# NTSB CEN11LA192: Beech E-90, N51DN, Des Moines, IA, February 15, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 15, 2011, 09:30 local (15:30 UTC) - Place: Des Moines, IA - Coordinates: 41.533889, -93.663055 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.5339&lon=-93.6631&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-climb to cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report July 21, 2011 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 78361 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA192 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78361/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78361 - Page: https://openairdocs.org/ntsb/CEN11LA192 ## Probable cause The improper installation of the right aileron by maintenance personnel. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Beech E-90, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=1152914), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) - [Wing structure: ailerons](https://openairdocs.org/ntsb-findings/01035751): Aircraft › Aircraft structures · Incorrect service/maintenance (probable cause); cases with it: [Beech E-90, 1 case](https://openairdocs.org/ntsb-findings/01035751/cases.md?model=1152914), [All aircraft, 12 cases](https://openairdocs.org/ntsb-findings/01035751/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-climb to cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Beech E-90, 2 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=1152914), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis The airplane had recently undergone maintenance, which included an inspection of the ailerons requiring removal, reinstallation, and a functional check. Prior to the test flight, the pilot performed a pre-flight inspection of the airplane and a flight control free and correct check with no anomalies noted. While executing a turn at flight level 180, the right aileron departed the airplane. The airplane landed without further incident. Examination of the airplane revealed the inboard and middle airframe aileron hinge brackets were attached to the aft spar, intact, and showed no visible damage. The outboard airframe aileron hinge bracket was pulled and separated from the aft spar. The aileron was not located. Based on the condition of the hinge brackets, the evidence indicated the aileron bolts were not properly engaged in the aileron nut plates which caused the bolts to fall out and the aileron to depart the airplane. ## Factual narrative On February 15, 2011, at 0930 central standard time, a Beech E-90 airplane, N51DN, sustained substantial damage when the right aileron departed in-flight near Des Moines, Iowa. The airline transport pilot and pilot-rated maintenance crew member were not injured. The airplane was registered to and operated by D-W Corporation, Des Moines, Iowa. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 test flight. The local flight departed the Des Moines International Airport (DSM), Des Moines, Iowa, at 0900. The airplane had recently underwent maintenance, which included a 800-hour inspection of the ailerons requiring removal, reinstallation, and a functional check. Prior to the test flight, the pilot performed a pre-flight inspection of the airplane, and a flight control free and correct check with no anomalies noted. The airplane departed runway 13L, and the pilot made a right turn to 160 degrees. Shortly thereafter, the pilot made a right turn to 270 degrees and was cleared to flight level (FL) 180. While level at FL180 with the autopilot engaged, the pilot and maintenance crew member performed various checks with the engines and flight instruments. After completing the checks, the pilot requested a left 180-degree turn back to DSM. Air traffic control approved the turn and the pilot selected the autopilot heading switch for a left turn to DSM. Approximately 140 degrees into the turn, the autopilot jerked, stabilized, and jerked again during the turn to level off. The pilot then noticed the right aileron had departed the airplane. The airplane landed at DSM without further incident. Examination of the airplane revealed the inboard and middle airframe aileron hinge brackets were attached to the aft spar, intact, and showed no visible damage. The outboard airframe aileron hinge bracket was pulled and separated from the aft spar. The aileron was not located. The aileron is attached to each of the three hinge brackets with two upper and two lower bolts (4 total) that engage into nut plates that are mounted on the aileron. The King Air 90 Series Maintenance Manual aileron installation procedure states, in part, "Carefully align the three hinges with the aileron and install the bolts in each hinge bracket and the aileron. Pull on the aileron straight away from the wing. If any movement is detected, carefully check the bolt installation." ## Aircraft - Registration: [N51DN](https://openairdocs.org/aircraft/N51DN), registered now, S/N LW-7, built 1972 (OpenAirDocs) - Reported make and model: BEECH E-90 - Registry model: [Beech E-90](https://openairdocs.org/model/beech-e-90) (registry code 1152914) (OpenAirDocs) - Registry engine: [U/A Canada PT6A-27-28](https://openairdocs.org/engine/u-a-canada-pt6a-27-28) (registry code 61504, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: LW-7 - Airframe hours: 9353 - Engines: P&W Canada PT6A-27-28 680 horsepower turbo prop; U/A CANADA PT6A-27-28 680 horsepower turbo prop - Damage: Substantial damage - Flight: Flight test, Part 91 - Operator: D-W Corporation - Registered owner: D-W Corporation - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, February 14, 2011, 0 hours before - Departed: DSM, Des Moines, IA - Destination: DSM, Des Moines, IA - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; injuries: none; flight instructor, airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review January 26, 2011; seat: left; flight hours: 15,449 total, 329 in this make and model, 13,037 as pilot in command, 60 in the last 90 days, 49 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 170° at 13 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 41 °F, dew point 32 °F - Altimeter: 30.03 inHg - Observed at: DSM, 45 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20110215001719A](https://openairdocs.org/incident/20110215001719A), Feb 15, 2011: Beech E-90, Des Moines, IA, Substantial damage. On 2/15/2011 the aircraft departed Des Moines international airport on a test flight for purposes unrelated to the accident. Approximately 20 minutes into the… ## Docket (7 files) The files NTSB released with the investigation on May 27, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78361. 2.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 241 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40348050&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Pilot Statement (item 2, .PDF, 17 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40348051&FileExtension=.PDF&FileName=Pilot%20Statement-Redacted.PDF - Airframe Logbook Entry (item 3, .PDF, 868 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40348052&FileExtension=.PDF&FileName=Airframe%20Logbook%20Entry-Redacted.PDF - King Air Maintenance Manual Excerpt (item 4, .PDF, 41 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40348054&FileExtension=.PDF&FileName=King%20Air%20Maintenance%20Manual%20Excerpt-Master.PDF - View of Outboard Aileron Hinge (item 5, .PDF, 338 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40348058&FileExtension=.PDF&FileName=View%20of%20Outboard%20Aileron%20Hinge-Master.PDF - View of Inboard Aileron Hinge (item 6, .PDF, 308 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40348067&FileExtension=.PDF&FileName=View%20of%20Inboard%20Aileron%20Hinge-Master.PDF - View of Aft Right Wing (item 7, .PDF, 371 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40348068&FileExtension=.PDF&FileName=View%20of%20Aft%20Right%20Wing-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.