Viscount Crash
The following is a reply received from Colin Torkington in 2006 who was one of the three who compiled the 2002 Study.
"You asked whether an aircraft could enter a spin or spiral dive as a result of a near miss and could subsequent loading cause structural fatigue failure. I will do my best to answer.
Any aircraft making a determined pull up or even a rolling manoeuvre to avoid a collision could probably stall, drop a wing and spin or spiral dive. This was considered. The Viscount like most large aircraft, is definitely a non-spin aircraft. There was one case of a Viscount recovering from a spin but with extreme difficulty by an experienced test pilot.
It is indeed quite possible to break an aircraft in an attempted recovery from loss of control following an upset. This often includes a spiral dive and there have been many such cases.
In Australia, we lost three Viscounts with in-flight structural failure ( I was structures Group- Leader in two of the investigations ) The first one involving VH-TVC at Sydney in 1961 is relevant to your question, the others being fire and metal fatigue.
TVC suffered a catastrophic structural failure in attempting to recover from an upset and loss of control in a storm. Most such cases result in wing failure which was not the case with AOM.
If I remember correctly there have also been cases of engine mount and empennage failure.
There is a definite 'NO' to your question about a fatigue failure. Excessive manoeuvre loading beyond the design strength of the aircraft will usually be a single application causing an' overload' failure as against 'fatigue' which normally requires thousands of load cycles.
One difficulty I had with the TVC type of overload failure is that when the aircraft breaks up, it is in a time scale of seconds. AOM flew for approximately 15 minutes after reporting loss of control. The Indonesian Viscount PK-IVS with springtab-flutter- fatigue causal factors flew for around 20 minutes from calling Mayday to crashing.
I have always regretted that the Irish Viscounts were not fitted with Flight Data and Cockpit Voice Recorders as were in the Australian aircraft at that time. Although early simple devices, they would have almost certainly answered all questions of altitude, speed, flutter and loading and narrowed down the causal factors. However.....
Hope this is of some interest to you
regards. Colin Torkington."
The question was asked of Colin because one of the findings in the 1970 Investigation stated " There is evidence which could be construed as indicative of the possible presence of another aircraft or airborne object in the vicinity which, by reason of collision, or by its proximity causing an evasive manoeuvre to be made, or by its wake turbulence, might have been the the initiating cause of an upsetting manoeuvre resulting in the Viscount entering a spin or spiral dive," (Page 20 para 2.2.2.1. 12)