Accident Vickers 803 Viscount EI-AOM, Sunday 24 March 1968
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Date:Sunday 24 March 1968
Time:10:58
Type:Silhouette image of generic VISC model; specific model in this crash may look slightly different    
Vickers 803 Viscount
Owner/operator:Aer Lingus
Registration: EI-AOM
MSN: 178
Year of manufacture:1957
Total airframe hrs:18806 hours
Cycles:16923 flights
Engine model:Rolls-Royce Dart 510A
Fatalities:Fatalities: 61 / Occupants: 61
Other fatalities:0
Aircraft damage: Destroyed, written off
Category:Accident
Location:3,1 km NE off Tuskar Rock -   Ireland
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Cork Airport (ORK/EICK)
Destination airport:London-Heathrow Airport (LHR/EGLL)
Investigating agency: AAIU
Confidence Rating: Accident investigation report completed and information captured
Narrative:
Aer Lingus Flight 712 departed Cork, Ireland at 10:32 UTC for a flight to London-Heathrow Airport, U.K. and was cleared for FL170. The take-off was normal. The flight was cleared by Air Traffic Control to proceed via Airways Blue 10, Green 1 at flight level 170. At 10:38, when the aircraft had passed through 7000 feet, clearance on course to Tuskar was given. At 10:40, after the flight had reported it was by Youghal at 7500 feet climbing to 17000 feet, ATC Cork suggested that if desired, the flight could route direct to Strumble. No direct acceptance of this suggestion was received. At 10:57 the flight reported "by Bannow (a reporting point on the route at 51°68'N - 06°12'W) level 170 estimating Strumble at 03". The flight was instructed to change to the London Airways frequency of 131.2, and this was acknowledged by the reply "131.2".
At 10:58, London Radar intercepted a call (garbled and simultaneous with another call) which appeared to be "Echo India Alpha Oscar Mike with you", and eight seconds later, a call was intercepted which was interpreted as "Twelve thousand feet descending spinning rapidly". This was the last call received from the aircraft. The Viscount descended and struck the sea 1,7nm from Tuskar Rock.
At 11:10, London ATC advised Shannon ATC that they had no radio contact with EI-AOM.
A search in the area led to the sighting and recovery of bodies and floating wreckage, the day after the accident. Eventually, on 5 June 1968 a ship was able to recover parts of the wreckage from a depth of about 75 meters. About 60-65% of the aircraft (by weight) was recovered.

A Report of the investigation carried out into this accident was published in 1970. This investigation was conducted by officials of the Aeronautical Section of the Department of Transport and Power. The exact cause of the accident was not established:
PROBABLE CAUSE: "There is not enough evidence available on which to reach a conclusion of reasonable probability as to the initial cause of this accident.
The probable cause of the final impact with the sea was impairment of the controllability of the aircraft in the fore and aft (pitching) plane."

Speculation continued since the time of the accident, prompted by a hypothesis posed in the report, that the Viscount may have been initially upset by the possible presence of another airborne object, drone or missile in its vicinity at the time. On the 30th anniversary of the accident, following newspaper articles and television programmes focusing on the possible involvement of U.K ships and missile ranges on the Welsh Coast in the downing of the aircraft, it was decided that Irish and U.K. officials would review all files held relating to the accident to see if the cause of the accident could be established. It was a.o. concluded that "the possibility of a cause other than a (near) collision with another airborne object being the initial cause of the upset ... does not appear to have been adequately examined in the 1970 Report."

Following the review, in July 2000, the Irish Minister for Public Enterprise commissioned an independent study of the accident circumstances. The International Study Team published their findings in December 2001:
- An initial event, which cannot be clearly identified, disturbed the air flow around the horizontal tail surfaces and the pitch control of the aircraft. In the light of what was observed by non-skilled people there was a strong indication that structural fatigue, flutter, corrosion or bird strike could have been involved.
- It is possible that the sensitivity of the engine fuel control units to negative accelerations imposed during the initial upset, had an adverse effect on the subsequent flight path of the aircraft.
- The severe manoeuvres of the aircraft following the initial upset and the subsequent flight would have been outside the airworthiness certification envelope and may have resulted in some deformation of the structure.
- A number of possible causes for an impairment of pitch control were examined and it is considered very possible that excessive spring tab free play resulted in the fatigue failure of a component in the tab operating mechanism thus inducing a tailplane-elevator tab free flutter condition.
- The loads induced by the flutter condition would be of sufficient magnitude and frequency to cause a fatigue failure of the port tailplane within the timescale estimated for EI-AOM.
- There was no involvement of any other aircraft or missile.

Accident investigation:
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Investigating agency: AAIU
Report number: AAIU Report No. 1970-001
Status: Investigation completed
Duration: 2 years and 3 months
Download report: Final report

Sources:


Statistics

  • 8th worst accident in 1968
  • 4th worst accident of this aircraft type
  • 2nd worst accident of this aircraft type at the time

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Revision history:

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