# SDR ASAA2023051643244

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 16, 2023
- Submitted: May 17, 2023
- Operation: Air carrier
- Aircraft: [N431AS](https://openairdocs.org/aircraft/N431AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 43255
- Aircraft time: 35,304 hours, 11,167 cycles
- System (JASC): [2910 · Hydraulic System, Main](https://openairdocs.org/jasc/2910)
- Part: Unknown
- Part number: UNKNOWN
- Condition: Unknown
- Location: Unknown
- Stage of operation: IN
- How discovered: V
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2023051643244

## Discrepancy

AIR TURN BACK FOR LOW PRESSURE HYD LIGHT ILLUMINATED AFTER ROTATION. PRESSURE DROPPED TO 1600 PSI. LIGHT EXTINGUISHED AND PRESSURE RETURN 2900 PSI. AFTER GEAR UP AND LOCK. GROUNDED - YES. AIR TURNBACK - INSPECTED HYDRAULIC SYSTEM FOUND NO DEFECTS. SUSPECTED AIR IN THE HYDRAULIC SYSTEM. BLED THE HYDRAULIC SYSTEM IN REF B737-900 AMM 29-00-00-870-801. CHECKED FOR HYDRAULIC EXTERNAL LEAKAGE IN REF AMM 29-00-00-790-801. LEAK CHECK GOOD. OPERATIONAL TEST OF THE HYDRAULIC SYSTEM A AND B GOOD PER AMM 29-11-00-700-801. OK FOR SVC.

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