# NTSB WPR19LA065: Piper PA28, N1697J, Salt Lake City, UT, January 15, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: January 15, 2019, 10:50 local (17:50 UTC) - Place: Salt Lake City, UT - Coordinates: 40.619445, -111.992774 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.6194&lon=-111.9928&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 98837 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR19LA065 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98837/pdf - Page: https://openairdocs.org/ntsb/WPR19LA065 ## Probable cause A partial loss of engine power due to the mechanic’s failure to properly secure the throttle lever locking nut and cotter pin. ## 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 · Incorrect service/maintenance (probable cause); cases with it: [Piper PA-28-140, 7 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=7102802), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) - [Misc hardware: fasteners](https://openairdocs.org/ntsb-findings/01071430): Aircraft › Fluids/misc hardware · Incorrect service/maintenance (probable cause); cases with it: [Piper PA-28-140, 1 case](https://openairdocs.org/ntsb-findings/01071430/cases.md?model=7102802), [All aircraft, 58 cases](https://openairdocs.org/ntsb-findings/01071430/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); 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) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-28-140, 137 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7102802), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was practicing takeoffs and landings when the engine became unresponsive to throttle inputs. He performed a forced landing onto a highway, during which the airplane was substantially damaged. Examination of the engine revealed that the carburetor throttle lever lock nut was finger-tight, and its cotter pin was absent, which likely resulted in the throttle lever intermittently disengaging from the serrated throttle shaft when the pilot manipulated the throttle. A review of the maintenance log books and an interview with the mechanic revealed that the throttle cable had been removed and subsequently reinstalled onto the carburetor as part of the most recent annual inspection, which was completed about 1 month before the accident. It is likely that, at this time, the mechanic did not install or inadequately installed the cotter pin through the locking nut and bolt. ## Factual narrative On January 15, 2019, about 1050 mountain standard time, a Piper PA28-140 airplane, N1697J, was substantially damaged when it was involved in an accident near Salt Lake City, Utah. The commercial pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he was practicing touch-and-go landings. While on landing approach, he reduced the throttle control to decrease engine rpm; however, the engine remained at 2,200 rpm. He then pushed the throttle back in and the power increased to 2,500 rpm. He attempted to reduce throttle again, but the engine remained at 2,500 rpm. The pilot initiated a go-around, and, shortly thereafter, engine power decreased from 2,500 to 1,500 rpm. With no usable runway remaining, the pilot performed a forced landing to a road, during which the propeller struck the road and the landing gear sheared off the airplane. The service manual for the Marvel-Schebler Model MA4 series carburetor lists a castellated nut and cotter pin to secure the serrated throttle arm to the throttle shaft of the carburetor (see figure 1). Examination of the engine revealed that the carburetor serrated throttle lever locking nut was finger-tight and the cotter pin was absent. When the throttle lever was retracted and extended, the loosely attached throttle shaft did not move, as shown in figures 2 and 3. Figure 1. Excerpt from the Marvel-Schebler Carburetor Service Manual. A review of the engine maintenance records revealed that, on December 14, 2018, as part of the annual inspection, the mechanic wrote, "Verified control movement and lubricated." In an interview with a Federal Aviation Administration (FAA) representative, the mechanic confirmed that he took the throttle cable off to do this work. Postaccident examination of the carburetor at Precision Air Power, Woods Cross, Utah revealed no anomalies that would have precluded normal operation. Figure 2. Note the serrated throttle lever and idle stop at the idle position. Figure 3. Photo showing the serrated throttle lever at full power setting while the idle stop lever remained at idle. ## Aircraft - Registration: [N1697J](https://openairdocs.org/deregistered/N1697J-2022-07-02), registration cancelled 2022-07-02, S/N 28-24103, built 1968 (OpenAirDocs) - Reported make and model: Piper PA28 (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: 28-24103 - Year built: 1968 - Airframe hours: 3661.93 - Engines: Lycoming O-320 SERIES 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 14, 2018 - Departed: U42, Salt Lake City, UT - Destination: U42, Salt Lake City, UT - Airport: U42, South Valley Regional Airport, runway 16, 5,808 × 100 ft, asphalt - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 1, with waivers/limitations; seat: left; flight hours: 3,859 total, 11 in this make and model, 3,753 as pilot in command, 158 in the last 90 days, 5 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 4 knots - Visibility: 8 statute miles - Lowest ceiling: 4,500 ft broken - Temperature: 30 °F, dew point 21 °F - Altimeter: 30.13 inHg - Observed at: KSLC, 115 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 20190115000219A](https://openairdocs.org/incident/20190115000219A), Jan 15, 2019: Piper PA-28-140, Salt Lake City, UT, Substantial damage. Pilot initiated approach at 2.2NM out high, (U42): pulled throttle back to reduce RPM, engine did not respond and remained at 2400-2500 indicated RPM. Pilot… 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.