# SDR USAASB01023

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 26, 2001
- Submitted: March 7, 2001
- Operation: Air carrier
- Aircraft: N785AU
- Make and model: Boeing 737-4B7
- Registry model: [Boeing 737-4B7](https://openairdocs.org/model/boeing-737-4b7) (OpenAirDocs)
- Aircraft serial: 25024
- System (JASC): [3441 · Inertial Guidance System](https://openairdocs.org/jasc/3441)
- Part: Iru
- Part number: HG1050AF04
- Condition: Failed
- Location: Ee Bay
- Part time: 36,199 hours
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USAASB01023

## Discrepancy

PHL - FLT 99 - EN ROUTE FROM PHL-SJU, THE NR 1 INERTIAL REFERENCE SYSTEM FAULT LIGHT ILLUMINATED.  FLIGHT RETURNED TO FIELD AT PHL AND LANDED WITHOUT FURTHER INCIDENT.  NO EMERGENCY WAS DECLARED.  MAINTENANCE REMOVED AND REPLACED THE NR 1 INERTIAL REF UNIT.  BITE CHECK GOOD.  (M)

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