# NTSB ERA20LA195: Piper PA24, N5948P, South Boston, VA, May 26, 2020

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: May 26, 2020, 14:30 local (18:30 UTC)
- Place: South Boston, VA
- Coordinates: 36.699184, -78.899894 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.6992&lon=-78.8999&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- NTSB case key (mKey): 101328
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA20LA195
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/101328/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=101328
- Page: https://openairdocs.org/ntsb/ERA20LA195

## Probable cause

The powerplant mechanic’s failure to properly affix the engine crankshaft gear lockplate during overhaul, resulting in a total loss of engine power.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Engine (reciprocating): recip eng rear section](https://openairdocs.org/ntsb-findings/01058540): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Piper PA-24-250, 1 case](https://openairdocs.org/ntsb-findings/01058540/cases.md?model=7102404), [All aircraft, 42 cases](https://openairdocs.org/ntsb-findings/01058540/cases.md)
- [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Maintenance personnel; cases with it: [Piper PA-24-250, 2 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=7102404), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/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 downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Piper PA-24-250, 23 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7102404), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Maneuvering: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-24-250, 23 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7102404), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-24-250, 55 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7102404), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

During a personal flight the private pilot proceeded to the destination airport and entered the airport traffic pattern for a planned full-stop landing. While on a close-in downwind leg of the airport traffic pattern the engine experienced a sudden and total loss of engine power. The pilot turned toward the approach end of the runway and attempted to restore engine power but was unsuccessful. The airplane impacted an obstruction light and touched down in tall grass on airport property before coming to rest upright. Postaccident examination of the engine revealed the crankshaft gear attachment bolt was loose, the lockplate was fractured, and the alignment dowel was sheared. The intact portion of the fractured lockplate was similar to an un-bent exemplar lockplate; therefore, it is likely the mechanic who overhauled the engine about 253 hours and 8 years earlier did not bend the lockplate against the flat of the crankshaft gear attachment bolt head. The crankshaft gear drives two idler gears in the accessory gearbox, which drive the camshaft, engine driven fuel pump, vacuum pump and the magneto drive couplings. The failure of the crankshaft gear to rotate would result in a loss of engine power.

## Factual narrative

On May 26, 2020, about 1430 eastern daylight time, a Piper PA-24-250, N5948P, was substantially damaged when it was involved in an accident near South Boston, Virginia. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that he performed a preflight inspection of the airplane before the intended 20 to 25 minutes flight, which included a check of each wing fuel tank sump drain and also the gascolator with no contaminants found. He also checked the flexible hoses in the engine compartment for condition and security, looked for fuel stains, and checked the P-Leads for condition and security. Prior to departure he performed an engine run-up noting that the magneto decreases were about 25 rpm or less from each magneto. After takeoff he proceeded towards the William M Tuck Airport (W78), South Boston, Virginia, where while on a close-in downwind leg of the airport traffic for runway 19 flying at 1,200 ft mean sea level, the engine experienced a sudden total loss of power. He turned on the auxiliary fuel pump, moved the fuel selector from the left tank where it had been since takeoff to the right tank, and moved the mixture control to full rich, but engine power was not restored. He turned towards the approach end of the runway with the airplane configured with the flaps and landing gear retracted and maintained 80 miles-per-hour (mph). The airplane subsequently impacted an obstruction light, touched down in tall/thick grass on airport property and slid an unknown distance before coming to rest upright. The airplane was recovered to W78 for examination of the engine. Examination of the engine following recovery by a Federal Aviation Administration (FAA) inspector revealed hand rotation of the crankshaft did not result in rotation of the magnetos, or valve train action at the No. 1 cylinder. The accessory case was removed and during rotation of the crankshaft, the crankshaft gear did not rotate. The crankshaft gear attachment bolt which was marked on the head with “2247”, was “found unsecured and loose.” The bolt, fractured remnants of the lockplate, and crankshaft gear were removed. It was noted that the alignment dowel pin was sheared. The profile of the intact portion of the accident lockplate was similar to an un-bent exemplar lockplate. The left and right magneto driven gears, crankshaft gear, and crankshaft gear attachment bolt were undamaged. It was not determined if there was Loctite anti-seize compound on the lower portion of the crankshaft gear attachment bolt threads. The crankshaft gear drives two idler gears in the accessory gearbox, which drive the camshaft, engine driven fuel pump, vacuum pump and the magneto drive couplings. A review of the engine maintenance records revealed the engine was overhauled by an airframe and powerplant (A&P) mechanic in 2011 and had accrued about 253 hours since overhaul at the time of the accident. The maintenancerecord entry for the engine overhaul did not specify installation of a new crankshaft gear attachment bolt or lockplate, or the final torque value of the crankshaft gear attaching bolt, as specified by Lycoming Service Bulletin 475C, dated January 30, 2003. According to the FAA inspector, the A&P mechanic was deceased; therefore, it could not be determined what procedures were used to install the crankshaft gear or whether a new crankshaft gear attachment bolt or lockplate was installed at the time of engine overhaul.

## Aircraft

- Registration: [N5948P](https://openairdocs.org/aircraft/N5948P), registered now, S/N 24-1039, built 1959 (OpenAirDocs)
- Reported make and model: Piper PA24 (250)
- Registry model: [Piper PA-24-250](https://openairdocs.org/model/piper-pa-24-250) (registry code 7102404) (OpenAirDocs)
- Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 24-1039
- Year built: 1959
- Airframe hours: 4628
- Engines: Lycoming O-540-A1A 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 5, 2019, 10 hours before
- Departed: W63, Clarksville, VA
- Destination: Same as departure
- Airport: W78, William M Tuck Airport, runway 19, 4,003 × 75 ft, asphalt
- Equipment: Stall warning system, ADS-B

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 62; injuries: none; private; airplane ratings: single-engine land; medical: basicmed; last flight review August 29, 2019; seat: left; restraint: lap only; flight hours: 1,903 total, 1,620 in this make and model, 1,903 as pilot in command, 5 in the last 90 days, 2 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 80° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: 3,800 ft broken
- Temperature: 79 °F, dew point 61 °F
- Altimeter: 30.15 inHg
- Observed at: W78

## 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 20200526008179A](https://openairdocs.org/incident/20200526008179A), May 26, 2020: Piper PA-24-250, South Boston, VA, Substantial damage. Pilot was executing a normal landing at W78, William M Tuck airfield. Aircraft performed normally throughout all phases of flight until a sudden engine failure…

## Docket (6 files)

The files NTSB released with the investigation on June 8, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=101328. 13.1 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12189196&FileExtension=pdf&FileName=6120%20Recd%206%2012%202020_Redacted-Rel.pdf
- Record of NTSB conversation (item 2, PDF, 5 pages, 2 photos, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12188884&FileExtension=pdf&FileName=Record%20of%20NTSB%20Conversation_Redacted-Rel.pdf
- FAA inspector statement (item 3, PDF, 1 page, 27 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=9826994&FileExtension=pdf&FileName=FAA%20Inspector%20Statement-Rel.pdf
- Maintenance record entry for engine overhaul (item 4, PDF, 1 page, 5.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12365876&FileExtension=pdf&FileName=Engine%20Overhaul%20Entry_Redacted-Rel.pdf
- Investigative photographs (item 5, PDF, 8 pages, 8 photos, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12365639&FileExtension=pdf&FileName=Investigative%20Photographs-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 6, PDF, 1 page, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=9826643&FileExtension=pdf&FileName=Fully%20Executed%20Wreckage%20Release%20Form_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.

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