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Date:Tuesday 8 September 1970
Type:Silhouette image of generic DC93 model; specific model in this crash may look slightly different
McDonnell Douglas DC-9-32
Operator:Delta Air Lines
Registration: N3329L
MSN: 47108/251
First flight: 1968
Total airframe hrs:7601
Engines: 2 Pratt & Whitney JT8D-7
Crew:Fatalities: 0 / Occupants: 5
Passengers:Fatalities: 0 / Occupants: 89
Total:Fatalities: 0 / Occupants: 94
Aircraft damage: Substantial
Aircraft fate: Repaired
Location:Louisville-Standiford Field, KY (SDF) (   United States of America)
Phase: Landing (LDG)
Nature:Domestic Scheduled Passenger
Departure airport:Chicago-O'Hare International Airport, IL (ORD/KORD), United States of America
Destination airport:Louisville-Standiford Field, KY (SDF/KSDF), United States of America
Delta Air Lines Flight 439 was a scheduled flight from Chicago to Atlanta with intermediate stops at Louisville and Lexington. The DC-9 departed Chicago at 20:13 on an Instrument Flight Rules (IFR) flight plan. At 21:01, Louisville Approach Control established radar contact with Flight 439. Vectors and altitude information were given the crew until the flight was turned to a heading that would intercept the inbound ILS localizer course to runway 29. The flight was subsequently cleared for an ILS approach. Landing weight had been computed to be 92,000 pounds, which established an approach reference airspeed of 123 knots. Flaps had been extended to 50 degrees. When Flight 439 made the approach which terminated in the accident, the high intensity runway lights were set at step 3, medium bright, and the reported flight visibility was 7 miles. Runway 29 did not have a prepared underrun/overrun area. The ground leading to the threshold slopes upward 2deg 44’, a gradient of approximately 5 percent. Flight 439 made initial ground contact on this incline 156 feet short of the threshold of the runway, rolled forward 73 feet, and became airborne. The aircraft then contacted the runway 262 feet beyond the threshold and continued to roll/skid on the runway before it came to rest 4,457 feet beyond the threshold. Wreckage examination showed that the fuselage had fractured and buckled in the area between fuselage stations 737 and 794. The tail cone rested on the runway.

Probable Cause:

PROBABLE CAUSE: "The National Transportation Safety Board determines that the probable cause of this accident was the pilot’s misjudgment of altitude due to the absence of sufficient lights in the approach area, misleading information produced by deceptive sloping terrain, and that the pilot did not position the aircraft on the ILS glide slope while he was establishing the final approach profile."

Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 2 months
Accident number: NTSB/AAR-71-15
Download report: Final report
Language: English


» NTSB-AAR-71-15


photo of DC-9-32-N3329L
accident date: 08-09-1970
type: McDonnell Douglas DC-9-32
registration: N3329L
photo of DC-9-32-N3329L
accident date: 08-09-1970
type: McDonnell Douglas DC-9-32
registration: N3329L

This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Chicago-O'Hare International Airport, IL to Louisville-Standiford Field, KY as the crow flies is 458 km (286 miles).

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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