# NTSB CEN14LA235: Pazmany PL 4, N44PL, Yates City, IL, May 10, 2014 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 10, 2014, 12:15 local (17:15 UTC) - Place: Yates City, IL - Coordinates: 40.773887, -90.074447 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.7739&lon=-90.0744&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report January 14, 2015 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Flight Standards - NTSB case key (mKey): 89196 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN14LA235 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/89196/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=89196 - Page: https://openairdocs.org/ntsb/CEN14LA235 ## Probable cause A loss of propeller thrust due to a failure of the reduction drive unit resulting from the improper installation of the unit. Contributing to the accident was a lack of documentation for the reduction drive unit installation. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Propeller system](https://openairdocs.org/ntsb-findings/01046100): Aircraft › Aircraft propeller/rotor · Malfunction (probable cause); cases with it: [Pazmany PL-4, 1 case](https://openairdocs.org/ntsb-findings/01046100/cases.md?model=0562314), [All aircraft, 20 cases](https://openairdocs.org/ntsb-findings/01046100/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Owner/builder (probable cause); cases with it: [Pazmany PL-4, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=0562314), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) - [Documentation/record keeping](https://openairdocs.org/ntsb-findings/04033000): Organizational issues › Support/oversight/monitoring · Manufacturer (probable cause); cases with it: [Pazmany PL-4, 1 case](https://openairdocs.org/ntsb-findings/04033000/cases.md?model=0562314), [All aircraft, 12 cases](https://openairdocs.org/ntsb-findings/04033000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Pazmany PL-4, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=0562314), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Pazmany PL-4, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=0562314), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Pazmany PL-4, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=0562314), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis While in the airport traffic pattern, the airplane sustained a complete loss of thrust and an increase in engine speed, which the pilot interpreted as a loss of engine power to the propeller. He subsequently executed a forced landing to an open field. A postaccident examination revealed that the propeller reduction drive pulley had moved downward within the mounting bracket slot, creating slack in the cog belts that resulted in a loss of input drive power to the propeller. The reduction drive manufacturer did not provide any formal documentation for the installation. As a result, the pilot/builder was not aware that a secondary fitting to secure the pulley within the bracket needed to be installed with the drive unit components. ## Factual narrative On May 10, 2014, about 1215 central daylight time, a Pazmany PL-4 light sport airplane, N44PL, was substantially damaged during a forced landing near Yates City, Illinois. The pilot sustained minor injuries. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight originated from the Tri-County Airport (2C6), Yates City, Illinois, at 1145.The pilot reported that he had completed a 20 minute flight in the local area, after which he returned to the airport and completed a landing and takeoff (touch and go) without incident. He remained in the airport traffic pattern after the touch and go. On the downwind leg, the pilot stated that he felt a complete loss of thrust as the engine speed increased, which he interpreted as a loss of engine power to the propeller. He established the airplane in a glide and set-up for a forced landing. During the glide, he increased engine speed without any accompanying increase in propeller thrust. He subsequently executed a forced landing to an open field; however, a hard landing resulted. The accident airplane was powered by a 65-horsepower Volkswagen engine, with a Culver Props 2-bladed, fixed pitch propeller. The installation included a Valley Engineering propeller speed reduction unit. The reduction unit utilized a cog belt/pulley arrangement to transmit power from the engine to the propeller. The most recent conditional inspection was reportedly completed on December 12, 2013; the airframe had accumulated 423 hours total time at the time of the inspection. The engine had accumulated 62 hours since overhaul, with 53 hours since the inspection. The propeller reduction unit had also accumulated 62 hours time in service. A postaccident examination revealed that the pulley supporting the propeller remained securely attached to the mounting bracket. However, the pulley had moved downward within the bracket slot creating slack in the cog-belts. The pilot/builder reported that the reduction drive unit was purchased from a private individual in combination with the engine, carburetor, and intake system. There was no documentation related to the reduction drive unit provided by the seller. The pilot/builder contacted the manufacturer of the unit to confirm compatibility to his installation. He also noted that the reduction drive components were not modified in any way prior to installation. The manufacturer stated that the reduction drive unit installed on the accident airplane was an earlier design. They noted that the installation included a fitting to support the pulley to prevent it from moving within the bracket slot during operation. However, no formal documentation was reportedly available for the initial design. He also noted that the mounting bracket used in the current design configuration does not include a slot.The fitting to support the pulley, preventing any downward movement within the bracket slot during operation, was not installed on the accident airplane. ## Aircraft - Registration: [N44PL](https://openairdocs.org/deregistered/N44PL-2015-03-13), registration cancelled 2015-03-13, S/N 001, built 1972 (OpenAirDocs) - Reported make and model: PAZMANY PL 4 - Registry model: [Pazmany PL-4](https://openairdocs.org/model/pazmany-pl-4) (registry code 0562314) (OpenAirDocs) - Registry engine: [Volkswagen CONVERSION](https://openairdocs.org/engine/volkswagen-conversion) (registry code 63501, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 001 - Year built: 1972 - Airframe hours: 428 - Engines: VOLKSWAGEN CONVERSION 36 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, December 12, 2013, 53 hours before - Departed: 2C6, Yates City, IL - Destination: 2C6, Yates City, IL - Airport: 2C6, Tri-County ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 74; injuries: minor; commercial; airplane ratings: single-engine land, multi-engine land, single-engine sea; medical: sport pilot, with waivers/limitations; seat: single; flight hours: 4,263 total, 53 in this make and model, 4,069 as pilot in command, 10 in the last 90 days, 3 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 73 °F, dew point 46 °F - Altimeter: 29.96 inHg - Observed at: PIA, 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 20140510005359A](https://openairdocs.org/incident/20140510005359A), May 10, 2014: Pazmany PL-4, Yates City, IL, Substantial damage. Pilot was in the airport traffic pattern descending to the Yates City, IL Tri-County Airport (2C6) and lost power about 300 feet AGL. The pilot made an… ## Docket (7 files) The files NTSB released with the investigation on December 15, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=89196. 1.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 259 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420035&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation - Pilot (item 2, .PDF, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420036&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Pilot-Master.PDF - Record of Conversation - Reduction Drive Manufacturer (item 3, .PDF, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420037&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Reduction%20Drive%20Manufacturer-Master.PDF - Photo 1 - Accident Airplane (item 4, .PDF, 289 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420039&FileExtension=.PDF&FileName=Photo%201%20-%20Accident%20Airplane-Master.PDF - Photo 2 - Reduction Drive Bracket (item 5, .PDF, 255 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420042&FileExtension=.PDF&FileName=Photo%202%20-%20Reduction%20Drive%20Bracket-Master.PDF - Photo 3 - Engine with Reduction Drive (item 6, .PDF, 335 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420043&FileExtension=.PDF&FileName=Photo%203%20-%20Engine%20with%20Reduction%20Drive-Master.PDF - Photo 4 - Engine with Reduction Drive (item 7, .PDF, 364 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40420044&FileExtension=.PDF&FileName=Photo%204%20-%20Engine%20with%20Reduction%20Drive-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.