The death of Air Chief Marshal Sir Trafford Leigh-Mallory, November 1944: a conjectural explanation

Air Chief Marshal Sir Trafford Leigh-Mallory was killed in an air crash in the French Alps in November 1944. This Note discusses some evidence relating to the disaster, and attempts a conjectural reconstruction of the fatal flight that might explain why the aircraft was several hundred miles from its planned course.

In June 2024, to mark the eightieth anniversary of the Allied landings in Normandy, I added a commemorative Note to the Martinalia section of my website: "Magdalene College Cambridge Notes: Tedder, Leigh-Mallory and D-Day" (https://www.gedmartin.net/martinalia-mainmenu-3/403-magdalene-d-day). This contrasted two College contemporaries, Arthur Tedder and Trafford Leigh-Mallory, both of whom rose to high rank in the Royal Air Force. Leigh-Mallory was killed in an air crash in November 1944, and my Note indicated that he was criticised at the time for having insisted, so it was believed, that the aircraft that had been assigned to him should take off in very poor weather conditions. Shortly afterwards, I received three pieces of valuable additional information from my Magdalene contemporary and friend, Alistair Pirie. This material enabled me to make some minor corrections to the Note. The evidence threw additional light upon the circumstances of Leigh-Mallory's death, which seemed to justify a separate Note. I stress that I am not an aviation historian, and that the conclusions offered here should be regarded as tentative suggestions which, I hope, may stimulate discussion – no doubt, more informed discussion – among those interested in the episode.
The three pieces of material were very different in character. One was an impressive published account of the entire episode by Denis C. Bateman (full reference given in the Note on Further Reading that follows the text). I stress my admiration for Bateman's ability to survey not only the technical and operational aspects of the subject but also to place it in the wider context of wartime policy. The other two were documents collected by the local history society at Woldingham in Surrey. One of these was a record of the memories of Beth Lancaster, sister-in-law of Squadron Leader Gordon Lancaster, the pilot of Leigh-Mallory's plane in his fatal last journey. The other was a typescript by Wendy Maclean, his sister, which usefully summarised the story of the flight, with some additional comment. Wendy Maclean had accompanied a party of aviation enthusiasts on a visit to the crash site in 1982, and her earlier recollections became interwoven with stories that she heard at that time. (The late Beth Lancaster had lived in Woldingham, which accounts for the local interest.)
Thus the information helpfully supplied by Alistair Pirie included a detailed scholarly account of events based upon written records, plus two pieces of oral tradition. As a product of an immediate postwar generation, I can testify to the importance of the latter. When a family member was lost on active service, relatives often sought information about the circumstances of the death. Sometimes comrades made contact to offer condolences and add lively detail concerning the people involved. Hence the oral tradition can convey colour and atmosphere that was absent from any official record – or was judiciously suppressed.
In this Note, I discuss some of the salient points that have emerged. First, there is an important basic timeline behind the process of explanation and the attribution of blame for the loss of Leigh-Mallory's flight in the Alps. The aircraft disappeared on 14 November 1944. A Court of Enquiry sat from 23 to 29 November, with the obvious and reasonable intention of searching for any immediate applicable lessons. Although there had been reports from French villagers in the Alps near Grenoble that an aircraft had crashed high in the mountains, an American military police patrol had lacked the equipment to search above the snowline. The Court of Enquiry considered various possible scenarios that might have explained the disappearance of the aircraft, but no connection was made with the unconfirmed reports from the Alps, which were remote from Leigh-Mallory's projected flight path. The crash site was not identified until the following June, when the snow finally melted high in the Alps. An accident investigation team made a close study of the area, but it was considered a "waste of time" to reopen the official enquiry. In effect, the Court of Enquiry was charged with drawing lessons from the disaster without in fact knowing what had happened, or even where it had happened. Its report noted the obvious point that the weather had been unusually bad, which indicated either that the flight should not have taken off or that it should have turned back as conditions deteriorated. In the absence of definite information, it was not surprising that the Court of Enquiry homed in on the fact that the crew were unfamiliar with the aircraft. By implication, this seemed to place much of the blame upon Squadron Leader Lancaster, evading the obvious question: who was responsible for his appointment? Given the decision not to reopen the formal enquiry in 1945, the provisional findings of November 1944 remained on the record, to the detriment of two of the airmen who had been killed, the pilot, Gordon Lancaster, and the navigator, Flight Lieutenant Keith Mooring.
It is hardly necessary to point out that flying an aeroplane is not like hiring a car, where a few minutes spent checking headlight and indicator switches on an unfamiliar model are enough to equip the driver to head into traffic. Hence the story of the disaster must start with the aircraft, and then seek to understand how a pilot with little experience of the machine came to be flying
it. On his appointment to command the Allied air forces in south-east Asia, Air Chief Marshal Sir Trafford Leigh-Mallory had originally planned to travel in his usual aircraft, a Dakota, with his personal pilot, Flight-Lieutenant Peter Chinn, operating a Mosquito as a back-up. (Chinn became Squadron Leader Lancaster's co-pilot, and appears only once in the subsequent story.) The Dakota was a workhorse transport plane, the Mosquito a smaller aircraft with a speed that made it suitable for various roles, notably as a fighter-bomber. In the event, Leigh-Mallory was offered a relatively new and larger Avro York to take him to the East. (It should also be noted that, although my original Note loosely refers to "India", the planned flight was actually to Kandy in Ceylon – now Sri Lanka – presumably to connect with the key naval base at Trincomalee.) The Avro York had been developed as a passenger version of the better-known Lancaster bomber. The pressures of wartime made its production a low priority and only a small number had entered service by 1944. The only pilots who had much experience in flying them were from Transport Command, a new element in the RAF structure that had only been established (from the former Ferry command) in 1943. The Avro York could carry up to 21 passengers, making it particularly suitable as a VIP aircraft, capable of flying top politicians or generals, along with their support staff. Both Churchill and Smuts used the Avro York. The Duke of Gloucester was flown to Australia on an Avro York in 1945 to take up his role as Governor-General, and the RAAF operated the aircraft for the next two years as his personal transport.
Historical episodes sometimes throw up odd combinations of names that no writer of fiction would dare to perpetrate: the Avro York was to be flown by Squadron Leader Lancaster. How did this curious juxtaposition come about? Gordon Lancaster was the personal choice of Leigh-Mallory himself, and was evidently appointed not simply to fly the new commander to south Asia but designated to act as the personal pilot responsible for ferrying his boss around the Indian Ocean theatre of war. Here it is useful to recall an anecdote from Tedder's journey to Moscow in 1942, which succeeded only at a second attempt. During the initial flight, the pilot came to him to report a possible malfunction and to request permission to turn back. Tedder bleakly reminded the young officer that, as pilot, he was in absolute command of the aircraft, and must make his own decision. Of course, this was a way of signalling approval, or – at least – of not interposing a veto. The flight returned to Tehran where a mechanical check confirmed that everyone on board would have been killed had the aircraft continued its journey. It seems highly unlikely that the habitually masterful Leigh-Mallory would have acted in the same spirit. Lancaster was chosen for a role akin to an aerial chauffeur: at thirty-two, and only recently promoted to Squadron Leader, he was twenty years younger and several ranks junior to his VIP passenger.
The reasons for Gordon Lancaster's selection as the commanding officer's pilot were not recorded, but it seems highly likely that he was personally agreeable to the Leigh-Mallorys. Indeed, it was suggested that Leigh-Mallory's wife Doris knew his family. Lancaster was a former pupil of Rugby School who had studied at Trinity College, Cambridge, an education parallel to Leigh-Mallory's track record of Haileybury and Magdalene. The Air Chief Marshal had managed Thirds in History and Law; the young Squadron Leader did not manage to gain any place in the University's Honours degree in Mechanical Sciences. Rather, he was awarded a Pass degree in Engineering on the basis of achieving a Certificate of Proficiency in Engineering Studies, having qualified in five of the six prescribed subjects. (It would be unkind to dwell on the point that the sixth, which he either failed or did not attempt, was Aeronautics.) He was also a sportsman: at the birthplace of Rugby Union, he had become a member of the First XV. Not least in his favour was the fact that he was a twice decorated war hero, who had won the Distinguished Flying Cross and bar. Given the conventions of the era, Leigh-Mallory was entitled to select as his personal pilot – other things being equal – somebody with whose background and personality he felt comfortable.
The problem was that other considerations were not equal: Gordon Lancaster massively lacked experience in flying the Avro York. True, he had over 2,000 hours of flying time to his record, but he had served in Coastal Command, where he had operated Sunderland flying boats. Like the Avro York, the Sunderland was a four-engine giant, but there the similarities ended. Sunderland pilots had to be able to land on choppy seas and take off from confined estuaries. Unlike the York, the Sunderland was heavily armed, capable of fending off fighter attack and also launching attacks on U-boats. It was much slower than the York, with a top speed of just over 200 mph, compared with the almost 300 mph of the passenger plane. It generally flew low and at a cruising speed that permitted search and observation. Gordon Lancaster's talents and experience may be gauged from the citation of his second DFC, which the London Gazette published on 25 August 1944 (and shortly before his final promotion). "This officer captained an aircraft which engaged a U-boat recently. When the vessel was sighted, Flight Lieutenant Lancaster immediately went into the attack. His aircraft was hit by anti-aircraft fire but he maintained his attacking run and straddled the vessel with his depth charges. This officer displayed great efficiency, gallantry and determination." Unfortunately, these impressive skills did not easily transfer to his new role.
The Avro York was designed to fly at much greater altitudes where, if it encountered freezing cloud, its windscreen was liable to be coated with impenetrable ice. The York was fitted with de-icing equipment but not with mechanical wipers, which would almost certainly have proved ineffective. Thus Gordon Lancaster was making an abrupt transition from piloting a plane which permitted close visual inspection almost at sea level to operating an aircraft that he might well have to fly blind. His preparation for his new role was a conversion course at RAF Lyneham in Wiltshire, where he logged nine hours and forty minutes of flying time on the Avro York, of which just four hours were solo. In aviation terms, this was not much more than checking the indicator switches on a hired car. The Court of Enquiry heard that another Avro York pilot advised him to delay Leigh-Mallory's departure to give himself the opportunity to make a long practice flight. Of course, Gordon Lancaster lacked the seniority to impose such a decision. His limited experience of the aircraft meant that he lacked sufficient standing to register any objection to flying it into the harsh conditions of 14 November 1944, even if he had wished to. It is noteworthy that the Court of Enquiry recommended that Transport Command should have a veto over the future selection of pilots for VIP flights. The lesson was clear: it was Transport Command that operated the Avro York, and its pilots were the obvious candidates to undertake major overseas missions. That ought to have been obvious before Leigh-Mallory's flight left Northolt on that November morning.
Wendy Maclean believed that the route originally planned was via Gibraltar. Since Spain was an unfriendly country, a flight to Gibraltar would have involved not only the dangerous transit of the Bay of Biscay and a lengthy detour around the Iberian peninsula. Their familiarity with hazardous maritime conditions, she suggested, explained why her brother was one of three airmen from Coastal Command seconded to the mission. However, it did not explain the selection of a crew which contained only one member, the flight engineer, who was familiar with the Avro York, while the runway under the Rock of Gibraltar was hardly the ideal place to gain experience of landing a large transport aircraft. According to Wendy Maclean, this planned leg of the journey was abandoned after Lord Haw-Haw, the German propagandist, announced that the Nazis knew that a VIP was expected on the Rock, hinting that they planned their own welcome. This story may be treated with some reserve. The broadcasts by the traitor William Joyce had a peculiar ability to get under the collective skin of the British people. In communities across the country, people swore that Lord Haw-Haw had known that church clock had stopped, or that Lord Haw-Haw had threatened to send the bombers to pulverise some village that had offended the Fuehrer. Leigh-Mallory's departure had already been delayed for ten days by an attack of bronchitis that had temporarily placed him on the sick list. If there had been a Gibraltar leg in the original flight plan, it would have added a day to an already gruelling journey, and this could explain its eventual omission. In any case, it would hardly have made sense to select a crew for a prolonged assignment on the basis of perceived special circumstances of a single day.
It is evident that relatives of the men who lost their lives felt considerable bitterness at what they regarded as the reckless attitude of the Leigh-Mallorys to the safety of the aircraft. Beth Lancaster believed that "Lady Leigh-Mallory intended to do some entertaining in India and her baggage included silver and a considerable amount of china." The commander of the Allied air forces in south-east Asia would certainly be supplied with official crockery: Beth Lancaster's allusion to "china" implies that the couple decided to take their own dinner service, presumably to boost his status by impressing guests with a display of family silver and monogrammed tableware. (Did this portend a campaign to undermine Mountbatten, the Supreme Allied Commander, by creating a rival 'court' within the command structure? Mountbatten was not enthusiastic about his new colleague.) In addition, Bateman accepted a report that, a few days before departure, Chinn informed Lancaster that Leigh-Mallory wished to have 500 cartridges loaded aboard. The British Raj was remarkably addicted to killing Asian wildlife, but – again – the necessary ammunition was easily available on the spot. Lancaster complained about the additional weight, but it seems that the cartridges came aboard.
To assess the validity of these much-resented stories, it is necessary to delve a little into the capabilities of the Avro York. It will appear that, on balance, the stories of selfish or reckless loading of baggage were primarily symbolic, evidence of Leigh-Mallory's attitude to the mission as a projection of his personal glorification rather than proof of an inexplicable disregard for safety. What Bateman called the "maximum permissible all-up weight" of the Avro York was 68,000 pounds (lbs). (For those who think metric, a kilogram is roughly equal to 2.2 lbs: for convenience I use the RAF's own system of measurement.) Taking off from RAF Northolt, the weight was reduced to 63,000 lbs, which I assume was explained by runway restrictions. (Northolt's runways were extended several times during the War.) Leigh-Mallory's aircraft underwent a refit before the mission which included the installation of a new and heavier undercarriage, but in-service modifications were standard practice, especially since the Avro York was a recent introduction. On the eve of the flight, it was reported to weigh around 43,500 lbs. I do not know if this included fuel. If the composition of aviation fuel has not substantially changed, the 1,860 gallons that the Avro York could carry would have weighed around 14,000 lbs. If that has to be deducted from the shortfall of 19,500 lbs between the pre-flight weight and the capacity of the Northolt runway, then it might indeed seem that loading unnecessary china, silverware and cartridges was irresponsible.
However, this may not be entirely fair. There were ten people on the flight, most of them young and fit airmen. Assuming an average weight of twelve stone (168 lbs), the human component, at around 1,700 lbs, would have been a small part of the overall load. (Leigh-Mallory himself was tall and solidly built.) But a small number of Avro Yorks in service with British Overseas Airways Corporation were configured to carry 21 passengers – 24 or 25 people, including crew. Commercial air travel in those days imposed tight baggage restrictions, but with fewer people on this flight, there was a leeway of around 2,400 lbs in absent persons. We have no way of estimating the weight of Lady Leigh-Mallory's silverware – perhaps she only took a few small items such as a reassuringly familiar milk jug – but some estimate may be made of the bulk of a dinner service. In 2024, a dozen mass-produced porcelain dinner plates weigh about 20 lbs. Bone china is lighter, but for a commissioned set, perhaps a wedding gift, the plates might well have been larger and heavier. If the Leigh-Mallorys were indeed planning to cultivate influence by throwing banquets, it is probable that their dinner service provided several dozen settings. In addition, there would have been side plates, soup and dessert bowls, tureens, platters, sauce boats and suchlike. Yet, however much we may inflate the Leigh-Mallory china, it is difficult to see it having weighed as much as one healthy passenger, and the flight could have carried up to fourteen extra people. Much the same can be said of the box of 500 cartridges, the one freight item that the official record shows was definitely queried. Twelve-bore cartridges were generally used for hunting rifles, and they took their name because twelve of them weighed one pound. The cartridges would have been locked in a secure and solid box, but it is unlikely that the whole item weighed more than 50 lbs.
There is further evidence that tends to discount any suspicion that the aircraft was overloaded or that the Leigh-Mallorys had abused their status to insist upon the carriage of unsuitable items. (They were, after all, going to a major appointment of indefinite duration, and were entitled to some consideration in the matter of personal belongings.) As noted, the runways at RAF Northolt required the imposition of additional limits. In accordance with normal practice, the baggage was carefully weighed. Loading was supervised by Gordon Lancaster himself, assisted by the flight engineer, Flying Officer John Enser, the one member of the crew who did possess extensive experience of the Avro York. It may also be worth noting that there seems to be no record that any traces of silverware at the crash site in the Alps, although this is not conclusive nor indeed surprising: the wreckage was looted before the authorities could take control of the scene – and for long afterwards. (This probably explains why Leigh-Mallory's engraved cigarette case never came to light.) Nearby residents overcame daunting mountaineering challenges to remove anything valuable: after six years of war, they can hardly be blamed for their enthusiastic salvaging. Twisted twelve-bore cartridges were reported to have been found among the wreckage and, decades later, there remained local memories of smashed china and cutlery – although the knives and forks that made their way into village kitchens seem to have been standard RAF issue. The shattered crockery may also have come from the galley.
Thus the evidence would seem to acquit the Leigh-Mallorys of deliberately overloading the aircraft, a course of action that would hardly have been in their own interests. It is more likely that their choice of baggage displayed a self-centred attitude towards personal convenience and status that did little for the morale of the crew. Wendy Maclean heard that the navigator, Flight Lieutenant Keith Mooring, had told his family shortly before the flight that "none of the crew had any great confidence in their expectation of survival". Mooring – another import from Coastal Command – would have been on embarkation leave, which was specifically intended for farewells before hazardous missions. Losses among RAF personnel were tragically high throughout the War, and Mooring was probably depressed and undoubtedly realistic about the risks involved, not just of a long flight in unknown conditions but of subsequent combat with the Japanese. More disturbing was another report, remembered by Beth Lancaster, that Mooring checked the aircraft's weight the night before the flight and told Gordon Lancaster: "we will not clear the Alps". Presumably the comment was overheard by ground staff, as it could not otherwise have made its way into the oral tradition.
However, while it seems likely that Keith Mooring was gloomy about the prospects of the flight, it is unlikely that he had warned the Squadron Leader that they would not clear the Alps, for the simple reason that the first day's planned flight path would take the Avro York nowhere near Europe's highest mountain range. The aircraft was to cross the French coast at Cherbourg and then head with some slight deviations, more or less due south to Toulouse, where it would make a sharp turn to the east and then skirt the Mediterranean coast to Naples. The dogleg flight path was probably chosen to allow the unheated aircraft to fly at an altitude low enough for the comfort of those on board. The western side of France is commendably free of mountains. A narrow valley to the east of Toulouse separates the foothills of the Pyrenees from the beginnings of the Massif Central and links the city to the Mediterranean: it is the route of the Canal du Midi, one of the oldest artificial waterways in Europe. If there had been even partial or intermittent visibility on that November day, the crew would have been able to confirm their position on the proposed route from outlines of prominent features on the ground. Tracking of the aircraft in British airspace confirmed that Lancaster took advantage of the well-known landmark of Selsey Bill to check his position. The jigsaw shape of the Cherbourg peninsula would also have been unmistakable while, later, there would have been a good chance of a glimpse of the Gironde estuary to the west. Most important of all, any view ahead through the windscreen would have reminded the crew that the looming Pyrenees pointed to a ninety-degree turn to port.
In the event, it is virtually certain that the windscreen became covered in ice, and such visual confirmation was impossible. Yet that alone could hardly explain why Leigh-Mallory's plane crashed 250 miles off course. It seemed obvious that the aircraft had strayed from – or deliberately departed from – its prearranged flight path. The Court of Enquiry took the straightforward view and assumed that the fact that the Avro York crashed at some still-untraced  location away from its official flight path (which had been searched by routine patrols) pointed to massive failure by the navigator. His colleagues indignantly rejected the charge: Wendy Maclean was told that Flight Lieutenant Mooring was "brilliant" at his job, and that it was ludicrous to think that he could have lost his way. Of course, the fact that the aircraft flew into a mountain incontrovertibly points to some error in calculation, but, if we accept – as we should – that it is inconceivable that Mooring could have become totally lost, then it becomes necessary to reconstruct, or at least guess, what happened on the flight.
Bateman described weather conditions at Northolt on the morning of 14 November as "not good", and they rapidly deteriorated. Fighter Command provided an escort to the Hampshire coast – a kind of guard of honour for Leigh-Mallory, as the Luftwaffe had been shot out of the sky before D-Day, and there was no real threat in English skies. As they turned back to base, the Spitfires ran into such bad weather that they only "just managed to get into North Weald", their Essex base. In French airspace, other pilots reported that the weather was "atrocious". Within an hour of Leigh-Mallory's departure, two other RAF pilots flying south were so battered and disoriented by clouds of snow and freezing rain that one turned back to England, and the other made an emergency landing in Brittany. For security reasons, Gordon Lancaster was ordered to observe radio silence and not to switch on the IFF (Identification Friend or Foe) until he reached 45 degrees North, the latitude of Bordeaux. IFF was a transponder system – non-specialists might think of it as a "pinger": one early version was nicknamed "pipsqueak" – which not only reduced the chances of "friendly fire" encounters but was also a useful navigation and tracking aid. Lancaster did have permission to turn on IFF in an emergency, but it seems that the system was not used.
Unfortunately, I am unable to track down any detailed weather report for 14 November 1944. Meteorological data was strategically sensitive, as the story of the timing of D-Day proved, and even stray details might help the enemy. The shreds of evidence confirm that the weather was unusually bad. On a morale-boosting visit to Free French troops in eastern France, Churchill encountered heavy snow in the Vosges. On 15 November, The Times reported that, during the previous twenty-four hours, ground and air operations in Holland had been "restricted … due to bad weather". However, no information was given about wind direction, a vital element in assessing an aircraft's speed and direction. Snow would naturally suggest a cold air mass from the north, but stormy weather in November would also point to westerly gales. Flying from Cherbourg towards Toulouse close to the Atlantic seaboard, the Avro York may well have found it difficult to maintain its north-south route, and this could explain an in-flight decision to turn east at a much earlier stage.
One of the pilots in the air that day who gave evidence to the Court of Enquiry about weather conditions over France was Wing-Commander Edward Whitaker, who had also flown an Avro York to Naples that same day. (It was Whitaker who had advised Lancaster that he needed more experience of the aircraft before undertaking such a long flight.) Whitaker had faced an even greater challenge since had taken off – from RAF Lyneham – several hours earlier, and was thus flying in darkness. An hour into his flight, the windscreen iced over, and he flew for the next ninety minutes "virtually blind". Although not enjoined to radio silence, he gained little help through wireless communication: his operator found it difficult to break through the crackling of static. Fortunately, as the aircraft approached the Mediterranean, it picked up a radio beacon that confirmed its location. Whitaker descended to about 1,000 feet – almost certainly about as low as it was safe to operate the giant machine – and this would have cleared the ice from the windscreen. He continued to Naples flying at the same height. It is noteworthy that a pilot experienced with the Avro York should have decided to press on and apparently did not consider turning back.
Whitaker's evidence makes it possible to hazard some guesses about the decisions taken in the cockpit of Leigh-Mallory's flight. During her 1982 visit to France, Wendy Maclean heard a story, "(source unknown)", that the crew had wished to return to base, but were overruled by Leigh-Mallory. Maybe this happened, but it is beyond the scope of human knowledge: the flight was out of radio contact and everyone on board was killed. The currency of the report is further evidence of the general dislike felt towards Leigh-Mallory, who was described to Wendy Maclean as "a very dominant character by a member of our party who had served under him". (Much the same can be said of reports that Leigh-Mallory had insisted on flying a direct route over the Alps: there is no evidence for such a claim, which would have been dangerous, not least because the Germans were still fighting hard in northern Italy.) In any case, turning back was hardly a straightforward operation, especially for a pilot who might not be sure of his exact location. An unexpected and possibly unidentified aircraft would be at risk from British air defences. The Court of Enquiry considered the possibility that the flight had indeed attempted to return, but had accidentally flown over the Channel Islands, still under Nazi occupation, and been shot down. Even if the Avro York had made it into British air space, it still had to locate an aerodrome with a runway long enough to take it, and to get its wheels on the ground in dangerous weather conditions.
There are two more likely possibilities. The first is that, when Lancaster found himself flying blind in appalling conditions, there was an emergency consultation – the two pilots, Mooring and Leigh-Mallory himself – which decided to shorten the planned journey to Naples. A pre-flight briefing had stressed one obvious point – that Toulouse was close to the Pyrenees, in fact about ten minutes' flying time from the mountains. (One of the scenarios considered by the Court of Enquiry was that the aircraft had crashed in the Pyrenees.) With no visibility, the margin of error in the turn-left-at-Toulouse plan was hardly large enough to provide reassurance. Hence the solution would have been to fly in a more south-easterly direction, a kind of hypotenuse route that would eliminate the right-angled bend and shorten the flight time. Such a route would have made it necessary to climb to cross the jagged Auvergne, where there were peaks of 5,000 to 6,000 feet: this would explain why the Avro York was flying at 7,500 feet when it crashed. (Gordon Lancaster had been advised in a pre-flight meteorological briefing that he might need to climb as high as 17,000 feet to escape the cloud cover.)
There is a second and related possibility, that the Avro York did make its turn to the east, but at least one hundred miles north of Toulouse, perhaps as early as the Loire valley. The intention would have been to fly along the northern edge of the Massif Central, relying on calculations of speed and compass bearings to determine when the aircraft reached the vicinity of Lyons. There it would turn south, down the Rhône valley until it was close to the Mediterranean, where Lancaster would bring the Avro York to a lower altitude – as Whitaker had done with his aircraft – to de-ice the windscreen and hope for gaps in the cloud that would make possible identification of features on the ground. The north-south course of the Rhône, the coastline, the city of Marseilles – a glimpse of any of these would confirm their position, and allow Lancaster, with his experience of low-level operations with the Sunderland flying boats, to continue on his way to Naples.
A considered decision to amend the flight path is certainly more persuasive than the conclusion that Mooring, an experienced navigator, had lost his way by several hundred miles. The hypothesis is strengthened by a finding that was not – and, of course, could not have been – available to the Court of Enquiry. The air accident team which investigated the crash site in the summer of 1945 concluded that the aircraft was apparently flying in a south-south-easterly direction when it hit the Alpine ridge, and this was the direction in which Lancaster and Mooring would have pointed it had they assumed they were over the Rhône valley. In fact, the aircraft was about sixty miles east of the river – an error equivalent to about fifteen minutes' flying time. There would seem to be two possible explanations for this fatal miscalculation. The first is that it was difficult to estimate the overall speed of the aircraft as it battled bursts of violent weather. The second would be that, if Lancaster had turned east to avoid the battering of an Atlantic gale, there would have been a tailwind, the force of which it was impossible to measure. Gordon Lancaster's lack of experience would have been crucial here. Whereas Wing-Commander Whitaker knew his Avro York well enough to coax it through the clouds and reach Naples, Lancaster presumably had no idea how the aircraft would handle in bad weather, and neither he nor Mooring could make a reliable estimate of its speed.  

One other piece of evidence also seems to fit with the hypothesis. The RAF scheduled its flights by Greenwich Mean Time. The French villagers who reported hearing aircraft engines overhead followed by an explosion gave the time as 12.40 p.m., or soon afterwards: this would have been about a quarter to twelve by British time. This would mean that the Avro York was just over two and a half hours out from Northolt, with slightly less than the same time still to fly to Naples. This would be very close to the point – about half way – we might expect it to have reached had there been the emergency adjustment to the flight plan suggested here, perhaps with some marginal delay caused by bad weather. The timing certainly rules out any possibility of an alternative, and frankly preposterous, explanation that Lancaster had attempted to follow the original flight plan by way of Toulouse but had become hopelessly lost, wandered at random and eventually flew into the Alps hundreds of miles off course. It is more likely that the flight was following a definite course, if one amended in-flight, while its south-south-east direction only makes sense if that the crew thought they were flying down the valley of the river Rhône.
All that we know for certain is that, shortly before 1 p.m. local time on 14 November, the Avro York struck an Alpine ridge about 7,500 feet above sea level, killing all ten people on board. Perhaps a few hundred extra feet in height would have enabled the aircraft to clear that particular obstacle, but the crash-investigation team bleakly noted that there were far higher mountains beyond. A box of cartridges and a few piles of china made no difference to the fate of the flight either way: Leigh-Mallory's aircraft was doomed.
I doubt whether families who lost a relative in the Second World War – and other conflicts too – ever fully came to terms with their grief. There may have been some slight consolation (although I doubt it) in knowing that a husband, son or brother had been killed attempting to save a wounded comrade, or in attacking a strategically crucial enemy position. But for a brave officer to die running a glorified errand for a man nobody liked, a bully who seemed to treat the mission as an ego trip, could only turn sorrow into inchoate anger. Worse still, for Gordon Lancaster's family, were Court of Enquiry findings that seemed to hold him responsible for the position that Leigh-Mallory had placed him in. (Beth Lancaster even believed that "a close relative of Leigh-Mallory" influenced the Court of Enquiry to shift the blame on to her brother-in-law.) In fact, the Court of Enquiry offered a nuanced verdict, that Lancaster's lack of experience with the Avro York was not sufficient "to enable him to make a correct decision" on dealing with the adverse weather conditions, and that the "wisdom" of flying at all that day was "questionable". Behind these carefully coded statements lurked the question: who had placed Gordon Lancaster in this position?
Essentially, there are two charges against Leigh-Mallory: he chose the wrong pilot and he insisted that the flight take off in dangerous conditions. It is only necessary to consider a plausible alternative scenario to appreciate that the two indictments elide into a single, overwhelming condemnation. Imagine Northolt aerodrome on the morning of 14 November 1944, but with a crew seconded from RAF Transport Command to fly the Leigh-Mallorys to Ceylon. It is highly likely that the pilot would have strongly advised against departure, arguing from his familiarity with the Avro York that he could not guarantee the safety of his distinguished passengers in such bad weather. The Air Chief Marshal might well have overruled him, even though his entitlement to do so would have been open to question. Yet that need not have been the end of the story. RAF Northolt was the headquarters of Transport Command, and our pilot might well have taken his case to more senior officers who, one hopes, would have stood by their subordinate. That, too, would not necessarily have deflected Leigh-Mallory from his determination to take to the stormy skies and, since he probably outranked everybody at the base, the outcome would still have been by no means certain. However, he would at least have been obliged to listen to the protests of a Group Captain or an Air Commodore. There was, too, one argument that could surely have been invoked by any experienced senior airman confronting the headstrong Air Chief Marshal. Leigh-Mallory's flight was due to reach Naples at 2 p.m. – presumably three o'clock, local time. A two-hour delay in departure to check on weather reports would still have permitted him to arrive at his destination in daylight, and would not seriously affect overnight maintenance for the next leg of the journey. As news came in of other aircraft turning back in French airspace or making emergency landings across the Channel, it is reasonable to assume that any delay in take-off would have been tantamount to cancellation of the flight that day.
None of these options was open to the young man who had only recently been promoted to Squadron Leader. Unlike the Transport Command pilots, he had very little experience of the Avro York and hence no standing to question its likely performance in poor conditions. His background was in Coastal Command, and he had flown the aircraft in to Northolt from Lyneham only a few days before. He was, literally, Leigh-Mallory's protégé and had no institutional connection with any officer in the Transport Command structure to whom he might have confided his doubts. If he did express any concerns about the flight – and none seem to have been recorded or remembered – he would have been overruled by Leigh-Mallory, who was noted for his dominant personality. As the notes supplied by the Woldingham local history society put it, "Beth phrased it in somewhat stronger terms."
A note on sources I repeat my admiration and acknowledge my debt to Denis C. Bateman, "The Death of Air Chief Marshal Leigh-Mallory", published in After the Battle (Stratford, East London), xxxix (1983). Information on Gordon Lancaster comes from The Times, 17 November 1930 and 14 June 1935 and from the London Gazette, 25 August 1944. There is a note about him on the website of the Trinity College Cambridge War Memorial: (http://trinitycollegechapel.com/media/filestore/general-documents/RollOfHonourWorldWarII_1.pdf). In addition to the biographical material about Leigh-Mallory discussed in " Magdalene College Cambridge Notes: Tedder, Leigh-Mallory and D-Day" (https://www.gedmartin.net/martinalia-mainmenu-3/403-magdalene-d-day), mention should be made of a 2014 University of Birmingham PhD thesis, "The Forgotten Career of Air Chief Marshal Sir Trafford Leigh-Mallory, 1892-1937: A Social and Cultural History of Leadership Development in the Inter-War Royal Air Force". Dr Mahoney made judicious appraisal of the general negative portrayal of his subject, but concluded by examining his career in terms of the 'Peter principle'. The thesis may be consulted via https://etheses.bham.ac.uk/id/eprint/6090/1/Mahoney15PhD.pdf.
I have used various internet sources, for instance for aircraft technical specifications. Any impression of omniscience that these may convey should be resisted: I repeat that my reconstruction is both amateur and conjectural, and is offered here solely for the consideration of those who may be better qualified to assess what happened on that fatal flight. For another discussion of the perils of long-distance travel during the Second World War, see Ged Martin, "Winston Churchill : Wartime Traveller":
https://www.gedmartin.net/martinalia-mainmenu-3/9-winston-churchill-wartime-traveller.
My warm thanks are due to Alistair Pirie for sending me this interesting material, and to Bernard Cope for his patient construction of my original sketch map. As so often, I also owe appreciation to Andrew Jones for his sage advice.