# NTSB CHI02LA111: Boeing 757-200, N516AT, Springfield, MO, April 18, 2002 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: April 18, 2002, 16:35 local (21:35 UTC) - Place: Springfield, MO - Coordinates: 37.486389, -93.456108 - Nearby events: https://openairdocs.org/map.md?lat=37.4864&lon=-93.4561&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 3 serious, 12 minor, 111 uninjured - Status: Completed, report December 30, 2003 - Report: Approved by Office Director - Parties: FAA-St. Louis, Missouri-FSDO, American Trans Air - NTSB case key (mKey): 54582 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI02LA111 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/54582/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=54582 - Page: https://openairdocs.org/ntsb/CHI02LA111 ## Probable cause The flightcrew's failure to follow weather avoidance prcedures and their delay in activating the seat belt sign. Factors were the turbulent thunderstorm weather conditions, and the failure of the National Weather Service to issue an applicable in-flight weather advisory. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, cruise - weather condition - thunderstorm (contributing factor) - weather condition - turbulence(thunderstorms) (contributing factor) - in-flight weather advisories - not issued, nws personnel (contributing factor) - procedures/directives - not followed, flightcrew (cause) - seat belt sign - delayed, flightcrew (cause) ## Analysis The air carrier passenger flight encountered severe turbulence while in cruise flight. Three passengers were seriously injured and nine passengers and three flight attendants received minor injuries during the turbulence encounter. The remaining passengers and crew were not injured. The airplane was traveling in a predominately northern direction at 37,000 feet altitude during the encounter. Weather products obtained showed that extreme intensity thunderstorms existed in the area where the turbulence was encountered. Weather data and aircraft position radar data show that the airplane was 9 miles south-southwest of a cloud buildup that extended to 39,000 feet. Additionally, the airplane was 5 miles west of an extreme intensity radar echo associated with the thunderstorms in the area. The airline's General Operations Manual states that thunderstorms that are identified as severe, or giving a intense radar echo should be avoided by at least 20 miles. No National Weather Service aviation weather advisories were in effect for the location and time of the turbulence encounter. Communications transcripts show that the flight crew requested and were granted a course deviation for weather about 10 minutes prior to the upset. However, the Digital Flight Data Recorder shows that the seat belt sign was illuminated only 10 seconds prior to the encounter. ## Factual narrative HISTORY OF FLIGHT On April 18, 2002, about 1635 central daylight time, a Boeing 757-200, N516AT, operated by American Trans Air (ATA), as flight 208, encountered severe turbulence during cruise flight at flight level 370 near Springfield, Missouri. The airplane was travelling in a predominately northern direction during the encounter. The flight diverted to the St. Louis International Airport (STL), St. Louis, Missouri without further incident. Three passengers received serious injuries and nine passengers and three flight attendants received minor injuries. The remaining 106 passengers, 4 cabin crewmembers, and 2 flight crewmembers were not injured. The airplane was not damaged during the encounter. The 14 CFR Part 121 airline flight was operating in instrument meteorological conditions and was on an instrument flight rules flight plan. The flight had departed Guadalajara, Mexico, and was destined for the Chicago Midway Airport, Chicago, Illinois. METEOROLOGICAL INFORMATION A Meteorological Specialist with the National Transportation Safety Board, Operational Factors Division, obtained and examined weather products related to the turbulence encounter. The full text of the Meteorological Report is included in the public docket of the accident report. Surface weather observations in the vicinity of the turbulence encounter indicated the presence of thunderstorms and lightning moving eastward. The National Weather Service (NWS) Radar Summary Chart indicated multiple areas of echoes from Wisconsin south-southwestward across Iowa, Missouri, Kansas, Oklahoma, Arkansas, and into Texas. The maximum intensity of the echoes in southern Missouri reached video integrator and processor (VIP) levels 5 and 6 or intense to extreme intensity, with echo tops ranging from 36,000 to 41,000 feet. The NWS Weather Surveillance Radar located in Springfield, Missouri, showed a band of echoes, at 1623, extending over the location of the turbulence encounter. The echoes had a reflectivity of 60 dBZ or VIP level 6 extreme intensity. This same radar station recorded, at 2138, a band of echoes in the area of the turbulence encounter. The strongest echo had a maximum intensity of 60 dBZ or VIP level 6 extreme intensity and was less than 5 miles east of the turbulence encounter. The echo intensities over the location of the turbulence encounter ranged from 36 to 45 dBZ or VIP level 3 to 4 strong to very strong intensity. Satellite data was used to determine cloud tops in the area of the turbulence encounter. An infrared image from April 18, 2002 at 1632 shows that the cloud tops along the flight path of the airplane were in the range of 28,000 to 33,000 feet. The image also showed the highest cloud tops in the vicinity to be about 39,000 feet. The highest cloud tops were located about 9 miles east-northeast of the turbulence encounter. At 1210, the Kansas City (ZKC) Center Weather Service Unit (CWSU) issued a Center Weather Advisory (CWA) for a line of VIP level 3 to 5 thunderstorms with tops to 33,000 feet. This CWA however, was only valid until 1410 and had expired by the time of the turbulence encounter. At 1640, after the turbulence encounter, the ZKC CWSU issued a CWA for an area of VIP level 3 to 5 thunderstorms with tops to 38,000 feet. This CWA covered the location of the turbulence encounter. No Significant Weather Information (SIGMET) advisories were issued by the NWS Aviation Weather Center that related to the accident flight. No Convective SIGMET's were in effect for the accident location. COMMUNICATIONS Transcripts of voice communications between Air Traffic Control (ATC) and the airplane were obtained. The transcripts show that the flight crew requested a course deviation for weather avoidance at 1627. The ATC controller approved the deviation and requested that the flight crew advise when they were able to return on course. At 1632, the flight crew advised ATC that they were able to return on course. At 1637, the flight crew requested a deviation to the Kansas City Missouri International Airport for landing. The flight crew subsequently informed ATC that they, "got too close to that ah thundershower there and we've got uh we've got some passengers on board who've been injured and uh we're gonna have to have ambulances standing by for them." The ATC controller asked the flight crew if they "would rather go to Saint Louis or would you want to go to Kansas City." The flight crew decided to divert to Saint Louis. When asked by the ATC controller as to what type of turbulence that the airplane had encountered, the flight crew replied, "we just caught the very corner of one of the build---ah or the only buildup that's out there just uh like got one wing into it on the right hand side and uh that was---got a good up draft and a good down draft." The airplane continued to STL where a landing was made without further incident. The full transcripts of the communications are included in the public docket of this report. FLIGHT RECORDERS The cockpit voice recorder was retained for examination. The 30-minute recording began as the airplane was on approach to STL and did not capture the turbulence event. No further examination of the recording was performed. The digital flight data recorder was retained for examination of the data. A Flight Data Recorder Specialist in the National Transportation Safety Board Vehicle Recorders Division examined the data. Among the parameters recorded were the vertical acceleration, seat belt sign (ON/OFF), roll angle of the airplane, and pitch angle of the airplane. The FDR Subframe Reference Number is a measure of relative time on the Flight Data Recorder. One frame is equivalent to one second. The data shows that the airplane experienced a series of vertical accelerations that began at a FDR Subframe Reference Number of 90903 and lasted for about 17 seconds. The maximum positive vertical acceleration of 2.099 g's occurred at a FDR Subframe Reference Number of 90906. The maximum negative vertical acceleration of -0.648 g's occurred at a FDR Subframe Reference Number of 90912. The data shows that the seat belt sign was turned on at a FDR Subframe Reference Number of 90894. TESTS AND RESEARCH According to a written statement by the first officer, the crew requested to deviate left of course for weather and ATC approved. He stated that the captain initiated the deviation and that he and the captain were monitoring the weather radar. He said that prior to being abeam the weather, the captain made an additional deviation to the west and turned on the fasten seat belt signs. He stated that the airplane subsequently encountered the turbulence and that he did not notice any "appreciable excursions in airspeed or attitude." He noted that the airplane had descended about 50 feet below the cruise altitude. The ATA General Operations Manual (GOM) states that thunderstorms that are identified as severe or giving an intense in-flight weather radar echo should be avoided by at least 20 miles. Plots of the Aircraft Situation Display from ATA Dispatch were obtained. The plots of the airplane's flight path are overlaid onto Doppler weather radar data. The plots show the airplane's flight path in relation to the Doppler weather radar returns in the area of the turbulence encounter. The plots are included in the public docket of this report. ## Aircraft - Registration: N516AT (not matched to a registry record) - Reported make and model: Boeing 757-200 - Category: Airplane - Serial number: 27972 - Airframe hours: 23720 - Engines: Rolls-Royce RB211-535E4 40100 lbs thrust turbo fan; Rolls-Royce RB211-535E4 40100 lbs thrust turbo fan - Damage: No damage - Flight: Part 121 - Registered owner: American Trans Air Inc - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, March 31, 2002, 210 hours before - Departed: GDL, GUADALAJARA - Destination: MDW, CHICAGO, IL - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: none; commercial, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; last flight review April 4, 2002; seat: left; flight hours: 21,225 total, 136 in the last 90 days, 57 in the last 30 days, 7 in the last 24 hours - Co-pilot; age 44; injuries: none; commercial, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; last flight review April 4, 2002; seat: right; flight hours: 7,046 total, 182 in the last 90 days, 71 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 8 statute miles - Lowest ceiling: 8,000 ft broken - Temperature: 73 °F, dew point 63 °F - Altimeter: 29.94 inHg - Observed at: KSGF, 15 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20020418037339A](https://openairdocs.org/incident/20020418037339A), Apr 18, 2002: Boeing 75723N, St Louis, MO. (-23) American trans air, flight 208, enroute from guadalajara, Mexico to chicago, Illinois, (midway), encountered turbulence while detouring around… ## Docket (29 files) The files NTSB released with the investigation on October 20, 2003, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=54582. 41.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 619 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40430614&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - ATC 3 - Factual Report of Group Chairman (item 2, .PDF, 17 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40163906&FileExtension=.PDF&FileName=ATC%203%20-%20Factual%20Report%20of%20Group%20Chairman-Master.PDF - ATC 3 - Attachment 1 - FAA Form 8020-11 Incident Report (item 3, .PDF, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40430611&FileExtension=.PDF&FileName=ATC%203%20-%20Attachment%201%20-%20FAA%20Form%208020-11%20Incident%20Report-Redacted.PDF - ATC 3 - Attachment 2 - Personnel Statement (item 4, .PDF, 126 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40430612&FileExtension=.PDF&FileName=ATC%203%20-%20Attachment%202%20-%20Personnel%20Statement-Redacted.PDF - ATC 3 - Attachment 3 - ZKC Weather Information (item 5, .PDF, 61 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164560&FileExtension=.PDF&FileName=ATC%203%20-%20Attachment%203%20-%20ZKC%20Weather%20Information-Master.PDF - ATC3 - Attachment 4 (item 6, .PDF, 82 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40163922&FileExtension=.PDF&FileName=ATC3%20-%20Attachment%204-Master.PDF - Meteorology 5 - Factual Report of Group Chairman (item 7, .PDF, 573 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164266&FileExtension=.PDF&FileName=Meteorology%205%20-%20Factual%20Report%20of%20Group%20Chairman-Master.PDF - Meteorology 5 - Attachment 1 - Surface Analysis Chart (item 8, .PDF, 231 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164533&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%201%20-%20Surface%20Analysis%20Chart-Master.PDF - Meteorology 5 - Attachment 2 - Weather Depiction Chart (item 9, .PDF, 220 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164536&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%202%20-%20Weather%20Depiction%20Chart-Master.PDF - Meteorology 5 - Attachment 3 - 500MB Constant Pressure Chart (item 10, .PDF, 282 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164537&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%203%20-%20500MB%20Constant%20Pressure%20Chart-Master.PDF - Meteorology 5 - Attachment 4 - 250MB Constant Pressure Chart (item 11, .PDF, 330 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164538&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%204%20-%20250MB%20Constant%20Pressure%20Chart-Master.PDF - Meteorology 5 - Attachment 5 - 200MB Constant Pressure Chart (item 12, .PDF, 319 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164539&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%205%20-%20200MB%20Constant%20Pressure%20Chart-Master.PDF - Meteorology 5 - Attachment 6 - Springfield Sounding (item 13, .PDF, 396 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164540&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%206%20-%20Springfield%20Sounding-Master.PDF - Meteorology 5 - Attachment 7 - Springfield Composite Reflectivity 2123Z (item 14, .PDF, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164549&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%207%20-%20Springfield%20Composite%20Reflectivity%202123Z-Master.PDF - Meteorology 5 - Attachment 8 - Springfield - Composite Reflectivity 2138Z (item 15, .PDF, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164551&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%208%20-%20Springfield%20-%20Composite%20Reflectivity%202138Z-Master.PDF - Meteorology 5 - Attachment 9 - Springfield - VAD Wind Profile (item 16, .PDF, 2.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164553&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%209%20-%20Springfield%20-%20VAD%20Wind%20Profile-Master.PDF - Meteorology 5 - Attachment 10 - Turbulence Terms (item 17, .PDF, 133 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164541&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%2010%20-%20Turbulence%20Terms-Master.PDF - Meteorology 5 - Attachment 11 - AC00-24B - Thunderstorms (item 18, .PDF, 492 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40430613&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%2011%20-%20AC00-24B%20-%20Thunderstorms-Redacted.PDF - Meteorology 5 - Attachment 12 - AIM Thunderstorm Flying (item 19, .PDF, 197 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40164543&FileExtension=.PDF&FileName=Meteorology%205%20-%20Attachment%2012%20-%20AIM%20Thunderstorm%20Flying-Master.PDF - Flight Data Recorder 10 - Factual Report of Group Chairman (item 20, .PDF, 11 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40175277&FileExtension=.PDF&FileName=Flight%20Data%20Recorder%2010%20-%20Factual%20Report%20of%20Group%20Chairman-Master.PDF - Flight Data Recorder 10 - Attachment 1 - Parameter Listing (item 21, .PDF, 8 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40175278&FileExtension=.PDF&FileName=Flight%20Data%20Recorder%2010%20-%20Attachment%201%20-%20Parameter%20Listing-Master.PDF - Flight Data Recorder 10 - Attachment 2 - Plots (item 22, .PDF, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40175279&FileExtension=.PDF&FileName=Flight%20Data%20Recorder%2010%20-%20Attachment%202%20-%20Plots-Master.PDF - Flight Data Recorder 10 - Attachment 3 - Data (item 23, .CSV, 29 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40175280&FileExtension=.csv&FileName=Flight%20Data%20Recorder%2010%20-%20Attachment%203%20-%20Data-Master.csv - Cockpit Voice Recorder 12 - Factual Report of Group Chairman (item 24, .PDF, 13 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40166461&FileExtension=.PDF&FileName=Cockpit%20Voice%20Recorder%2012%20-%20Factual%20Report%20of%20Group%20Chairman-Master.PDF - Crew Statements (item 25, .PDF, 667 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40430615&FileExtension=.PDF&FileName=Crew%20Statements-Redacted.PDF - ATC Transcripts (item 26, .PDF, 277 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40430616&FileExtension=.PDF&FileName=ATC%20Transcripts-Redacted.PDF - Plots of Aircraft Situation Display From ATA Dispatch (item 27, .PDF, 28.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40198661&FileExtension=.PDF&FileName=Plots%20of%20Aircraft%20Situation%20Display%20From%20ATA%20Dispatch-Master.PDF - Excerpt From ATA General Operations Manual (item 28, .PDF, 507 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40198665&FileExtension=.PDF&FileName=Excerpt%20From%20ATA%20General%20Operations%20Manual-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 29, .PDF, 323 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40430617&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.