NTSB Identification: CHI91FA152.
The docket is stored on NTSB microfiche number 44072.
Scheduled 14 CFR operation of SIMMONS AIRLINES/AM.EAGLE
Accident occurred Saturday, May 11, 1991 in CHICAGO, IL
Probable Cause Approval Date: 03/31/1993
Aircraft: SHORT BROTHERS SD3-60, registration: N715NC
Injuries: 21 Uninjured.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

THE PILOT REPORTED THAT DURING POST LANDING TAXI OPERATIONS, HE WAS UNABLE TO STEER THE AIRPLANE OR APPLY NORMAL BRAKES. THE AIRPLANE DEPARTED THE TAXIWAY, AND RAN ACROSS A GRASS MEDIAN AND SERVICE ROAD BEFORE IT IMPACTED A LIGHT POLE AND CAME TO A STOP. POST ACCIDENT INVESTIGATION REVEALED A FAILED NOSEWHEEL STEERING HYDRAULIC LINE, WHICH ALLOWED SYSTEM FLUID TO BE PORTED OVERBOARD INTO THE NOSE WHEELWELL. FURTHER EXAMINATION REVEALED THE LINE FAILED AS A RESULT OF A PUNCTURE OF THE INTERNAL HOSE BY THE WORN/FRAYED OUTER BRAID. RECORDS INDICATE THE FAILED LINE WAS ORIGINAL EQUIPMENT AND HAD OPERATED THROUGH 17,969 HOURS AND 21,324 CYCLES.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

THE FAILURE OF THE NOSE WHEEL STEERING HYDRAULIC LINE DURING AFTER LANDING GROUND OPERATIONS. A RELATED FACTOR IS THE MANUFACTURER'S INADEQUATE INSPECTION AND/OR REPLACEMENT STANDARDS.

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