Sequence of Events
A Beech liner, a Boeing 757, and an Israel Westwind (WW) were vectored for landings on runway 19R. The 757 and WW were sequenced for visual approaches behind the Beech. Before being cleared for visual approach, the WW was closing to 3.5 miles from the 757 on a converging course.
Both the 757 and WW crews were instructed to slow to 150 knots. The 757 slowed below 150 knots and was positioned high on final approach with a 5.6° descent. The WW continued to converge, reaching about 2.1 miles behind the 757 on a 3° approach.
ATC Communications
Air traffic control did not specifically advise the WW pilots that they were behind a Boeing 757. The ATC handbook did not require such an advisory.
Cockpit Discussions
The WW captain discussed the possibility of wake turbulence, flew the ILS one dot high, noted the proximity to the 757, and indicated there should be no problem.
Encounter and Crash
While descending through approximately 1,100 feet MSL, the WW encountered wake turbulence from the 757. The aircraft rolled into a steep descent and subsequently crashed.
Investigation Findings
The crew lacked specific wake turbulence training. Toxicological analysis detected chlorpheniramine (an over-the-counter antihistamine not approved for flying) in the pilot's lung tissue at a concentration of 0.094 μg/ml.
The official probable cause was the pilot-in-command's failure to maintain adequate separation behind the Boeing 757 and/or remain above its flight path during the approach, which resulted in an encounter with wake vortices from the 757. Contributing factors included an inadequacy in the ATC procedure related to visual approaches and VFR operations behind heavier airplanes, and the resultant lack of information to the Westwind pilots for them to determine the relative flight path of their airplane with respect to the Boeing 757's flight path.