NTSB Identification: SEA93GA041.
The docket is stored on NTSB microfiche number 51009.
Accident occurred Friday, December 18, 1992 in BILLINGS, MT
Probable Cause Approval Date: 12/09/1993
Aircraft: CESSNA 550, registration: N6887Y
Injuries: 8 Fatal.

: 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 public aircraft accident report.

DURING DESCENT INTO BILLINGS, THE CITATION WAS SEQUENCED BEHIND A BOEING 757, AND BOTH AIRPLANES WERE EVENTUALLY CLEARED FOR VISUAL APPROACHES. ABOUT 1-1/2 MI FROM THE RUNWAY THE CITATION WAS OBSERVED TO ROLL RAPIDLY TO THE INVERTED POSITION & DESCEND ALMOST VERTICALLY INTO THE GROUND. ACCORDING TO ATC TRANSCRIPTS AND THE AIRPLANES'S COCKPIT VOICE RECORDER, THE CREW OF THE CITATION HAD MAINTAINED VISUAL AWARENESS OF THE POSITION OF THE B-757 THROUGHOUT THE APPROACH. AT THE TIME OF THE UPSET, THE VERTICAL SEPARATION BETWEEN AIRPLANES WAS 600-1000 FT, AND THE HORIZONTAL SEPARATION WAS DECREASING BELOW 2.6 MI. ONE OF THE CITATION CAPTAIN'S LAST COMMENTS WAS 'ALMOST RAN OVER A SEVEN FIFTY SEVEN.' WINDS WERE 5 KTS.

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

THE PILOT-IN-COMMAND'S FAILURE TO FOLLOW ESTABLISHED VORTEX AVOIDANCE PROCEDURES, AS PUBLISHED IN THE AIRMAN'S INFORMATION MANUAL, TO PROVIDE HIS OWN WAKE TURBULENCE SEPARATION.

Index for Dec1992 | Index of months