# NTSB Incident ENG23LA045
> **BELL 407** · 2023-09-21 · Linden, NJ, USA · —
## Event
- **NTSB number:** ENG23LA045
- **Event ID:** 20240117193675
- **Type:** Incident
- **Date:** 2023-09-21
- **Location:** Linden, NJ, USA
- **Coordinates:** 40.616379, -74.242562
## Injuries
- **Highest injury:** —
- **Fatal:** 0
- **Serious:** 0
- **Minor:** 0
- **Uninjured:** 0
- **Total aboard:** 0
## Aircraft
- **Make:** BELL
- **Model:** 407
- **Registration:** N406TD
- **FAR Part:** UNK
- **Engines:** —
- **Damage:** —
## Conditions
- **Light:** NR
- **Weather:** Unk
## Probable cause

The fracture of the upper-left tail boom attachment bolt due to abnormal loading of the bolt caused by a gap and misalignment between the upper-left longeron and the tail boom. Contributing to this incident was the lack of a check to verify the absence of gaps or misalignments at the conclusion of installation for the upper-left longeron.

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*Source: [NTSB CAROL](https://data.ntsb.gov/carol-main-public/basic-search?source=ntsb&type=event&ntsb_number=ENG23LA045) · AI Analytics · CC0 1.0*