# NTSB Accident LAX90LA187
> **HUGHES 269C** · 1990-05-23 · RIALTO, CA, USA · NONE
## Event
- **NTSB number:** LAX90LA187
- **Event ID:** 20001212X23186
- **Type:** Accident
- **Date:** 1990-05-23
- **Location:** RIALTO, CA, USA
- **Coordinates:** 34.099674, -117.380584
## Injuries
- **Highest injury:** NONE
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 1
- **Total aboard:** 1
## Aircraft
- **Make:** HUGHES
- **Model:** 269C
- **Registration:** N7441F
- **FAR Part:** 091
- **Engines:** 1
- **Damage:** SUBS
## Conditions
- **Light:** DAYL
- **Weather:** VMC
## Probable cause

IMPROPER MAINTENANCE PROCEDURE BY MAINTENANCE PERSONNEL TO TROUBLESHOOT A REPORTED DEFICIENCY AND THE PILOT'S DECISION TO DEMONSTRATE THE VIBRATION, EXCEEDING THE DESIGN LIMITS OF THE HELICOPTER AND INDUCING GROUND RESONANCE. CONTRIBUTING TO THE ACCIDENT WAS THE LOW NITROGEN CHARGE OF THE LANDING GEAR DAMPERS.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=LAX90LA187) · AI Analytics · CC0 1.0*