# NTSB CEN16IA103: Cessna 560, N774SB, Dallas, TX, February 9, 2016 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: February 9, 2016, 08:00 local (14:00 UTC) - Place: Dallas, TX - Coordinates: 32.847221, -96.851669 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.8472&lon=-96.8517&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed, report April 20, 2020 - Report: Approved by Office Director - NTSB office: Central Region - Parties: SevenBar Aviation, FAA - NTSB case key (mKey): 92705 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN16IA103 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/92705/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=92705 - Page: https://openairdocs.org/ntsb/CEN16IA103 ## Probable cause The loss of aileron trim due to the lack of separation between the cannon head on the back of autopilot cannon plug and the aileron trim tab control gear. Contributing to the incident was the lack of guidance in the airplane maintenance manual to verify separation of the autopilot control head and aileron trim tab control gear before completing work on the control pedestal. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system: aileron control system](https://openairdocs.org/ntsb-findings/01022710): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Cessna 560, 1 case](https://openairdocs.org/ntsb-findings/01022710/cases.md?model=2076750), [All aircraft, 45 cases](https://openairdocs.org/ntsb-findings/01022710/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 560, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=2076750), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Cessna 560, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=2076750), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) ## Analysis The airline transport pilot and the copilot, who was the pilot flying, were conducting an on-demand air taxi flight with three passengers onboard. The copilot reported that, during the takeoff rotation, he had difficulty maintaining the runway heading and that the airplane experienced a right rolling tendency. He noted that, while continuing to take off and as the airspeed was increased, the pressure required on the control yoke to maintain level attitude also increased. The copilot transferred control of the airplane to the pilot who then attempted to adjust the aileron trim; however, the trim control knob would not move, and the trim indicator appeared centered. The flight crew declared an emergency to air traffic control and requested to return to the airport. When the airspeed was decreased during the approach, the right roll control pressure decreased, and the flight crew was able to free the aileron trim control and land uneventfully. Postincident examination of the aileron trim system revealed that the cannon plug on the back of the autopilot control head was contacting the aileron trim control gear within the cockpit pedestal. Additionally, the wires extending from the cannon plug exhibited chafing. The day before the incident, maintenance personnel had inspected the cockpit pedestal, which required removal of the control heads for the autopilot from the pedestal. The pedestal was then cleaned and reassembled. Therefore, it is likely that, when maintenance personnel reassembled the pedestal, they did not ensure that the cannon head on the back of the autopilot control head and the aileron trim control gear were adequately separated, which resulted in binding of the aileron trim control gear and chafing of the wiring and led to the in-flight loss of aileron trim. A review of the airplane maintenance manual revealed that the Control Pedestal Area General Inspection procedures did not include a step to ensure that sufficient separation existed between the autopilot control head/wiring harness and the aileron trim tab control gear. The lack of guidance in the maintenance manual to verify separation of the autopilot control head and aileron trim tab control gear before completing work on the control pedestal likely contributed to the incident. Following the incident, the airplane manufacturer implemented a change to the maintenance manual to include a step to wrap the wiring harness in a protective sleeve and verify separation between the autopilot control head/wiring harness and the aileron trim tab control. The manufacturer also issued a mandatory service letter that provided instructions to inspect for damage and correct wire harness positioning. ## Factual narrative On February 9, 2016, about 0800 central standard time, a Cessna 560 Encore airplane, N774SB, experienced a flight control malfunction during the takeoff from Dallas Love Field Airport (DAL), Dallas, Texas. The two flight crewmembers and three passengers on-board were not injured. The airplane did not sustain damage. The airplane was registered to Bridgeway Enterprises, Inc. and operated by SevenBar Aviation under the provisions of Title 14 Code of Federal Regulations Part 135 as an on-demand air taxi. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan. The flight was destined for Mc Curtain County Regional Airport (4O4), Idabel, Oklahoma. The copilot stated that during takeoff rotation he had difficulty maintaining runway heading and the airplane experience a tendency to roll to the right. As speed was increased, the pressure required on the control yoke to maintain level attitude increased. The copilot transferred control of the airplane to the Captain who experienced the same flight control difficulty. The Captain attempted to adjust the aileron trim; however, the trim control knob would not move, and the trim indicator appeared centered. The flight crew contacted air traffic control, requested to return to DAL, and declared an emergency. When the airspeed was decreased during the approach, the right roll control pressure decreased, and the flight crew was able to free the aileron trim control. The flight crew landed the airplane at DAL without further incident. The day before the flight, on February 8, 2016, maintenance personnel had completed an inspection of the cockpit pedestal; which required removal of the control heads for the autopilot, the flight management systems, the multi-functional displays, etc. from the pedestal. The pedestal was cleaned and reassembled. After the crew returned from the incident flight stating the aileron trim tab control knob was "jammed" and "wanted to roll right," the mechanic opened the pedestal area and observed the cannon plug on the back of the autopilot control head was contacting the aileron trim gear mechanism. Additionally, the wires extending from the cannon plug exhibited chaffing. Maintenance personnel then inspected the aileron trim system for any other possible anomalies, finding the trim indicator position in the cockpit indicted a neutral position when the trim was elevated above the trailing edge of the aileron. Maintenance personnel adjusted the trim tab and verified its' correct indication in the cockpit. A review of the Cessna Model 560 Maintenance Manual revealed there was no step in the maintenance procedure for "Control Pedestal Area General Inspection" to ensure there was enough separation between the autopilot control head/wiring harness and the aileron trim tab control gearing to prevent interference. Following the incident, in August 2016, Textron Aviation implemented a change to the C560 and C550 airplane'smaintenance manuals to include a step to wrap the wiring harness in a protective sleeve and verify separation between the autopilot control head/wiring harness and the aileron trim tab control. Textron Aviation also issued a mandatory Service Letter for the C560 and C550 that provided instructions to inspect for damage and correct wire harness positioning. ## Aircraft - Registration: [N774SB](https://openairdocs.org/aircraft/N774SB), registered now, S/N 560-0684, built 2005 (OpenAirDocs) - Reported make and model: Cessna 560 (Undesignat) - Registry model: [Cessna 560](https://openairdocs.org/model/cessna-560) (registry code 2076750) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PW535A](https://openairdocs.org/engine/pratt-whitney-canada-pw535a) (registry code 52134, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 560-0684 - Year built: 2005 - Airframe hours: 2512.3 - Engines: Pratt & Whitney Canada PW535A 3400 lbs thrust turbo fan; Pratt & Whitney Canada PW535A 3400 lbs thrust turbo fan - Damage: No damage - Flight: Part 135 - Operator: Seven Bar Flying Service Inc - Registered owner: Bridgeway Enterprises Inc - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, February 8, 2016 - Departed: DAL, Dallas, TX - Destination: 4O4, Idabel, OK - Flight plan: IFR - Airport: DAL, Dallas Love Field, runway 31R, 7,752 × 150 ft, concrete - Equipment: Satellite tracking device, Stall warning system, Angle of attack indicator, Auto-pilot, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: none; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review October 8, 2015; seat: right; restraint: 4-point; flight hours: 9,025 total, 300 in this make and model, 8,219 as pilot in command, 53 in the last 90 days, 13 in the last 30 days - Co-pilot; age 49; 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 January 29, 2016; seat: left; restraint: 4-point; flight hours: 4,031 total, 23 in this make and model, 3,880 as pilot in command, 56 in the last 90 days, 13 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Temperature: 37 °F, dew point 12 °F - Altimeter: 30.29 inHg - Observed at: KDAL ## 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 20160209006999I](https://openairdocs.org/incident/20160209006999I), Feb 9, 2016: Cessna 560, Dallas, TX, No damage. 02/09/2016, N774SB, Cessna citation 560, s/ 560-0684, during climb-out, crew experienced increasing right roll as airspeed increased. Unable to move aileron… ## Docket (6 files) The files NTSB released with the investigation on October 18, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=92705. 3.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476865&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Captain's Statement (item 2, .PDF, 145 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476866&FileExtension=.PDF&FileName=Captain%27s%20Statement-Master.PDF - First Officer's Statement (item 3, .PDF, 207 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476867&FileExtension=.PDF&FileName=First%20Officer%27s%20Statement-Master.PDF - Aircraft Maintenance Technician's Statement (item 4, .PDF, 184 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476868&FileExtension=.PDF&FileName=Aircraft%20Maintenance%20Technician%27s%20Statement-Master.PDF - Cessna 560 Maintenance Manual Excerpt (item 5, .PDF, 535 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476869&FileExtension=.PDF&FileName=Cessna%20560%20Maintenance%20Manual%20Excerpt-Master.PDF - Statement of Party Representatives to NTSB Investigation (SevenBar) (item 6, .PDF, 323 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476870&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation%20(SevenBar)-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.