Date:	Tuesday 31 July 1973
Time:	11:08
Type:	McDonnell Douglas DC-9-31
Owner/operator:	Delta Air Lines
Registration:	N975NE
MSN:	47075/166
Year of manufacture:	1967
Total airframe hrs:	14639 hours
Engine model:	Pratt & Whitney JT8D-7
Fatalities:	Fatalities: 88 / Occupants: 89
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	Boston-Logan International Airport, MA (BOS) -   United States of America
Phase:	Approach
Nature:	Passenger - Scheduled
Departure airport:	Manchester Municipal Airport, NH (MHT/KMHT)
Destination airport:	Boston-Logan International Airport, MA (BOS/KBOS)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

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 385 km/h (80 km/h too fast) and was 60 m 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 500 m with 60 m 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."

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

photo (c) Bob Weinwurzel; Philadelphia International Airport, PA (PHL/KPHL); August 1972

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