NTSB Identification: SEA93FA094A.
The docket is stored on NTSB microfiche number 50895.
Accident occurred Wednesday, April 14, 1993 in STEPTOE, WA
Probable Cause Approval Date: 03/18/1994
Aircraft: GRUMMAN A6E, registration: USN
Injuries: 2 Serious,1 Minor.

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 A6E WAS TRACKING 033 DEG LEVEL AT 200 FT AGL AT 468 KTS VFR IN PUBLISHED ROUTE VR-1354. THE AGCAT WAS TRACKING 334 DEG LEVEL AT 200 FT AGL AT 96 KTS VFR ACROSS THE ROUTE TO HIS DESTINATION SPRAY FIELD. THE TWO AIRCRAFT CONVERGED ON A 59 DEG COLLISION ANGLE WITH A CLOSURE SPEED OF 429 KTS. THE A6E NOTIFIED FSS THAT HE WAS ENTERING THE ROUTE LATE AND PROJECTED EXITING 8 MINUTES AFTER THE PUBLISHED CLOSURE OF THE ROUTE. THE AGCAT PILOT REPORTED HE WAS UNAWARE OF ANY INFORMATION/PUBLICATIONS REGARDING THE OPERATION OF MILITARY AIRCRAFT IN THE AREA. THE LOCAL FSS WAS IN THE HABIT OF REPORTING THE ROUTE 'HOT' 24 HRS A DAY RATHER THAN THE PRECISE SCHEDULE. THE CONVERGENCE ANGLE OF THE A6E WAS 111 DEG (8 O'CLOCK POSITION & BEHIND THE AGCAT'S LEFT WING). THE CONVERGENCE ANGLE OF THE AGCAT WAS 10 DEG. AT THE PROJECTED CLOSURE SPEED THE AGCAT WOULD HAVE SUBTENDED AN ANGLE OF 0.2 DEG 8.6 SECS BEFORE IMPACT; THE A6E 19.2 SECS.

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

THE INHERENT LIMITATIONS OF THE SEE-AND-AVOID CONCEPT OF SEPARATION OF AIRCRAFT OPERATING UNDER VISUAL FLIGHT RULES THAT PRECLUDED THE CREW OF THE A6E AND THE PILOT OF THE AGCAT FROM RECOGNIZING A COLLISION HAZARD AND TAKING ACTIONS TO AVOID A MIDAIR COLLISION.

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