SDR 20001212SH020

Service difficulty report · Spring · Boeing 737*

Difficulty date: November 16, 2000
Submitted: December 12, 2000
Operation: Air carrier
Make and model: Boeing 737*
System (JASC): 2740 · Stabilizer Control System
Part: Spring
Part number: 69778551
Condition: Broken
Location: Horiz Stab Trim
Component: Auxiliary Brake · Boeing
Component part number: 654997025
Stage of operation: IN
How discovered: V
Nature of condition: O
Precautionary procedure: K

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

SPRINGS, PN 69-77855-1, ARE BROKEN IN THE AUXILIARY BRAKE SYSTEM CAUSING THE UNIT TO BIND AND JAM. 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 ASSEMBLIES MANUFACTURED PRIOR TO S/N KEO1730 PER BOEING SL 737-SL-27-090-B. (X)