Page:NTSB Southern Airways Flight 932 report.pdf/6

 Probable Cause

The National Transportation Safety Board determines the probable cause of this accident was the descent below Minimum Descent Altitude during a nonprecision approach under adverse operating conditions, without visual contact with the runway environment. The Board has been unable to determine the reason for this descent, although the two most likely explanations are (a) improper use of cockpit instrumentation data, or (b) an altimetry system error.

Recommendations

The Board recommends that:


 * 1) All segments of the aviation industry continue to focus attention on the unique demands for crew coordination and vigilance during nonprecision approaches. Particular emphasis should be placed on the accelerated development of area navigation systems with vertical guidance capability and on heads-up display system.
 * 2) The Administrator evaluate the need for the installation and use of ground proximity warning devices on air carrier aircraft.
 * 3) The FAA continue to emphasize the importance of the provisions of Part 121. 445 in its surveillance and inspections of of flight operations of Part 121. Such emphasis is needed to assure that these operators (1) using the best means available to enable pilots to qualify under 121, 445, and (2) requiring pilots to show that they have acquired the requisite knowledge prior to completion of a flight release.