Crash-aerien 05 APR 1991 d'un Embraer EMB-120RT Brasilia N270AS - Brunswick-Glynco Jetport, GA (BQK)
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Statuts:Accident investigation report completed and information captured
Date:vendredi 5 avril 1991
Heure:14:51
Type/Sous-type:Silhouette image of generic E120 model; specific model in this crash may look slightly different
Embraer EMB-120RT Brasilia
Operated by:Atlantic Southeast Airlines - ASA
On behalf of:Delta Connection
Immatriculation: N270AS
Numéro de série: 120218
Année de Fabrication: 1990
Heures de vol:816
Cycles:845
Moteurs: 2 Pratt & Whitney Canada PW118
Equipage:victimes: 3 / à bord: 3
Passagers:victimes: 20 / à bord: 20
Total:victimes: 23 / à bord: 23
Dégats de l'appareil: Détruit
Conséquences: Written off (damaged beyond repair)
Lieu de l'accident:3 km (1.9 milles) W of Brunswick-Glynco Jetport, GA (BQK) (   Etats-Unis d'Amérique)
Phase de vol: En approche (APR)
Nature:Transport de Passagers Nat.
Aéroport de départ:Atlanta-William B. Hartsfield International Airport, GA (ATL/KATL), Etats-Unis d'Amérique
Aéroport de destination:Brunswick-Glynco Jetport, GA (BQK/KBQK), Etats-Unis d'Amérique
Numéro de vol:2311
Détails:
Atlantic Southeast Flight 2311 was scheduled initially for Embraer EMB-120RT Brasilia N228AS to depart at 13:24 EST. Because of mechanical problems an airplane change was made to N270AS. The flight departed Atlanta at 13:47 and arrived in the Brunswick area about 14:44. At 14:48 the flight was cleared for a visual approach to runway 07. The Embraer had just turned from base leg to final approach when the aircraft was seen to pitch up about 5 degrees and roll to the left until the wings were vertical. The airplane then nosed down into the ground, 9975 feet short of the runway.

The left propeller blade angle at the time of impact was about 3 degrees, which is below the range for normal flight. The right propeller blade angle was above the flight idle low pitch stop.
It was determined that the left propeller actuator did not respond to a PCU action to increase blade angle because the PCU quill spline teeth were severely worn and could not engage the transfer tube spline. The extreme and rapid wear of the nitrided quill spline teeth was the result of the sliding contact with the titanium nitrided surface of the transfer tube spline.
This harder titanium-nitrided coating on the transfer tube was selected by the manufacturer, Hamilton Standard, to improve manufacturing efficiency compared to the originally certificated nitrided transfer tube.

Probable Cause:

PROBABLE CAUSE: "The loss of control in flight as a result of a malfunction of the left engine propeller control unit which allowed the propeller blade angles to go below the flight idle position. Contributing to the accident was the deficient design of the propeller control unit by Hamilton Standard and the approval of the design by the Federal Aviation Administration. The design did not correctly evaluate the failure mode that occurred during this flight, which resulted in an uncommanded and uncorrectable movement of the blades of the airplane's left propeller below the flight idle position."

Accident investigation:

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Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year
Accident number: NTSB/AAR-92-03
Download report: Final report

Sources:
» NTSB/AAR-92/03


Opérations de secours

NTSB issued 6 Safety Recommendations

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Photos

photo of Embraer-EMB-120RT-Brasilia-N270AS
Radar data
photo of Embraer-EMB-120RT-Brasilia-N270AS
Hamilton Standard propeller system Model 14RF
 

Video, social media

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 Atlanta-William B. Hartsfield International Airport, GA et Brunswick-Glynco Jetport, GA est de 381 km (238 miles).
Accident location: Exact; as reported in the official accident report.

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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Embraer EMB-120

  • 357 built
  • 4ème loss
  • 4ème accident fatal
  • le accident The le plus grave (à ce moment là)
  • le accident 3ème le plus grave (en ce moment)
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