Accident description
Last updated: 16 April 2014
Status:Final
Date:Tuesday 31 July 1973
Time:11:08 EDT
Type:Silhouette image of generic DC93 model; specific model in this crash may look slightly different
McDonnell Douglas DC-9-31
Operator:Delta Air Lines
Registration: N975NE
C/n / msn: 47075/166
First flight: 1967
Total airframe hrs:14639
Engines: 2 Pratt & Whitney JT8D-7
Crew:Fatalities: 6 / Occupants: 6
Passengers:Fatalities: 82 / Occupants: 83
Total:Fatalities: 88 / Occupants: 89
Airplane damage: Damaged beyond repair
Location:Boston-Logan International Airport, MA (BOS) (   United States of America) show on map
Phase: Approach (APR)
Nature:Domestic Scheduled Passenger
Departure airport:Manchester Municipal Airport, NH (MHT/KMHT), United States of America
Destination airport:Boston-Logan International Airport, MA (BOS/KBOS), United States of America
Flightnumber: 723
Narrative:
As Delta Flight 723 was descending, the approach clearance was given by the controller after a delay, because the controller was preoccupied with a potential conflict between two other aircraft. This caused the flight to be poorly positioned for approach. The aircraft passed the Outer Marker at a speed of 385km/h (80km/h too fast) and was 60m above the glide slope.
The flight director was inadvertently used in the 'go-around-mode', which led to abnormal instrument indications. This caused some confusion. The first officer, who was flying the approach became preoccupied with the problem. The DC-9 continued to descend and struck a seawall 3000 feet short of and 150 feet to the right of runway 04R, crashed and caught fire. RVR at the time was 500m with 60m overcast.
All occupants, except one passenger, were killed in the crash. The lone survivor, who had been injured critically, died on December 11, 1973.


PROBABLE CAUSE: "The failure of the flight crew to monitor altitude and to recognize passage of the aircraft through the approach decision height during an unstabilized precision approach conducted in rapidly changing meteorological conditions. The unstabilized nature of the approach was due initially to the aircraft's passing the outer marker above the glide slope at an excessive airspeed and thereafter compounded by the flight crew's preoccupation with the questionable information presented by the flight director system. The poor positioning of the flight for the approach was in part the result of nonstandard air traffic control services."

Sources:
» Air Disasters / D.Gero (118-120)
» ICAO Circular 132-AN/93 (79-90)
» NSTB-AAR-74-3

Official accident investigation report
investigating agency: National Transport Safety Bureau (NTSB) - USA
report status: Final
report number: NTSB/AAR-74-03
report released:07-MAR-1974
duration of investigation:219 days (7.3 months)
download report: Delta Air Lines, Inc., DC-9-31, N975NE, Boston, Massachusetts, July 31, 1973 (NTSB/AAR-74-03)

Follow-up / safety actions

NTSB issued 8 Safety Recommendations

Show all AD's and Safety Recommendations

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Map
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 Manchester Municipal Airport, NH to Boston-Logan International Airport, MA as the crow flies is 72 km (45 miles).

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DC-9-30

  • 14th loss
  • 662 built
  • 3rd worst accident (at the time)
  • 8th worst accident (currently)
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 United States of America
  • 5th worst accident (at the time)
  • 20th worst accident (currently)
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