# NTSB ERA10LA005: Cessna 210, N9443T, Louisville, KY, October 4, 2009 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 4, 2009, 12:40 local (16:40 UTC) - Place: Louisville, KY - Coordinates: 38.228054, -85.663612 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.2281&lon=-85.6636&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report September 19, 2011 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 74847 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA10LA005 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74847/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74847 - Page: https://openairdocs.org/ntsb/ERA10LA005 ## Probable cause A malfunction of the landing gear extension system due to a fractured hydraulic line. Contributing to the accident was the inadequate inspection and maintenance of the hydraulic line. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Inspection](https://openairdocs.org/ntsb-findings/02061500): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 210, 1 case](https://openairdocs.org/ntsb-findings/02061500/cases.md?model=2073402), [All aircraft, 29 cases](https://openairdocs.org/ntsb-findings/02061500/cases.md) - [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 210, 2 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=2073402), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md) - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Cessna 210, 6 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=2073402), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Cessna 210, 6 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=2073402), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Cessna 210, 6 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=2073402), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Cessna 210, 6 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2073402), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Dragged wing/rotor/float/other](https://openairdocs.org/ntsb-events/093); cases with it: [Cessna 210, 1 case](https://openairdocs.org/ntsb-events/093/sequence.md?model=2073402), [All aircraft, 319 cases](https://openairdocs.org/ntsb-events/093/sequence.md) ## Analysis During a flight review, the commercial pilot attempted to lower the landing gear but, after the gear-up light extinguished, the gear down light would not illuminate. After multiple attempts to lower the landing gear, the flight instructor declared an emergency, took control of the airplane, and prepared for a gear-up landing. During touchdown, the airplane left the paved portion of the runway, and was substantially damaged. A postaccident examination of the landing gear system revealed that the hydraulic nose gear door actuator line on the right side of the aircraft failed due to fatigue at the flared end of the line. Review of maintenance records revealed that a high pressure electric fuel pump had been installed in close proximity to the failed line. No identification information or manufacturer information was present on the line and the straight sections of the tubing were not completely straight indicating that it had been bent by hand. A wear mark corresponding to significant contact with another object was observed on the aft side of the upper horizontal portion of the line which was covered by a plastic sleeve wrapped in electrical tape. It was likely that contact at that location produced excessive bending loads on the hydraulic line at the flare which lead to the fatigue fracture. Removal of the plastic sleeve which appeared to have been installed as a chaff guard revealed the existence of two other wear marks on the hydraulic line, one of which was approximately 50 percent of the wall thickness deep. The location of the wear marks corresponded to the location of the electric pump that had been installed and its fuel line fittings. According to the Federal Aviation Administration, tubing should not be nicked, cut, dented, collapsed, or twisted beyond approved limits. When inspection shows a line to be damaged or defective, the entire line should be replaced or, if the damaged section is localized, a repair section may be inserted. Minor dents and scratches in tubing may be repaired. Scratches or nicks not deeper than 10 percent of the wall thickness in aluminum alloy tubing, that are not in the heel of a bend, may be repaired by burnishing with hand tools. Lines with severe die marks, seams, or splits should be replaced. Any crack or deformity in a flare is unacceptable and cause for rejection. A dent less than 20 percent of the tube diameter is not objectionable unless it is in the heel of a bend. ## Factual narrative HISTORY OF FLIGHT On October 4, 2009, about 1240 eastern daylight time, a Cessna 210, N9443T, was substantially damaged during landing, after the landing gear failed to completely extend at Bowman Field Airport (LOU), Louisville, Kentucky. The certificated flight instructor and commercial pilot were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the instructional flight conducted under 14 Code of Federal Regulations Part 91. According to the flight instructor, the purpose of the flight was to conduct a flight review and instrument competency check for the commercial pilot. The takeoff was uneventful. During the flight which including holding, instrument approaches, and landings at nearby airports, the landing gear and flaps (both of which were hydraulically actuated) were cycled several times without incident. Upon returning to LOU, and being cleared for landing on runway 24, the commercial pilot attempted to lower the landing gear but, after the gear-up light extinguished, the gear down light would not illuminate, and "no wheels" were observed when looking out of the airplane's side windows. After advising the tower of the problem, they were "directed to orbit," south of the airport while they "worked on the problem." The circuit breaker for the landing gear "checked OK," and the flaps would not extend. The flight instructor also "pumped" the manual gear extension lever for "many minutes," without result. They next flew past the tower for a visual inspection and at the same time, the flight instructor noticed that the airplane and landing gear was creating a shadow on the ground. The shadow indicated to him by its outline, that the nose landing gear was partially extended, its doors were partially open, and the main landing gear was "slightly" extended. After multiple attempts to lower the landing gear, the flight instructor declared an emergency and asked for "fire trucks and EMS." He then took over control of the airplane while the commercial pilot stowed all of the unsecured items that were in the cockpit. Once the emergency vehicles were in position, the flight instructor flew a "no flaps approach," and touched down at the "minimum safe speed." The commercial pilot then "pulled" the mixture control, shutoff the magnetos, used the starter to move the propeller so it would not be damaged by ground contact, turned off the master switch, and shutoff the fuel, to reduce the chance of fire. As the airplane "scraped" down the runway, the airplane veered to the left, left the paved portion of the runway, tilted to the left, and came to rest with the left horizontal stabilizer and left wingtip contacting the ground. PERSONNEL INFORMATION According to FAA and pilot records, the flight instructor held a commercial pilot certificate with ratings for airplane single engine land, and instrument airplane. He reported 2878.7 total hours of flight experience. His most recent application for an FAA third-classmedical certificate was dated July 23, 2008. According to FAA records, the commercial pilot held ratings for airplane single engine land, and instrument airplane. His most recent application for an FAA third-class medical certificate was dated April 1, 2009. AIRCRAFT INFORMATION According to FAA and maintenance records, the airplane was manufactured in 1960. The airplane's most recent annual inspection was completed on December 12, 2008 and as part of that activity a new high pressure electrical fuel pump was installed in the nose wheel well. At that time the airplane had accrued 4,354.4 total hours of operation. METEOROLOGICAL INFORMATION The reported weather at LOU, at 1253, included: winds 220 degrees at 3 knots, visibility 10 miles, a few clouds at 3,800 feet, temperature 16 degrees C, dew point 6 degrees C, and an altimeter setting of 30.11 inches of mercury. AIRPORT INFORMATION According to the Airport Facility Directory, LOU had two runways oriented in a 6/24 and 15/33 configuration. Runway 24 was asphalt, in fair condition. The total length of the runway was 4,326 feet, and its width was 75 feet. WRECKAGE AND IMPACT INFORMATION Post accident examination by a Federal Aviation Administration (FAA) inspector revealed that the horizontal stabilizer had received substantial damage. Examination of the nose landing gear wheel well reveled that a considerable amount of hydraulic fluid was present on the visible surfaces of the interior of the nose landing gear wheel well. The right side of the nose wheel tire was also wet with hydraulic fluid, as was the strut assembly. Examination of the landing gear hydraulic lines in the nose gear wheel well area revealed that they were made of aluminum. Further examination also revealed that the nose gear door actuator line on the right side of the aircraft had separated at the ferrule and flare of the line. The "B" nut however, was still attached to the actuator, and the line was dripping hydraulic fluid. Examination of the rest of the hydraulic lines within the wheel well area exhibited no further indication of breakage or leaks. Examination of the main landing gear wheel wells revealed no visual signs of leakage or line breakage. TESTS AND RESEARCH Examination of the failed hydraulic line by the Safety Board investigators revealed that no aluminum tubing identification was present on the failed hydraulic line. The failed hydraulic line was fractured at the flared end which attached to the nose landing gear actuator port. The straight lengths of the hydraulic line were not perfectly straight and generally included slight bends along the length. A portion of the fracture surface was in flat planes perpendicular to the outer surface of the tube with curving crack arrest lines and ratchet marks, which are features consistent with fatigue. Further examination revealed that the fatigue emanated from multiple origins on the lower surface of the tube. The fatigue region covered approximately one third of thefracture surface, and the features were relatively rough, which along with the multiple origins were consistent with low-cycle fatigue. Beyond the fatigue boundary, the fracture features were rougher, and the fracture plane transitioned toward the aft direction. The changes in fracture plane were consistent with fracture under an upward bending load. Post-fracture rubbing and smearing was also observed across the surface. Crack arrest lines and transgranular features consistent with fatigue were observed in the fatigue region. The next approximately 1/3 of the fracture surface had a more dimpled appearance with some faint crack arrest lines, which was consistent with relatively high stress loading, possibly under cyclic loads. The remainder of the fracture surface was rough with dimple features consistent with overstress. A portion of the hydraulic line was covered with a longitudinally-split black flexible tube wrapped with black electrical tape. An area of the covered portion of the hydraulic line showed a mark where the black wrapping tape and part of the underlying flexible tube was worn away consistent with contact with another object. The contact area was located on the aft side of the hydraulic line in the upper horizontal length near the bend at the right end of the horizontal length. After removal of the black electrical tape and plastic sleeve, two other contact marks were discovered on the opposite side of the plastic sleeve. Examination of the underlying tubing also revealed the existence of two other wear marks, one of which exhibited a groove that was approximately 50 percent of the wall thickness deep. ADDITIONAL INFORMATION During review of photographs taken by the FAA it was discovered, that the mounting location of the high pressure electrical fuel pump that was installed as part of the maintenance activities associated with the annual inspection was located above and in close proximity to the failed hydraulic line. The contact marks which were discovered also were in close proximity to the fuel line fitting which were attached to the pump. According to Advisory Circular, AC-43-13-1B CHG 1, (Acceptable Methods, Techniques, and Practices, Aircraft Inspection and Repair), hydraulic and pneumatic systems should be inspected for leakage, worn or damaged tubing, worn or damaged hoses, wear of moving parts, security of mounting for all units, safetying, and any other condition specified by the maintenance manual. A complete inspection includes considering the age, cure date, stiffness of the hose, and an operational check of all subsystems. Tubing should not be nicked, cut, dented, collapsed, or twisted beyond approved limits. When inspection shows a line to be damaged or defective, the entire line should be replaced or, if the damaged section is localized, a repair section may be inserted. In replacing lines, tubing of the same size and material as the original line should be used. Minor dents and scratches in tubing may berepaired. Scratches or nicks not deeper than 10 percent of the wall thickness in aluminum alloy tubing, that are not in the heel of a bend, may be repaired by burnishing with hand tools. Lines with severe die marks, seams, or splits in the tube should be replaced. Any crack or deformity in a flare is unacceptable and cause for rejection. A dent less than 20 percent of the tube diameter is not objectionable unless it is in the heel of a bend. A severely-damaged line should be replaced; however, it may be repaired by cutting out the damaged section and inserting a tube section of the same size and material. ## Aircraft - Registration: [N9443T](https://openairdocs.org/deregistered/N9443T-2014-11-24), registration cancelled 2014-11-24, S/N 57243, built 1960 (OpenAirDocs) - Reported make and model: CESSNA 210 - Registry model: [Cessna 210](https://openairdocs.org/model/cessna-210) (registry code 2073402) (OpenAirDocs) - Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 57243 - Airframe hours: 4354 - Engines: CONT MOTOR I0-470-DCE 260 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 12, 2008 - Departed: LOU, Louisville, KY - Destination: LOU, Louisville, KY - Flight plan: Unknown - Airport: LOU, Bowman Field Airport, runway 24, 4,326 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 55; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review March 21, 2009; seat: right; flight hours: 2,979 total, 1,142 in this make and model, 2,838 as pilot in command, 12 in the last 90 days, 6 in the last 30 days - Pilot; age 51; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review October 4, 2009; seat: left; flight hours: 2,580 total, 477 in this make and model, 2,500 as pilot in command, 5 in the last 90 days, 3 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 43 °F - Altimeter: 30.11 inHg - Observed at: LOU ## 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 20091004050459A](https://openairdocs.org/incident/20091004050459A), Oct 4, 2009: Cessna 210, Louisville, KY, Substantial damage. On October 4, 2009, at 1640 eastern daylight time, a Cessna 210, N9443T, registered to a private owner, operating under title 14 code of federal regulations… ## Other investigations on N9443T (1) 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. - [NTSB UNK64X0138](https://openairdocs.org/ntsb/UNK64X0138), Jan 3, 1964: Cessna 210 (N9443T), Ojai, CA, substantial damage ## Docket (7 files) The files NTSB released with the investigation on June 30, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74847. 6.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 641 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40349901&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Witness Statements and Interview Summaries (item 2, .PDF, 281 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40349887&FileExtension=.PDF&FileName=Witness%20Statements%20and%20Interview%20Summaries-Redacted.PDF - Weather Reports and Records (KLOU METARS) (item 3, .PDF, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40349886&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records%20(KLOU%20METARS)-Master.PDF - Excerpt From Maintenance Records (item 4, .PDF, 315 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40349898&FileExtension=.PDF&FileName=Excerpt%20From%20Maintenance%20Records-Redacted.PDF - Materials Laboratory 15 - Factual Report 10-024 (item 5, .PDF, 132 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40327010&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2010-024-Master.PDF - FAA Photographs of Fractured Line (Contains 2 Photographs) (item 6, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40349890&FileExtension=.PDF&FileName=FAA%20Photographs%20of%20Fractured%20Line%20(Contains%202%20Photographs)-Master.PDF - NTSB Photographs of Fracture and Wear Marks (Contains 6 Photographs) (item 7, .PDF, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40349894&FileExtension=.PDF&FileName=NTSB%20Photographs%20of%20Fracture%20and%20Wear%20Marks%20(Contains%206%20Photographs)-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.