# NTSB CEN23LA087: World WA-3, N71SN, Shreveport, LA, January 20, 2023

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: January 20, 2023, 16:34 local (22:34 UTC)
- Place: Shreveport, LA
- Coordinates: 32.545827, -93.75031 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.5458&lon=-93.7503&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern downwind: Fuel related](https://openairdocs.org/ntsb-events/190)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Central Region
- Parties: FAA FSDO
- SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs)
- NTSB case key (mKey): 106619
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA087
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106619/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106619
- Page: https://openairdocs.org/ntsb/CEN23LA087

## Probable cause

The loss of engine power due to carburetor icing.

## Findings

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

- [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [World WA-3, 1 case](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=06001AM), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md)
- [Performance/control parameters: descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [World WA-3, 1 case](https://openairdocs.org/ntsb-findings/01062040/cases.md?model=06001AM), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/01062040/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: Fuel related](https://openairdocs.org/ntsb-events/190) (defining event); cases with it: [World WA-3, 1 case](https://openairdocs.org/ntsb-events/190/sequence.md?model=06001AM), [All aircraft, 361 cases](https://openairdocs.org/ntsb-events/190/sequence.md)
- [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [World WA-3, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=06001AM), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md)

## Analysis

When the experimental airplane was on the downwind leg of the traffic pattern, abeam the numbers, the engine started to run rough and vibrate. The pilot added power and the engine smoothed out. The pilot ensured the backup electric fuel pump was in the “on” position and turned the airplane to land on the runway. While on short final, the pilot reduced power and received a low rpm warning from his avionics. When he increased the throttle, the engine stopped producing power. A high sink rate developed, and the airplane landed hard on the runway, which resulted in substantial damage to the empennage. Postaccident examination of the airplane and engine did not reveal any anomalies that would have precluded normal operation. The airplane was operating in an area conducive to the formation of serious carburetor icing at glide power settings. The airplane was fueled with 93-octane automotive fuel which could make carburetor icing more likely. The airplane was not equipped with a carburetor temperature gauge or a carburetor heat control, nor were they required.

## Factual narrative

On January 20, 2023, about 1634 central standard time, an experimental World Aircraft Company WA-3 light sport airplane, N71SN, was substantially damaged when it was involved in an accident near Shreveport, Louisiana. The pilot was not injured. The flight operated under the provisions of the Title 14 Code of Federal Regulations Part 91 as a personal flight. The pilot reported that he departed for takeoff on runway 14 following a normal engine runup. He remained in the traffic pattern and when the airplane was on the downwind leg of the traffic pattern, abeam the numbers, the engine started to run rough and vibrate. The pilot added power and the engine smoothed out. The pilot ensured the backup electric fuel pump was in the on position and he turned the airplane to land on runway 14. While on short final, the pilot reduced power and received a low rpm warning from his avionics. When he increased the throttle, the engine stopped producing power. A high sink rate developed, and the airplane landed hard on the runway, which resulted in substantial damage to the empennage. Postaccident examination of the airplane revealed no anomalies with the airframe or engine that would have precluded normal operation. A review of the Carburetor Icing Probability Chart located in the FAA’s Special Airworthiness Information Bulletin CE-09-35, Carburetor Icing Prevention, dated June 30, 2009, found that the airplane was operating in an area conducive to the formation of serious icing at glide power settings and close to the area of serious icing at cruise power. The airplane was fueled with 93-octane automotive fuel which, as noted below, could make carburetor icing more likely. Additionally, the airplane was not equipped with a carburetor temperature gauge or a carburetor heat control, nor was it required to be by the FAA. Figure 1. Carburetor Icing Probability Chart According to Transport Canada TP 10737 (Use of Automotive Gasoline [Mogas] in Aviation), Mogas is generally higher in volatility than Avgas and will thus absorb more heat from the mixing air when vaporizing, resulting in ice accumulation at higher ambient temperatures. It goes on to say that “the likelihood of carb icing while flying on Mogas is higher,” and advises that, “[a]lthough the severity of the carb icing and the methods to deal with it are similar for both Avgas and Mogas, its ONSET is likely to occur at HIGHER AMBIENT TEMPERATURES and at LOWER HUMIDITY with Mogas. In other words, conditions under which a pilot may feel there is only a slight risk for carb icing on Avgas may in fact be ideal for the formation of ice while using more volatile Mogas. This will result in the need to select ‘carb heat on’ in less severe icing conditions and for a longer duration while using Mogas.”

## Aircraft

- Registration: [N71SN](https://openairdocs.org/deregistered/N71SN-2023-05-21), registration cancelled 2023-05-21, S/N 3061421101 (OpenAirDocs)
- Reported make and model: WORLD AIRCRAFT CO WA-3
- Registry model: [World WA-3](https://openairdocs.org/model/world-wa-3) (registry code 06001AM) (OpenAirDocs)
- Registry engine: [Rotax 912ULS2](https://openairdocs.org/engine/rotax-912uls2) (registry code 55599, 4 cycle) (OpenAirDocs)
- Category: Airplane
- Serial number: 3061421101
- Year built: 2014
- Airframe hours: 4
- Engines: Rotax 912ULS 100 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental light sport (Special)
- Last inspection: Condition, June 22, 2022, 1 hours before
- Airport: DTN, Shreveport Downtown, runway 14, 5,016 × 150 ft, asphalt
- Equipment: Electronic primary flight display, ADS-B, Electronic multifunction display

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 60; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: center; restraint: 3-point; flight hours: 365 total, 0 in this make and model, 1 in the last 30 days

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 130° at 4 knots
- Visibility: 10 statute miles
- Lowest ceiling: 9,000 ft overcast
- Temperature: 54 °F, dew point 36 °F
- Altimeter: 30.23 inHg
- Observed at: KDTN
- METAR: SPECI KDTN 202236Z 13004KT 10SM OVC090 12/02 A3023 RMK AO2 T01220017=

## 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 20230120001409A](https://openairdocs.org/incident/20230120001409A), Jan 20, 2023: World Aircraft Co WA-3, Shreveport, LA, Substantial damage. An experimental light sport (elsa), model WA-3, departed the Shreveport, LA Downtown (kdtn) airport to conduct pattern work. After a normal engine run-up and…

## Docket (7 files)

The files NTSB released with the investigation on March 28, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106619. 10.3 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 5.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16810281&FileExtension=pdf&FileName=CEN23LA087%20NTSB%206120_Redacted-Rel.pdf
- Photos (item 2, PDF, 3 pages, 2 photos, 657 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16810505&FileExtension=pdf&FileName=Photos%202-Rel.pdf
- Logbook excerpt (item 3, PDF, 3 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16810632&FileExtension=pdf&FileName=Log%20Excerpt_Redacted-Rel.pdf
- Carburetor icing documents (item 4, PDF, 3 pages, 844 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16810642&FileExtension=pdf&FileName=CEN23LA087%20Carburetor%20Icing%20Probability%20Chart-Rel.pdf
- Record of conversation FAA (item 5, PDF, 2 pages, 92 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16810057&FileExtension=pdf&FileName=Record%20of%20Conversation%20FAA-Rel.pdf
- Rotax service information SI-04-1994 (item 6, PDF, 4 pages, 155 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16818831&FileExtension=pdf&FileName=SI-04-1994_Carburetor%20icing%20on%20UL-engines-Rel.pdf
- Use of automobile gasoline (mogas) in aviation (item 7, PDF, 28 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16848932&FileExtension=pdf&FileName=tp10737e-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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