# NTSB Accident DCA91MA023
> **BOEING 737-291** · 1991-03-03 · COLORADO SPGS, CO, USA · FATL
## Event
- **NTSB number:** DCA91MA023
- **Event ID:** 20001212X16583
- **Type:** Accident
- **Date:** 1991-03-03
- **Location:** COLORADO SPGS, CO, USA
## Injuries
- **Highest injury:** FATL
- **Fatal:** 25
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 0
- **Total aboard:** 25
## Aircraft
- **Make:** BOEING
- **Model:** 737-291
- **Registration:** N999UA
- **FAR Part:** 121
- **Engines:** 2
- **Damage:** DEST
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

A loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=DCA91MA023) · AI Analytics · CC0 1.0*