# NTSB ATL96LA131: Beech A23, N8879M, Tarboro, NC, September 20, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 20, 1996, 12:00 local (16:00 UTC) - Place: Tarboro, NC - Coordinates: 35.899814, -77.550277 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.8998&lon=-77.5503&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report April 3, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 3763 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL96LA131 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3763/pdf - Page: https://openairdocs.org/ntsb/ATL96LA131 ## Probable cause fatigue failure of the propeller blade. Factors relating to the accident were: corrosion pit(s) on the propeller blade, and inadequate maintenance/inspection of the propeller. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - normal - propeller system/accessories,blade - corroded (contributing factor) - maintenance,inspection - inadequate, other maintenance personnel (contributing factor) - propeller system/accessories,blade - fatigue (cause) - propeller system/accessories,blade - failure (cause) - Forced landing, emergency descent/landing ## Analysis During cruise flight, about half of one propeller blade separated from the airplane, resulting in substantial damage. An uneventful landing was made to a nearby airport. Metallurgical examination of the propeller blade revealed that it had failed from fatigue; the fatigue originated from a single corrosion pit on the camber side of the blade. Other corrosion pits were also noted on the camber side of the remaining portion of the blade. There was no record in the airplane log that the propeller had been reconditioned since its installation. The propeller was manufactured in September 1963 and sold to Beech Aircraft Corporation in August 1964. The airplane was manufactured in December 1964 and had accumulated 1851 hours of flight time. The propeller manufacturer recommended that the propeller be reconditioned after each 1,000 hours of operation. ## Factual narrative On September 20, 1996, about 1200 eastern daylight time, a Beech A-23, N8879M, experienced the separation of about one half of one propeller blade during cruise flight, near Tarboro, North Carolina. The airplane was operated by the pilot/co-owner under the provisions of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed. A flight plan was not filed for the business flight. There were no injuries to the commercial pilot or the pilot rated passenger, and the airplane was substantially damaged. Origination of the flight was Lake Ridge, North Carolina, about 1130 on the same day. The flight was destined for Williamston, North Carolina. According to the pilot, while in cruise flight about 3,500 feet mean sea level, one propeller blade separated from the airplane. At the time, the airplane was about one half mile southeast of the Tarboro-Edgecombe County Airport. The pilot turned the airplane toward the airport and landed uneventfully. The propeller had separated through one airfoil on a chordwise plane about 14.5 inches outboard of the propeller centerline. During a metallurgical examination of the remaining fracture surface, fracture features typical of fatigue progression from a single origin were observed. A corrosion pit was observed at the origin, located on the camber surface of the blade, about 2.75 inches aft of the leading edge. The camber surface was not painted and several other corrosion pits were visible in the surface. A longitudinal pattern of scratches consistent with hand polishing was visible on the camber surface from the fracture inboard to the edge of the hub area. The flat surface of the propeller was painted black. According to the Federal Aviation Administration (FAA) airworthiness inspector who participated in the investigation, the failed propeller, a Sensenich M74DC-O-60, serial number B920, was manufactured on September 23, 1963, and sold to Beech Aircraft Corporation on August 17, 1964. The airplane logs indicated that the airplane was initially issued an Airworthiness Certificate on December 11, 1964. The airplane log did not reflect the propeller serial number. The airplane log contained the following entries regarding the propeller: * 10/13/95 installed new spinner, backing plate, and front plate; total hours-1820.1 * 12/24/79 dressed and painted propeller; annual inspection; total hours-1111.15 * 09/08/76 dressed nicks in propeller and painted blades. Retorqued propeller and repaired spinner backplate; total hours-795.88 There was no indication in the aircraft logs that the propeller had been replaced or reconditioned, since its original installation. The FAA inspector stated that ,after the accident, the hour meter on the airplane indicated 1851.21 hours. Propeller specifications provided by the propeller manufacturer indicated that the recommended time between reconditioning of the propeller was 1,000 hours. ## Aircraft - Registration: [N8879M](https://openairdocs.org/aircraft/N8879M), registered now, S/N M-626 (OpenAirDocs) - Reported make and model: Beech A23 - Registry model: [Beech A23](https://openairdocs.org/model/beech-a23) (registry code 1151204) (OpenAirDocs) - Registry engine: [Continental IO-346 series](https://openairdocs.org/engine/continental-io-346-series) (registry code 17033, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: M-626 - Airframe hours: 1851 - Engines: Continental IO-346-A 165 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Operator: Dean L. Liken - Registered owner: M.W.Hollingsworth/D. L. Liken - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 11, 1996, 18 hours before - Departed: W65, LAKE RIDGE, NC - Destination: MCZ, WILLIAMSTON, NC ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 2,000 total, 100 in this make and model, 2,000 as pilot in command, 4 in the last 90 days, 3 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 5 knots - Visibility: 7 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 52 °F - Altimeter: 30.00 inHg - Observed at: RWI, 18 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 19960920031409A](https://openairdocs.org/incident/19960920031409A), Sep 20, 1996: Beech A23, Tarboro, NC, Substantial damage. Lost half of prop blade at cruise. Original propeller installed on aircraft in 1964. Correded and pitted. (-23) prop blade broke at cruise power 3500 feet.… 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.