# NTSB DCA21LA208: Boeing 737-990ER, N479AS, SeaTac, WA, August 24, 2021

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Class 4 · Limited · Final report
- Date: August 23, 2021, 20:45 local (Aug 24, 2021, 03:45 UTC)
- Place: SeaTac, WA
- Coordinates: 47.443719, -122.31173
- Nearby events: https://openairdocs.org/map.md?lat=47.4437&lon=-122.3117&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Defining event: [Taxi-from runway: Evacuation](https://openairdocs.org/ntsb-events/460)
- Highest injury: Serious injuries
- Injuries: 1 serious, 3 minor, 130 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Major Investigations Division
- Parties: FAA, Alaska Airlines, Boeing, ALPA
- NTSB case key (mKey): 103753
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA21LA208
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103753/pdf
- Page: https://openairdocs.org/ntsb/DCA21LA208

## Probable cause

The passenger’s use of the evacuation slide resulted in the serious injury.

## Findings

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

- [Aircraft](https://openairdocs.org/ntsb-findings/01060000): Aircraft › Aircraft oper/perf/capability · Related operating info; cases with it: [Boeing 737-990ER, 1 case](https://openairdocs.org/ntsb-findings/01060000/cases.md?model=13848CE), [All aircraft, 63 cases](https://openairdocs.org/ntsb-findings/01060000/cases.md)

## Sequence of events

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

- [Taxi-from runway: Evacuation](https://openairdocs.org/ntsb-events/460) (defining event); cases with it: [Boeing 737-990ER, 1 case](https://openairdocs.org/ntsb-events/460/sequence.md?model=13848CE), [All aircraft, 103 cases](https://openairdocs.org/ntsb-events/460/sequence.md)

## Analysis

Even though an overheated passenger cell phone was put into a battery containment bag (BCB) by the cabin crew, a large amount of smoke remained in the cabin with a strong acrid smell. As a result, the captain commanded an evacuation on taxiway A spot 6A at the Seattle-Tacoma International Airport (SEA), Seattle Washington. One passenger broke their elbow while descending on the evacuation slide.

## Aircraft

- Registration: [N479AS](https://openairdocs.org/aircraft/N479AS), registered now, S/N 60576, built 2015 (OpenAirDocs)
- Reported make and model: BOEING 737-990ER
- Registry model: [Boeing 737-990ER](https://openairdocs.org/model/boeing-737-990er) (registry code 13848CE) (OpenAirDocs)
- Registry engine: [CFM International CFM56-7B27E series](https://openairdocs.org/engine/cfm-international-cfm56-7b27e-series) (registry code 13078, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 60576
- Year built: 2015
- Engines: CFM INTL CFM56-7B27E 27300 lbs thrust turbo fan; CFM INTL CFM56-7B27E 27300 lbs thrust turbo fan
- Damage: No damage
- Fire: On-Ground
- Flight: Part 121
- Operator: Alaska Airlines Inc
- Registered owner: Alaska Airlines Inc
- Airworthiness certificate: Standard, Transport
- Departed: MSY, New Orleans, LA
- Destination: SEA, Seattle, WA
- Flight plan: IFR
- Airport: SEA, Seattle-Tacoma Intl

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: variable at 4 knots
- Visibility: 10 statute miles
- Lowest ceiling: 7,500 ft broken
- Temperature: 63 °F, dew point 32 °F
- Altimeter: 29.89 inHg

## 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 20210823017459A](https://openairdocs.org/incident/20210823017459A), Aug 23, 2021: Boeing 737-990ER, Seatac, WA, No damage. At 2045(l),on 8/23/2021, an [privacy data omitted]737-990ER, registration number N479AS, performed an evacuation due to smoke emanating from a passenger's…

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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