# NTSB DEN06IA056: Swearingen SA226TC, N770S, Denver, CO, April 5, 2006 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: April 5, 2006, 06:23 local (12:23 UTC) - Place: Denver, CO - Coordinates: 39.861389, -104.673057 - Nearby events: https://openairdocs.org/map.md?lat=39.8614&lon=-104.6731&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 29, 2006 - Report: Approved by Office Director - Parties: Federal Aviation Administration - ADs cited in the narratives: [AD 87-02-02](https://openairdocs.org/ad/87-02-02) (OpenAirDocs) - NTSB case key (mKey): 63460 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN06IA056 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/63460/pdf - Page: https://openairdocs.org/ntsb/DEN06IA056 ## Probable cause the failure of the elevator down cable due to an improperly routed cable by unknown maintenance personnel. A contributing factor was the improper inspection of the elevator cable by the operator's maintenance personnel. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - maintenance,installation - improper, other maintenance personnel (cause) - maintenance,inspection - improper, company maintenance personnel (contributing factor) - flt control syst,elevator control cable/rod - failure,total (cause) - precautionary landing - performed, pilot in command ## Analysis Prior to departure, the pilot completed the pre-takeoff checklist, which included checking the flight controls. While at 80-85 knots during the takeoff roll, the pilot "noticed pitch seemed very light. At rotation speed, [pilot] pulled back on yoke and aircraft left ground. At this point, yoke came back all the way back and aircraft began to quickly pitch upward." The pilot reported that moving the yoke forward had no effect and it felt disconnected from the elevators. The pilot quickly began to trim nose down and reduced power to stop excessive nose up pitch. After gaining marginal control of the aircraft, the pilot advised air traffic control he had a "flight control problem" and requested a return for landing. During the downwind leg to runway 17L, the pilot "experimented with various configurations...to determine the method of approach and landing." The pilot executed a gradual descent to the runway and landed uneventfully. Examination of the airplane by company maintenance personnel revealed that "the elevator down cable was improperly routed at the pulley in the vertical stab, just below the elevator bell crank. This caused the cable to wear against a guide until the cable failed." The aircraft underwent an inspection 10 days prior to the incident. According to the inspection checklist, the elevator cables and related components were inspected with no anomalies noted. Upon discovery of the improper routed cable, the operator checked the other 18 aircraft in their fleet. No discrepanices were found. ## Factual narrative On April 5, 2006, at 0623 mountain daylight time, a Swearingen SA226TC twin-engine turboprop airplane, N770S, operated as Key Lime 515, sustained an in-flight failure of an elevator control cable during initial climb from the Denver International Airport, Denver, Colorado. The airplane was registered to EDB Air, Inc., Wilsonville, Oregon, and operated by Key Lime Air, Inc., Englewood, Colorado. Visual meteorological conditions prevailed at the time of the incident. The unscheduled domestic cargo flight was being operated under the provisions of Title 14 Code of Federal Regulations Part 135 under an instrument flight rules flight plan. The airline transport pilot, who was the sole occupant, was not injured. The flight was originating at the time of the incident and was en route to Dodge City, Kansas. According to a statement provided by the pilot, prior to departure he completed the pre-takeoff checklist, which included checking the flight controls. While at 80-85 knots during the takeoff roll, the pilot "noticed pitch seemed very light. At rotation speed, [pilot] pulled back on yoke and aircraft left ground. At this point, yoke came back all the way back and aircraft began to quickly pitch upward." The pilot reported that moving the yoke forward had no effect and it felt disconnected from the elevators. The pilot quickly began to trim nose down and reduced power to stop excessive nose up pitch. After gaining marginal control of the aircraft, the pilot advised air traffic control he had a "flight control problem" and requested a return for landing. During the downwind leg to runway 17L, the pilot "experimented with various configurations...to determine the method of approach and landing." The pilot executed a gradual descent to the runway and landed uneventfully. Examination of the airplane by company maintenance personnel revealed that "the elevator down cable was improperly routed at the pulley in the vertical stab, just below the elevator bell crank. This caused the cable to wear against a guide until the cable failed." Upon discovery of the improper routed cable, the operator checked the other 18 aircraft in their fleet. No discrepancies were found. According to the aircraft maintenance records, the elevator cable was installed by another operator on February 4, 1998, as required by Airworthiness Directive 87-02-02. Key Lime Air, Inc. maintained the aircraft under a manufacturer approved continuous airworthiness inspection program. On March 24, 2006, the aircraft underwent a "Letter Check E" inspection. According to the inspection checklist, the elevator cables and related components were inspected with no anomalies noted. ## Aircraft - Registration: [N770S](https://openairdocs.org/deregistered/N770S-2017-06-27), registration cancelled 2017-06-27, S/N TC-248, built 1978 (OpenAirDocs) - Reported make and model: Swearingen SA226TC - Registry model: [Swearingen SA226TC](https://openairdocs.org/model/swearingen-sa226tc) (registry code 8780404) (OpenAirDocs) - Registry engine: [AiResearch TPE331 series](https://openairdocs.org/engine/airesearch-tpe331-series) (registry code 01514, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: TC-248 - Airframe hours: 32479 - Engines: Garrett TPE-331-10UA 715 hp turbo prop - Damage: No damage - Flight: Part 135 - Registered owner: Key Lime Air - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, March 1, 2006 - Departed: DEN, Denver, CO - Destination: DDC, Dodge City, KS - Flight plan: IFR - Airport: DEN, Denver Intl ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review November 1, 2005; seat: left; flight hours: 201 in the last 90 days, 82 in the last 30 days ## Weather - Conditions: Visual (VMC), Dawn - Wind: 210° at 12 knots, gusting 18 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 21 °F - Altimeter: 29.67 inHg - Observed at: DEN 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.