# NTSB CEN15IA076: Cessna 182S, N661SP, Springfield, IL, December 10, 2014 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: December 10, 2014, 14:40 local (20:40 UTC) - Place: Springfield, IL - Coordinates: 39.844444, -89.67778 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.8444&lon=-89.6778&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report July 7, 2015 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Textron Aviation, FAA - NTSB case key (mKey): 90485 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN15IA076 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/90485/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=90485 - Page: https://openairdocs.org/ntsb/CEN15IA076 ## Probable cause The improper installation of a doubler patch, which prevented the right flap from actuating and moving properly and led to the subsequent interference with the aileron. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wing structure: trailing edge flaps](https://openairdocs.org/ntsb-findings/01035753): Aircraft › Aircraft structures · Failure (probable cause); cases with it: [All aircraft, 33 cases](https://openairdocs.org/ntsb-findings/01035753/cases.md) - [Wing structure: plates/skins (on wing)](https://openairdocs.org/ntsb-findings/01035730): Aircraft › Aircraft structures · Incorrect service/maintenance (probable cause); cases with it: [All aircraft, 11 cases](https://openairdocs.org/ntsb-findings/01035730/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Maneuvering: 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 During a proficiency flight for one of the pilots, he was demonstrating a slow-flight recovery procedure, and he added power and began retracting the flaps. When the flaps passed through 10 degrees toward fully retracted, the pilot felt an uncommanded right yoke control movement. As the pilot applied more pressure to the control yoke to maintain level flight, both pilots heard a loud pop, and the uncommanded right yoke control movement stopped. The pilots assessed the airplane and noted that the right flap was buckled. They then conducted a precautionary landing without incident. A postaccident examination of the airplane found that the inboard portion of the right flap had become dislodged from its track and that the flap had shifted outboard and contacted the aileron. Further examination of the flap system found that a doubler patch had been improperly installed on the lower trailing edge skin; the improper installation altered the curvature of the lower trailing edge skin and infringed on the normal actuation of the flap rollers. Both the inboard and outboard brackets surrounding the flap track had fractured due to the repeated stress applied during the flap roller actuation. A review of the public agency's fleet of airplanes found similar curvature of the lower trailing edge skin and bracket damage due to the improper installation of doubler patches. ## Factual narrative On December 10, 2014, about 1440 central standard time, a Cessna 182S, N661SP, had a flap malfunction that interfered with the aileron near Springfield, Illinois. The commercial pilots were not injured and the airplane had minor damage. The airplane was registered to and operated by the Illinois State Police, Springfield, Illinois, as a public use airplane flight. Visual meteorological conditions prevailed for the flight.According to a statement provide by the Illinois State Police, the pilots were performing a proficiency check for one of the pilots. While demonstrating slow flight recovery procedures, the airplane was configured with flaps fully extended. During the recovery procedure, power was added to the airplane and pilot began retracting the flaps. As the airplane passed through about 80 knots indicated airspeed and the flaps were retracted from 10 degrees to fully retracted, the pilot felt the yoke being pushed to the right. The pilot ensured that the other pilot was not also on the controls and confirmed that the autopilot was off. As more control authority was needed to maintain level flight, both pilot heard a popping sound and the uncommanded right yoke control ceased. The pilot assessed the airplane and noted that the right flap was buckled. They performed a precautionary landing without incident. A postaccident inspection of the airplane found that the inboard portion of the right flap had become dislodged from its track and the flap had shifted outboard and had contacted the aileron. Further examination of the flap system found cracks in both inboard and outboard brackets surrounding the inboard flap track, with the inboard bracket being completely fractured. Both brackets had been bent downwards. Paint abrasions were found on the brackets consistent with contact from the flap roller support arm. At a time prior to the accident, doubler patches had been added to the lower trailing edge skin in order to repairs cracks in the area where rivets were attached. These doublers flattened the curve of the lower trailing edge skin. A review of other agency maintained airplane found similar discrepancies with regards the curvature of the lower trailing edge skin and bracket damage. ## Aircraft - Registration: N661SP (not matched to a registry record) - Reported make and model: CESSNA 182S - Category: Airplane - Serial number: 18280825 - Year built: 2000 - Airframe hours: 6417 - Engines: Lycoming IO-540-AB1A5 230 horsepower reciprocating - Damage: Minor damage - Flight: Public aircraft - local, Public use - Operator: Illinois State Police - Registered owner: Illinois State Police - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 22, 2014, 75 hours before - Departed: Springfield, IL - Destination: Springfield, IL - Equipment: Stall warning system, Auto-pilot ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review December 9, 2014; seat: right; restraint: 3-point; flight hours: 3,850 total, 2,750 in this make and model, 3,750 as pilot in command, 17 in the last 90 days, 12 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 1,900 ft overcast - Temperature: 34 °F, dew point 25 °F - Altimeter: 30.31 inHg - Observed at: KSPI ## 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 20141210020979I](https://openairdocs.org/incident/20141210020979I), Dec 10, 2014: Cessna 182S, Springfield, IL, Minor damage. Following slow flight maneuvers, the pilot increased power and started bring the flaps up in five degree increments. The pilot felt the aircraft begin to roll… ## Docket (4 files) The files NTSB released with the investigation on June 3, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=90485. 8.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 4.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40427352&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Photo 1 Flap Damage (item 2, .PDF, 957 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40427353&FileExtension=.PDF&FileName=Photo%201%20Flap%20Damage-Master.PDF - Photo 2 Installed Doubler (item 3, .PDF, 3.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40427354&FileExtension=.PDF&FileName=Photo%202%20Installed%20Doubler%0D%0A-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 4, .PDF, 271 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40427358&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.