# NTSB ERA13LA058: Cessna 172RG, N9985B, Lexington, KY, November 15, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: November 14, 2012, 19:27 local (Nov 15, 2012, 00:27 UTC) - Place: Lexington, KY - Coordinates: 38.035278, -84.605278 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.0353&lon=-84.6053&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report April 10, 2014 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 85596 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA13LA058 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85596/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85596 - Page: https://openairdocs.org/ntsb/ERA13LA058 ## Probable cause The rupture of the landing gear’s hydraulic pressure hose, which resulted in the depletion of all of the hydraulic fluid, and the inability of the landing gear to raise or lower. Contributing to the accident was the installation of an unapproved hydraulic hose by unknown maintenance personnel. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [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 172RG, 10 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=2072438), [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 172RG, 10 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=2072438), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) - [Fluids: hydraulic fluid](https://openairdocs.org/ntsb-findings/01071015): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Cessna 172RG, 3 cases](https://openairdocs.org/ntsb-findings/01071015/cases.md?model=2072438), [All aircraft, 33 cases](https://openairdocs.org/ntsb-findings/01071015/cases.md) - [Maintenance: replacement](https://openairdocs.org/ntsb-findings/02062020): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 172RG, 1 case](https://openairdocs.org/ntsb-findings/02062020/cases.md?model=2072438), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/02062020/cases.md) - [Maintenance/inspections](https://openairdocs.org/ntsb-findings/01010500): Aircraft › Aircraft handling/service · Incorrect service/maintenance (probable cause); cases with it: [Cessna 172RG, 1 case](https://openairdocs.org/ntsb-findings/01010500/cases.md?model=2072438), [All aircraft, 103 cases](https://openairdocs.org/ntsb-findings/01010500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Cessna 172RG, 11 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=2072438), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing-flare/touchdown: Landing gear not configured](https://openairdocs.org/ntsb-events/095); cases with it: [Cessna 172RG, 15 cases](https://openairdocs.org/ntsb-events/095/sequence.md?model=2072438), [All aircraft, 584 cases](https://openairdocs.org/ntsb-events/095/sequence.md) - [Landing-landing roll: Dragged wing/rotor/float/other](https://openairdocs.org/ntsb-events/093); cases with it: [Cessna 172RG, 1 case](https://openairdocs.org/ntsb-events/093/sequence.md?model=2072438), [All aircraft, 319 cases](https://openairdocs.org/ntsb-events/093/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Cessna 172RG, 4 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=2072438), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis Upon arrival at the intended destination airport during an instructional flight, the pilot receiving instruction attempted to extend the airplane's landing gear. Only the nose gear and the left main landing gear extended and locked in the down position. Both pilots reported they attempted to retract the landing gear; however, the left main landing gear remained in the down and locked position and the nose landing gear's position could not be determined. The flight instructor reported that he performed the emergency gear extension procedure specified in the airplane's flight manual, but the right main landing gear did not extend or lock into position. The pilots elected to divert to a nearby airport. During the landing roll, the airplane veered off the runway, resulting in substantial damage to the elevator. An examination of the airplane revealed that a landing gear pressure hose had ruptured and the hydraulic fluid was depleted. It was constructed of material similar to that used in the automotive industry, thus, the hose likely was not an approved airplane part. No logbook entry was provided that disclosed when the hose was replaced or inspected. Because of the rupture, the lack of hydraulic fluid within the system precluded the right main landing gear from extending and locking as well as the left main and nose landing gear from retracting. ## Factual narrative On November 14, 2012, about 1915 eastern standard time, a Cessna 172RG, N9985B, was substantially damaged while landing after diverting to Blue Grass Airport (LEX), Lexington, Kentucky. Night visual meteorological conditions prevailed and an instrument flight rules flight plan was filed. The certificated flight instructor (CFI) and private pilot were not injured. The airplane was owned by Christensen Aviation, Inc. and was operated by Eastern Kentucky University. The instructional flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91 and had departed from Madison Airport (I39), Richmond, Kentucky at 1730 with an intended destination of Warren County Airport/John Lane Field (I68), Lebanon, Ohio. According to both pilots, during the approach to I68, the left main and nose landing gear extended; however, the right main landing gear would not extend. An attempt was made to raise the landing gear; however, the left main landing gear and nose gear would not retract. Attempt was made to extend the landing gear with the emergency gear extension; however, no resistance was felt while manually pumping. Determination was made to divert to LEX to perform an emergency landing; upon landing, the airplane veered off the runway and came to rest in the grass. According to a Federal Aviation Administration inspector who examined the wreckage, the right stabilator was substantially damaged. Further examination of the hydraulic reservoir for the landing gear revealed that it was devoid of hydraulic oil. The airplane's landing gear system was examined and a hydraulic hose was observed with a full thickness rupture as well as evidence of hydraulic oil around the hose's rupture. Examination of the hose by the NTSB Materials Laboratory revealed the full thickness rupture and secondary parallel fractures, feather –like structures and micropeaks. The fractures were consistent with environmental stress crack growth. Examination of the stress crack growth revealed the initial fracture likely initiated on the interior near the collar on the fitting. Examination of the hose material revealed that it was a polyester/polyurethane co-polymer and the cloth sleeving material was consistent with polyester and contained similar characteristics of the polyester component in the hose material. The hose construction did not match any of the three specifications provided by the manufacturer, and had similar material makeup of hoses within the automotive industry. According to the airframe maintenance records, during a 100-hour inspection, on November 2, 2012 the landing gear retraction test was performed three times. During the same inspection the emergency landing gear extension was checked. Following the inspections the airplane was determined to be in an airworthy condition. According to the "Cessna 172RG Pilot's Operating Handbook", Chapter 7 "Aircraft & Systems Descriptions", states in part; "The landing gear extension, retraction, and main geardown lock release operation is accomplished by hydraulic actuators powered by an electrically-driven hydraulic power pack… a hand-operated hydraulic pump, located between the front seats, is provided for manual extension of the landing gear in the event of a hydraulic system failure. The landing gear cannot be retracted with the hand pump…" Chapter 3 "Emergency Procedures" contains a "Landing Gear Fails to Extend" checklist which defines the procedures as: 1. Master Switch – ON 2. Landing Gear Lever – DOWN 3. Landing Gear and Gear Pump Circuit Breakers – IN 4. Emergency Hand Pump – EXTEND HANDLE, and PUMP (perpendicular to handle until resistance becomes heavy – about 35 cycles) 5. Gear Down Light – ON 6. Pump Handle – STOW According to a Cessna Service Letter (SN85-54), dated November 27, 1985, the landing gear hydraulic system hoses were revised from a "5 year overhaul/replacement interval" to an "on condition overhaul replacement interval." According to the Cessna Aircraft Company Continued Airworthiness Program, the Hydraulic Hose was to be inspected every 1000 hours or every 3 years. The maintenance information provided to the NTSB could not accurately determine if the hydraulic hose had been inspected in the required time frame. ## Aircraft - Registration: [N9985B](https://openairdocs.org/aircraft/N9985B), registered now, S/N 172RG1107, built 1982 (OpenAirDocs) - Reported make and model: CESSNA 172RG - Registry model: [Cessna 172RG](https://openairdocs.org/model/cessna-172rg) (registry code 2072438) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 172RG1107 - Engines: LYCOMING O-360-F1A6 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Eastern Kentucky University - Registered owner: Christiansen Aviation Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, November 2, 2012 - Departed: I39, Richmond, KY - Destination: I68, Lebanon, OH - Flight plan: IFR - Airport: LEX, Blue Grass Airport, runway 04, 7,003 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 23; injuries: none; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review March 20, 2012; seat: right; restraint: 3-point; flight hours: 1,014 total, 70 in this make and model, 945 as pilot in command, 126 in the last 90 days, 39 in the last 30 days, 4 in the last 24 hours - Pilot; age 20; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: left; restraint: 3-point; flight hours: 158 total, 16 in this make and model, 125 as pilot in command, 24 in the last 90 days, 6 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 20° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 36 °F, dew point 28 °F - Altimeter: 30.38 inHg - Observed at: LEX ## 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 20121114027949A](https://openairdocs.org/incident/20121114027949A), Nov 14, 2012: Cessna 172RG, Lexington, KY, Substantial damage. N9985B a Cessna 172RG was on a IFR flight plan to I68, lebanon-warren co. airport when they selected gear down and got an unsafe indication. Emergency gear… ## Docket (9 files) The files NTSB released with the investigation on March 13, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85596. 7.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 739 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40405708&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Airplane Most Recent 100-hour Inspection (item 2, .PDF, 190 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40405709&FileExtension=.PDF&FileName=Airplane%20Most%20Recent%20100-hour%20Inspection-Redacted.PDF - Cessna Service Newsletter for Hydraulic Hoses (item 3, .PDF, 93 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40405803&FileExtension=.PDF&FileName=Cessna%20Service%20Newsletter%20for%20Hydraulic%20Hoses-Redacted.PDF - Excerpt from Cessna Continued Airworthiness Program (item 4, .PDF, 152 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40405804&FileExtension=.PDF&FileName=Excerpt%20from%20Cessna%20Continued%20Airworthiness%20Program-Master.PDF - Materials Laboratory 15 - Factual Report 13-073 (Hydraulic hose) (item 5, .PDF, 5 photos, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404923&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2013-073%20(Hydraulic%20hose)-Master.PDF - Memorandum of Record - Lexington Weather (item 6, .PDF, 80 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382233&FileExtension=.PDF&FileName=Memorandum%20of%20Record%20-%20Lexington%20Weather-Master.PDF - Photo 1: Right Side of Airplane At Rest (Courtesy of the Lexington Airport Police) (item 7, .PDF, 508 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382235&FileExtension=.PDF&FileName=Photo%201%3A%20Right%20Side%20of%20Airplane%20At%20Rest%20(Courtesy%20of%20the%20Lexington%20Airport%20Police)-Master.PDF - Photo 2: Aft View of Airplane At Rest (Courtesy of the Lexington Airport Police Department) (item 8, .PDF, 416 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382236&FileExtension=.PDF&FileName=Photo%202%3A%20Aft%20View%20of%20Airplane%20At%20Rest%20(Courtesy%20of%20the%20Lexington%20Airport%20Police%20Department)-Master.PDF - Photo 3: Hydraulic Line at Nose Gear with Leak (Courtesy of the FAA) (item 9, .PDF, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382237&FileExtension=.PDF&FileName=Photo%203%3A%20Hydraulic%20Line%20at%20Nose%20Gear%20with%20Leak%20(Courtesy%20of%20the%20FAA)-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.