# SDR 2026F00126

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 16, 2026
- Submitted: June 17, 2026
- Operation: General aviation
- Aircraft: [N253AL](https://openairdocs.org/aircraft/N253AL), registered now
- Make and model: Lear 45LEAR
- Aircraft serial: 361
- Aircraft time: 5,880 hours, 4,491 cycles
- System (JASC): [5510 · Horizontal Stabilizer Structure](https://openairdocs.org/jasc/5510)
- Part: Attach Bolt
- Part number: 4527401706003
- Condition: Defective
- Location: Zone 300
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2026F00126

## Discrepancy

DURING INSTALLATION OF HORIZONTAL STABILIZER ATTACHMENT HARDWARE, PRIMARY BOLTS (P/N 4527401706-003) WERE FOUND TO BE DIMENSIONALLY OUT OF TOLERANCE, PREVENTING INSTALLATION OF SECONDARY BOLTS.  INITIAL DISCREPANCIES WERE IDENTIFIED WITH UNDERSIZED INTERNAL DIAMETERS; HOWEVER, THIS REPORT IS PRIMARILY DRIVEN BY A SUBSEQUENT SHIPMENT OF REPLACEMENT PARTS THAT WERE ALSO NONCONFORMING.  A FOLLOW-ON SHIPMENT OF THREE (3) PRIMARY BOLTS RECEIVED UNDER A SEPARATE DELIVERY AND FAA FORM 8130-3 (FORM TRACKING NUMBER 170002982826-1; ASSOCIATED TRACE IDENTIFIERS INCLUDE RACE 21081 AND 21110) WERE INSPECTED AND ALL UNITS WERE FOUND TO BE BELOW THE REQUIRED INTERNAL DIAMETER SPECIFICATION (0.3125"–0.3135"). NONE OF THE REPLACEMENT BOLTS WERE USABLE FOR INSTALLATION.  MEASURED INTERNAL DIAMETERS OF THE AFFECTED BOLTS WERE APPROXIMATELY 0.3090"–0.3095". SECONDARY BOLTS WERE MEASURED WITH OUTER DIAMETERS BETWEEN 0.3115"–0.3120", CONSISTENT WITH EXPECTED DIMENSIONS, CONFIRMING THE NONCONFORMANCE IS ISOLATED TO THE PRIMARY BOLT INTERNAL DIAMETER.  THIS REPRESENTS A REPEAT OCCURRENCE ACROSS MULTIPLE SHIPMENTS INDICATING A SYSTEMIC MANUFACTURING OR QUALITY CONTROL ISSUE RATHER THAN AN ISOLATED DEFECT.

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