# NTSB Incident CHI91IA058
> **BOEING B727-223** · 1991-01-04 · DES MOINES, IA, USA · MINR
## Event
- **NTSB number:** CHI91IA058
- **Event ID:** 20001212X16272
- **Type:** Incident
- **Date:** 1991-01-04
- **Location:** DES MOINES, IA, USA
- **Coordinates:** 41.530643, -93.659301
## Injuries
- **Highest injury:** MINR
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 2
- **Uninjured:** 102
- **Total aboard:** 104
## Aircraft
- **Make:** BOEING
- **Model:** B727-223
- **Registration:** N6821
- **FAR Part:** 121
- **Engines:** 3
- **Damage:** —
## Conditions
- **Light:** NDRK
- **Weather:** VMC
## Probable cause

AN OIL LEAK ORIGINATING FROM THE AUXILIARY POWER UNIT WHICH CREATED SMOKE IN THE PASSENGER CABIN AFTER IT PASSED THROUGH THE AIR CONDITIONING/HEATING SYSTEM EQUIPMENT AND ASSOCIATED DUCT WORK.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=CHI91IA058) · AI Analytics · CC0 1.0*