# NTSB ERA12IA459: Socata TB10, N189TB, Pawtucket, RI, July 15, 2012 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: July 15, 2012, 14:00 local (18:00 UTC) - Place: Pawtucket, RI - Coordinates: 41.920555, -71.491386 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.9206&lon=-71.4914&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 12, 2013 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 84345 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA12IA459 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84345/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84345 - Page: https://openairdocs.org/ntsb/ERA12IA459 ## Probable cause The in-flight separation of the propeller blade tip due to a fatigue fracture. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Aircraft](https://openairdocs.org/ntsb-findings/01040000): Aircraft › Aircraft propeller/rotor · Fatigue/wear/corrosion (probable cause); cases with it: [Socata TB 10, 1 case](https://openairdocs.org/ntsb-findings/01040000/cases.md?model=8680696), [All aircraft, 11 cases](https://openairdocs.org/ntsb-findings/01040000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Socata TB 10, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=8680696), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Initial climb: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Socata TB 10, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=8680696), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis During departure, as the airplane reached an altitude of about 800 feet above ground level, the tip of one propeller blade separated. The flight instructor returned the airplane to the runway and landed without incident. The separated blade tip was not located; however, the remaining section of propeller blade was examined, and a fracture analysis was performed. The results of the analysis revealed fatigue crack propagation, followed by a final overstress fracture. The fatigue crack origin could not be accurately determined because the pertinent portion of blade’s leading edge suffered from postfracture damage, which likely occurred during removal or shipment. This postfracture damage also precluded determination of fatigue crack growthe timing or propagation. However, the fatigue and overstress fractures were consistent with other blade tip fractures that have occurred as a result of excessive vibrations within the propeller blade, typically as a result of a propeller ground strike. The incident airplane’s propeller blades were manufactured 32 years before the incident, and the manufacturer imposed no life limits on the blades as long as they passed the required overhaul inspections. The incident propeller blades were overhauled twice in the 3 years before the incident. The first overhaul was performed as a result of a propeller strike, and the reason for the second overhaul was not documented. At the time of the incident, the blades had accumulated 852 hours since the most recent overhaul, which occurred 18 months before the incident. ## Factual narrative HISTORY OF FLIGHT On July 15, 2012, at 1400 eastern daylight time, a Socata TB 10, N189TB, experienced a partial propeller blade separation after takeoff from North Central State Airport (SFZ), Pawtucket, Rhode Island. The airplane was not damaged, and the private pilot and certified flight instructor (CFI) were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local, instructional flight. The flight was operated under the provisions of Title 14 Code of Federal Regulations Part 91. According to the CFI, the private pilot was at the controls as the airplane departed from runway 23. As it reached an altitude of 800 feet, the pilots heard what sounded like a "shotgun blast," followed by the airplane vibrating "violently." The CFI took over the flight controls, reduced the power, and initiated a 180-degree turn, to land on runway 33. He pulled the mixture to reduce power on the engine and landed without incident, on runway 33. The CFI noted that during the event, he observed no oil on the windscreen, and no abnormal engine indications from the cockpit gauges. He reported that the airplane continued to vibrate until it touched down on the runway and the propeller stopped windmilling. Examination of the airplane revealed the tip of one propeller blade had separated with approximately 3.5 inches missing. The remaining section of propeller blade was retained and sent to the NTSB Materials Laboratory for examination. According to the examination, visual inspection revealed 80 percent of the fracture surface was relatively flat with a reflective luster, indicative of fatigue propagation. The remaining 20 percent had an uneven rough matte surface, indicative of an overstress fracture region. Microscopic inspection of the fatigue regions revealed an exact origin could not be identified. Additionally, the blade's cross-sectional profile appeared different than the expected blade cross-sectional profile, in the region near the origin's general location. Further scanning electron microscope imaging of this surface revealed markings indicative of mechanical abrasion. X-ray examination revealed the blade's material composition was consistent with type AA2025 aluminum alloy. Additionally, hardness and conductivity testing determined measurements consistent with the specified material for the blade. According to the propeller logbook, a major overhaul was performed on the propeller blades on February 18, 2009, as a result of a propeller strike. The propeller was reinstalled on the airplane on March 3, 2009, at a tachometer time of 5,007 hours. Another entry was noted in the propeller logbook on April 27, 2011, at a tachometer time of 5,449 hours. The entry stated "reinstalled propeller assembly after repair by Sensenich Propeller." The reason for the repair was unidentified in the logbook, and there was no associated entry in the airframe logbook. The most recent annual inspection was completed on the propeller onJanuary 18, 2012 at a tachometer time of 5,677 hours. The time since propeller overhaul was 669 hours, as of this date. The tachometer time noted at the time of the incident was 5,860 hours. Both propeller blades were manufactured by Hartzell Propellers on March 14, 1980. According to Hartzell, as long as the propeller blades pass the required overhaul inspections, there is no life limit imposed. ## Aircraft - Registration: [N189TB](https://openairdocs.org/aircraft/N189TB), registered now, S/N 891 (OpenAirDocs) - Reported make and model: SOCATA TB10 (NO SERIES) - Registry model: [Socata TB 10](https://openairdocs.org/model/socata-tb-10) (registry code 8680696) (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: 891 - Airframe hours: 5860 - Engines: Lycoming O-360 180 horsepower reciprocating - Damage: No damage - Flight: Instructional, Part 91 - Operator: Pacca Club Inc - Registered owner: Pacca Club Inc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 18, 2012 - Departed: SFZ, Pawtucket, RI - Destination: SFZ, Pawtucket, RI - Airport: SFZ, North Central State Airport, runway 33, 3,211 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; last flight review May 25, 2012; seat: left; flight hours: 360 total, 228 in this make and model, 277 as pilot in command, 39 in the last 90 days, 14 in the last 30 days, 0 in the last 24 hours - Flight instructor; age 28; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: right; flight hours: 5,500 total, 200 in this make and model, 5,300 as pilot in command, 300 in the last 90 days, 100 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 70 °F - Altimeter: 30.04 inHg - Observed at: SFZ ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20120715014529I](https://openairdocs.org/incident/20120715014529I), Jul 15, 2012: Socata TB 10, Pawtuckett, RI, Minor damage. A flight instructor and student were on a training flight. While in the traffic pattern climbing through 800 feet, they heard a very loud noise, followed by… ## Docket (9 files) The files NTSB released with the investigation on April 12, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84345. 14.3 MB in all. - CFI Interview (item 1, .PDF, 26 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377494&FileExtension=.PDF&FileName=CFI%20Interview-Master.PDF - Photo 1: Prop blade tip seperation (photo courtesy of FAA) (item 2, .PDF, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377496&FileExtension=.PDF&FileName=Photo%201%3A%20Prop%20blade%20tip%20seperation%20(photo%20courtesy%20of%20FAA)-Master.PDF - Photo 2: Prop blade tip separation from front(photo courtesy of FAA) (item 3, .PDF, 2.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377497&FileExtension=.PDF&FileName=Photo%202%3A%20Prop%20blade%20tip%20separation%20from%20front(photo%20courtesy%20of%20FAA)-Master.PDF - Photo 3: Prop blade tip separation from rear (photo courtesy of FAA) (item 4, .PDF, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377498&FileExtension=.PDF&FileName=Photo%203%3A%20Prop%20blade%20tip%20separation%20from%20rear%20(photo%20courtesy%20of%20FAA)-Master.PDF - Materials Laboratory 15 - Factual Report 12-093 (w 7 images) (item 5, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377560&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2012-093%20(w%207%20images)-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 6, .PDF, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40381746&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Propeller Logbook (item 7, .PDF, 344 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40381788&FileExtension=.PDF&FileName=Propeller%20Logbook-Redacted.PDF - FAA Inspector Summary of Maintenance Documents (item 8, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40381792&FileExtension=.PDF&FileName=FAA%20Inspector%20Summary%20of%20Maintenance%20Documents-Redacted.PDF - Flight Instructor 6120 Pilot/Operator Report flight time page (item 9, .PDF, 231 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40384073&FileExtension=.PDF&FileName=Flight%20Instructor%206120%20Pilot%2FOperator%20Report%20flight%20time%20page-Redacted.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.