# NTSB Accident CHI91FA235
> **AERO COMMANDER 500B** · 1991-07-31 · SILICA, KS, USA · FATL
## Event
- **NTSB number:** CHI91FA235
- **Event ID:** 20001212X17487
- **Type:** Accident
- **Date:** 1991-07-31
- **Location:** SILICA, KS, USA
## Injuries
- **Highest injury:** FATL
- **Fatal:** 2
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 0
- **Total aboard:** 2
## Aircraft
- **Make:** AERO COMMANDER
- **Model:** 500B
- **Registration:** N904DF
- **FAR Part:** 135
- **Engines:** 2
- **Damage:** DEST
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

THE FAILURE OF BOTH PILOTS TO MAINTAIN ADEQUATE SEPARATION DURING FORMATION FLIGHT.  RELATED FACTORS ARE OVERCONFIDENCE IN PERSONAL ABILITY AND POOR PLANNING/DECISION.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=CHI91FA235) · AI Analytics · CC0 1.0*