# SDR 98ZZZX502

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 22, 1998
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: [N120VT](https://openairdocs.org/aircraft/N120VT), registered now
- Make and model: Amtr MINI500
- Aircraft serial: 0222
- System (JASC): [5310 · Fuselage Main, Structure](https://openairdocs.org/jasc/5310)
- Part: Frame
- Condition: Cracked
- Location: M/R Gearbox
- Stage of operation: IN
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/98ZZZX502

## Discrepancy

MOST ALL MINI-500 AIRFRAMES HAVE CRACKED NEAR THE MAIN ROTOR GEARBOX MOUNT BOLT HOLES.  ALL ARE LOW TIME ANYWHERE FROM 6 HOURS AND UP.  AIR FRAME TUBE STRUCTURE MAY BE OF TOO THIN MATERIAL.  SUBMITTER BELIEVES CRACKS FORM BECAUSE OF THE INABILITY TO TRACK AND BALANCE ROTOR BECAUSE OF A FLAW IN THE MAIN ROTOR MAST.  THE INSIDE OF MAST IS NOT CONCENTRIC WITH THE OUTSIDE.  THE LOWER SWASHPLATE ATTACHES TO THE INSIDE OF SHAFT AND NOW HAS A SEVERE WOBBLE SINCE IT IS NOT CONCENTRIC.  THIS AIRCRAFT, SN 0222, CONTINUES TO CRACK EVEN AFTER APPROVED REPAIRS.

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