# NTSB WPR19LA092: Cessna 172, N6486J, Melba, ID, March 1, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: March 1, 2019, 13:45 local (20:45 UTC) - Place: Melba, ID - Coordinates: 43.426944, -116.621109 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.4269&lon=-116.6211&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - 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): 99075 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR19LA092 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99075/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99075 - Page: https://openairdocs.org/ntsb/WPR19LA092 ## Probable cause The total loss of engine power due to a separated carburetor idle mixture adjustment screw and spring assembly for reasons that could not be determined. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Not specified (probable cause); cases with it: [Cessna 172N, 4 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=2072434), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) - [Engine starting](https://openairdocs.org/ntsb-findings/01058000): Aircraft › Aircraft power plant · Damaged/degraded (probable cause); cases with it: [Cessna 172N, 1 case](https://openairdocs.org/ntsb-findings/01058000/cases.md?model=2072434), [All aircraft, 7 cases](https://openairdocs.org/ntsb-findings/01058000/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Cessna 172N, 24 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2072434), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 172N, 28 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072434), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172N, 31 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072434), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Emergency descent: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340); cases with it: [Cessna 172N, 11 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=2072434), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 172N, 134 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072434), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The flight instructor and student pilot were performing maneuvers when the engine lost total power. The instructor pitched the nose of the airplane down and asked the student pilot to restart the engine. The student pilot was unable to rotate the engine using the starter, and the flight instructor verified that the master switch was in the “ON” position. The instructor tried to start the engine himself and was unsuccessful. The flight instructor performed a forced landing in a field. Examination revealed that the idle mixture adjustment screw and spring assembly had separated from the carburetor and were found in the lower cowling area. After the airplane was relocated to a nearby road the engine rotated via the starter. Examination of the idle mixture adjustment screw and spring assembly revealed no anomalies. The reason that the screw backed out of the carburetor could not be determined. The starter solenoid was removed and disassembled. The starter solenoid was examined and revealed a frayed and separated wire from the coil to a terminal end. The reasons for this fraying and separation could not be determined. Although the starter solenoid was faulty, it is unlikely that the engine would have restarted due to the separated idle mixture screw and spring assembly. ## Factual narrative On March 1, 2019, about 1345 mountain standard time, a Cessna 172N airplane, N6486J, was substantially when it was involved in an accident near Melba, Idaho. The flight instructor and student pilot were not injured. The airplane operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The instructor reported that they had performed about 12 power-off and power-on stalls, while maintaining an altitude between 4,500 ft and 2,000 ft during the maneuvers. While performing the last power-off stall, with the nose of the airplane pitched up, the engine lost total power. During that maneuver, the throttle lever was in the closed position, and the carburetor heat was in the “ON” position. The instructor pitched the nose of the airplane down and asked the student to restart the engine. The student pilot was unable to rotate the engine using the starter, and the instructor verified that the master switch was in the “ON” position. The instructor tried to start the engine himself and was also unsuccessful. The instructor performed a forced landing in a field about 12 miles southwest of the departure airport. During the landing roll, the right wing impacted the ground and the right wing spar sustained substantial damage. The initial examination of the airplane at the accident site was performed by the operator's mechanic. The examination revealed that the idle mixture adjustment screw and spring assembly had separated from the carburetor and was found in the lower cowling area. While on site, the flight instructor told the mechanic about the inability to rotate the engine with the starter after the power loss. The airplane was moved to a nearby road and the mechanic was able to rotate the engine via the starter. The airplane was recovered for further examination. The examination of the airplane by a Federal Aviation Administration inspector revealed no other anomalies, and the airplane was released back to the owner. During a conversation with the National Transportation Safety Board investigator-in-charge after the accident, the owner stated that he could not rotate the engine using the starter following the accident. The ignition switch and associated wiring were subsequently examined, and no anomalies were noted. The starter rotated when the starter cable was removed from the starter solenoid and connected to the battery. The starter solenoid was removed and disassembled. The examination of the starter solenoid revealed a frayed and separated wire from the coil to a terminal end. The owner replaced the starter solenoid with a new solenoid and installed the idle mixture adjustment screw and spring assembly; the engine operated normally. He concluded by stating that, with the idle mixture adjustment screw assembly removed from the carburetor, the engine would not operate below 1,000 rpm. Maintenance records indicated that, on October 18, 2016, 1,281.6 flight hours before the accident, the carburetor was removed and the throttle shaftassembly, accelerator pump assembly, throttle shaft bushings, gaskets and cotter keys were replaced with new. The carburetor was reinstalled, and the engine was test run with no anomalies noted. On January 19, 2016, a faulty starter solenoid was replaced with a new starter solenoid and the part number was correct for this airplane. The last annual inspection was completed on January 29, 2019, about 24 flight hours before the accident. ## Aircraft - Registration: [N6486J](https://openairdocs.org/aircraft/N6486J), registered now, S/N 17273877, built 1980 (OpenAirDocs) - Reported make and model: Cessna 172 (N) - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17273877 - Year built: 1980 - Airframe hours: 17797.1 - Engines: Lycoming O-320-H2AD reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Avcenter Inc. - Registered owner: Gliege Allan C - Airworthiness certificate: Standard, Normal; Standard, Utility - Last inspection: 100 hour, January 29, 2019, 24 hours before - Departed: KMAN, Nampa, ID - Destination: KMAN, Nampa, ID - Airport: MAN, Nampa Muni - Equipment: Stall warning system, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 66; injuries: none; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review November 25, 2017; seat: right; restraint: 4-point; flight hours: 10,100 total, 1,700 in this make and model, 10,020 as pilot in command, 45 in the last 90 days, 15 in the last 30 days, 0 in the last 24 hours - Student pilot; age 77; injuries: none; student; medical: class 3, waiver time limited special; seat: left; restraint: 4-point; flight hours: 223 total, 223 in this make and model, 45 as pilot in command, 7 in the last 90 days, 3 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 45 °F, dew point 39 °F - Altimeter: 30.10 inHg - Observed at: KMAN, 10 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 20190301000719A](https://openairdocs.org/incident/20190301000719A), Mar 1, 2019: Cessna 172N, Melba, ID, Substantial damage. Cessna 172 N6486J is leased to the av center at kman for the purpose of CFR part 61 instruction. The CFI and student pilot were conducting emergency stall… ## Other investigations on N6486J (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 SEA99LA002](https://openairdocs.org/ntsb/SEA99LA002), Oct 12, 1998: Cessna 172N (N6486J), Buhl, ID, substantial damage. Probable cause: The pilot's failure to follow the aircraft's recommended balked landing procedure, resulting in a stall. Factors include the pilot's failure to maintain directional control during the landing flare,… - [NTSB SEA86LA070](https://openairdocs.org/ntsb/SEA86LA070), Mar 3, 1986: Cessna 172 (N6486J), American Falls, ID, substantial damage ## Docket (10 files) The files NTSB released with the investigation on April 19, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99075. 64.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 5.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7805313&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Aerial image (item 2, PDF, 1 page, 476 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7805216&FileExtension=pdf&FileName=Aerial%20Image-Rel.pdf - Student pilot-statement (item 3, PDF, 1 page, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7805258&FileExtension=pdf&FileName=N6486J%20Student%20Statement_Redacted-Rel.pdf - Statement from mechanic (item 4, PDF, 1 page, 821 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7805394&FileExtension=pdf&FileName=N6486J%20Derick%20Johns%20Scanned%20statement_Redacted-Rel.pdf - Record of conversation-mechanic (item 5, PDF, 1 page, 96 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7806028&FileExtension=pdf&FileName=Record%20of%20Conversation-Derick%20Johns_Redacted-Rel.pdf - Record of conversation-owner (item 6, PDF, 1 page, 139 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7805593&FileExtension=pdf&FileName=Record%20of%20Conversation-Mr.%20Gliege_Redacted-Rel.pdf - FAA statement (item 7, PDF, 1 page, 27 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13695860&FileExtension=pdf&FileName=FAA%20Statement-Rel.pdf - Logbook entries (item 8, PDF, 5 pages, 54.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7806309&FileExtension=pdf&FileName=Logbook%20Entries_Redacted-Rel.pdf - Work order-starter solenoid (item 9, PDF, 1 page, 503 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=7805753&FileExtension=pdf&FileName=Work%20Order%20for%20Starter%20Relay_Redacted-Rel.pdf - Photo array-courtesy of the airplane owner (item 10, PDF, 6 pages, 2 photos, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13625331&FileExtension=pdf&FileName=DMS%20Photo%20Array-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.