LAFAYETTE, LA, USA
N42CV
Piper PA 31T
The personal flight departed from Lafayette Regional Airport/Paul Fournet Field (LFT), Lafayette, Louisiana, and entered the clouds when the airplane was at an altitude of about 200 ft above ground level. Before takeoff, the controller issued an instrument flight rules clearance to the pilot, instructing him to turn right onto a heading of 240° and climb to and maintain an altitude of 2,000 ft mean sea level (msl) after takeoff. Automatic dependent surveillance broadcast (ADS-B) data for the accident flight started at 0920:05, and aircraft performance calculations showed that the airplane was climbing through an altitude of 150 ft msl at that time. The calculations also showed that the airplane then turned slightly to the right toward the assigned heading of 240° and climbed at a rate that varied between 1,000 and 2,400 ft per minute and an airspeed that increased from about 151 to 165 knots. At 0920:13, the airplane started rolling back toward wings level and, 7 seconds later, rolled through wings level and toward the left. At that time, the airplane was tracking 232° at an altitude of 474 ft and an airspeed of 165 knots. The airplane’s airspeed remained at 165 knots for about 10 seconds before it started increasing again, and the airplane continued to roll steadily to the left at an average roll rate of about 2° per second. The aircraft performance calculations further showed that, at 0920:40, the airplane reached a peak altitude of 925 ft msl. At that time, the airplane was tracking 200°, its bank angle was about 35° to the left, and its airspeed was about 169 knots. The airplane then started to descend while the left roll continued. At 0920:55, the airplane reached a peak airspeed of about 197 knots, which then started decreasing. At 0920:57, the airplane descended through 320 ft at a rate of descent of about 2,500 ft per minute and reached a bank angle of 75° to the left. At 0920:58, the controller issued a low altitude alert, stating that the pilot should “check [the airplane’s] altitude immediately” because the airplane appeared to be at an altitude of 300 ft msl. The pilot did not respond, and no mayday or emergency transmission was received from the airplane. The last ADS-B data point was recorded at 0920:59; aircraft performance calculations showed that, at that time, the airplane was descending through an altitude of 230 ft msl at a flightpath angle of about -7°, an airspeed of 176 knots, and a rate of descent of about 2,300 ft per minute. (The flightpath angle is in the vertical plane—that is, relative to the ground. The ground track, as discussed previously, is in the horizontal plane—that is, relative to north.) The airplane struck trees and power lines before striking the ground, traveled across a parking lot, and struck a car. The car rolled several times and came to rest inverted at the edge of the parking lot, and a postcrash fire ensued. The airplane continued to travel, shedding parts before coming to rest at the far end of an adjacent field. At the accident site, the surviving passenger told a local police officer that “the plane went straight up and then straight down.” Weight and balance calculations showed that the airplane’s total weight and center of gravity were within limits, with the center of gravity near the aft limit. The pilot likely obtained weather information for the flight about 0736 on the day of the accident. This information indicated that low visibility conditions would be present at the time of takeoff. The pilot would most likely have been aware of these conditions because, according to his wife, he had mentioned (on the night before the accident flight) that cloud ceilings would be “low” during takeoff. In addition, the pilot told the controller that he had the current automatic terminal information service report, which was based on the 0853 automated surface observing system observation. That observation indicated a visibility of 0.75 mile in mist and a vertical visibility of 200 ft above ground level. These weather conditions were conducive to the development of spatial disorientation. The surviving passenger also recalled that the airplane “pitched up like the pilot was trying to get above or over the clouds” and that a “harder than normal pitching movement” had occurred. Thus, the pilot had likely become spatially disoriented at this point in the initial climb due to the lack of visual references and the airplane’s increasing pitch attitude. Another indication that the pilot had become spatially disoriented was the airplane’s continuing and tightening turn to the left away from the intended course. The pilot’s most recent recurrent training in the airplane occurred in April 2019, but the training was conducted by a pilot whose Federal Aviation Administration-issued flight instructor certificate had expired in February 2019. No Federal Aviation Administration records indicated that the flight instructor’s certificate had been reinstated at the time of the training event. (The National Transportation Safety Board [NTSB] recognizes that the accident pilot might not have been aware that the flight instructor’s certificate had expired.) The flight instructor stated that the accident pilot’s training was conducted in visual meteorological conditions and that he did not simulate instrument conditions by having the pilot wear a hood (a view-limiting device). Further, the available pilot logbook evidence did not note the accident pilot’s recent flight experience or flight time in instrument meteorological conditions. As a result, the NTSB was unable to determine if the accident pilot met the regulatory requirements in Title 14 Code of Federal Regulations 61.57(c)(1) for instrument experience. The left and right engines were impact and fire damaged. The damage to the turbine engine blades and shrouds was consistent with operation at the time of impact. No anomalies were found that would have precluded normal operation of both engines. The damage to the propellers was symmetrical and consistent with impact forces. In addition, surveillance cameras at two private residences captured the sounds of the accident airplane as it passed overhead. No abnormal propeller sounds were heard on either recording. The NTSB’s sound spectrum analysis of the audio recording from one of these residences found that the recorded passing frequency was consistent with a four-bladed propeller rotating between 2,000 and 2,100 rpm, which was just below the propeller’s maximum continuous and takeoff allowable speed of 2,200 rpm. Aircraft performance calculations showed that each engine’s horsepower began decreasing from 500 horsepower at 0920:55, consistent with the decrease in airspeed after that time. The left engine torque gauge needle, as found in the wreckage, pointed to a value of about 525 lb-ft. This torque level, at a propeller speed between 2,000 and 2,100 rpm, would produce about 200 horsepower, indicating a power reduction on both engines during the last 5 seconds of flight. At that time, the airplane would have been descending through the clouds. The performance calculations indicated that the power applied to the airplane after 0920:56 would have been negligible. The airplane was not equipped, and was not required to be equipped, with a flight data recorder or a cockpit voice recorder. As a result, to determine the operational status of the autopilot during the accident flight, the NTSB conducted examinations of the annunciator panel and the autopilot servos. An analysis of light bulb filaments from the annunciator panel showed that none of the filaments from the autopilot, yaw damper, and flight director light bulbs were stretched, indicating that these annunciators were likely not illuminated at the time of impact. None of the examined autopilot servo components had failed, and no witness marks were noted on the gear teeth of the autopilot roll servo, indicating that the servos were not engaged at the time of impact. The annunciator panel and autopilot servo evidence was consistent with information provided by pilots who were familiar with the accident pilot. Specifically, the company owner reported that the accident pilot would hand fly the airplane up to an altitude of at least 2,000 ft, and the flight instructor stated that the accident pilot “was not an autopilot pilot” because he enjoyed hand flying the airplane. These statements, along with the physical evidence, indicated that the autopilot was likely not engaged during the accident flight. Even though there were no maintenance writeups or reported anomalies with the flight deck display system before the accident flight, the NTSB considered whether the airplane’s attitude heading and reference system (AHRS) unit failed or malfunctioned during the accident flight, which could have caused erroneous attitude and heading information to be displayed to the pilot. The AHRS manufacturer successfully completed initial continuity tests of the AHRS. However, after the unit was connected to the test bench and power was applied, the test equipment was unable to communicate with the AHRS to conduct additional tests, which precluded a determination about the AHRS’ functionality at the time of the accident. Further, the information that was recorded and stored in the AHRS had been overwritten by the test equipment. Afterward, the NTSB conducted a visual inspection of the AHRS and discovered a dislodged internal connector, which was not detected during the NTSB’s initial inspection of the unit (before the manufacturer’s testing). The internal connector, which likely became dislodged as a result of impact forces, might have contributed to the manufacturer’s inability to conduct AHRS bench testing. Because no recorded data were available to show the functionality of the AHRS unit, the NTSB was unable to determine the attitude and heading information displayed to the pilot during the flight. However, if an internal AHRS sensor had failed and a loss of attitude and heading information had occurred, red “X” flags would have appeared on the flight deck displays to prevent the pilot from referencing erroneous data. In that case, the standby digital attitude indicator, which was located directly beneath the flight deck displays, would have provided independent attitude and heading information to the pilot. Because the left and right elevator trim tabs were found in their full airplane nose up setting, the pitch trim servo was bench tested to determine if the servo was functioning properly. The servo actuator passed the manual and auto-trim tests of the manufacturer’s acceptance test procedure but did not pass the torque test. During that test, the actuator rotated but skipped because the solenoid plunger did not fully engage with the gears. No evidence showed actuator gear teeth wear due to the teeth not engaging fully, indicating that the actuator was likely not skipping during the accident flight. The left and right horizontal stabilizers and their respective elevators were found fragmented throughout the debris field. When these structures separated from the airplane, the elevator trim cables and elevator trim tabs were likely pulled in the airplane-nose-up direction. Thus, the elevator trim tabs were found in their full airplane-nose-up position likely as a result of the airplane’s impact and subsequent breakup. The angle-of-attack sensor and the stability augmentation system computer failed portions of their respective functional tests. Although the manufacturer stated that the test results were typical of incoming in-use units, the NTSB was unable to determine the systems’ functionality at the time of the accident. However, these components likely did not contribute to the loss of control; the stability augmentation system is a pitch stability system, and the aircraft performance calculations showed that the airplane’s bank angle progressed continuously from about 13° right at 0920:13 to about 75° left at 0920:57. (Note: the stability augmentation system is further discussed in the NTSB Systems Group Chairman’s Factual Report in the docket for this accident.) The stall margin indicator needle (part of the stability augmentation system) was found pointing to the red and black stall warning area. However, the needle had likely moved to that position during the impact sequence given the results of the aircraft performance calculations. Specifically, the flaps up lift coefficient calculations for the accident flight showed that the airplane remained below the maximum flaps-up lift coefficient (the value of the lift coefficient just before the wing stalls and loses lift) during the period in which ADS-B data were recorded, indicating that an aerodynamic stall did not occur. In summary, postaccident examination of the airplane structures and systems revealed no anomalies that would have precluded normal operation. The weather conditions at the time of takeoff were conducive to the development of spatial disorientation. The lack of visual references and the airplane’s increasing pitch attitude likely caused the pilot to become spatially disoriented during the initial climb, as evidenced by the airplane’s continuing and tightening turn to the left away from the intended course. Thus, the pilot’s spatial disorientation led to his loss of control of the airplane.
HISTORY OF FLIGHTOn December 28, 2019, about 0921 central standard time, a Piper PA-31T airplane, N42CV, impacted terrain shortly after takeoff from Lafayette Regional Airport/Paul Fournet Field (LFT), Lafayette, Louisiana. The commercial pilot and four passengers were fatally injured, and one passenger was seriously injured. One person in a nearby car sustained serious injuries, and two people in a nearby building sustained minor injuries. The airplane was destroyed by impact forces and a postimpact fire. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. Instrument meteorological conditions prevailed at the time of the accident. At 0913:16, the pilot contacted the local controller at the LFT air traffic control tower and requested an instrument flight rules (IFR) clearance to the flight’s destination, Dekalb Peachtree Airport (PDK), Atlanta, Georgia. The controller issued the clearance to the pilot and instructed him to climb to and maintain an altitude of 2,000 ft mean sea level after departure. (All altitudes in this report are expressed as mean sea level unless otherwise indicated.) The controller then instructed the pilot to taxi the airplane to runway 22L. At 0918:26, the pilot advised the controller that the airplane was ready for takeoff, and the controller cleared the airplane to depart and instructed the pilot to turn right onto a heading of 240°. After takeoff, the controller provided the pilot with a frequency change; at 0920:26, the pilot established communications with the departure controller and stated that the airplane was at an altitude of 700 ft. The controller then instructed the pilot to climb the airplane to 10,000 ft and turn right onto a heading of 330°. At 0920:36, the pilot acknowledged this instruction. No further transmissions were received from the airplane. The Federal Aviation Administration (FAA) provided automatic dependent surveillance-broadcast (ADS-B) data for the accident flight. These data were used to calculate the airplane’s performance, including its true altitude. (See the Tests and Research section of this report for more information.) The ADS-B data started at 0920:05 as the airplane climbed through an altitude of 150 ft. The airplane then began a slight right turn immediately afterward toward its assigned heading of 240°. The airplane reached a peak altitude of 925 ft from about 0920:37 to 0920:40 and then started a continuous descent toward the ground. At 0920:58, the controller issued a low altitude alert, stating that the pilot should “check [the airplane’s] altitude immediately” because the airplane appeared to be at an altitude of 300 ft. The pilot did not respond, and no mayday or emergency transmission was received from the airplane. The last ADS-B data point, at 0920:59, showed the airplane descending through an altitude of 230 ft. Figure 1 shows the airplane’s flight track and key points based on aircraft performance calculations and radio transmission information. Figure 1. Flight track overview. Multiple witnesses on the ground heard an airplane flying overhead at a low altitude. Several of these witnesses stated that the engines sounded as if they were operating at “full throttle.” Multiple witnesses also observed the airplane descending through low clouds while in a steep left turn. One witness stated that the airplane was in “a very steep left diving turn” before rolling wings level and striking trees and power lines. The airplane then struck the road and continued across a parking lot, and a postcrash fire ensued. An officer from the Lafayette Police Department spoke briefly with the surviving passenger at the accident site. According to the police officer, the passenger recalled only that “the plane went straight up and then straight down.” One person was seriously injured after the airplane struck her car in the parking lot. The car then rolled several times before it came to rest inverted; a postimpact fire ensued that consumed the car. Two people inside a building sustained minor injuries from glass that shattered during the impact sequence. PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate with an airplane multiengine land rating. The pilot also held a second-class medical certificate, dated November 14, 2019, with a limitation that required him to wear corrective lenses. According to FAA medical records, the pilot wore bifocal glasses “all the time.” On his most recent medical application, dated November 4, 2019, the pilot reported 1,531 hours of total flight experience, 46 hours of which were accumulated during the preceding 6 months. The pilot also had about 730 hours of flight experience in the accident airplane make and model. The pilot’s most recent logbook was not located. The last entry in the pilot’s previous logbook showed that he had 1,194 hours of total flight experience and 910 hours of flight experience in a multiengine airplane as of July 25, 2017. The owner of the company for which the pilot worked stated that he and the accident pilot would generally hand fly the airplane up to an altitude of at least 2,000 ft (rather than engage the autopilot soon after takeoff). The company owner also stated that the accident pilot was “proficient” in the airplane. According to the owner of the airplane (who was also a pilot), the accident pilot had “a lot of involvement” with the airplane and “wanted to be the very best that he could be” at operating it. The airplane owner stated that the accident pilot was involved in selecting and installing the airplane’s flight instruments and that he was “very meticulous” about understanding the flight instruments. The pilot’s most recent recurrent training in the airplane occurred on April 22, 2019. The training was conducted by a pilot whose FAA-issued flight instructor certificate had expired in February 2019, and no FAA records indicated that his certificate had been renewed or reinstated at the time of the training. The flight instructor reported that the accident pilot’s most recent recurrent training was conducted at the same time as the airplane owner’s recurrent training. The flight instructor stated that ground training included using the airplane manuals and discussing any anomalies that either pilot had experienced during the previous 12 months. The flight instructor stated that, according to the pilots, no “big anomalies” had occurred during that timeframe. During flight training, the pilots performed stall recovery maneuvers at the first indication of an impending stall, steep turns at 5,000 ft, and go-arounds with a simulated failed engine at 4,000 ft. After the maneuvers were completed, the pilots returned to the airport to conduct instrument landing system and VOR approaches. (A VOR approach uses a very-high-frequency omnidirectional radio range system for navigation.) The flight instructor stated that all the training was conducted in visual meteorological conditions. He did not simulate instrument conditions by having the pilots wear a hood (a view limiting device) but stated that he could “load a pilot up enough so he would not have a chance to look outside.” The flight instructor also stated that the accident pilot was a “great stick and rudder guy” and that he “was not an autopilot pilot as he enjoyed [manually] flying the airplane.” The accident airplane’s flight log showed that, on April 22, 2019, the airplane flew from LFT to David Wayne Hooks Memorial Airport, Spring, Texas, for the pilots’ training and then returned to LFT. The entry included the accident pilot’s initials and showed a total flight time of 2.7 hours. As stated above, the accident pilot’s most recent logbook was not found, and the accident pilot’s previous logbook did not include a flight review endorsement for this training. The last flight review endorsement recorded in that logbook was dated March 12, 2017. The airplane owner’s logbook did not include a flight review endorsement but showed the training event; the logbook entry stated, “Recurrent training per FAR [Federal Aviation Regulation] Part 91. Steep turns, Engine out, Emergency and Normal procedures.” The entry also included the signature of the flight instructor and his pilot certificate number, but “CFI” (certificated flight instructor) and the CFI certificate expiration date did not appear after his pilot certificate number, as required for flight reviews. AIRCRAFT INFORMATIONThe accident airplane, which was owned by Cheyenne Partners LLC, was equipped with two Pratt & Whitney Canada PT6A-28 turbopropeller engines with two Hartzell constant speed, four bladed propellers. The airplane was configured with pilot and copilot seats, an aft-facing seat and a forward-facing seat on both the left and right sides of the airplane, and a side-facing seat opposite the left-side main entry door. The airplane was equipped with a King (now Honeywell) autopilot and a KAP 315 annunciator panel that displayed vertical and lateral flight director and autopilot system modes. The airplane was also equipped with a Garmin G600 integrated avionics display system that presented primary flight instrumentation, a full-color moving map with navigation information, and supplemental data. A Garmin GRS 77H attitude heading and reference system (AHRS) unit provided attitude and heading information to the airplane’s Garmin G600 flight deck displays. The Garmin G500/G600 Pilot’s Guide stated, “any failure of the internal AHRS inertial sensors results in loss of attitude and heading information. This is indicated by red ‘X’ flags over the corresponding flight instruments.” There were no maintenance writeups or reported anomalies with the display system before the accident flight. A standby digital attitude indicator was located directly beneath the Garmin G600 flight deck displays. In addition, the airplane was equipped with a Collins Aerospace stability augmentation system (SAS), which was designed to improve the static longitudinal stability of the airplane by providing variable elevator forces through tension changes to the elevator down spring. A major component of the SAS is the angle-of-attack (AOA) sensor vane, which is mounted on the right side of the airplane’s nose. The SAS computer uses the information from the AOA sensor vane to drive the servo actuator, which is attached to the elevator down spring. The SAS includes a stall margin indicator that is mounted on the upper left side of the instrument panel. This indicator receives a signal from the AOA vane to provide a pilot with a visual representation, via the indicator needle, of the ratio of airspeed to stall speed. The indicator face presents (from top to bottom) a red “stall” area, a red and black barber pole stall warning area, a yellow “slow” area, a white “1.3 VS” (stall speed) area, and a green (cruise) area. The last entry recorded in the airplane’s flight log was a flight from West Houston Airport, Houston, Texas, to LFT on December 18, 2019. The accident airplane was stored in a hangar at LFT, and the manager of that hangar reported that he added about 200 gallons of Jet A fuel to the airplane after it arrived on December 18. The airplane’s total weight was 8,869 pounds, which was less than the maximum takeoff weight of 9,000 pounds. The calculated center of gravity was 137.3 inches aft of datum; the center-of-gravity aft limit was 138.0 inches aft of datum. The airplane was not equipped, and was not required to be equipped, with a cockpit voice recorder or flight data recorder. METEOROLOGICAL INFORMATIONLFT had an automated surface observing system located about 2 miles north-northeast of the accident location. The 0853 observation indicated a visibility of 0.75 mile in mist and a vertical visibility of 200 ft above ground level (agl). At 0913:16, the pilot told the controller that he had the current automatic terminal information service report, which was based on the 0853 observation. Weather radar imagery revealed no pertinent radar returns near the accident location at the time of the accident. Satellite imagery depicted clouds over the accident region with cloud top heights at an altitude of about 9,000 ft. An AIRMET that was issued at 0845 on the day of the accident (and was valid until 1500 that day) described IFR conditions in fog and mist for an area that included the accident location. The National Weather Service’s weather forecast office in Lake Charles, Louisiana, issued two terminal aerodrome forecasts (TAF) for LFT during the 2.5 hours preceding the accident time. A TAF issued at 0700 indicated, for the accident time, a visibility of 4 miles, mist, and an overcast ceiling at 300 ft agl. A TAF issued at 0905 indicated, for the accident time, a visibility of 0.75 mile, mist, and an overcast ceiling at 200 ft agl. This TAF also stated that, between 0900 and 1000, temporary conditions (fluctuations to forecast conditions) would be a visibility of 2 miles, mist, scattered clouds at 200 ft agl, and a ceiling overcast at 700 ft agl. During a postaccident interview, the pilot’s wife stated that, on the night before the accident, the pilot told her that the ceilings would be “low” for takeoff. In addition, Leidos (a flight management and briefing services source) provided the National Transportation Safety Board (NTSB) with three documents that outlined weather information for the planned flight, including the low-visibility conditions at the time of takeoff. Each document, titled “Route Standard Briefing at Dec 28, 1336Z for N42CV KLFT to KPDK,” was retrieved by a third-party vendor about 0736 local time. AIRPORT INFORMATIONThe accident airplane, which was owned by Cheyenne Partners LLC, was equipped with two Pratt & Whitney Canada PT6A-28 turbopropeller engines with two Hartzell constant speed, four bladed propellers. The airplane was configured with pilot and copilot seats, an aft-facing seat and a forward-facing seat on both the left and right sides of the airplane, and a side-facing seat opposite the left-side main entry door. The airplane was equipped with a King (now Honeywell) autopilot and a KAP 315 annunciator panel that displayed vertical and lateral flight director and autopilot system modes. The airplane was also equipped with a Garmin G600 integrated avionics display system that presented primary flight instrumentation, a full-color moving map with navigation information, and supplemental data. A Garmin GRS 77H attitude heading and reference system (AHRS) unit provided attitude and heading information to the airplane’s Garmin G600 flight deck displays. The Garmin G500/G600 Pilot’s Guide stated, “any failure of the internal AHRS inertial sensors results in loss of attitude and heading information. This is indicated by red ‘X’ flags over the corresponding flight instruments.” There were no maintenance writeups or reported anomalies with the display system before the accident flight. A standby digital attitude indicator was located directly beneath the Garmin G600 flight deck displays. In addition, the airplane was equipped with a Collins Aerospace stability augmentation system (SAS), which was designed to improve the static longitudinal stability of the airplane by providing variable elevator forces through tension changes to the elevator down spring. A major component of the SAS is the angle-of-attack (AOA) sensor vane, which is mounted on the right side of the airplane’s nose. The SAS computer uses the information from the AOA sensor vane to drive the servo actuator, which is attached to the elevator down spring. The SAS includes a stall margin indicator that is mounted on the upper left side of the instrument panel. This indicator receives a signal from the AOA vane to provide a pilot with a visual representation, via the indicator needle, of the ratio of airspeed to stall speed. The indicator face presents (from top to bottom) a red “stall” area, a red and black barber pole stall warning area, a yellow “slow” area, a white “1.3 VS” (stall speed) area, and a green (cruise) area. The last
The pilot’s loss of airplane control due to spatial disorientation during the initial climb in instrument meteorological conditions.
Source: NTSB Aviation Accident Database
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