South Bend, IN, USA
N847C
CIRRUS DESIGN CORP SR-22
The pilot was performing a landing approach with a known, gusting crosswind present. A witness stated that the airplane was being “bounced around” by the wind gusts and that it “stalled and rolled to the left.” Another witness heard the accident airplane go to full power. The airplane was then in a 15- to 30-degree left bank with a nose-down attitude before it impacted the ground. The airplane’s left wing impacted the ground first, then the airplane cartwheeled one-half turn. A postaccident examination of the airplane revealed no preimpact airframe or engine anomalies that would have precluded normal operation of the airplane. About 8 months before the accident, the airplane's annual inspection was completed, and 2 days later the airplane's recoverable data module (RDM) stopped recording data due to a failed transient voltage suppressor (TVS) and did not record data during the accident flight. The airplane underwent a 100-hour inspection about midway through the 8 month period, and the failed RDM was not detected at that time. The system does not provide a failure indication to the pilot, and there is no requirement during the 100-hour inspection to check the RDM. A likely cause of the TVS failure could have been electrical overstress: the airplane was tied down overnight, and lightning was present when the RDM stopped recording. A similar airplane sustained substantial lightning strike airframe and avionics damage while tied down and at least two other airplanes sustained lightning strikes at that time. An Air Force Research Lab report recommended that a “review of the system design be conducted to determine if a cockpit indicator could be installed to alert the pilot when data logging is not functioning."
HISTORY OF FLIGHT On April 4, 2011, about 1158 eastern daylight time, a Cirrus Aircraft Corporation SR22, N847C, sustained substantial damage on impact with terrain during landing on runway 27L (8,414 feet by 150 feet, asphalt) at the South Bend Regional Airport (SBN), near South Bend, Indiana. The private pilot, the sole occupant, sustained serious injuries and was transported to a hospital. The pilot subsequently died from the injuries that he sustained. The airplane was registered to Canoecouple Inc. and was operated as a rental airplane by Windy City Flyers, Inc., under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual flight rules conditions prevailed for the flight, which operated on an activated instrument flight rules flight plan. The flight originated from the Chicago Executive Airport (PWK), near Wheeling, Illinois, about 1106, and was destined for SBN. Prior to the accident, as the pilot flying N847C approached SBN, he contacted the approach controller who issued N847C the current weather at SBN, which included the winds that were “3-0-0 at 1-5” and “gusts to 2-4.” After the weather brief, the pilot responded, “Roger.” The pilot was then vectored for and was cleared to conduct the instrument landing system runway 27L approach. The pilot changed to the tower frequency and the tower controller issued updated wind information and a landing clearance to land on runway 27L. The pilot did not ask for any further wind updates and the tower did not issue any prior to the airplane impacting terrain. About 1158, a witness, who worked at SBN, saw an airplane landing. He indicated that the airplane was being “bounced around” by wind gusts. He reported that the airplane “stalled and rolled to the left.” The airplane’s left wing impacted terrain first and then the airplane cartwheeled one-half turn. Another witness, who worked at a fixed base operator at SBN, stated that he heard the accident airplane go to “full” power and he looked out the line office window. The airplane was in a 15 to 30 degree left bank and it had a nose-down attitude. The airplane then impacted the ground and a puff of smoke was observed. PERSONNEL INFORMATION The pilot held a Federal Aviation Administration (FAA) private pilot certificate with an airplane single-engine land, single-engine sea, and instrument ratings. He had been issued a FAA third-class medical certificate on June 2, 2009, with a limitation for corrective lenses. The pilot reported on the application for that medical certificate that he had accumulated 217.8 hours of total flight time and 45.8 hours of flight time in the six months prior to that application. A copy of excerpts from the pilot’s logbook indicated the pilot’s last entry in his logbook was dated March 15, 2011. The pilot recorded that he had accumulated 372.1 hours of total flight time, 16.5 hours of flight time in the 90 days prior to the accident, and 5.7 hours of flight time in the 30 days prior to the accident. The pilot’s logbook showed that the pilot received 259.4 hours of dual instruction. The logbook had a certified flight instructor’s (CFI) endorsement for a flight review and an endorsement for an instrument proficiency check, which were both dated March 15, 2011. According to a recovered certificate, also dated March 15, 2011 and endorsed by the CFI as an "Authorized Cirrus Aircraft Instructor," showed that the pilot completed the course requirements for Advanced Transition Training. The CFI was employed by the airplane operator. AIRCRAFT INFORMATION N847C, a 2007 model Cirrus Aircraft Corporation SR22, serial number 3218, was a four-place single engine low-wing airplane powered by a six-cylinder, 310-horsepower, Teledyne Continental Motors model IO-550-N51 engine, with serial number 691913, that drove a three-bladed Hartzell constant speed propeller. The airplane's airworthiness certificate was issued on August 21, 2008. The Cirrus Aircraft Corporation SR22 was certified under Part 23. The airplane owner flew the airplane the day before the accident. The owner, in part, stated: I flew Cirrus N847C from Georgetown, TX (KGTU) to Chicago Executive (KPWK) via Houston, MO (M48) on April 3, 2011. The vent fan was placarded as INOP. Other than a greatly reduced volume of fresh air into the cabin, the airplane functioned as expected during all phases of flight. An airplane logbook entry showed that on March 22, 2011, a mechanic removed the blower, sent it for repairs, and updated the airplane’s weight and balance to reflect the blower removal. Airplane logbook entries showed that last airplane annual inspection was completed on August 6, 2010, and a 100-hour inspection was completed on December 15, 2010. The airplane accumulated 556.9 hours of total flight time as of the annual inspection and 654.5 hours of total flight time at the 100-hour inspection. The airplane was equipped with a Garmin Primary Flight Display (PFD) and a Multi-Function Display (MFD) for the pilot’s flight instruments. Integrated avionics units, located behind the MFD and instrument panel, functioned as the main communication hub, linking all integrated avionics system components with the PFD. A secure data (SD) card, when inserted in the top SD card slot of the MFD, can have the MFD log flight data on the SD card at 1 Hertz, generating a text file for each power cycle. The accident airplane was also equipped with a Recoverable Data Module (RDM), which was a crash-hardened flight recording device installed in the tail of the aircraft and it recorded flight and aircraft information. The RDM recorded data at 1 Hz. The RDM was designed to record airplane performance, configuration data, and navigation data to include the flight's groundspeed and global positioning system track. The Cirrus Aircraft Corporation SR22 airplane maintenance manual (AMM), in part, stated: The Aircraft Data Logger (ADL) consists of the RDM. The RDM, located in the shear web of the aft vertical spar in front of the rudder, receives airplane data from the primary GIA 63W integrated avionics unit. The ADL system is powered by 28 VDC through the 2-amp STALL WARNING circuit breaker on the Essential Bus 2 and the 3-amp FUEL QTY circuit breaker on the Main Bus 1. ... (2) Operational Tests - Aircraft Data Logger System ... (a) Set BAT 1 switch to ON position. (b) Open center armrest console and remove glove box trim to access diagnostic LED [light emitting diode]. ... (c) Verify diagnostic LED indicates normal operation with several 0.03 flashes once per second. If diagnostic LED does not indicate normal operation, refer to the following troubleshooting table. ... (d) Install glove box trim. ... (e) Set BAT 1 switch to OFF position. The AMM required an annual operational test of the ADL system. Cirrus Aircraft Corporation initially issued service bulletin (SB) 2X-31-05 R2 on April 16, 2009 and issued a revised version on August 27, 2009. SB 2X-31-05 R2, in part, stated: PURPOSE Cirrus Design recently discovered a condition on aircraft with Perspective Avionics where the Aircraft Data Logger (ADL) fails to store data correctly. Upon investigation, it was determined that the condition is caused by the Recoverable Data Module (RDM) internal software. To correct this condition, the affected RDM must be replaced with an RDM with improved software. N847C had a RDM with improved software installed on September 10, 2009. Additionally, at the airplane’s last annual inspection, the required inspection of the ADL system, indicated that the RDM was operational. The airplane's flight manual indicated that the airplane's maximum demonstrated crosswind component was 20 knots. METEOROLOGICAL INFORMATION At 1154, the recorded weather at SBN was: Wind 310 degrees at 16 knots gusting to 24 knots; visibility 7 statute miles; sky condition overcast 1,500 feet; temperature 7 degrees C; dew point 4 degrees C; altimeter 29.41 inches of mercury. AIRPORT INFORMATION SBN was a public, towered airport, owned by the St Joseph County Airport Authority, located 3 miles northwest of South Bend, Indiana, at a surveyed elevation of 799 feet above mean sea level. The airport featured three runways, Runway 9R/27L, 18/36, and 9L/27R with asphalt surfaces. The airport listed 118.9 megahertz as its common traffic advisory frequency and reported that it meets the fire and rescue requirements of aircraft rescue and fire fighting index B. Runway 27L had a four-light precision approach path indicator (PAPI) on located on the left side of the runway and that PAPI provided a 3.00 degree glide path. Runway 27L obstruction remarks listed a 36-foot tree, located 1,741 feet from the runway, and 588 feet right of centerline, which indicated a 42:1 slope to clear that obstruction. FLIGHT RECORDERS The airplane's RDM was manufactured by Heads Up Technologies Inc. The module was installed in the airplane's empennage. The unit was designed to record airplane performance, configuration data, and navigation data to include the flight's groundspeed and global positioning system track. The flight's data was stored on flash memory chips within the module. WRECKAGE AND IMPACT INFORMATION The wreckage and on-scene ground scars were examined and documented by FAA inspectors. Some of the ground scars, consistent propeller slashes, were observed along the path that the airplane took prior to coming to rest in the grass south of runway 27L. The wreckage was located approximately 2,500 feet from the runway’s approach end and a approximately 200 feet south of the its centerline. A safety representative from the airplane manufacturer assisted the FAA inspectors with the examination. Flight control continuity was established and no preimapct anomalies were detected during the postaccident examination of the wreckage. The cockpit avionics display units sustained damage. The display units’ recovered SD cards and the airplane’s RDM were retained for examination. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the 50-year-old pilot by the Cook County Medical Examiner's Office. The autopsy listed the date of death as May 1, 2011, and the cause of death as a result of multiple injuries due to an airplane crash. Samples for toxicological examination were not sent to the FAA Civil Aerospace Medical Institute and a Final Forensic Toxicology Accident Report was not produced. TESTS AND RESEARCH Three SD cards were recovered from the onboard Garmin MFD and were sent to the National Transportation Safety Board (NTSB) Vehicle Recorder Laboratory. Two of the SD cards had Garmin labels and contained various charting and navigation databases. The third was an unlabeled SanDisk 1 gigabyte SD card. When this accident SD card was inserted into a card reader connected to a PC, the SD card did not mount and became heated. The card was transported to the Federal Bureau of Investigation (FBI) Cryptologic and Electronic Analysis Unit for examination. The FBI lab was able communicate with the card, but was unable to read valid sector data. X-ray examination found no obvious defect in the packaging. The not-and (NAND) flash die was exposed using acid decapsulation and cracks were observed in a “T” shape on its die. No data was recovered from the damaged SD card. The RDM was sent to the National Transportation Safety Board (NTSB) vehicle recorder laboratory. A NTSB specialist subsequently powered the unit by the universal serial bus connection and downloaded the data from the RDM. The RDM contained over 145 hours of flight data. The most recent record was from August 8, 2010, at 1630 central daylight time when the aircraft was on the ground at Gogebic-Iron County Airport (IWD), near Ironwood, Michigan. The RDM was transported to its manufacturer, Heads Up Technologies, near Carrollton, Texas, for examination and an attempt to download additional data under NTSB supervision. The unit failed to power up and disassembly revealed its power supply had failed. The failed power supply was removed, an exemplar power supply directly powered the RDM, and the RDM’s data was downloaded. The data set matched the data set initially downloaded at the NTSB Vehicle Recorder Laboratory. The power supply unit was sent to the Air Force Research Laboratory (AFRL) at Wright-Patterson Air Force Base, Ohio, to determine the cause of power supply failure. Examination of the failed power supply showed charring on the top of the circuit card. Further x-ray analysis revealed a failed R9 resistor and shorted transient voltage suppressor (TVS). Both the R9 resistor and TVS are part of the power supply’s input protection and filtering section and found near the charred area of the power supply. According to the AFRL report, “the most likely cause of the TVS failure is either electrical overstress or possible manufacturing defect. … If lightning were the cause, one would normally expect to see additional damage to other electronics or structure.” According to the RDM manufacturer, this is the first observed TVS failure. ADDITIONAL INFORMATION The RDM data showed that on August 7, 2010, the accident airplane was flown from PWK, about 1344 central daylight time (CDT) and it landed at IWD about 1555 CDT. Data was consistent with electrical power being turned on a couple times on August 8, 2010, at IWD. The owner of the airplane indicated that he flew that flight to IWD and that he did not use any external power to start the airplane at IWD on August 8, 2010. A lighting strike report for the 5-mile radius around IWD was completed for the time period between August 7, 2010, 1100 CDT to August 8, 2010, 1059 CDT. The National Lightning Detection Network detected ten strikes during that period and location. The NTSB received a notification that on July 10, 2008, a Cirrus Aircraft Corporation SR22, N596CD, serial number 1710, sustained substantial damage consistent with a lightning strike while tied down on the ramp at PWK. The airplane also sustained damage to its avionics. A lighting strike report for the 5-mile radius around PWK was completed for the time period between July 10, 2008, 0200 CDT to July 11, 2008, 0159 CDT. The National Lightning Detection Network detected 31 strikes during that period and location. Two other Cirrus Aircraft Corporation SR22 airplanes, N616JG, serial number 0151, and N6053U, serial number 0621, were reported by Cirrus Aircraft Corporation as having been involved in lightning strikes. The strikes occurred on about March 6, 2003, for N616JG and on November 16, 2005, for N6053U. The AFRL Evaluation Report on the RDM power supply indicated that a “review of the RDM power supply design is recommended. A single point failure of the TVS, failing in an electrical short condition, will cause secondary damage to the RDM power supply.” The report found that there is no indication, visible to the pilot, that data logging has failed in the event of a power supply failure. It further recommended that a “review of the system design be conducted to determine if a cockpit indicator could be installed to alert the pilot when data logging is not functioning."
The pilot’s failure to maintain airplane control while on final approach with a gusting crosswind and the subsequent aerodynamic stall and spin during the attempted go-around.
Source: NTSB Aviation Accident Database
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