# NTSB WPR21LA301: Piper PA-28-140, N44245, Amado, AZ, August 2, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: August 2, 2021, 09:30 local (16:30 UTC) - Place: Amado, AZ - Coordinates: 31.65156, -111.04788 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.6516&lon=-111.0479&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA-FSDO - NTSB case key (mKey): 103608 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA301 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103608/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103608 - Page: https://openairdocs.org/ntsb/WPR21LA301 ## Probable cause The inflight separation of a section of a propeller blade due to a fatigue crack, which resulted in a forced landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Propeller system: propeller blade section](https://openairdocs.org/ntsb-findings/01046111): Aircraft › Aircraft propeller/rotor · Fatigue/wear/corrosion (probable cause); cases with it: [Piper PA-28-140, 1 case](https://openairdocs.org/ntsb-findings/01046111/cases.md?model=7102802), [All aircraft, 51 cases](https://openairdocs.org/ntsb-findings/01046111/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Piper PA-28-140, 47 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=7102802), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Enroute: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Piper PA-28-140, 6 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=7102802), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Enroute: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Piper PA-28-140, 4 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=7102802), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) ## Analysis The pilot reported that during the flight, the airplane suddenly started vibrating. After checking the magneto switch and looking over the instruments for any cylinder anomalies, he shut down the engine. The pilot initiated a forced landing to a field during which the right wing impacted a tree. The airplane landed hard in a muddy field, collapsing the nose landing gear. Postaccident examination of the airplane revealed a portion of the propeller blade had separated in flight. Examination of the propeller revealed that the propeller blade exhibited a fatigue crack that initiated near the trailing edge of the blade. Metal transfer from an alloy dissimilar to that of the blade’s material likely resulted from an object that impacted the blade face near the trailing edge. The red transfer marks on the blade were likely impact marks from contacting the engine cowling during the accident sequence. ## Factual narrative On August 2, 2021, about 0930 mountain standard time, a Piper PA-28-140 airplane, N44245, was substantially damaged when it was involved in an accident near Amado, Arizona. The pilot and pilot-rated passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that while in level cruise flight, about 6,000 ft mean sea level, the airplane suddenly started vibrating. He checked the magneto switch and looked over the instruments for any cylinder anomalies and found none. He decided to shut down the engine to stop the vibrations. Soon after shutting down the engine, he said that he was committed to force land in a nearby field. He stated that, while preparing for the forced landing, he was too fast and tried to make it to the next field that was situated over the next tree line and fence. During the landing, he impacted a tree with the right wing and subsequently landed hard in a muddy field. The airplane’s nose landing gear collapsed during the landing, and the pilot and pilot-rated passenger were able to exit without injury. Examination of the accident site photos revealed that the right wing remained attached to the rear spar, separated at the main spar near the wing root and was bent upwards. The outboard right wing was buckled, and the leading edge had circular impact damage. The fuselage was buckled near the firewall and near the empennage. One of the propeller blades was separated about 5 inches outboard of the blade root. The separated propeller blade portion was not found during the investigation. The remaining propeller blade section was retained for further examination. Review of the propeller logbooks revealed that the propeller was installed on the accident airplane on March 17, 2020, with 116.1 hours of operation since overhaul. The last annual inspection was completed on April 10, 2021. At the time of the accident, the propeller had about 245 hours of operation since overhaul. Examination of the propeller blade section by the National Transportation Safety Board Materials Laboratory revealed that the propeller exhibited a fatigue crack that initiated near the trailing edge of the blade. Red transfer marks were found near the trailing edge of the blade. The fatigue crack initiated at multiple sites along the blade face surface adjacent to the trailing edge. The edge area exhibited indications of copper, as well as iron and manganese. These indicate material transfer from an alloy dissimilar to that of the blade’s material. ## Aircraft - Registration: [N44245](https://openairdocs.org/aircraft/N44245), registered now, S/N 28-7425397, built 1974 (OpenAirDocs) - Reported make and model: PIPER PA-28-140 - Registry model: [Piper PA-28-140](https://openairdocs.org/model/piper-pa-28-140) (registry code 7102802) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28-7425397 - Year built: 1974 - Airframe hours: 9136 - Engines: Lycoming Engines O-360-F2A 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Riter Robert M - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 10, 2021, 57 hours before - Departed: OLS, Nogales, CA - Equipment: Stall warning system, ADS-B, Electronic primary flight display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; injuries: none; flight instructor, commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: right; restraint: lap only - Pilot-rated passenger; injuries: none; private; airplane ratings: single-engine land; medical: unknown; seat: left ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 66 °F - Altimeter: 30.22 inHg - Icing: Unknown - Turbulence: Unknown - Observed at: KOLS, 17 nm away - METAR: KOLS 021554Z AUTO 00000KT 10SM CLR 27/19 A3022 RMK AO2 SLP165 T02720194 ## 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 20210802012349A](https://openairdocs.org/incident/20210802012349A), Aug 2, 2021: Piper PA-28-140, Tubac, AZ, Substantial damage. On 2 August, 2021 around 0945 local time a cherokee 140 made an off airport landing into a field a couple miles NE of Tubac outside of nogales, Arizona. Pilot… ## Other investigations on N44245 (2) 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 CHI96LA283](https://openairdocs.org/ntsb/CHI96LA283), Aug 7, 1996: Piper PA-28-140 (N44245), Rensselaer, IN, substantial damage. Probable cause: the student pilot's improper flare and improper recovery from a bounced landing. - [NTSB CHI80FET22](https://openairdocs.org/ntsb/CHI80FET22), Jul 23, 1980: Piper PA-28 (N44245), Peru, IN, substantial damage ## Docket (5 files) The files NTSB released with the investigation on April 19, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103608. 5.9 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 698 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12572409&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Record of memorandum-pilot (item 2, PDF, 1 page, 86 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15245356&FileExtension=pdf&FileName=Record%20of%20Memorandum-Pilot-Rel.pdf - Email-pilot information and statement from owner (item 3, PDF, 1 page, 138 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15245264&FileExtension=pdf&FileName=Email%20from%20Owner%20on%20Pilot%20Statement_Redacted-Rel.pdf - Materials laboratory factual report (item 4, PDF, 12 pages, 17 photos, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13941498&FileExtension=pdf&FileName=22-034%20-%20Materials%20Lab%20Factual%20Report%20(WPR21LA301)-Rel.pdf - Photo array-accident site (courtesy of the santa cruz county sheriffs office) (item 5, PDF, 4 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15245557&FileExtension=pdf&FileName=Photo%20Array-SCCSO%20Onsite%20Photos-Rel.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.