By 1931 the rest of the world was building sleek metal monoplanes. Imperial Airways bought a fabric-covered biplane with four engines, a fixed undercarriage and a cruising speed of about 100 mph, and flew it for nine years without killing anybody.

The Handley Page H.P.42 was slow, draughty, and by any technical measure already obsolete when it entered service. It was also, by a distance, the most comfortable and most trusted airliner of its generation.

Two aircraft with one name

This trips up almost everybody, so it is worth getting right. The eight aircraft were built in two batches. The H.P.42 Eastern boats — Hannibal, Horsa, Hanno y Hadrian — went to the Empire routes: Cairo to Baghdad, Sharjah, Karachi and on toward India, plus the African run.

El H.P.45 Western aircraft — Heracles, Horatius, Hengist y Helena — worked Croydon to Paris, Cologne, Zurich and Basle, with more powerful supercharged engines and 38 seats instead of 24, at the cost of the baggage hold.

Imperial Airways called them all H.P.42 in public, which is why the distinction has been muddled ever since. If you see the phrase "H.P.42 Western", it is the wrong way round.

Slow on purpose

The specification Imperial wrote was not about speed. It was about carrying paying passengers, in comfort, across places where a forced landing was survivable and a rescue was not quick. That produced an aircraft with a very low wing loading, an enormous wing area, and the ability to come down slowly almost anywhere.

The cabins were genuinely luxurious — panelled, curtained, with proper meals served at proper tables. Passengers reported being able to hold a conversation, which was not a given in 1931.

The price was paid in turbulence. A very light wing loading makes for a soft landing and an appalling ride in rough air, something the aviation writer Peter Masefield pointed out two decades later when comparing it with post-war types.

The safety record, accurately stated

You will often read that the H.P.42 never killed a passenger. That is not quite true, and the true version is still impressive.

Across nine years and more than ten million miles of Imperial Airways peacetime service, from 1931 until the outbreak of war on 1 September 1939, no passenger or crew member was killed in an H.P.42 or H.P.45. That includes an early incident in which Hannibal lost two engines and put down at Five Oak Green in Kent with twenty people aboard and no serious injuries.

The record ends there. On 1 March 1940, on wartime service between Calcutta and London, Hannibal disappeared over the Gulf of Oman with eight people aboard — four crew and four passengers, among them Group Captain Harold Whistler and Sir A. T. Pannirselvam. No wreckage was ever found, and the Air Ministry could not rule out fuel starvation.

Blown away

What finished the fleet was weather and bad luck rather than the enemy. Hengist burned in a hangar fire at Karachi in 1937. Horatius was wrecked in a forced landing on a golf course at Tiverton in November 1939. Hanno y Heracles were blown into each other and destroyed in a gale at Whitchurch in March 1940. Horsa burned out after a forced landing in Cumberland; Hadrian was torn from its moorings in a gale at Doncaster and cartwheeled onto a railway line; Helena was condemned for corrosion and scrapped.

All eight were gone by the end of 1940, and not one survives. For an aircraft that carried the Empire’s passengers for a decade without losing one, that is a thin legacy.

When it first flew at Radlett in November 1930, the newsreels reached for the only superlative that mattered.

The newsreel of Hannibal’s first flight at Radlett in 1930 — note the description of it as the largest passenger machine in the world:

Imperial Airways operations at Croydon in the mid-1930s:

And Heracles landing, filmed in 1934:

Sources: British Pathe archive; Bureau of Aircraft Accidents Archives; Peter Masefield in The Aeroplane, December 1951; Library of Congress.