# NTSB CEN21LA031: Piper PA28, N5932U, Buda, TX, October 21, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: October 20, 2020, 20:20 local (Oct 21, 2020, 01:20 UTC) - Place: Buda, TX - Coordinates: 30.077712, -97.965563 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.0777&lon=-97.9656&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: 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: Central Region - Parties: Flight Standards District Office - NTSB case key (mKey): 102197 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA031 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102197/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102197 - Page: https://openairdocs.org/ntsb/CEN21LA031 ## Probable cause An improperly torqued oil line fitting during an engine overhaul, which resulted in oil exhaustion and a total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Misc hardware: hoses and tubes](https://openairdocs.org/ntsb-findings/01071410): Aircraft › Fluids/misc hardware · Incorrect service/maintenance (probable cause); cases with it: [Piper PA-28-140, 1 case](https://openairdocs.org/ntsb-findings/01071410/cases.md?model=7102802), [All aircraft, 40 cases](https://openairdocs.org/ntsb-findings/01071410/cases.md) - [Engine (reciprocating): recip eng oil sys](https://openairdocs.org/ntsb-findings/01058550): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Piper PA-28-140, 1 case](https://openairdocs.org/ntsb-findings/01058550/cases.md?model=7102802), [All aircraft, 130 cases](https://openairdocs.org/ntsb-findings/01058550/cases.md) - [Maintenance: repair](https://openairdocs.org/ntsb-findings/02062015): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Piper PA-28-140, 1 case](https://openairdocs.org/ntsb-findings/02062015/cases.md?model=7102802), [All aircraft, 99 cases](https://openairdocs.org/ntsb-findings/02062015/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Piper PA-28-140, 1 case](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=7102802), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md) - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Piper PA-28-140, 10 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=7102802), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Piper PA-28-140, 12 cases](https://openairdocs.org/ntsb-events/040/sequence.md?model=7102802), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Piper PA-28-140, 42 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7102802), [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: [Piper PA-28-140, 56 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7102802), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis During a night training flight, the flight instructor and student pilot experienced a total loss of engine power and executed a forced landing onto rough terrain, which damaged the airplane’s right-wing spar. Postaccident examination of the airplane revealed a nearly empty oil reservoir and oil residue on the underside of the fuselage and elevator, with significant thermal damage to the engine. The examination also found a disconnected oil line fitting. No material or structural anomalies were noted with the oil line or fitting. The engine had been recently overhauled, and the two mechanics who performed the overhaul stated it was very possible that they did not properly torque the oil line fitting. Following the accident, the overhaul facility implemented a requirement to torque seal applicable components to help ensure compliance with torque specifications. ## Factual narrative On October 20, 2020, about 2020 central daylight time, a Piper PA-28-140 airplane, N5932U, was substantially damaged when it was involved in an accident near Buda, Texas. The flight instructor and student pilot were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 flight. The flight instructor stated that while in cruise flight during the night training flight, the engine started to lose rpm, vibrate, and subsequently lost all power. During the descent, the flight instructor and student coordinated to select the closest runway and attempted to land at a private airport. After noticing the airplane was not able to the glide to the runway, the flight instructor conducted a forced landing onto rough terrain, which damaged the right-wing spar. A postaccident examination revealed significant thermal damage to the engine, a nearly empty oil reservoir, and a disconnected oil line fitting to the oil pressure indicator. Oil residue was trailing on the underside of the fuselage and the bottom of the elevator surface. Examination of the oil line fitting revealed no material or structural anomalies with the oil line or fitting. The accident was the airplane’s second flight following an engine overhaul due to a propeller strike. The two mechanics who conducted the overhaul stated that since both were involved and no procedure was in place to “verify all lines” were torqued properly, it was very possible the oil line fitting may have been missed. Following the accident, the overhaul facility implemented a requirement to torque seal applicable components during an overhaul to ensure compliance with torque specifications. This best practice is described in NTSB Safety Alert SA-056, “Take Time to Torque” (available at https://www.ntsb.gov/Advocacy/safety-alerts/Documents/SA-056.pdf) as well as in a maintenance article highlighting the importance of proper torque protocols that was published in the July 2018 FAA Safety Brief (located in the docket for this investigation). ## Aircraft - Registration: [N5932U](https://openairdocs.org/aircraft/N5932U), registered now, S/N 28-7125143, built 1971 (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: 28-7125143 - Year built: 1971 - Airframe hours: 7960 - Engines: Lycoming O-320 160 hp reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 21, 2020, 3 hours before - Departed: 1T8, Bulverde, TX - Destination: KAUS, Austin, TX - Flight plan: VFR - Equipment: ADS-B, Handheld GPS, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 51; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; last flight review December 12, 2019; seat: right; restraint: lap only; flight hours: 775 total, 491 in this make and model, 687 as pilot in command, 190 in the last 90 days, 54 in the last 30 days, 1 in the last 24 hours - Student pilot; age 39; injuries: none; student; medical: class 3, without waivers/limitations; seat: left; restraint: lap only; flight hours: 54 total, 54 in this make and model, 1 as pilot in command, 23 in the last 90 days, 8 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 140° at 7 knots - Visibility: 10 statute miles - Temperature: 82 °F, dew point 66 °F - Altimeter: 29.93 inHg - Observed at: KAUS, 16 nm away - METAR: KAUS 210053Z 14007KT 10SM FEW060 FEW150 28/19 A2993 RMK AO2 SLP125 T02780189 ## 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 20201020018759A](https://openairdocs.org/incident/20201020018759A), Oct 20, 2020: Piper PA-28-140, Buda, TX, Substantial damage. During night instruction pilot reported engine began not to make power, all indications normal, turned on carb heat, no change noted. Engine began to shake,… ## Other investigations on N5932U (1) 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 CHI96LA121](https://openairdocs.org/ntsb/CHI96LA121), Mar 31, 1996: Piper PA-28-140 (N5932U), Thief Rvr Falls, MN, substantial damage. Probable cause: A ruptured oil line, which resulted in oil exhaustion and subsequent loss of engine power. ## Docket (6 files) The files NTSB released with the investigation on April 28, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102197. 33.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 3.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11717861&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - FAA exam observations and interview with mechanics (item 2, PDF, 1 page, 47 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11717871&FileExtension=pdf&FileName=FSDO%20Inspector%20Observations-Rel.pdf - FAA photos of disconnected engine oil line (item 3, PDF, 2 pages, 861 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11721761&FileExtension=pdf&FileName=Photos%20of%20Disconnected%20Engine%20Oil%20Line-Rel.pdf - Engine overhaul logs (item 4, PDF, 2 pages, 28.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11720842&FileExtension=pdf&FileName=Engine%20Overhaul%20Logs_Redacted-Rel.pdf - Operator initiatives (item 5, PDF, 1 page, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11718142&FileExtension=pdf&FileName=Operator%20Initiatives_Redacted-Rel.pdf - FAA safety briefing article (item 6, PDF, 2 pages, 435 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11718080&FileExtension=pdf&FileName=FAA%20Safety%20Briefing%20-%202018-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.