# NTSB Accident DCA18MA142
> **BOEING 737 7H4** · 2018-04-17 · Philadelphia, PA, USA · FATL
## Event
- **NTSB number:** DCA18MA142
- **Event ID:** 20180417X23642
- **Type:** Accident
- **Date:** 2018-04-17
- **Location:** Philadelphia, PA, USA
- **Coordinates:** 39.871944, -75.239997
## Injuries
- **Highest injury:** FATL
- **Fatal:** 1
- **Serious:** 8
- **Minor:** 125
- **Uninjured:** 6
- **Total aboard:** 140
## Aircraft
- **Make:** BOEING
- **Model:** 737 7H4
- **Registration:** N772SW
- **FAR Part:** 121
- **Engines:** 2
- **Damage:** SUBS
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

A low-cycle fatigue crack in the dovetail of fan blade No. 13, which resulted in the fan blade separating in flight and impacting the engine fan case at a location that was critical to the structural integrity and performance of the fan cowl structure. This impact led to the in-flight separation of fan cowl components, including the inboard fan cowl aft latch keeper, which struck the fuselage near a cabin window and caused the window to depart from the airplane, the cabin to rapidly depressurize, and the passenger fatality.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=DCA18MA142) · AI Analytics · CC0 1.0*