NTSB Identification: BFO87FA057.
The docket is stored on NTSB microfiche number 35786.
Accident occurred Friday, August 21, 1987 in WASHINGTON, DC
Probable Cause Approval Date: 10/06/1988
Aircraft: BELL 206B, registration: N83080
Injuries: 3 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 HELICOPTER WAS ON A LCL PHOTOGRAPHY (SIGHT-SEEING) FLT. WHILE HOVERING AT APRX 200' ABV THE POTOMAC RIVER, THE ENG LOST PWR. THE PLT INITIATED AN AUTOROTATION & DEPLOYED THE EMERG FLOATS. SUBSEQUENTLY, THE HELICOPTER IMPACTED IN THE RIVER & ROLLED OVR, BUT WAS SUPPORTED (UPSIDE DOWN) IN THE WATER BY THE FLOATS. AFTER RECOVERY, NO PREIMPACT PART FAIL- URE OR MALFUNCTION OF THE AIRFRAME WAS FND. HOWEVER, A TEARDOWN OF THE ENG REVEALED THE SPUR ADAPTER GEARSHAFT (SAG), PN 6890482, HAD FAILED FROM WEAR & SUBSEQUENT FATIGUE. THE FAILURE OCCURRED AT THE FWD, SPLINED END OF THE SAG. DEBRIS (82% SILICON) WAS FND INSIDE THE OIL DELIVERY TUBE. THE OIL JETS FOR THE #2 & #3 BRGS WERE OBSTRUCTED, BUT THE JET FOR SAG WAS NOT OBSTRUCTED. THE PRECISE NATURE OF THE CONDS & CIRCUMSTANCES THAT LED TO EXCESSIVE WEAR WAS NOT DETERMINED. THE HEIGHT/VELOCITY DIAGRAM IN THE FLT MANUAL SHOWED HOVERING FLT BTN 10 & 400 FT SHOULD BE AVOIDED (TO ALLOW FOR SUCCESSFUL AUTOROTATIVE LNDG IN THE EVENT OF A PWR LOSS).

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

TURBOSHAFT ENGINE,GAS GENERATOR TURBINE SHAFT..WORN

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

TURBOSHAFT ENGINE,GAS GENERATOR TURBINE SHAFT..FATIGUE


Contributing Factors

IN-FLIGHT PLANNING/DECISION..IMPROPER..PILOT IN COMMAND


Contributing Factors

FLUID,OIL..CONTAMINATION




Index for Aug1987 | Index of months