the flight

 

According the official documentation, the flight of JP137 only lasted for some 3 minutes. Anecdotal evidence suggests it may have been a little longer -- but only by a couple of minutes. The aircraft had  flown for less than 10 miles when it hit the ground.

JP137 was a very heavily laden aircraft when it took off from RAF Hurn. It was carrying over a ton of supplies, in addition to enough fuel for the long flight to North Africa.

Only some 2 minutes after take off, whilst still at a height of only some 300 ft, the AM1180 record card notes that the port wing was 'seen to drop'....
This would strongly suggest some sort of problem with one of the port engines - a dangerous situation at any time - but during the take off phase of the flight, this presented Sgt. Evans with a very difficult problem to try and overcome.
 
The Merlin engined MKII Halifax was an underpowered aircraft. In addition, it was fitted with triangular tail fins which we now know had a tendency to overbalance, and could 'lock' the rudder fully in one direction or the other. (See HERE
for further details on that). 
Sgt. Evans would probably have tried to correct for the loss of engine power by applying both aileron and rudder control, to try and counter the wing dropping.  At that stage of the flight, with the engines already at full power for the take off phase, there would have been little else he could have done. 

It seems as if this engine problem was a very serious one.  Although there is no mention of an engine fire in the 'official' documents, we have a number of eyewitness reports that do indicate that one of the engines was on fire whilst the aircraft was still in the air. (You can click HERE to see copies of those reports). 

With the loss of power, the full load, and the lack of height and airspeed, the aircraft was essentially doomed from this time onward. With the rudder probably locked, and the port wing suffering from a significant loss of lift from the engine failure, then JP137 would have developed an 'incipient stall spin', which inevitably ended in the final crash.   
Again, from contemporary reports - both official and anecdotal - we can make an assumption of the path the aircraft followed. A likely track of that route is shown below....(click on the image for a higher resolution PDF version)

There has been some speculation that Sgt. Evans, faced with this serious problem, was actually trying to return to Hurn. This seems extremely unlikely.  Most expert opinion - including that from other Halifax crew members - seems to agree that if Sgt. Evans did still have any effective control over his stricken aircraft, then he would have simply tried to gain some height, fly straight out towards the sea (less than 2 miles away), and hope that the crew would be able to bail out before the aircraft was ditched into the water. The chances of him being able to control his damaged - and fully loaded - aircraft well enough to effect a safe landing back at RAF Hurn were virtually nil. And he would have known that.

The photographic evidence also suggests that the aircraft almost certainly struck the ground upside down. In the final stages of a flat stall spin, the port wing would eventually have lost virtually all lift.  At that stage - and especially if the rudder was fully 'locked' in the direction of the spin by an intrinsic design flaw - then the aircraft would have tipped vertically to port, and continued on into an inverted position, before it actually struck the ground behind Meadow Court.
That would help explain several of the apparent 'mysteries'  that seem to result from examination of some of the Civil Defence photos.

- How the gable end of 13 Malvern Rd was damaged, but the chimney behind it survived?
- How the telegraph pole behind number 4 Malvern Rd survived?
- How the tail wheel and the port tailplane of the aircraft survived the impact?

(Click HERE to see a collection of images for some possible positions of JP137 in those last few seconds)

In short therefore, the fate of JP137 was sealed the moment the engine failed during take off. Once that engine caught fire, there was absolutely nothing more that Sgt. Evans could have done to save the aircraft and its crew...