NTSB Identification: BFO92FA044.
The docket is stored on NTSB microfiche number 47805.
Accident occurred Thursday, March 19, 1992 in ACCOKEEK, MD
Probable Cause Approval Date: 06/30/1993
Aircraft: CESSNA 172P, registration: N65737
Injuries: 2 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 aircraft accident report.

ON AN ILS APPROACH TO RUNWAY 36, THE AIRPLANE DISAPPEARED OFF RADAR AT 2,500 FT MSL ABOUT 12 NAUTICAL MILES SOUTH OF THE AIRPORT. DURING THE APPROACH, THE AIRPLANE WAS WEST OF THE LOCALIZER AND WAS BEING VECTORED TO INTERCEPT THE LOCALIZER. A COMPLETE LEFT 360 DEGREE TURN WAS MADE AT THE REQUEST OF APPROACH CONTROL (ARR). THE PILOT WAS THEN CLEARED TO THE ILS OUTER MARKER. UPON ARRIVAL TO THE OUTER MARKER THE PILOT WAS TOLD TO CONTACT THE LOCAL CONTROLLER (LC). BEFORE INTERCEPTING THE LOCALIZER, THE AIRPLANE STARTED AN APPROXIMATE 9.5 DEGREE LEFT TURN AWAY FROM THE LOCALIZER. DURING THIS TURN, ARR QUERIED THE PILOT ABOUT THE AIRPLANE'S HEADING. THERE WAS NO RESPONSE. THE LC BROADCASTED TO THE AIRPLANE AND REQUESTED THE PILOT TO SWITCH BACK TO ARR. THE PAX ACKNOWLEDGED THE REQUEST. THERE WERE NO FURTHER TRANSMISSIONS BY THE PILOT OR PAX. THE INVESTIGATION DID NOT DISCLOSE ANY EVIDENCE OF STRUCTURAL, INSTRUMENT, OR ENGINE FAILURE.

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

THE PILOT EXPERIENCED SPATIAL DISORIENTATION WHICH RESULTED IN LOSS OF CONTROL OF THE AIRPLANE.

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