# NTSB ERA11LA239: Beech BE99, N899AE, Cedartown, GA, April 10, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 10, 2011, 11:45 local (15:45 UTC) - Place: Cedartown, GA - Coordinates: 34.017776, -85.141113 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.0178&lon=-85.1411&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: 1 uninjured - Status: Completed, report February 23, 2012 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO, Hawker-Beechcraft Corporation - NTSB case key (mKey): 78834 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA11LA239 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78834/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78834 - Page: https://openairdocs.org/ntsb/ERA11LA239 ## Probable cause The failure of the left main landing gear bearings and supports due to inadequate lubrication by unknown maintenance personnel. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Beech 99, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=1154002), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) - [Landing gear system: landing gear actuator](https://openairdocs.org/ntsb-findings/01023233): Aircraft › Aircraft systems · Not specified (probable cause); cases with it: [Beech 99, 1 case](https://openairdocs.org/ntsb-findings/01023233/cases.md?model=1154002), [All aircraft, 54 cases](https://openairdocs.org/ntsb-findings/01023233/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: [Beech 99, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=1154002), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Approach: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Beech 99, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=1154002), [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: [Beech 99, 2 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=1154002), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot received an unsafe landing gear indication for the left main landing gear when he configured the airplane for landing. He cycled the gear and then attempted a manual extension, both without success. The pilot then completed the landing on the nose and right main landing gear. A postaccident examination of the left main landing gear actuator revealed that the supports for the actuator bearings lacked lubrication and that the bearings displayed wear due to inadequate lubrication. The overhauled actuator had accumulated 377.5 hours and 285 cycles since overhaul and was installed about 31 months before the accident; the manufacturer's maintenance manual prescribed lubrication of the retract actuator and actuator support bearings every 1,000 cycles or 30 months (whichever occurs first). It could not be determined if inadequate lubrication was applied at installation or if a loss of lubrication was not detected in subsequent inspections. The manufacturer’s maintenance manual cautioned: "When washing the airplane with soap and water, use special care to avoid washing grease away from lubricated area. After washing the wheel well areas with solvent, lubricate all lubrication points. Premature wear of the lubricated surfaces may result if these precautions are not observed." ## Factual narrative On April 10, 2011, about 1145 eastern daylight time, a Beech Model 99, N899AE, was substantially damaged during landing at Polk County Airport (4A4), Cedartown, Georgia. The airplane was registered to Aerodynamics Worldwide, Inc., and operated by Skydive Georgia, under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the local sport-parachuting flight that departed 4A4 about 1110. In a telephone interview, the pilot explained that he was returning to 4A4 after deploying parachutists. He configured the airplane for landing, and only two of the three landing gear lamps illuminated when he lowered the landing gear. The pilot confirmed that he had an unsafe gear indication on the left main landing gear. He then actuated the test switch, and all three lamps illuminated, demonstrating that he did not have a burned-out indicating lamp. The pilot then retracted the landing gear, and attempted to lower it again. On this attempt, no lamps illuminated. He then lowered the gear manually, and again received an unsafe indication on the left main landing gear. While lowering the gear, he said the pressure required to pump the gear down became greater and greater until "something gave way." The pilot completed the landing on the nose and right main landing gear, which resulted in substantial damage to the left wing and fuselage. The pilot held a commercial pilot certificate with ratings for airplane single engine, multiengine, and instrument airplane. He held a flight instructor certificate with ratings for airplane single engine, multiengine, and instrument airplane. His most recent Federal Aviation Administration (FAA) second class medical certificate was issued March 16, 2011. The pilot reported 6,800 hours of total flight experience, of which 8 hours was in the accident airplane make and model. According to FAA records, an airworthiness certificate was issued for the airplane in 1968. The airplane had accrued 48,953 total aircraft hours. The most recent 100-hour inspection was completed February 14, 2011, at 48,945 total aircraft hours. Examination of the airplane at the scene by an FAA inspector revealed that the left main landing gear actuator displayed evidence of wear or failure where the drive entered the actuator housing. The floor access panel to the landing gear motor was removed, the manual landing gear extend feature was found engaged, and the circuit breaker for the motor was "popped." On June 21, 2011, the examination of the left landing gear actuator was supervised by the FAA inspector at 4A4. The overhauled actuator was installed on August 31, 2008, at 48,575 aircraft hours and 66518 cycles. The actuator accumulated 377.5 hours and 285 cycles since overhaul. Examination revealed that the supports for the actuator bearings lacked lubrication, and that the bearings also displayed wear due to inadequate lubrication. Due to the calendar months, aircraft hours,and cycles that had elapsed since the installation of the actuator, it could not be determined if the lubrication was inadequate at installation or if subsequent inspections failed to reveal a loss of lubrication (grease). According to the Hawker-Beechcraft Model 99 Series Maintenance Manual, a repetitive lubrication of the retract actuator and actuator support bearings at 1,000 cycles or 30 months (whichever occurs first) was prescribed. Additionally, Chapter 20-08-00 Standard Practices, page 201, included the following caution: "When washing the airplane with soap and water, use special care to avoid washing grease away from lubricated area. After washing the wheel well areas with solvent, lubricate all lubrication points. Premature wear of the lubricated surfaces may result if these precautions are not observed." ## Aircraft - Registration: [N899AE](https://openairdocs.org/deregistered/N899AE-2019-12-27), registration cancelled 2019-12-27, S/N U23, built 1968 (OpenAirDocs) - Reported make and model: BEECH BE99 - Registry model: [Beech 99](https://openairdocs.org/model/beech-99) (registry code 1154002) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-27 series](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-27-series) (registry code 52247, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: U23 - Airframe hours: 48953 - Engines: Pratt & Whitney Canada PT6A-20 550 horsepower turbo prop; Pratt & Whitney Canada PT6A-20 550 horsepower turbo prop - Damage: Substantial damage - Flight: Skydiving, Part 91 - Operator: Skydive Georgia - Registered owner: Aerodynamics Worldwide Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, February 14, 2011, 7 hours before - Departed: 4A4, Cedartown, GA - Destination: 4A4, Cedartown, GA - Airport: 4A4, Polk County Airport- Cornelius ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 40; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review April 7, 2011; seat: left; flight hours: 6,200 total, 8 in this make and model, 6,000 as pilot in command, 66 in the last 90 days, 40 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 63 °F - Altimeter: 30.12 inHg - Observed at: PUJ, 12 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 20110410007159A](https://openairdocs.org/incident/20110410007159A), Apr 10, 2011: Beech 99, Cedartown, GA, Substantial damage. The PIC advised that he had the "green" down and lock lights illuminated for both the nose gear and the right wing landing gear, but could not get the light… ## Docket (9 files) The files NTSB released with the investigation on December 30, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78834. 6.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 695 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360506&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Interview (Pilot) (item 2, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360529&FileExtension=.PDF&FileName=Record%20of%20Interview%20(Pilot)-Master.PDF - FAA Inspector Statement (item 3, .PDF, 48 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360508&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement-Master.PDF - FAA Inspector Gear Exam (item 4, .PDF, 14 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360509&FileExtension=.PDF&FileName=FAA%20Inspector%20Gear%20Exam-Redacted.PDF - Maintenance Manual Excerpt (Hawker-Beechcraft) (item 5, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360510&FileExtension=.PDF&FileName=Maintenance%20Manual%20Excerpt%20(Hawker-Beechcraft)-Master.PDF - Landing Gear Diagram with FAA Notes (item 6, .PDF, 45 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360511&FileExtension=.PDF&FileName=Landing%20Gear%20Diagram%20with%20FAA%20Notes-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 7, .PDF, 102 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360512&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Photo 1: View of Fractured Actuator Housing (item 8, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360518&FileExtension=.PDF&FileName=Photo%201%3A%20View%20of%20Fractured%20Actuator%20Housing-Master.PDF - Photo 2: View of Actuator and Broken Bearing Mount (item 9, .PDF, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40360519&FileExtension=.PDF&FileName=Photo%202%3A%20View%20of%20Actuator%20and%20Broken%20Bearing%20Mount-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.