Vie, 12/08/2011 - 16:53 | 
ALZ334
http://aviation-safety.net/database/record.php?id=19581204-0
Narrative:
The aircraft took off from Vigo airport at 15:40 hours on a scheduled flight to Madrid. The flight was cleared IFR for cruising level 95. At 16:54 the aircraft advised Madrid D.F. station that it had overflown Salamanca at 16:50 at level 95 and estimated Madrid at 17:30 - also that its VHF equipment was out of order, and it was, therefore, requesting Barajas Tower to stand by on 3023.5 kc/s. At 17:10 Madrid control cleared the aircraft to proceed directly to Barajas radio range, maintaining flight level 95. At 17:15 Madrid control authorized the aircraft to switch over to 3023.5 kc/s and to establish contact with Barajas Tower on that frequency. This was the last communication with the aircraft. Between 17:15 and 17:20 the aircraft crashed and burst into flames on the peak of "La Rodina de la Mujer Muertal' which is 1999 metres, 800 m below FL095.
PROBABLE CAUSE: "The above leads to the conclusion that if the accident was due to meteorological factors, icing would have been the factor most directly responsible. It is assumed that during its flight through innocuous stratiform clouds, the aircraft may have encountered a cumulus congestus where sudden severe icing occurred. The following may have taken place: a) A sudden change in the aerodynamic characteristics of the aircraft may have caused stalling without giving the time to initiate recovery action; b) the aircraft may have lost height rapidly, down to a level where th downdrafts over the lee slope swept it into a lower zone of erratic turbulence that sent it out of control; c) When icing occurred the captain may, in the belief he had already passed the mountain divide, have decided to fly below the freezing level which, as he knew was to be found at about 2 200 metres. It is possible that in assumptions (a) and (b) turbulence within the cumuli may have been a contributing factor. Under severe icing conditions the mechanical de-icing equipment is practically inoperative.
About 40 minutes before the accident, the mountain divide was overflown, also at level 95, by a scheduled Santiago-Madrid flight. This aircraft found nothing unusual to report, since light icing and turbulence are the normal accompaniments of winter weather in a low pressure area. This fact however in no way precludes the possibility that shortly thereafter conditions of severe icing may have prevailed."
Sources:
» ICAO Aircraft Accident Digest No.10, p.238