On December 16, 1996, a Cessna 425 Conquest (registration N425EW) operated by US Dynamics Corporation was involved in an aviation accident near Ronkonkoma-Long Island-McArthur Field, United States of America during landing or approach. 3 people were killed. Investigators recorded the probable cause as: The pilot's early descent to decision height and his failure to perform the missed approach procedure. A factor was the failure of air traffic control to issue a safety advisory. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A).
During an ILS Runway 6 approach, the airplane descended to decision height early, continued at or below that altitude for 28 seconds, and collided with trees and terrain about 1.5 miles from the runway.
Approach and Descent
The pilot was cleared for the ILS Runway 6 approach. The previous landing traffic reported breaking out at minimums. Radar data showed that the airplane descended in instrument meteorological conditions to the decision height of 294 feet, approximately 3 miles from the missed approach point. The pilot did not perform the missed approach procedure. The airplane then leveled off and continued at or below decision height altitude for approximately 28 seconds, covering a distance of about 1 mile.
Air Traffic Control Interaction
Four low altitude alerts appeared on the tower controller's display. The controller stated that he withheld the alert because it was a critical phase of flight and the aircraft appeared to be climbing.
Collision
The airplane collided with trees and terrain approximately 1.5 miles from the approach end of the landing runway.
Probable Cause
The official findings state that the probable cause was the pilot's early descent to decision height and his failure to perform the missed approach procedure. A factor was the failure of air traffic control to issue a safety advisory.