# NTSB WPR21LA071: Co Z Cozy, N82V, Compton, CA, November 17, 2020 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: November 17, 2020, 14:18 local (22:18 UTC) - Place: Compton, CA - Coordinates: 33.890981, -118.24368 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.8910&lon=-118.2437&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-climb to cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 102428 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA071 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102428/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102428 - Page: https://openairdocs.org/ntsb/WPR21LA071 ## Probable cause The partial loss of engine power due to an improperly installed sparkplug. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Ignition system: spark plugs/igniters](https://openairdocs.org/ntsb-findings/01057421): Aircraft › Aircraft power plant · Not installed/available (probable cause); cases with it: [Herzstein Donald L COZY IV, 1 case](https://openairdocs.org/ntsb-findings/01057421/cases.md?model=05612GS), [All aircraft, 38 cases](https://openairdocs.org/ntsb-findings/01057421/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Herzstein Donald L COZY IV, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=05612GS), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-climb to cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Herzstein Donald L COZY IV, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=05612GS), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Herzstein Donald L COZY IV, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=05612GS), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis Approximately 3 minutes after departure, at an altitude of 1,500 ft, the airplane’s engine experienced a partial loss of power, and the pilot initiated a return to the airport. During the landing roll, the airplane bounced, veered off the runway, and ground looped. A postaccident examination of the airplane revealed the No. 2 cylinder bottom spark plug was laying loose in the engine compartment with the ignition lead still attached. The spark plug threads and corresponding threads in the cylinder displayed no signs of damage, which was consistent with the improper installation of the spark plug. The engine was repaired about 11 months before the accident, which is likely when the spark plug was improperly installed. The airplane accumulated approximately 8 hours since the maintenance. ## Factual narrative On November 17, 2020, about 1418 Pacific standard time, an experimental amateur-built Co-Z COZY airplane, N82V, sustained substantial damage when it was involved in an accident in Compton, California. The pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, approximately 3 minutes after departure, at an altitude of 1,500 ft., the engine started to “run rough” so he decided to return to the airport. During the landing roll, the airplane bounced, veered off the runway, and ground looped. The left main landing gear separated from the airplane during the accident sequence. The pilot reported to a Federal Aviation Administration (FAA) inspector that when he opened the engine cowling after the accident, he noticed a spark plug on the bottom of the engine compartment. A postaccident examination of the airplane by the FAA inspector confirmed the No. 2 cylinder bottom spark plug was laying loose in the engine compartment with the ignition lead still attached. The spark plug threads and corresponding threads in the cylinder displayed no signs of damage. The engine was repaired in December 2019 and reinstalled on the airplane. The airplane accumulated approximately 8 hours since the maintenance. ## Aircraft - Registration: [N82V](https://openairdocs.org/aircraft/N82V), registered now, S/N 0379 (OpenAirDocs) - Reported make and model: CO Z COZY (IV) - Registry model: [Herzstein Donald L COZY IV](https://openairdocs.org/model/herzstein-donald-l-cozy-iv) (registry code 05612GS) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 0379 - Year built: 2004 - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Airport: CPM, Compton/Woodley, runway 25L, 3,322 × 60 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 83; injuries: minor; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3; flight hours: 2,150 total ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 73 °F, dew point 54 °F - Altimeter: 30.01 inHg - Observed at: HHR, 5 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 20201117019599A](https://openairdocs.org/incident/20201117019599A), Nov 17, 2020: Herzstein Donald L COZY IV, Compton, CA, Substantial damage. On November 17, 2020, at approx. 1415 local time, N82V, a Cozy IV certificated in the experimental armature built category landed on runway 25L at cpm (Compton… ## Docket (3 files) The files NTSB released with the investigation on September 27, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102428. 318 KB in all. - FAA exam (item 1, PDF, 1 page, 115 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13317820&FileExtension=pdf&FileName=FAA%20exam-Rel.pdf - Synopsis of events (item 2, PDF, 1 page, 149 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13317561&FileExtension=pdf&FileName=Memo%20for%20record%20-%20synopsis-Rel.pdf - Email exchange (item 3, PDF, 2 pages, 54 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13317368&FileExtension=pdf&FileName=Email%20exchage_Redacted-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.