# NTSB CEN23LA014: Diamond Aircraft Ind DA 62, N84LT, Dallas, TX, October 15, 2022

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: October 15, 2022, 14:48 local (19:48 UTC)
- Place: Dallas, TX · Urban
- Coordinates: 32.706286, -96.925575 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.7063&lon=-96.9256&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach: Electrical system malf/failure](https://openairdocs.org/ntsb-events/332)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Central Region
- Parties: FAA Flight Standards District Office, Austrian Federal Safety Investigation Authority, Transportation Safety Board of Canada
- NTSB case key (mKey): 106135
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA014
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106135/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106135
- Page: https://openairdocs.org/ntsb/CEN23LA014

## Probable cause

A total loss of airplane electrical power for undetermined reasons, which resulted in a complete loss of engine power to both engines. Contributing was the worn main battery and the incorrectly wired ECU backup batteries.

## Findings

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

- [Electrical power system: battery/charger](https://openairdocs.org/ntsb-findings/01022432): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-findings/01022432/cases.md?model=2990107), [All aircraft, 37 cases](https://openairdocs.org/ntsb-findings/01022432/cases.md)
- [Electrical power system: electrical pwr sys wiring](https://openairdocs.org/ntsb-findings/01022497): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-findings/01022497/cases.md?model=2990107), [All aircraft, 44 cases](https://openairdocs.org/ntsb-findings/01022497/cases.md)
- [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=2990107), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md)
- [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=2990107), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md)
- [Selection/certification/testing: document/info verification](https://openairdocs.org/ntsb-findings/04012025): Organizational issues › Development · Manufacturer (probable cause); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-findings/04012025/cases.md?model=2990107), [All aircraft, 6 cases](https://openairdocs.org/ntsb-findings/04012025/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Unknown: Unknown or undetermined](https://openairdocs.org/ntsb-events/000); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-events/000/sequence.md?model=2990107), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md)
- [Approach: Electrical system malf/failure](https://openairdocs.org/ntsb-events/332) (defining event); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-events/332/sequence.md?model=2990107), [All aircraft, 182 cases](https://openairdocs.org/ntsb-events/332/sequence.md)
- [Approach: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=2990107), [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: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=2990107), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Diamond Aircraft Ind DA 62, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=2990107), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

While descending in preparation to fly a visual approach, the pilot lowered the landing gear and contacted the tower controller for landing clearance. During the controller’s response, the pilot reported hearing a “pop” and observed the avionics display screens lose power. A few seconds later, he observed that both engines had lost power. The pilot executed a forced landing on to a road, during which the airplane struck a power line in the descent, and after touchdown, two road signs, which resulted in substantial damage to the right wing. A postaccident examination of the airplane revealed that the electronic control unit (ECU) backup batteries were wired incorrectly (parallel versus series) and the in-line fuses for the backup ECU power system for both engines were blown. The incorrect wiring would have resulted in only 12 volts instead of 24 volts being available which would have resulted in a higher current draw and subsequent blown fuses. According to the airplane’s maintenance records, 4 new ECU battery backup batteries were installed during the annual maintenance inspection about 4 months before the accident. The 1,000 hour/12-month Concorde battery capacitance check was also completed, and the battery had 92% capacitance. It is likely that during this maintenance the batteries were incorrectly rewired in parallel. A review of the aircraft maintenance manual showed that it did not provide a procedure to verify the ECU backup batteries were functioning correctly after replacement. The last step in the ECU back-up battery installation was to run engines and verify that the electrical system operated correctly. However, this step does not verify that the ECU backup batteries were installed correctly and were ready to provide power to the ECUs. In addition, there was no ECU backup battery operational test. If there had been such a test, the improperly connected batteries would have been discovered immediately after replacement. Completing this check on a routine basis would determine if the in-line fuse has blown. Furthermore, the pilot did not have the ability to check for the proper functioning of the ECU batteries before every flight during the before-takeoff checklist. The airplane manufacturer does complete a test of the ECU back-up batteries as part of the production process. Per the airplane’s maintenance records, the main battery was a serviceable one that was installed while maintenance waited for a new battery that was on order. The battery had been installed 23 days before the accident. The airplane had flown about 15 hours from the time the serviceable battery was installed to the accident. The main battery capacitance was tested and found to be 11.04 Amperes-hours (Ah) or 81.2% of rated capacity. The battery capacitance requirement was 85% or better. The loss of main battery power most likely occurred during the landing gear extension when the hydraulic pump turned on, and simultaneous with the radio transmissions. However,during the aircraft and component testing a definitive root cause of the initial power failure could not be determined. Testing could not duplicate the conditions of the flight when the electrical system anomaly occurred or the anomaly itself. With the ECU backup batteries and the alternator relays wired incorrectly, there was no back-up power to the ECU, which resulted in the complete loss of power to both engines and the inability for the engines to restart. While multiple anomalies with the wiring and battery system were documented, a definitive root cause of the initial power failure could not be determined. An electrical system anomaly caused the aircraft electrical system to shutdown and subsequent engine shutdown due to the mis-connected ECU back-up batteries. The testing done could not duplicate the actual conditions of the flight when the electrical system anomaly occurred or the anomaly itself.

## Factual narrative

On October 15, 2022, about 1448 central daylight time, a Diamond Aircraft DA62, N84LT, was substantially damaged during a forced landing near the Dallas Executive Airport (RBD), Dallas, Texas. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. A review of ADS-B data revealed that the airplane departed Winston Field Airport (SNK), Snyder, Texas, about 1448, and climbed to a cruise altitude of 11,500 ft mean sea level (msl). On arrival, the pilot descended to fly a visual approach to Runway 13 at RBD, extended the landing gear, and contacted the tower controller for landing clearance. During the controller’s response, the pilot heard a “pop” and observed the avionics display screens lose power. A few seconds later, he observed that both engines had lost power. The pilot executed a forced landing on to a road, during which the airplane struck a power line in the descent, and after touchdown, two road signs, which resulted in substantial damage to the right wing. A review of downloaded engine and flight data indicated the airplane lost electrical power to the avionics system and both engines nearly simultaneously while at 2,000 ft msl and about 5 miles west of RBD. The airplane was equipped with two Austro Engine E4P-C liquid-cooled, in-line four-stroke four-cylinder diesel engines. All engine components are controlled by an electronic engine control unit (ECU) system. Each engine can only be operated with the engine master switch ON. Each engine has its own ECU which receives its electrical power from the alternator when at least one engine is running. When both engines are off, the ECU receives its electrical power from the main battery or the back-up ECU batteries. The engine master switch must be set to ON to activate the engine ECU. To support the alternator electrical power supply to the ECUs in case of a malfunction of the main battery, additional sealed-lead-acid batteries are connected to the left and right engine ECU buses. These batteries are designed to provide 30 minutes of engine operation in case of a complete airplane electrical failure. Both engines may stop if the 30 minutes have elapsed. Postaccident examination of the airplane revealed the backup ECU batteries for both engines had been wired in parallel, rather than in series, and the in-line fuses to the ECU batteries were blown. The main battery capacitance was tested and found to be 11.04 Amperes-hours (Ah), or 81.2% of its rated capacity. The battery capacitance requirement was 85% or better. Additionally, the alternator relays were wired such that the alternator would not disconnect the alternator power from the main electrical system. The relays would cut power to the glow plugs for the respective engines. The Garmin G1000 NXi electronic flight instrument system (EFIS) recorded data indicated that the accident flight had a duration of 1 hour 25 minutes and 49 seconds. The Austo Engine ECUscontained non-volatile memory used to store 16 channels of data signals. The right engine data contained 23 sessions of recording to include the accident flight. The left engine data contained 11 sessions to include the accident flight. However, while the right engine event flight recording had one hour 25 minutes 3 seconds of recording, the left engine data ended earlier and had only 18 minutes and 46 seconds of recording. The ECU right engine data of the event showed the right engine circuitry bus voltage was at 27 volts until 1447:41, when it suddenly dropped to 11.7 volts, after which the recording stopped. Airplane and component testing did not reveal a definitive root cause of the initial power failure. Testing could not duplicate the actual conditions of the flight when the electrical system anomaly occurred or the anomaly itself. According to the airplane’s maintenance records, as part of the annual maintenance inspection on June 24, 2022, the 12-month ECU battery backup replacement check was completed, and 4 new ECU battery backup batteries were installed. The 1000 hour/12-month Concorde battery capacitance check was also completed, and the battery had 92% capacitance. On September 21, 2022, the airplane’s main battery was replaced with a serviceable one as the maintenance facility waited for a new battery that was on order. The airplane had flown about 15 hours from the time the serviceable battery was installed to the accident. A review of the aircraft maintenance manual showed it did not provide a procedure to verify the ECU back-up batteries were functioning correctly after replacement. The last step in the ECU backup battery installation was to run engines and verify that the electrical system operated correctly. However, this step does not verify that the ECU backup batteries were installed correctly and were ready to provide power to the ECUs. In addition, there was no ECU backup battery operational test. Diamond Aircraft issued a service information letter requiring inspection of ECU backup batteries wiring installation on all DA 62 aircraft.

## Aircraft

- Registration: [N84LT](https://openairdocs.org/aircraft/N84LT), registered now, S/N 62.C003 (OpenAirDocs)
- Reported make and model: DIAMOND AIRCRAFT IND INC DA 62
- Registry model: [Diamond Aircraft Ind DA 62](https://openairdocs.org/model/diamond-aircraft-ind-da-62) (registry code 2990107) (OpenAirDocs)
- Registry engine: [Austro E4P(SERIES)](https://openairdocs.org/engine/austro-e4p-series) (registry code 06405, 4 cycle) (OpenAirDocs)
- Category: Airplane
- Serial number: 62.C003
- Year built: 2018
- Airframe hours: 577
- Engines: Austro Engines E4P-C 180 horsepower reciprocating; Austro Engines E4P-C 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 24, 2022, 54 hours before
- Departed: SNK, Snyder, TX
- Destination: RBD, Dallas, TX
- Airport: RBD, Dallas Executive Airport, runway 13, 7,136 × 100 ft, concrete
- Equipment: Electronic flight bag or handheld device, Auto-pilot, ADS-B, Stall warning system, Electronic primary flight display, Electronic multifunction display

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 60; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review June 6, 2022; seat: left; restraint: 3-point; flight hours: 905 total, 332 in this make and model, 818 as pilot in command, 46 in the last 90 days, 26 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 11 knots, gusting 20
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 91 °F, dew point 64 °F
- Altimeter: 29.93 inHg
- Observed at: KRBD, 3 nm away
- METAR: KRBD 151953Z 18011G20KT 10SM CLR 33/18 A2993 RMK AO2 SLP125 T03330178 $

## 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 20221015022289A](https://openairdocs.org/incident/20221015022289A), Oct 15, 2022: Diamond DA-62, Dallas, TX, Substantial damage. On October 15, 2022, the pilot of DA-62 [privacy data omitted]s/n: 62.C003 made an emergency landing on kiest rd. in Dallas, TX approximately 2 miles from rbd.…

## Docket (14 files)

The files NTSB released with the investigation on November 26, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106135. 82.4 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 7.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16430698&FileExtension=pdf&FileName=Pilot%206120%20report%20-%20redacted-Rel.pdf
- CEN23LA014 systems factual report (item 2, PDF, 34 pages, 3.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17412572&FileExtension=pdf&FileName=CEN23LA014%20Systems%20Factual%20Report%20final-Rel.pdf
- CEN23LA014 systems factual report - attachment 1 (item 3, PDF, 2 pages, 122 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17413716&FileExtension=pdf&FileName=CEN23LA014%20Systems%20factual%20-%20Attachment%201%20-%20final-Rel.pdf
- CEN23LA014 systems factual report - attachment 2 (item 4, PDF, 5 pages, 347 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17413058&FileExtension=pdf&FileName=CEN23LA014%20Systems%20factual%20-%20Attachment%202%20-%20final-Rel.pdf
- CEN23LA014 systems factual report - attachment 3 (item 5, PDF, 7 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17416693&FileExtension=pdf&FileName=CEN23LA014%20Systems%20factual%20-%20Attachment%203%20final-Rel.pdf
- Electronic devices - specialist's factual report (item 6, PDF, 17 pages, 3.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15535583&FileExtension=pdf&FileName=Electronic%20Devices%20-%20Specialist%27s%20Factual%20Report_CEN23LA014-Rel.pdf
- Attchment 1 to electronic recorder devices - specialist's factual report_CEN23LA014_tabular data (item 7, CSV, 612 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15534379&FileExtension=csv&FileName=Attchment%201%20to%20Electronic%20Recorder%20Devices%20-%20Specialist%27s%20Factual%20Report_CEN23LA014_Tabular%20Data-Rel.csv
- Attchment 2 to electronic recorder devices - specialist's factual report_CEN23LA014_tabular data (item 8, CSV, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15535850&FileExtension=csv&FileName=Attchment%202%20to%20Electronic%20Recorder%20Devices%20-%20Specialist%27s%20Factual%20Report_CEN23LA014_Tabular%20Data-Rel.csv
- Attchment 3 to electronic recorder devices - specialist's factual report_CEN23LA014_tabular data (item 9, CSV, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15535500&FileExtension=csv&FileName=Attchment%203%20to%20Electronic%20Recorder%20Devices%20-%20Specialist%27s%20Factual%20Report_CEN23LA014_Tabular%20Data-Rel.csv
- Mx log - excerpt of last annual inspection and main battery replacement (item 10, PDF, 1 page, 54.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17075458&FileExtension=pdf&FileName=Mx%20Log%20-%20Excerpt%20of%20Last%20Annual%20Inspection%20and%20Main%20Battery%20Replacement_Redacted-Rel.pdf
- ADS-B - google earth view (item 11, KML, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16431463&FileExtension=KML&FileName=CEN23LA014-Rel.KML
- ADS-B - raw data (item 12, CSV, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16430940&FileExtension=csv&FileName=accident%20flt%20-%20log_221015_132317_KSNK-Rel.csv
- Photos of airplane (item 13, PDF, 3 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16431048&FileExtension=pdf&FileName=Photos%20of%20Airplane%20-%20Right%20Wing%20Damage-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 14, PDF, 1 page, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16430930&FileExtension=pdf&FileName=Wreckage%20release%20--_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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