Date: May 30, 1972
Type: McDonnell-Douglas DC-9-14
Registration: N3305L
Operator: Delta Airlines, Inc.
Where: Fort Worth, Texas 
Report No. NTSB-AAR-73-3
Report Date: March 13, 1973
Pages: 38

A Delta Air Lines, Inc., DC-9 crashed while attempting a go-around 
following a landing approach to Runway 13 at Greater Southwest 
International Airport, Ft. Worth, Texas, at 0724 c.d.t., May 30, 1972. 
Three Delta pilots and a Federal Aviation Administration air carrier 
operations inspector, the only occupants, were killed. The aircraft was 
destroyed by impact and fire. The landing approach was conducted 
following a McDonnell Douglas DC-10 which made a "touch and go" landing 
ahead of the DC-9.  The final approach phase of the DC-9 flight appeared 
normal until the aircraft passed the runway threshold. It then began to 
oscillate about the roll axis and,after several reversals, rolled rapidly 
to the right and struck the runway in an extreme right-wing-low attitude. 
Fire occurred shortly after initial impact. The National Transportation 
Safety Board determines that the probable cause of the accident was an 
encounter with a trailing vortex generated by a preceding "heavy" jet 
which resulted in an involuntary loss of control of the airplane during 
the final approach. Although cautioned to expect turbulence the crew did 
not have sufficient information to evaluate accurately the hazard or the 
possible location of the vortex.

Existing FAA procedures for controlling VFR flight did not provide the 
same protection from a vortex encounter as was provided to flights being 
given radar vectors in either IFR or VFR conditions.