# NTSB CHI00IA221: Aerospatiale ATR 42-300, N421TE, Champaign, IL, July 23, 2000 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: July 23, 2000, 17:31 local (22:31 UTC) - Place: Champaign, IL - Coordinates: 40.109088, -88.239616 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.1091&lon=-88.2396&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 37 uninjured - Status: Completed, report January 2, 2002 - Report: Approved by Office Director - NTSB case key (mKey): 49813 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI00IA221 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/49813/pdf - Page: https://openairdocs.org/ntsb/CHI00IA221 ## Probable cause The failure of the aileron trim switch due to foreign material contamination. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - flt control syst,aileron trim/tab control - contamination (cause) - flt control syst,aileron trim/tab control - failure (cause) - precautionary landing - performed, pilot in command ## Analysis The airplane was undamaged during a precautionary landing following a flight control difficulty while in cruise flight. The flight crew was unable to trim the aircraft for level flight. The pilot reported initially that 80 to 100 pounds of control wheel force was required to maintain wings level. Subsequently, the pilot estimated the force required as 50 to 70 pounds. The trim switch was found to be intermittent and subsequent examination confirmed this. The switch was found to be contaminated with, "... salt, dust, hairs and other organic materials." Corrosion of the switch contacts was also found. ## Factual narrative On July 23, 2000, at 1731 central daylight time, an Aerospatiale ATR 42-300, N421TE, operated as Trans States Airlines Flight 7495, piloted by an airline transport pilot, experienced a flight control difficulty while in cruise flight near Champaign, Illinois. An uneventful landing was made and the airplane sustained no damage. The 14 CFR Part 121 passenger flight was operating on an instrument flight plan. Visual meteorological conditions prevailed at the time of the incident. No injuries were reported. The flight originated from the Michiana Regional airport, South Bend, Indiana, at 1640 eastern standard time, and was en route to the Lambert-St. Louis International Airport, Saint Louis, Missouri. While in cruise flight at 14,000 feet msl, the flight crew was unable to trim the aircraft for level flight. According to the pilot's original report of the incident, approximately 80 to 100 pounds of aileron force was required to maintain level flight. The flight crew declared an emergency and diverted to the University of Illinois-Willard Airport, Champaign, Illinois, where an uneventful landing was made. Following the incident, a mechanic for the airline determined that the, "...right section of [the] aileron control switch for trim to be very intermittent (mostly inoperative)." The mechanic also stated that the trim indicator showed 1/2 trim to the left. The mechanic stated that he was able to center the trim by using the intermittent switch. A ferry flight was performed so that the switch could be replaced. According to a report filed by the airline, the switch had accumulated 26,747 hours time in service at the time of the incident. The switch was examined by the manufacturer under the supervision of the Bureau Enquetes-Accidents. The malfunction of the switch was confirmed. The switch was found to have been contaminated with, "... salt, dust, hairs and other organic materials." Corrosion of the switch contacts was also found. The pilot stated, in a written document dated after his original statement, that he may have overestimated the required force to hold wings level. He stated, "...it was probably 50 to 70 pounds of force to hold wings level. ## Aircraft - Registration: [N421TE](https://openairdocs.org/deregistered/N421TE-2005-01-21), registration cancelled 2005-01-21, S/N 102, built 1988 (OpenAirDocs) - Reported make and model: Aerospatiale ATR 42-300 - Registry model: [Aerospatiale/Aeritalia ATR 42-300](https://openairdocs.org/model/aerospatiale-aeritalia-atr-42-300) (registry code 8680920) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PW120](https://openairdocs.org/engine/pratt-whitney-canada-pw120) (registry code 52114, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 102 - Airframe hours: 26773 - Engines: P&W PW120 2000 horsepower turbo prop - Damage: No damage - Flight: Part 121 - Operator: Trans States Airlines, doing business as Twa Express - Registered owner: Chase Manhattan Bank - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, July 9, 2000, 122 hours before - Departed: SBN, SOUTH BEND, IN - Destination: STL, SAINT LOUIS, MO - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 5,500 total, 100 in this make and model, 100 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 167 °F, dew point 135 °F - Altimeter: 30.00 inHg - Observed at: CMI ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20000723027699I](https://openairdocs.org/incident/20000723027699I), Jul 23, 2000: Aerosp ATR42300, Champaign-Urban, IL. (-23)Enroute to saint louis, MO from south bend, IL, while in cruise at 14000 feet, the first officer informed the pilot in command that the aileron trim could… 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.