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Last updated: 11 December 2019
Statuts:Enquête Officielle
Date:mardi 31 décembre 1968
Heure:11:34
Type/Sous-type:Silhouette image of generic VISC model; specific model in this crash may look slightly different
Vickers 720C Viscount
Opérant pour:MacRobertson Miller Airlines
Loué à :Ansett-ANA
Immatriculation: VH-RMQ
Numéro de série: 45
Année de Fabrication: 1954-10-20 (14 years 3 months)
Heures de vol:31746
Cycles:25336
Moteurs: 4 Rolls-Royce Dart 505
Equipage:victimes: 4 / à bord: 4
Passagers:victimes: 22 / à bord: 22
Total:victimes: 26 / à bord: 26
Dégats de l'appareil: Détruit
Conséquences: Written off (damaged beyond repair)
Lieu de l'accident:45 km (28.1 milles) S of Port Hedland, WA (   Australie)
Phase de vol: En vol (ENR)
Nature:Transport de Passagers Nat.
Aéroport de départ:Perth Airport, WA (PER/YPPH), Australie
Aéroport de destination:Port Hedland Airport, WA (PHE/YPPD), Australie
Numéro de vol:1750
Détails:
MacRobertson Miller Airlines flight 1750 departed Perth, Australia at 08:36 hours local time on a domestic flight to Port Hedland. The flight climbed to Flight Level 190, encountering light to moderate turbulence. The en route part of the flight was uneventful. At 11:20 hours the flight advised that it would be commencing its descent from FL190 in three minutes. At 11:34 hours the flight reported that it was then 30 miles by Distance Measuring Equipment (DME) south of Port Hedland and had left 7,000 feet on descent. This was the last message received from the aircraft. The aircraft was seen to descend rapidly and steeply a little later. The wreckage was found at 28 miles from Port Hedland.
Investigation showed that at 11:34:12 hours the starboard wing of the aircraft, outboard of Station 143 and including the No. 4 engine installation, separated from the aircraft in flight. Immediately following this failure some components of the starboard wing struck the starboard tailplane and elevator causing the outboard portions of these two components to fail and the tail section and rear fuselage to separate from the aircraft. At the same time fuel released into the air from the ruptured fuel tanks burned momentarily and affected, superficially, some external surfaces of the aircraft.
The gyrations of the aircraft subsequent to the wing failure were violent enough to cause the other three engine installations to separate inflight. The remainder of the aircraft, comprising the cabin, cockpit, port wing and the inboard portion of the starboard wing, struck the ground at 11:34:38 hours.
Investigation further revealed that the starboard inner wing had failed in upward bending at Station 143, where the strength of the lower boom of the main spar had been substantially reduced by fatigue cracking extending over some 85% of its cross-sectional area. It is probable that, at the time of the failure, flight loads close to 1g steady flight loads were being applied to the wing.

Probable Cause:

CAUSE: "The cause of the accident was that the fatigue endurance of the starboard inner main spar lower boom was substantially reduced by the insertion of a flared bush at station 143 when the margin of safety associated with the retirement life specified for such booms did not ensure that this boom would achieve its retirement life in the presence of such a defect."

Accident investigation:
cover
Investigating agency: ASIB
Status: Investigation completed
Duration: 244 days (8 months)
Accident number: Final report
Download report: Final report

Sources:
» ICAO Circular 107-AN/81 (71-95)


Opérations de secours
Immediately after the accident the Australian Department of Civil Aviation temporarily grounded all Australian-registered Viscount Type 700 aircraft. The temporary grounding of Australian-registered Viscounts was eventually made permanent, pending investigations into the cause of the accident

Photos

photo of Vickers-720C-Viscount-VH-RMQ
accident date: 31-12-1968
type: Vickers 720C Viscount
registration: VH-RMQ
photo of Vickers-720C-Viscount-VH-RMQ
accident date: 31-12-1968
type: Vickers 720C Viscount
registration: VH-RMQ
photo of Vickers-720C-Viscount-VH-RMQ
 

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 Perth Airport, WA et Port Hedland Airport, WA est de 1309 km (818 miles).
Accident location: Approximate; accuracy within a few kilometers.

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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