# NTSB CEN14IA121: Cessna 680, N531RC, Wheeling, IL, January 12, 2014 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: January 12, 2014, 16:15 local (22:15 UTC) - Place: Wheeling, IL - Coordinates: 42.114166, -87.901664 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.1142&lon=-87.9017&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: No injuries - Status: Completed, report March 10, 2015 - Report: Approved by Office Director - NTSB office: Central Region - NTSB case key (mKey): 88711 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN14IA121 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/88711/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=88711 - Page: https://openairdocs.org/ntsb/CEN14IA121 ## Probable cause The disconnection of the left elevator trim driveshaft from the trim actuator due to the elevator trim tab drive pin becoming dislodged, which resulted in full nose-down elevator trim. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system: elevator tab control system](https://openairdocs.org/ntsb-findings/01022731): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [All aircraft, 37 cases](https://openairdocs.org/ntsb-findings/01022731/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) ## Analysis The pilot reported that, while climbing to 15,000 ft mean sea level, the autopilot disengaged and the autopilot disconnect chime sounded accompanied by an "AP fail A-B" message. At this point, the flight crew decided to return to the departure airport. The pilot noted that, while trying to slow the climb, "extra" force was required to push the airplane's nose down. He attempted to apply nose-down trim but felt no change and then noted that the elevator trim tab indicator was showing full nose-down trim. He subsequently landed the airplane without incident. Following the incident, the operator tested the stabilizer trim through its full range of travel and noted no discrepancy with the system or the elevator trim tab indicator. The operator contacted the manufacturer to assist in troubleshooting the problem. They found that the connecting pin linking the drive shaft to the left elevator trim tab actuator had become dislodged, which likely caused the left elevator trim driveshaft to disconnect from the trim actuator. The operator stated that it was aware that the elevator trim tab drive shaft pin on the same make and model airplane had dislodged on two previous occasions. The manufacturer is in the process of proposing changes to the drive pin dimensions and the method of securing the pin to prevent the elevator trim tab drive pin from dislodging. ## Factual narrative On January 12, 2014, about 1615 central standard time (CST), a Cessna 680 Sovereign, N531RC, experienced a left-hand elevator trim driveshaft failure. The two flight crewmembers on-board were not injured. The airplane was registered to Great Dane Financial, LLC and operated by CC Industries under the provisions of 14 Code of Federal Regulations Part 91 as a flight test. Visual meteorological conditions prevailed for the flight, which originated from Chicago Executive Airport (KPWK) in Wheeling, Illinois. The pilot reported that, while climbing to 15,000 ft mean sea level, the autopilot disengaged and the autopilot disconnect chime sounded accompanied by an "AP fail A-B" message. At this point, the flight crew decided to return to the departure airport. The pilot noted that, while trying to slow the climb, "extra" force was required to push the airplane's nose down. He attempted to apply nose-down trim but felt no change and then noted that the elevator trim tab indicator was showing full nose-down trim. He subsequently landed the airplane without incident. During post flight examinations, the operator tested the stabilizer trim though its full range of travel and no discrepancy in the system was noted. Additionally, no abnormality of the elevator trim tab indicator was noted throughout the range of stabilizer travel. The operator contacted a Cessna Aircraft Company Service Center to assist in troubleshooting the problem; it was determined the connecting pin linking the drive shaft to the left-hand elevator trim tab actuator had become dislodged. This failure of the Cessna 680 Sovereign elevator trim tab drive shaft pin occurred on two other occasions. Cessna Aircraft Company is in the process of proposing a change in the drive pin dimensions and method of securing the pin; this pending change will prevent the elevator trim tab drive pin from dislodging. ## Aircraft - Registration: N531RC (not matched to a registry record) - Reported make and model: CESSNA 680 (NO SERIES) - Category: Airplane - Serial number: 680-0107 - Year built: 2006 - Airframe hours: 3147 - Engines: Pratt & Whitney PW306C 5770 lbs thrust turbo fan; Pratt & Whitney PW306C 5770 lbs thrust turbo fan - Damage: No damage - Flight: Flight test, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, October 28, 2013 - Departed: PWK, CHICAGO/PROSPECT HEIGHTS/WHEELING, IL - Destination: PWK, CHICAGO/PROSPECT HEIGHTS/WHEELING, IL - Flight plan: IFR - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; injuries: none; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review July 28, 2013; seat: left; flight hours: 13,000 total, 3,000 in this make and model, 12,000 as pilot in command - Co-pilot; age 41; injuries: none; airline transport, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review November 7, 2013; seat: right; flight hours: 6,330 total, 1,547 in this make and model, 3,800 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 13 knots, gusting 22 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 39 °F, dew point 28 °F - Altimeter: 29.62 inHg - Observed at: KPWK ## Docket (5 files) The files NTSB released with the investigation on January 22, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=88711. 4.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40421455&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Event Notification Letter from CC Industries to Cessna Aircraft Company (item 2, .PDF, 610 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40421456&FileExtension=.PDF&FileName=Event%20Notification%20Letter%20from%20CC%20Industries%20to%20Cessna%20Aircraft%20Company-Redacted.PDF - Certification of Party Representatives (item 3, .PDF, 94 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40421550&FileExtension=.PDF&FileName=Certification%20of%20Party%20Representatives-Redacted.PDF - Photo 1 - Trim Actuator and Drive Shaft (Photo Courtesy of CC Industries) (item 4, .PDF, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40421457&FileExtension=.PDF&FileName=Photo%201%20-%20Trim%20Actuator%20and%20Drive%20Shaft%20(Photo%20Courtesy%20of%20CC%20Industries)-Master.PDF - Revised Factual Report (item 5, .PDF, 34 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40422799&FileExtension=.PDF&FileName=Revised%20Factual%20Report-Master.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.