Williamsburg, PA, USA
N451TD
CIRRUS DESIGN CORP SR22
The private pilot was conducting a personal, cross-country flight with one passenger onboard. According to air traffic control (ATC) communications and radar data, while en route to the destination airport about 5,425 ft mean sea level, the pilot reported to ATC that the airplane was accumulating ice, and he requested to divert to the nearest airport. However, due to the overcast cloud layer at 200 ft above ground level (agl) at the nearest airport, the pilot chose to attempt an instrument landing system (ILS) approach into another airport with a slightly higher overcast cloud layer of 500 ft agl. During the descent to intercept the localizer for the ILS approach, the pilot flew through the localizer path, and he did not realize it until the controller notified him that he had done so. The pilot subsequently requested additional vectors to attempt to intercept the localizer again, and the controller instructed the pilot to turn left. The airplane subsequently turned left toward the north. About 39 seconds into the turn, the airplane began to descend, and the airspeed increased. About 10 seconds later, the left turn tightened, and the airplane began to spiral until the radar data ended. The airplane subsequently impacted the ground in a steep, nose-low, wings-level attitude. A review of weather information current at the time of the flight revealed that the airplane likely encountered instrument meteorological conditions (IMC) about 500 ft agl on the initial climbout from the departure airport and remained in IMC and conditions favorable to icing for the rest of the flight. The airplane likely encountered some turbulence along the flight route in the cloud cover and would have had to climb above 10,400 ft msl to escape the IMC and icing conditions. Super-cooled liquid droplets (SLD) and icing conditions were likely present along the flight route throughout the flight. Before the flight, a forecast icing potential (FIP) indicated that light-to-moderate intensity icing existed near the accident site, and a current icing potential product indicated that SLD existed near the accident site; this information would have been available to the pilot before the accident flight departed. The pilot received a weather briefing via the ForeFlight application on his mobile device about 10 hours before the accident flight. At that time, the forecast showed cloud cover, snow showers, and instrument flight rules conditions. Since the AIRMET received in the weather briefing expired at 0500 the pilot should have requested an updated briefing with the valid AIRMET. In the time between the weather briefing and the accident, an AIRMET was issued for moderate icing, IFR/mountain obscuration, and low-level turbulence, and was valid until 1100. An updated AIRMET advisory was recorded via the flight plan identification number less than 2 hours before departure. No records were found indicating whether the pilot retrieved any other weather information before or during the flight. Therefore, although the pilot had sufficient weather forecast information available to him before departure to have known about the existing icing conditions along the flight route, the investigation could not determine whether he received all of the pertinent information before the flight. Although the pilot reported that the airplane had accumulated ice, the investigation could not determine if the airplane was significantly affected by structural icing during the approach. The airplane was not equipped with an anti-icing or deicing system, which prohibited the pilot from flying into known icing conditions per Title 14 Code of Federal Regulations Section 91.527, "Operating in Icing Conditions." Although postaccident examination of the wreckage was limited due to postimpact fire damage, the examinations of the airframe and engine did not reveal evidence of any preaccident mechanical malfunctions or anomalies that would have precluded normal operation. The examination revealed that the Cirrus Airframe Parachute System (CAPS) handle remained in its holder, and that its safety pin, which was supposed to be removed before flight, remained installed. The CAPS was found deployed, and the CAPS solid rocket propellant was expended. All evidence revealed that the CAPS was not activated in flight but rather that it deployed due to impact forces and thermal exposure. The autopsy of the pilot revealed that he had heart disease; however, this would not have affected his decision-making, his ability to identify and respond to icing on the plane, or his ability to fly the airplane in IMC; therefore, his heart disease did not contribute to the accident. Although toxicology testing detected ethanol in the pilot's liver tissue, no ethanol was found in his muscle tissue. Given that, after absorption, ethanol is uniformly distributed throughout all tissue and body fluids, it is likely that the ethanol detected in the liver occurred postmortem and did not contribute to the accident. The toxicology testing also detected two impairing psychoactive substances, diphenhydramine and clonazepam, in tissue specimens. These drugs alone or in combination could have affected the pilot's decision-making and/or slowed his detection of potential hazards and his reaction to them. However, antemortem levels of these two drugs could have been low enough to not have affected him, but, because antemortem levels cannot be calculated from tissue levels, it could not be determined whether effects from the pilot's use of diphenhydramine and clonazepam contributed to the accident. The radar data showed that the airplane was flying a relatively smooth and consistent flightpath with altitude and heading changes that were indicative of the pilot using the autopilot for a majority of the flight, until the final turn after flying through the localizer course. The pilot's failure to recognize that he had not intercepted the localizer is consistent with his failure to appropriately configure the avionics for the approach or with his attention being diverted from navigational tasks due to his workload while trying to conduct the approach. Conditions conducive to the development of spatial disorientation, including restricted visibility and IMC while maneuvering, existed. Further, the accident circumstances, including the spiraling radar track data and the subsequent high-velocity impact were consistent with the known effects of spatial disorientation. Therefore, the airplane's entry into a descending left turn while the pilot was being vectored back toward the localizer course, which subsequently tightened, was likely due to the pilot experiencing the effects of spatial disorientation due to a vestibular illusion referred to as a "graveyard spiral," which can occur when an airplane returns to level flight following a prolonged bank turn. The spatial disorientation resulted in the pilot's loss of airplane control and a high-velocity impact with terrain.
HISTORY OF FLIGHTOn April 19, 2018, at 0843 eastern daylight time, a Cirrus SR22 airplane, N451TD, impacted terrain near Williamsburg, Pennsylvania. The private pilot and one passenger were fatally injured. The airplane was destroyed, and a postimpact fire consumed most of the wreckage. The airplane was registered to CPD-JJD, LLC, and operated by the pilot as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. Instrument meteorological conditions (IMC) prevailed along the flight route about the time of the accident, and an instrument flight rules (IFR) flight plan had been filed. The airplane departed Lancaster Airport (LNS), Lancaster, Pennsylvania, at 0734 and was initially en route to South Bend International Airport (SBN), South Bend, Indiana, but the pilot chose to divert toward Altoona-Blair County Airport (AOO), Altoona, Pennsylvania. The pilot received a weather briefing the night before the accident and filed a flight plan. Refer to the Meteorological Information section for more information. A review of air traffic control (ATC) communications and radar data provided by the Federal Aviation Administration (FAA) revealed that, about 0828, while the airplane was en route to SBN on a 284° heading and about 5,425 ft mean sea level (msl), the pilot contacted an approach controller at John Murtha Johnstown-Cambria County Airport (JST), Johnstown, Pennsylvania, and requested to divert to JST (18 miles southwest of the airplane's position) due to ice accumulation on the airplane. The controller advised the pilot that the clouds at JST were overcast at 200 ft above ground level (agl) and that the clouds at AOO (30 miles southeast of the airplane's position) were overcast at 500 ft agl. About 0831, the pilot requested vectors to AOO for an instrument landing system (ILS) approach. After the controller provided the vectors, the pilot requested to descend to 4,000 ft msl, but the controller cleared him to 4,500 ft msl, which was the lowest altitude he could clear the airplane to descend to in that geographical area. Figure 1 shows a Google Earth overlay of the airplane's radar track in red, the AOO approach localizer path in white. Figure 1. Radar track and accident location (Google Earth overlay) About 0842, the controller advised the pilot that the airplane had passed through the localizer for the ILS approach to runway 21 at AOO, and the pilot stated that he still wanted to land at AOO and requested vectors to intercept the localizer. The controller issued additional vectors for the pilot to make a box pattern to intercept the localizer; the airplane then turned left turn toward the north. At 0842:33, the airplane began a left standard rate turn and remained about 4,000 ft msl. At 0843:12, the airplane started to descend, and the airspeed increased. At 0843:38, the airplane descended through 2,525 ft msl and continued in a tight, left spiral turn. The final radar point was recorded at 0843:52 at 1,850 ft msl, at which point the airplane was still in a tight, left spiraling turn. Subsequently, radar contact was lost, and no additional communications were received from the pilot. See figure 2 for a radar track showing the initial left turn followed by the spiraling left turns. Figure 2. Radar track showing the spiraling left turns (Google Earth overlay) Before the final left turn and descending spiral, the flight path and altitudes were normal with no erratic maneuvers or anomalies noted. PERSONNEL INFORMATIONA review of the pilot's logbook revealed that he accumulated 70 hours of total flight experience from 1980 to 1985. He did not log any additional flight time until 2011. He first flew the accident airplane on January 31, 2014, and then exclusively logged flights in the accident airplane from April 9, 2014, until the accident date. The pilot's flight instructor stated that he had flown with the pilot six times in the 6 months before the accident. Four of the flights were conducted for the purpose of maintaining instrument currency and proficiency. Their most recent flight was on November 30, 2017, during which the pilot completed ILS and GPS approaches in simulated IMC. The pilot's logbooks showed that he had completed the recent instrument experience requirements in accordance with 14 CFR Section 61.57, "Recent flight experience: Pilot in command." AIRCRAFT INFORMATIONGeneral The altitude indicating system and transponder, which were most recently tested in accordance with the requirements of 14 CFR Sections 91.411 and 91.413, "Altimeter system and altitude reporting equipment tests and inspections" and "ATC transponder tests and inspections," respectively, on September 26, 2017. The airplane was not equipped with an anti-icing or deicing system, thus it was not equipped for flight in icing conditions. The pilot had the ForeFlight application on a mobile device, which provided instrument approach plates; paper approach plates were found at the accident site. The cockpit instrumentation included an airspeed indicator, attitude indicator, altimeter and a turn coordinator, vertical speed indicator, Garmin mechanical course deviation indicator, and Sandel SN3308 electronic horizontal situation indicator. The airplane was also equipped with an S-TEC 55X autopilot, a Garmin GTX345 transponder, dual Garmin GNS 430 units, and an ARNAV ICDS-2000 multifunction display (MFD) with an engine monitoring module (EMM-35) that displayed engine data. The ARNAV unit displayed, in part, navigational waypoints, course line, and ground speed and had a separate database, which displayed terrain elevations based on position. The Garmin GNS 430 was approved for IFR operations; however, the ARNAV MFD was for reference only and was not certified for flight in IMC. Cirrus Airframe Parachute System (CAPS) The airplane was equipped with a Ballistic Recovery Systems ballistic recovery parachute system. According to Cirrus, the CAPS will lower the airplane's entire airframe to the ground when all alternatives to land the airplane have been exhausted. The CAPS consisted of a parachute, a solid-propellant rocket to deploy the parachute, a rocket activation handle, and a Kevlar harness embedded within the fuselage structure. The pilot could activate the system by pulling on a T-handle mounted on the cockpit ceiling above the pilot's right shoulder, which in turn activated the firing pin mechanism that then ignited the solid-propellant rocket in the parachute enclosure. In the airplane's Pilot's Operating Handbook "Normal Procedures, Preflight Walk-Around" checklist, item 1 states, "CAPS Handle…Pin Removed." In the "Before Starting Engine" checklist, item 4 states, "Verify CAPS handle safety pin is removed." In the "Before Takeoff" checklist, item 2 states, "CAPS Handle…Verify Pin Removed." METEOROLOGICAL INFORMATIONThe pilot received a weather briefing the night before the accident flight at 2127 and filed an IFR flight plan via the Foreflight mobile application with a planned flight route of LNS-EWC-NORNA-SBN at 6,000 ft msl. The pilot entered the same route into the application two times before he filed the flight plan, which is consistent with his comparing the winds aloft at two different flight altitudes. The ForeFlight weather briefing contained the standard weather information valid for a departure time of 0645 on April 19, but some of the weather forecast products did not provide forecast information of the weather conditions at the time of departure because the weather briefing was requested 10 hours before the flight. The graphical forecast products from the weather briefing predicted cloud cover as low as 2,000 ft msl along the flight route, and the surface forecast predicted marginal visual flight rules conditions with likely snow shower activity. The AOO and JST TAFs called for IFR and low IFR conditions between 0200 and 1000 on April 19. The AIRMET received during the weather briefing was only valid until 0500 on April 19, which was before the intended departure time. At the time of the accident, there was an active AIRMET for moderate icing, IFR/mountain obscuration, and low-level turbulence. An updated AIRMET advisory from as late as 0452 on April 19 was recorded via the flight plan identification number, but it could not be determined if the pilot checked the updated AIRMET information before the flight. No records were found indicating whether the pilot retrieved any other weather information before or during the flight. Icing Potential Current icing potential (CIP) and forecast icing potential (FIP) products are intended to be supplemental to other icing advisories, such as AIRMETs and SIGMETs. The FIP products indicated a 50 to 70% probability of icing at trace-to-moderate levels above the accident site from 4,000 to 6,000 ft msl at 0900. The FIP indicated a 40 to 50% probability of supercooled large droplet (SLD) over the accident area around the accident time at 6,000 ft msl. The CIP product indicated a 60 to 85% probability of icing at light-to-moderate levels above the accident site from 4,000 to 6,000 ft msl at 0900. The CIP also indicated a 10 to 40% probability of SLD near the accident site at 0900 between 4,000 and 6,000 ft msl and a 0 to 40% probability of SLD near the accident site at 0800 between 4,000 and 6,000 ft msl. The CIP/FIP information would have been available to the pilot before the accident flight departed. The National Weather Service Aviation Weather Center that issues the CIP and FIP advises, "NOTE: CIP/FIP is intended for flight planning purposes and should always be used in combination with icing information from all available sources including AIRMETs, SIGMETs, and PIREPs. CIP/FIP aid flight planning and situational awareness through graphical depiction of current and forecast icing conditions across an area or along a route of flight. NOTE: Pilots of aircraft that are not certified for flight into known or forecast icing conditions should be especially cautious of areas displaying any type of icing severity, regardless of the probability indicated on CIP graphics." Satellite Data Figure 3 shows the compiled Geostationary Operational Environmental Satellite 16 (GOES-16) infrared and visible data and the pilot's communication with ATC at the time he requested to divert with the direction of travel indicated with a red arrow. This imagery indicated that the airplane was in areas of abundant cloud cover with cloud top temperatures between -5° and -15°C throughout the flight. The airplane turned back toward the east before reaching an area of cloud top temperatures between -15° and -25°C. The cloud-top heights above the accident site at around the time of the accident were about 10,400 ft msl. The IMC and icing conditions would have ended above the cloud layer. Figure 3. GOES-16 satellite imagery with the airplane's position when the pilot diverted AIRPORT INFORMATIONGeneral The altitude indicating system and transponder, which were most recently tested in accordance with the requirements of 14 CFR Sections 91.411 and 91.413, "Altimeter system and altitude reporting equipment tests and inspections" and "ATC transponder tests and inspections," respectively, on September 26, 2017. The airplane was not equipped with an anti-icing or deicing system, thus it was not equipped for flight in icing conditions. The pilot had the ForeFlight application on a mobile device, which provided instrument approach plates; paper approach plates were found at the accident site. The cockpit instrumentation included an airspeed indicator, attitude indicator, altimeter and a turn coordinator, vertical speed indicator, Garmin mechanical course deviation indicator, and Sandel SN3308 electronic horizontal situation indicator. The airplane was also equipped with an S-TEC 55X autopilot, a Garmin GTX345 transponder, dual Garmin GNS 430 units, and an ARNAV ICDS-2000 multifunction display (MFD) with an engine monitoring module (EMM-35) that displayed engine data. The ARNAV unit displayed, in part, navigational waypoints, course line, and ground speed and had a separate database, which displayed terrain elevations based on position. The Garmin GNS 430 was approved for IFR operations; however, the ARNAV MFD was for reference only and was not certified for flight in IMC. Cirrus Airframe Parachute System (CAPS) The airplane was equipped with a Ballistic Recovery Systems ballistic recovery parachute system. According to Cirrus, the CAPS will lower the airplane's entire airframe to the ground when all alternatives to land the airplane have been exhausted. The CAPS consisted of a parachute, a solid-propellant rocket to deploy the parachute, a rocket activation handle, and a Kevlar harness embedded within the fuselage structure. The pilot could activate the system by pulling on a T-handle mounted on the cockpit ceiling above the pilot's right shoulder, which in turn activated the firing pin mechanism that then ignited the solid-propellant rocket in the parachute enclosure. In the airplane's Pilot's Operating Handbook "Normal Procedures, Preflight Walk-Around" checklist, item 1 states, "CAPS Handle…Pin Removed." In the "Before Starting Engine" checklist, item 4 states, "Verify CAPS handle safety pin is removed." In the "Before Takeoff" checklist, item 2 states, "CAPS Handle…Verify Pin Removed." WRECKAGE AND IMPACT INFORMATIONThe airplane impacted a field behind a residential property 9.5 miles northeast of AOO (see figure 4, which shows the initial impact point and the airplane wreckage). The wreckage debris path was about 200 ft long, on a magnetic heading of 150°, and at an elevation 1,025 ft msl. Figure 4. Initial impact point and airplane wreckage Ground scars at the accident site and damage to the airplane were consistent with the airplane impacting terrain in a steep, nose-low, wings-level attitude. The left wing inspection panels and the pitot tube were found in the horizontal ground scar, which can be seen on the lower left side of figure 4. The ground scars surrounding the center impact crater were consistent with the shape of the wing leading edges and the tricycle landing gear. The engine, firewall, and all three propeller blades were found in the center impact crater, which was about 3 ft deep. A postimpact fire consumed most of the wreckage, but all major airplane structural components were located within the debris field. The engine mounts and nose landing gear brace remained attached to the engine with the firewall. The throttle, mixture, and propeller control cables remained attached to their respective control levers. The front portion of the oil sump was flattened against the bottom side of the engine, and the aft portion of the oil sump was impact-damaged and displaced aft, exposing the bottom crankcase halves. The three-bladed, constant-speed propeller remained attached to the crankshaft, but two of the blades were separated just outboard of the shank. The third blade remained attached to the hub and was bent aft around the engine's left side and twisted toward low pitch; the outboard tip was impact-separated from the blade. The leading edge of one of the separated blades exhibited deep gouges. The propeller spinner was crushed aft around the propeller hub. Both the directional and turn coordinator gyros exhibited rotational scoring and signs of rotation at impact. The ARNAV ICDS-2000 and EMM-35 were destroyed by fire, and data extraction was not possible. The CAPS activation handle remained in its holder with the safety pin installed as shown in figure 5. The CAPS was found deployed, and the CAPS solid rocket propellant was expended. The parachute was found deployed, and it extended along the debris path. Portions of the CAPS that remained within the main wreckage were consumed by fire. All evidence revealed that the CAPS was not activated in flight but rather that it deployed due to impact forces and thermal exposure. Figure 5. Safety pin installed in the CAPS activation handle Although the postaccident examination was limited due to postimpact fire damage, examinations of the airframe and engine did not reveal evidence of any preaccident mechanical malfunctions or an
The pilot's failure to obtain an updated weather briefing before the flight and his subsequent loss of airplane control due to spatial disorientation while maneuvering in instrument meteorological conditions during a diversion to an alternate airport after encountering forecast icing conditions.
Source: NTSB Aviation Accident Database
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