NTSB Identification: FTW86FA025.
The docket is stored on NTSB microfiche number 30986.
Accident occurred Thursday, December 12, 1985 in COLLEGE STATION, TX
Aircraft: GATES LEARJET 35A, registration: N723GL
Injuries: 2 Fatal,1 Serious.

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 ACFT ROLLED TO THE RIGHT AND CRASHED AFTER A CATASTROPHIC (UNCONTAINED) FAILURE OF THE RT ENG DURING TAKEOFF FOR A NIGHT FLT. THE RT ENG FAN ROTOR DISC SEPARATED FROM THE HUB WHICH DAMAGED THE COWLING AND SOME DISC FRAGMENTS BURIED IN THE FUSELAGE BUT WITHOUT DAMAGE TO THE FLT CONTROLS. THE DRAG CREATED BY THE LOSS OF THRUST AND THE DISTORTED COWLING LED TO YAW AND ROLL WITH LOSS OF CONTROL OF THE ACFT. THE FAN FAILURE PROPAGATED FROM A LOW GRADE FATIGUE CRACK ON THE HIGH TIME FAN WHICH WAS NOT DETECTED BY THE VISUAL INSPECTION PROCEDURES EXISTING AT THE TIME. THE MAUNUFACTURER HAS SINCE IMPROVED THE MANUFACTURING AND INSPECTION TECHNIQUES. AN AD 86-04-02 WAS ISSUED ON 2/14/86 WHICH DEALS WITH FAN REMOVAL FROM SERVICE ACCORDING TO AN OPERATING CYCLE SCHEDULE.

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

COMPRESSOR ASSEMBLY,FORWARD FAN..FATIGUE

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

COMPRESSOR ASSEMBLY,FORWARD FAN..FAILURE,TOTAL

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

COMPRESSOR ASSEMBLY,FORWARD FAN..SEPARATION



Contributing Factors

INSUFFICIENT STANDARDS/REQUIREMENTS..MANUFACTURER

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