# SDR ASAA2026071967455

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 19, 2026
- Submitted: July 21, 2026
- Operation: Air carrier
- Aircraft: [N457AS](https://openairdocs.org/aircraft/N457AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 36355
- Aircraft time: 44,797 hours, 14,115 cycles
- System (JASC): [2710 · Aileron Control System](https://openairdocs.org/jasc/2710)
- Part: Pcu
- Part number: 251A21602
- Part serial: 19313
- Condition: Faulty
- Location: Left Mlg Wheel W
- Part time: 44,797 hours, 14,115 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: F
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2026071967455

## Discrepancy

AIRCRAFT ROLLED RIGHT AS AIRSPEED INCREASED USED EXCESSIVE AILERON TRIM, ATTEMPTED TO COMPENSATE WITH RUDDER TRIM. AT CRUISE THERE WAS (FL360) SHUDDERING AT .78 SLOWED TO .75 AND SHUDDERING WAS SIGNIFICANTLY LESS. USED AILERON TRIM W/ A/P OFF BUT DID NOT CORRECT SITUATION. GROUNDED - YES. DIVERSION - PERFORMED LEFT AND RIGHT AILERON INSPECTION REF 27-11 TASK 802. ITEM A THRU D. NO DEFECTS NOTED. REMOVED AND REPLACED UPPER AILERON PCU (SYS B) REF AMM 27-11-71. REMOVED & REPLACED LOWER AILERON PCU (SYS A) REF AMM 27-11-71. ACCOMPLISHED BLEED, LEAK CHK, ADJUSTMENT, OPERATIONAL, AND TRAVEL TESTS FOR BOTH PCUS REF SAME AMM. ALL TESTS PASSED. ACCOMPLISHED RUDDER TRIM SYSTEM TEST REF AMM 27-21-00, NO DEFECTS NOTED.

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