# SDR QR9R20211005004

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 5, 2021
- Submitted: October 5, 2021
- Operation: General aviation
- Filed by: [M1 Support Services, repair station QR9R369D](https://openairdocs.org/faa-repair-station/QR9R369D/m1-support-services.md) (OpenAirDocs)
- Make and model: Bolkms BK117C2
- Aircraft serial: 14723269697
- Aircraft time: 2,375 hours
- System (JASC): [3400 · Navigation System](https://openairdocs.org/jasc/3400)
- Part: None
- Part number: C17133AA01
- Part serial: 3960
- Condition: Faulty
- Stage of operation: IN
- How discovered: V
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/QR9R20211005004

## Discrepancy

#2 ADC READS NEGATIVE ALTITUDE AND CAUSES AN FLI DEGRADE. REPLACED #2 ADU IAW 34-11-00, 4-1.

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