# SDR 99ZZZX3631

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 9, 1999
- Submitted: March 26, 2000
- Operation: General aviation
- Filed by: [Aero Controls, LLC, repair station IU6R626N](https://openairdocs.org/faa-repair-station/IU6R626N/aero-controls-llc.md) (OpenAirDocs)
- Make and model: Boeing 737*
- System (JASC): [2740 · Stabilizer Control System](https://openairdocs.org/jasc/2740)
- Part: Spring
- Part number: 69778551
- Condition: Cracked
- Location: Horiz Stabilizer
- Part time: 26,692 hours
- Component: 654997025
- Stage of operation: IN
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/99ZZZX3631

## Discrepancy

SPRINGS PN 69-77855-1 ARE BROKEN IN THE AUXILIARY BRAKE SYSTEM.  POSSIBLE CAUSE, IMPROPER HEAT TREATING, AUSTENITE, FATIGUE AND INCREASED SPRING COIL STRESSES.  SPRINGS PN 69-77855-1 ARE TO BE REPLACED WITH PN 69-77855-2 SPRINGS ON ACTUATOR ASSYS MANUFACTURED PRIOR TO S/N KE01730 PER BOEING SL 737-SL-27-090-B.

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