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Accident
Last updated: 15 December 2017
Statuts:Enquête Officielle
Date:mardi 31 juillet 1973
Heure:11:08
Type/Sous-type:Silhouette image of generic DC93 model; specific model in this crash may look slightly different
McDonnell Douglas DC-9-31
Compagnie:Delta Air Lines
Immatriculation: N975NE
Numéro de série: 47075/166
Année de Fabrication: 1967
Heures de vol:14639
Moteurs: 2 Pratt & Whitney JT8D-7
Equipage:victimes: 6 / à bord: 6
Passagers:victimes: 82 / à bord: 83
Total:victimes: 88 / à bord: 89
Dégats de l'appareil: Détruit
Conséquences: Written off (damaged beyond repair)
Lieu de l'accident:Boston-Logan International Airport, MA (BOS) (   Etats-Unis d'Amérique)
Élévation des lieux de l'accident: 6 m (20 feet) amsl
Phase de vol: En approche (APR)
Nature:Transport de Passagers Nat.
Aéroport de départ:Manchester Municipal Airport, NH (MHT/KMHT), Etats-Unis d'Amérique
Aéroport de destination:Boston-Logan International Airport, MA (BOS/KBOS), Etats-Unis d'Amérique
Numéro de vol:DL723
Détails:
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:

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."

Accident investigation:
cover
Investigating agency: NTSB
Status: Investigation completed
Duration: 219 days (7 months)
Accident number: NTSB/AAR-74-03
Download report: Final report

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


Opérations de secours

NTSB issued 8 Safety Recommendations

Show all AD's and Safety Recommendations

Photos

photo of McDonnell Douglas DC-9-31 N975NE
Northeast Airlines merged with Delta in August 1972
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Plan
Ce plan montre l'aéroport de départ ainsi que la supposée destination du vol. La ligne fixe reliant les deux aéroports n'est pas le plan de vol exact.
La distance entre Manchester Municipal Airport, NH et Boston-Logan International Airport, MA est de 72 km (45 miles).

Les informations ci-dessus ne représentent pas l'opinion de la 'Flight Safety Foundation' ou de 'Aviation Safety Network' sur les causes de l'accident. Ces informations prélimimaires sont basées sur les faits tel qu'ils sont connus à ce jour.
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DC-9-30

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