# NTSB Accident DEN07LA122
> **Beech C-45H** · 2007-07-19 · Longmont, CO, USA · SERS
## Event
- **NTSB number:** DEN07LA122
- **Event ID:** 20070730X01039
- **Type:** Accident
- **Date:** 2007-07-19
- **Location:** Longmont, CO, USA
- **Coordinates:** 40.119445, -105.055557
## Injuries
- **Highest injury:** SERS
- **Fatal:** 0
- **Serious:** 1
- **Minor:** 1
- **Uninjured:** 0
- **Total aboard:** 2
## Aircraft
- **Make:** Beech
- **Model:** C-45H
- **Registration:** N9562Z
- **FAR Part:** 091
- **Engines:** 2
- **Damage:** DEST
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

The instructor pilot's improper preflight in that he failed to close the rocker box recovery system drain valves, resulting in a total loss of lubricating oil and subsequent oil starvation to both engines.  A contributing factor was the trees.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=DEN07LA122) · AI Analytics · CC0 1.0*