We know that for whatever reason the enquiry stated that the crew were given an accurate weather forecast.… this seems open to opinion but unfortunately no forecast can ever take highly localised conditions into account and it is not intended to do so.
However it is also the basis for navigation, particularly in poor visibility and was issued a very short time before the accident so it was reasonable to have expected it to be correct.
Although the crew knew about the horrendous conditions at Portsmouth, they had been flying at a higher level when they crossed the Isle of Wight on the outward flight and thus had no idea of what visibility was like below the cloud. They were totally reliant on the forecast for the safe planning of their return flight and with the pressure that may have been put on them to try and land at Portsmouth, the forecast became critical. Indeed the detail provided may very well have been the factor that persuaded them that it was safe to make a low level flight round the Island and on to Portsmouth.
Flying a local route in 1962 wasn't like today's choreographed operations and the
crew were relying on split second timing, their own navigation using dead reckoning,
literally lines drawn on a chart with a pencil, and a sharp lookout to position the
plane just off the Island for the next part of the approach. It was pencil, paper,
and Mk 1 eyeball. Today, radar and GPS satellite navigation would have the position
fixed within a few yards -
In this case they would have been allowing 5 miles between the plane and any solid
obstruction, and thus they were either reckless, which seems highly unlikely, or
badly deceived as to the correct position. Given that the aircraft appears to
have been aborting the descent when it hit the hill, it is possible that the crew
believed they were at the edge of their safety margin -
Dead reckoning relies on plotting a projected track and positions at any given time,
based on input from known factors. The main ones are the speed of the plane and
the wind which will blow the aircraft off course -
Weather reports after the accident hinted at a slight but significant difference in the wind direction, although both were virtually on the tail for the main part of the flight. There is just a possibility that a higher speed and a more Westerly wind would have made a significant difference to the plane's track, blowing it further East and increasing the ground speed. My amateur plotting indicates that the difference, taking the worst case, would have been about 5 miles ahead of the expected position and making landfall at the very point where the Isle of Wight reaches furthest South, St Boniface Down, thus two factors would be reducing the safety margin.
Additionally the first leg to Alderney would have had the wind to Port (left) and
thus pushing the plane East. It is perhaps interesting that although the 'official'
flight plan provided by the enquiry shows the plane's track crossing Alderney, the
crew reported Alderney 'in sight'. They did not say they were overhead. This may
be irrelevant -
If the cloud was lower than 500', then by maintaining a safe altitude, the crew would
actually have been too high to see the sea and to get into position to make a visual
approach, but reducing height to low level in poor visibility can be dangerous as
it is difficult to determine where the sea ends and the sky begins. Everything they
did in these circumstances would have been aimed at fixing their position off the
coast or giving up the attempt in good time to climb clear of the Island, so by adhering
to the rules the problem was potentially made worse. Normally this would have been
no concern as the aircraft would not have been attempting to land at an airport where
an ordinary instrument approach was highly unlikely to succeed. However, for reasons
not entirely clear, they were doing just that, Channel did operate to the limit of
weather minima, and they had no modern navigation aids to help them. It was all perfectly
Immediately before the accident the plane was climbing and turning right and while this may have been an evasive manoeuvre, as suggested by the airline, but there is no record we have seen to suggest any violent alteration in direction or emergency increase in engine noise until immediately before the impact. One of the survivors commented years later that he had been reading the newspaper and the flight had been uneventful, then suddenly the Pilot had ‘banged on power and started to turn’. Moments later they hit the hillside.
Unlike a jet aircraft, with piston engines any change would have been immediately
noticeable. The fact that there was no unusual change in engine power until evasive
action was taken seems to imply that the crew were not concerned and while power
was being re-
Having found that the cloud did not clear at 600 feet as forecast they began a climb
back to their original cruising altitude and were turning away from the coast which
was hidden in a wall of fog and cloud. Unfortunately the weather had closed in and
instead of breaking into clear air they found themselves still in a wall of cloud
that was lower than expected ( although the forecast did clearly state 8/8 cloud
on exposed coasts ) -
You can’t blame the weather forecast for the accident but if it had reflected local conditions more accurately, and the crew had not felt under huge pressure to reach Portsmouth, there is a good chance that the aircraft would never have been in that position.
After ten years research, that is my best guess as to why this tragedy happened.
|Radio Hams Raise the Alarm|
|An Alternative Theory|
|Pressure On Crews|