NTSB Identification: ANC94FA036.
The docket is stored in the Docket Management System (DMS). Please contact Records Management Division
Accident occurred Monday, February 28, 1994 in FAIRBANKS, AK
Probable Cause Approval Date: 06/05/1995
Aircraft: LOCKHEED L-1011, registration: N303EA
Injuries: 14 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.

AS FULL POWER WAS APPLIED FOR TAKEOFF, THERE WAS A RUPTURE OF THE 6TH STAGE DISC ON THE INTERMEDIATE COMPRESSOR 6/7TH ROTOR SHAFT ASSEMBLY IN THE #3 ENGINE. PIECES OF DISC SEVERED A FUEL INLET LINE & PENETRATED THE #1 ENGINE & THE FUSELAGE. FIRE WARNINGS FOR THE #3 & #1 ENGINES WERE ACTIVATED & ENGINE FIRE BOTTLES WERE DISCHARGED DURING AN ABORTED TAKEOFF. RESIDUAL FIRE IN ONE ENGINE WAS EXTINGUISHED BY AIRPORT FIRE FIGHTERS. ABOUT 80% OF THE FAILED DISC WAS FOUND; METALLURGICAL EXAMINATION SHOWED CORROSION PITTING & SMALL FATIGUE CRACKS AT THE ATTACHMENT HOLES. THE LARGEST CRACK WAS 0.13' DEEP & 0.23' WIDE. ACCORDING TO ROLLS ROYCE CALCULATIONS, THIS SIZE CRACK WOULD NOT HAVE RESULTED IN FAILURE UNLESS THE N2 ROTOR RPM HAD REACHED 118%. A TELLTALE MARKER FOR THE FLIGHT ENGINEER'S #3 N2 GAUGE SHOWED 106% (RED-LINE WAS 102.5%), BUT THE TELLTALE MARKER WAS OUT OF CALIBRATION; THEREFORE, OVERSPEED WAS NOT VERIFIED. MAX EPR FOR TAKEOFF WAS WITHIN LIMITS. SERVICE BULLETIN (SB) RB.211-72-9569 REQUIRED THAT ROTORS EXCEEDING 14,000 CYCLES BE REMOVED BY 4/30/93; THE FAILED ROTOR HAD 16,327 CYCLES. THE SB WAS 'S-MANDATORY' IN THE U.K., BUT IT WAS NOT MANDATORY IN THE U.S.

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

FAILURE OF THE SIXTH STAGE DISC ON THE INTERMEDIATE COMPRESSOR STAGE 6/7TH ROTOR SHAFT ASSEMBLY IN THE NUMBER THREE ENGINE, DUE TO CORROSION PITTING AND FATIGUE CRACKING OF THE FAILED DISC. A FACTOR RELATED TO THE ACCIDENT WAS: FAILURE OF THE AIRLINE COMPANY TO FOLLOW PROVISIONS OF THE SERVICE BULLETIN. FOREIGN OBJECT DAMAGE TO THE NUMBER ONE ENGINE WAS THE RESULT OF THE UNCONTAINED FAILURE OF THE NUMBER THREE ENGINE.

Full narrative available

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