# NTSB ERA21LA250: Diamond DA20, N458MA, Matthews, VA, June 14, 2021

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Class 3 · Limited · Final report
- Date: June 14, 2021, 12:30 local (16:30 UTC)
- Place: Matthews, VA · Bay
- Coordinates: 37.371667, -76.228333 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.3717&lon=-76.2283&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO, Transportation Safety Board of Canada
- NTSB case key (mKey): 103257
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA250
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103257/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103257
- Page: https://openairdocs.org/ntsb/ERA21LA250

## Probable cause

The mechanic’s failure to properly secure the oil sump drain plug during a 100-hour maintenance inspection, which resulted in a total loss of engine power due to oil starvation.

## Findings

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

- [Engine (reciprocating): recip eng oil sys](https://openairdocs.org/ntsb-findings/01058550): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 1 case](https://openairdocs.org/ntsb-findings/01058550/cases.md?model=2990001), [All aircraft, 130 cases](https://openairdocs.org/ntsb-findings/01058550/cases.md)
- [Action: forgotten action/omission](https://openairdocs.org/ntsb-findings/02041035): Personnel issues › Action/decision · Maintenance personnel (probable cause); cases with it: [Diamond Aircraft Ind DA20-C1, 1 case](https://openairdocs.org/ntsb-findings/02041035/cases.md?model=2990001), [All aircraft, 440 cases](https://openairdocs.org/ntsb-findings/02041035/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: [Diamond Aircraft Ind DA20-C1, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=2990001), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md)
- [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Diamond Aircraft Ind DA20-C1, 12 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2990001), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Ditching](https://openairdocs.org/ntsb-events/441); cases with it: [Diamond Aircraft Ind DA20-C1, 2 cases](https://openairdocs.org/ntsb-events/441/sequence.md?model=2990001), [All aircraft, 186 cases](https://openairdocs.org/ntsb-events/441/sequence.md)

## Analysis

Due to an active military operations area, the flight instructor and student pilot on a short cross-country instructional flight to an island were instructed by air traffic control to descend from 5,500 ft mean sea level (msl) to 2,500 ft msl. After the student pilot leveled the airplane at 2,500 ft msl, the engine shook violently and lost all power. The flight instructor took control of the airplane and realized that there was not enough altitude to glide to shore. The flight instructor then ditched the airplane near a fishing trawler where he and the student pilot were rescued. The wreckage was recovered about 2 weeks after the accident and examined at a recovery facility. Examination of the engine revealed that the oil sump drain plug was missing, and the Nos. 1 and 2 connecting rods were fractured in a manner consistent with oil starvation. Review of maintenance records revealed that the airplane’s most recent 100-hour inspection was completed 4 days and 9.3 operating hours before the accident. During an interview, the mechanic who performed the 100-hour inspection stated that he remembered draining the old oil, reinstalling the drain plug with a new gasket, torquing it per the maintenance manual, and securing it with safety wire. He did not remember anything abnormal or any interruptions during the work. Although the mechanic stated that he torqued and safety wired the drain plug, the findings of the investigation the accident suggest that the mechanic likely installed the plug finger-tight and forgot to secure it. Due to normal engine vibration, the plug unscrewed, and the engine oil drained out, which resulted in the total loss of engine power due to oil starvation.

## Factual narrative

On June 14, 2021, about 1230 eastern daylight time, a Diamond DA20-C1, N458MA, was substantially damaged when it was involved in an accident near Matthews, Virginia. The flight instructor and student pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that during preflight inspection, he added 1 quart of oil to the engine to bring the total quantity to 5 quarts. During a short cross-country flight to Tangier Island in the Chesapeake Bay, air traffic control instructed the flight to descend from 5,500 ft mean sea level (msl) to 2,500 ft msl, due to an active military operations area. After the student pilot leveled the airplane at 2,500 ft msl, the flight instructor noticed engine vibration and roughness that he initially corrected by advancing the throttle from 1,900 to 2,200 rpm; however, the engine subsequently shook “violently” followed by a total loss of engine power. The flight instructor took control of the airplane and realized that there was not enough altitude to glide to a shore. The flight instructor then ditched the airplane in the Chesapeake Bay near a fishing trawler where he and the student pilot were rescued. The wreckage was recovered about 2 weeks after the accident and examined at a recovery facility. Examination of the wreckage revealed that the right wing sustained substantial damage. Examination of the engine revealed that that oil sump drain plug was missing, and the Nos. 1 and 2 connecting rods were fractured in a manner consistent with oil starvation. Review of maintenance records revealed that the airplane’s most recent 100-hour inspection was completed 4 days and 9.3 operating hours before the accident. During an interview, the mechanic who performed the 100-hour inspection stated that he remembered draining the old oil, reinstalling the drain plug with a new gasket, torquing it per the maintenance manual, and securing it with safety wire. He did not remember anything abnormal or any interruptions during the work.

## Aircraft

- Registration: [N458MA](https://openairdocs.org/aircraft/N458MA), registered now, S/N C0340, built 2005 (OpenAirDocs)
- Reported make and model: DIAMOND DA20 (C1)
- Registry model: [Diamond Aircraft Ind DA20-C1](https://openairdocs.org/model/diamond-aircraft-ind-da20-c1) (registry code 2990001) (OpenAirDocs)
- Registry engine: [Continental IO-240-B](https://openairdocs.org/engine/continental-io-240-b) (registry code 17177, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: C0340
- Year built: 2005
- Airframe hours: 6133
- Engines: Continental IO-240-B 125 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: American Aviation LLC
- Registered owner: Magrahen Air LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, June 9, 2021, 9.3 hours before
- Departed: HEF, Manassas, VA
- Destination: TGI, Tangier Island, VA
- Flight plan: VFR
- Airport: NONE
- Equipment: Electronic multifunction display, Electronic flight bag or handheld device, ADS-B, Stall warning system, Onboard weather, Handheld GPS

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Flight instructor; age 46; injuries: minor; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review September 1, 2019; seat: right; restraint: 4-point; flight hours: 997 total, 96 in this make and model, 783 as pilot in command, 32 in the last 90 days, 9 in the last 30 days, 4 in the last 24 hours
- Student pilot; age 22; injuries: minor; seat: left; restraint: 4-point; flight hours: 7 total, 7 in this make and model, 0 as pilot in command, 7 in the last 90 days, 7 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 7 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 82 °F, dew point 70 °F
- Altimeter: 29.85 inHg
- Observed at: KPHF, 19 nm away
- METAR: METAR KPHF 141654Z 26007KT 10SM CLR 28/21 A2985

## 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 20210614007489A](https://openairdocs.org/incident/20210614007489A), Jun 14, 2021: Diamond Aircraft Ind Inc DA20-C1, Matthews, VA, Destroyed. The pilot stated he was the PIC for an instrument familiarization flight with a student. They were simulating an instrument approach into tangier island…

## Docket (6 files)

The files NTSB released with the investigation on March 1, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103257. 5.1 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 12 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13095184&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf
- Interview summaries (item 2, PDF, 2 pages, 122 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13095748&FileExtension=pdf&FileName=Interview%20Summaries_Redacted-Rel.pdf
- Excerpts from maintenance records (item 3, PDF, 2 pages, 292 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13095568&FileExtension=pdf&FileName=Mx%20Excerpts_Redacted-Rel.pdf
- Engine examination report (item 4, PDF, 4 pages, 924 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13096443&FileExtension=pdf&FileName=Engine%20Examination%20Report-Rel.pdf
- Photo array (item 5, PDF, 5 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13095194&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 6, PDF, 1 page, 535 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13095758&FileExtension=pdf&FileName=Wreckage%20Release%20Signed_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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