-horsepower Continental Motors TSIO-520-NB engines and McCauley constant-speed propellers, but was subsequently modi