NTSB Identification: FTW88IA037.
The docket is stored on NTSB microfiche number 40012.
Scheduled 14 CFR (D.B.A. CONTINENTAL AIRLINES )
Incident occurred Thursday, December 03, 1987 in HOUSTON, TX
Probable Cause Approval Date: 11/28/1989
Aircraft: BOEING 727-243, registration: N571PE
Injuries: 87 Uninjured.

NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.

DURING THE APPROACH TO LANDING THE NUMBER SIX LEADING EDGE SLAT ASSEMBLY FAILED. THE INBOARD SECTION OF THE SLAT HUNG DOWN AND BENT AFT. THE PILOT LANDED THE ACFT WITHOUT FURTHER INCIDENT. METALLURGICAL ANALYSIS OF COMPONENTS REVEALED THAT A SLAT TRACK ROLLER BEARING CONTAINED EVIDENCE OF CORROSION AND SPALLING. ADDITIONALLY, THE SLAT TRACK BEARING BOLT THAT HAD BEEN INSTALLED THROUGH THE ABOVE MENTIONED BEARING HAD HEAVY CIRCUMFERENTIAL GOUGES CONTAINED IN THE SURFACE OF A CROSS-DRILLED HOLE AT THE AREAS OF FATIGUE INITIATION. THERE WAS ALSO EVIDENCE OF TEARING, TYPICAL OF DAMAGE PRODUCED DURING DRILLING WITH A DULL DRILL BIT. THE AIRPLANE HAD COMPLETED A MAJOR STRUCTURAL MAINTENANCE CHECK 48 FLIGHT HOURS AND 28 CYCLES PRIOR TO THE INCIDENT.

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

IMPROPER DRILLING OF THE CROSS HOLE IN THE SLAT TRACK BEARING BOLT, WHICH LED TO ITS FAILURE FROM FATIGUE CRACKING.

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