North Atlantic, 13 March 1928: the disappearance of Endeavour

At about half past one on the afternoon of Tuesday 13 March 1928, the chief lighthouse keeper at Mizen Head, on the south-western corner of County Cork, looked up and saw a black-fuselaged, gold-tipped monoplane crossing the sky over the village of Crookhaven, heading out over the Atlantic on a west-south-west bearing. The aircraft was a Stinson SM-1 Detroiter, registered G-EBTU, and christened Endeavour. It carried two people and the better part of a hundred US gallons of long-range fuel. It was bound, on a great-circle course, for Newfoundland and then for Mitchel Field on Long Island, New York, and it was making the first attempt at a nonstop east-to-west crossing of the North Atlantic by aeroplane.

Some hours later, in the open ocean west of Ireland, the French steamer SS Josiah Macy is consistently reported in the secondary literature to have sighted an aircraft still on course. No primary press citation for that sighting has been located here, and the steamer’s name is sometimes given as Macey. After it, nothing. Endeavour did not arrive at Mitchel Field. No distress signal was logged. No wreckage was found that spring or summer.

In December 1928, eight months after the takeoff, a single wheel and a piece of undercarriage strut washed ashore on the County Donegal coast. The Air Ministry matched a stamped serial number on the wheel to G-EBTU. The exact beach where it came in is not consistently named in the open-source record; the recovery is documented, the townland is not. Nothing else from the aircraft was ever recovered. Ninety-eight years later, that wheel is still the only piece of Endeavour anyone has produced.

This is the documented account of the loss, the evidence that has accumulated around it, and the hypotheses that have followed. The three are kept separate. One of those hypotheses, the séance episode of May 1928, is reported here as a documented historical artefact of 1920s spiritualism and not as evidence. The Donegal wheel directly contradicts the geography the séance asserted.

The documented account

The pilot was Captain Walter George Raymond Hinchliffe, DFC, known as “Hinch.” He was born on 10 June 1893 in Munich to British parents. He served in the Royal Artillery from 1914 to 1916, transferred to the Royal Naval Air Service, gained his Royal Aero Club Certificate in September 1916, and was posted to 10 Squadron RNAS. He went into the RAF with 210 Squadron in April 1918, was credited with seven enemy aircraft between February and July 1918, and was awarded the Distinguished Flying Cross. In a night engagement near Hazebrouck he was shot through the forehead, crashed in Nieppe Forest, and lost the sight in one eye. Most secondary sources record the left eye; at least one says the right. He wore a black eye-patch for the rest of his life.

After the war he became chief pilot of KLM in 1922 and 1923, joined Instone Air Line and then, on the 1924 merger, Imperial Airways, and flew more than forty aircraft types. By 1928 he was rated one of the most experienced civil pilots in Europe. He was married to Emilie, whose surname is variously given as Gallizien and Galizia and whose nationality is given as Dutch and as German-born; both are flagged in the sources. The Hinchliffes had two daughters, Joan, born in 1923, and Pamela, born in 1928 and an infant at the time of the flight. He was 34.

The financier and second-seat pilot was the Hon. Elsie Mackay, born 21 August 1893 in Simla, British India, daughter of James Lyle Mackay, 1st Earl of Inchcape, chairman of the Peninsular and Oriental Steam Navigation Company. She trained as a nurse during the First World War, eloped in 1917 with the actor Dennis Wyndham against her family’s wishes, had the marriage annulled in 1922, and reconciled with her father. Between 1919 and 1921 she acted in British silent film under the name Poppy Wyndham. From 1923 she designed interiors for P&O liners, including RMS Maloja. She trained at the de Havilland Flying School and was one of the first women in Britain to hold a Royal Aero Club pilot’s licence. She was 34.

Mackay’s objective was the first nonstop east-to-west crossing of the North Atlantic by aeroplane. Lindbergh had made the west-to-east crossing the previous May. East-to-west, against the prevailing westerlies, was the harder problem and was still open. She had been impressed by the equipment used in Ruth Elder’s failed October 1927 attempt and resolved to buy the same type. She financed and chartered the venture personally. She kept the plan from her father, who had publicly opposed her aviation ambitions; she had given the family an explicit promise that she would not attempt the crossing; she timed the departure for a period when he was in Egypt.

The aircraft was a Stinson SM-1 Detroiter, a US-built high-wing cabin monoplane, UK civil registration G-EBTU, christened Endeavour. The fuselage was painted black, the wingtips gold. The powerplant, on the consistent reading of the secondary aviation sources, was a 300 hp Wright Whirlwind J-6-9 (R-975) radial. The standard production SM-1 of 1927 carried the 220 hp J-5; the modal published reading is that Endeavour was fitted with the more powerful J-6-9, although a primary check of the Stinson build records or the Air Ministry entry for G-EBTU would be needed to settle it. Wingspan was 46 ft 8 in, length 32 ft 8 in. The aircraft had been fitted with auxiliary long-range tanks for the Atlantic attempt; the precise as-fitted fuel capacity and theoretical range are not nailed down in the open-source record.

Endeavour was based at RAF Cranwell aerodrome in Lincolnshire under a cover story that the aircraft was undergoing tests for a later attempt. Mackay was registered for the flight under the pseudonym “Gordon Sinclair.”

The takeoff was at about 08:35 BST on Tuesday 13 March 1928. The BAAA-ACRO database gives 08:45; most other sources give 08:35. The stated destination was Mitchel Field, Long Island, New York; some secondary accounts say Philadelphia. The Mitchel Field version is supported by the Wikipedia and P&O Heritage accounts and by contemporary New York press, which reported a crowd of around five thousand at the field waiting on the arrival that did not come.

At about 13:30 local time, five hours into the flight, the chief lighthouse keeper at Mizen Head sighted Endeavour over Crookhaven, heading west-south-west on the great-circle course for Newfoundland. The SS Josiah Macy sighting later that day is the next entry in the secondary literature and is the last claimed observation; the primary press citation has not been located in this research. After it, no confirmed sighting.

When the aircraft failed to arrive at Mitchel Field, the Inchcape family was forced to acknowledge that Mackay had been aboard. Lord Inchcape made a public statement of grief. Hinchliffe’s widow Emilie was left in immediate financial difficulty, because the life-insurance premium had not cleared at the moment of the flight, and she pursued recovery through the courts and the press, and was paid after legal action and a public campaign. Imperial Airways and the Royal Aero Club rallied to the family.

In December 1928 a single wheel and an associated piece of undercarriage strut washed ashore on the County Donegal coast and were identified by serial number as belonging to G-EBTU. The Air Ministry confirmed the identification. The 1928 Air Ministry inquiry, the specific TNA reference for which would need a Discovery catalogue search in the AVIA series, produced no determinative finding. The probable cause most often cited in the contemporary aviation press, and in the histories since, was fuel exhaustion in adverse weather on 13 and 14 March, with breakup on or after a ditching. Structural failure, icing and navigational error were considered, and could not be established on the evidence available.

On 12 December 1928, Lord and Lady Inchcape gave £500,000 to the British nation in trust, the income to be applied to reduction of the national debt over a fifty-year term. The gift was the Elsie Mackay Fund, debated in the Commons on 12 July 1928 when first announced; Hore-Belisha and Sir Bertram Falle raised the Hinchliffe widow’s position in the same exchange, and the then Chancellor, Winston Churchill, formally thanked the family.

The evidence

Strip the case to its documents and it sits on three channels. None is large.

The official record. The Air Ministry registration entry for G-EBTU and the inquiry file are in the TNA AVIA series; the specific catalogue reference is not recovered here. The Hansard exchange of 12 July 1928 is in the record. The National Archives Discovery catalogue carries the Elsie Mackay Fund file. The Imperial War Museum holds at least one tranche of Hinchliffe’s papers and his flying logbook, catalogued under object 1030013738. The contemporary press of March to December 1928, in The Times, the Daily Mail, the Manchester Guardian and the New York Times, carries the takeoff, the overdue arrival, and the December 1928 wreckage identification.

The testimonial record. Two named witnesses are in the record. The first is the chief lighthouse keeper at Mizen Head, whose 13:30 sighting placed Endeavour over Crookhaven heading west-south-west. The second is the SS Josiah Macy mid-Atlantic sighting, consistently reported in the secondary aviation literature but with no primary press citation located here. A third channel of testimony, of a very different character, runs through the séance sittings of May 1928, discussed in the hypotheses section below as a cultural artefact and not as evidence.

The physical record. One wheel and one piece of undercarriage strut from G-EBTU, recovered on the County Donegal coast in December 1928 and identified by stamped serial number. The exact beach is not consistently named in the sources. The present holding institution of the recovered component, if it survives, is not established here; the RAF Museum at Hendon and the Imperial War Museum are the obvious candidates. No other wreckage. No bodies. Hinchliffe’s flying logbook is at the Imperial War Museum.

There has been no modern wreck-search expedition for Endeavour. The probable search area, the eastern North Atlantic between Ireland and Newfoundland, is too vast and too deep for any plausible recovery without a debris-field localisation that does not exist for this case.

Hypotheses and open questions

The Air Ministry’s 1928 inquiry was inconclusive. The hypotheses below are not findings.

A. Fuel exhaustion in adverse weather. A documented Atlantic depression was active over 13 and 14 March 1928, and the prevailing westerlies against the east-to-west track would have substantially raised fuel burn. For: the consistency of the Donegal wheel and strut with breakup after a ditching; the absence of any distress signal, which fits a slow degradation rather than a sudden catastrophe. Against: no single weather event has been positively identified in the record as the specific cause. This is the modal modern reading.

B. Structural failure or severe icing. The SM-1 was a competent general-purpose monoplane and was not designed for the loads or the icing of a North Atlantic March crossing. For: the violent state of the recovered wheel; the season. Against: no specific structural defect or icing event is documented.

C. Engine failure. The Wright Whirlwind family was among the most reliable radials of the era. For: single-engine ocean flight is inherently vulnerable to any failure. Against: no positive evidence of failure; the engine’s general reliability record is high.

D. Navigation error. East-to-west Atlantic navigation in 1928 relied on dead reckoning with no radio aids. For: the era; the lack of training data for the leg. Against: Hinchliffe’s experience; the absence of any distress traffic; the on-course mid-Atlantic Josiah Macy sighting, if real.

E. The séance episode (cultural artefact, not evidence). Within weeks of the disappearance, Hinchliffe was claimed to “come through” in a sequence of séances in London. The documented dates, from the Historic Croydon Airport Trust account, are 19 May 1928, via the amateur medium Beatrice Egerton, and 22 May 1928, a sitting with the professional medium Eileen J. Garrett. Hinchliffe’s widow Emilie attended, took notes in shorthand and engaged the medium anonymously. Sir Arthur Conan Doyle, then President of the Spiritualists’ National Union, facilitated the introduction. The messages attributed to Hinchliffe included the claim that he had drowned with Mackay and a geographical reference identifying the loss in the vicinity of the Azores. The precise wording of the séance “Azores” message would need a primary-text check.

Two things, on the record, hold this strand to its proper place. The first is that the December 1928 Donegal wheel directly contradicts the Azores geography. The recovered serial-identified component came ashore on the coast of north-western Ireland, not on a coast or in waters near the mid-Atlantic Azores group. The second is that Garrett herself, in her 1939 autobiography My Life as a Search for the Meaning of Mediumship, attributed her phenomena to a “magnetic field” rather than to survival of death, and remained sceptical of the spiritualist hypothesis. The contemporary aviation press did not credit the messages. The Cold File reports the episode as a documented artefact of 1920s spiritualism. The séance messages are not evidence of anything about the flight, and the location they implied is contradicted by the only physical evidence ever recovered.

F. A combination. The most defensible modern reading is the conjunction of A and B or C, with a ditching that broke up rapidly under load and left the Donegal wheel as the sole surviving fragment.

What remains unknown

The honest residue is narrow.

The exact position of the loss is unknown. The exact moment is unknown. Whether Hinchliffe and Mackay survived the ditching for any interval before drowning is unknown. Whether the primary failure was meteorological, structural, mechanical or navigational is unknown. The present whereabouts of the recovered Donegal wheel and strut, if either survives, is not established in the open-source record. The precise text of the Air Ministry inquiry’s conclusions, and its specific TNA reference, would need a National Archives Discovery search.

What is on the record is small and specific. A black-and-gold monoplane took off from RAF Cranwell at about 08:35 on the morning of 13 March 1928. A lighthouse keeper at Mizen Head saw it heading west-south-west over Crookhaven at about half past one that afternoon. A French steamer is reported to have seen it still on course later in the day. In December 1928 a single wheel from it washed up on the coast of Donegal and was identified by its stamped serial. In May, a séance in London told a grieving widow that the aircraft had gone down near the Azores; the wheel that came ashore eight months later said otherwise. On 12 December 1928 the Earl of Inchcape gave half a million pounds to the British nation in his daughter’s name, and a Chancellor wrote a letter of thanks. The aircraft, and the two people aboard it, are still out there. The file is open.

North Atlantic, 13 March 1928: the disappearance of Endeavour

The documented account

The evidence

Hypotheses and open questions

What remains unknown

Sources

Primary

Secondary