The de Havilland DH.86 in Australian operations (Part 1)

It was the accidents that unexpectedly occurred with the DH-86 in Australia, causing difficulties to operators with a new aircraft with an expected safety margin from its four engines, built by a renowned aircraft company. However, what was later uncovered was that similar accidents had occurred in Europe and this information had not been conveyed to Australia. What emerged was a series of events pointing to an aircraft that was difficult to fly in normal airline operations, requiring a higher level of skills and attention from pilots. Although the aircraft did deliver years of reliable service, over time this was interrupted with some seemingly inexplicable accidents. Investigations eventually uncovered a design with flaws, not helped by some production inconsistency.

The history of the DH.86 began in 1933 following the issue of a specification by the Australian government for a multi-engined 10-seat aircraft to operate a fast and safe service over the Java and Timor Seas. At last, it was seen as commercially and technically feasible to have the long wanted Britain to Australia air service in place. This led to an agreement struck that year between the governments of Australia, Britain and India for the service to commence in 1934. Imperial Airways Ltd would operate from Croydon in England to Singapore continuing with an Australian airline carrying the passengers and mail to Australia.

Production of the aircraft was awarded to de Havilland who designed and built the unnamed DH.86 in just four months, later also known as the DH.86 Express. The aircraft was the company’s first four-engined aircraft. Intended for passenger, mail and freight use, the DH.86 was a four-engined biplane with a braced taper-wing of 12:3 aspect ratio with steel tube interplane struts with the outer ‘I’ struts of faired steel sheet. The wings had wooden spars, the leading edges were plywood covered and wings were fabric covered. There were ailerons on all four wings. The fuselage was a wooden box structure with spruce members outside a plywood skin. A fabric covering was then applied over the formers giving a slightly rounded look with space between packed with Cabot’s quilting to reduce noise. The aircraft initially was intended to be flown by one pilot situated in the nose with a wireless operator/navigator behind him located on the starboard side.

Powerplants for the aircraft were four 200hp Gipsy Six Series I six-cylinder inline inverted engines of 213kg (+ or – 3.5kg) weight on welded steel-tube mountings installed in front of the lower wings. Starting was accomplished with Eclipse direct-drive electric starters controlled from the cockpit. Fuel was carried in a 57-gallon (259-litre) tank on each side in a fairing behind the trousered undercarriage. Dimensions were span 19.66m, length 13.38m (single pilot) or 14.04m (two-pilot), and height 3.97m. In two-pilot operation there was either a throw-over control column or twin controls. The empty weight excluding cabin equipment of furniture, heating, ventilating and lighting was 2,837kg, payload 993kg, loaded weight with all operating items such as wireless equipment, passenger fittings, crew and fuel and oil was 4,654kg, maximum speed 267km/h at sea level, cruising speed at 1,000ft 228km/h, initial rate of climb 282m/min, climb to 5,000ft 6.5 mins, climb to 10,000ft 15 mins, service ceiling 17,400ft, absolute ceiling 19,500ft, ceiling with one engine stopped 3,960m, ceiling with two engines stopped 610-1,220m according to combination, range prototype 724km, production DH.86 1,223km, DH.86A (Gipsy Six I) 1,223km, (Gipsy Six II) 1,204km and DH.86B 1,287km.

The first flight of the prototype DH.86 E-2/G-ACPL, construction number 2,300 took place on 14 January 1934 from Stag Lane flown by Hubert Broad. To cope with long range flights the Australian government requested an increase in fuel capacity to 183 gallons (832 litres) and provision for side-by-side two-pilot operation. This saw a revised extended nose designed to accommodate this change. To meet this requirement the prototype was modified with an extended nose and the rebuilt two-pilot aircraft joined Imperial Airways named Delphinus. The modified nose of the two-pilot development extended length by 66cm.

Production took place at the de Havilland Hatfield factory and by the time it ended in 1937, 62 aircraft had been built with construction numbers ranging from 2,300 to 2,361. During production various changes were made to improve performance. Production comprised four single pilot examples, 28 two crew, 20 DH.86A with survivors converted to DH.86B in 1937 and 10 production DH.86Bs. Changes during production included revised undercarriage fairings which were straight rather than curved, fin strengthening and removal of the rudder servo tab with the space filled in. The Qantas aircraft and subsequent deliveries had split trailing edge flaps fitted to the upper mainplane permitting an all-up weight of 4,536kg. In late 1935 the improved DH.86A had pneumatic undercarriage legs, larger brakes and tail wheel, a metal rudder and a more angled windscreen for the pilot. Two versions offered had different engine options, one with Gipsy Six I engines with either two-blade wooden or Fairey-Reed duralumin propellers with a 4,649kg AUW or the Gipsy Six II high compression engine with de Havilland variable pitch propeller and 4990kg AUW. 

The loss of a British Airways aircraft, G-ADYF, on 15 September 1936 during a night departure from Gatwick led to an investigation at Martlesham Heath which expressed concern with the rudder and aileron control. This saw the improved DH.86B which had large auxiliary fins fitted to the tailplane ends. Existing DH-86As were then modified to this standard. The last batch of ten DH.86Bs embodied later changes such as higher gearing in the aileron circuit and increased chord in the tailplane tips.

Like so many de Havilland products the DH.86 was an attractive looking aircraft which inspired confidence with the expected safety margins of operations from its four engines. No doubt this feature proved its worth over the years. But other unexpected characteristics emerged to cast doubts on the aircraft’s airworthiness.

Over time, sixteen DH-86s served in Australia with varying degrees of satisfaction with both operators and pilots. It became evident that all was not well with the DH.86 in terms of its flying characteristics, which was thought could have links to some serious accidents. This progressed to investigations in an effort to try to identify what the problem may be with the aircraft.

Deliveries to Australian operators begin

Among sales were those to Australian operators seeking a larger aircraft to fly on a variety of routes both domestic and international, carrying the mix of passengers, cargo and mail. The first sale to Australia to Holyman’s Airways Pty Ltd was the second aircraft built after the prototype, the single-pilot crewed VH-URN c/n 2301 Miss Hobart, which received a British Certificate of Airworthiness on 25 July 1934. Others to join the Holyman’s fleet were VH-URT Loina (the sun), VH-USW Lepana (the eye) and VH-UUB Loila (the sky), all two-crew DH.86 versions, the names selected in recognition of Tasmania’s Aboriginal languages and heritage. The unit cost of each aircraft was £12,000. Two of these aircraft, VH-USW and VH-UUB later flew with Australian National Airways. 

Qantas Empire Airways acquired six two-crew aircraft, called the DH.86 Express in their fleet, also alternatively known as the DH.86 Commonwealth Class, with names prefixed by RMA for Royal Mail Aircraft, VH-UUA RMA Adelaide, VH-USC RMA Canberra, VH-USD RMA Brisbane, VH-USE RMA Sydney, VH-USF RMA Melbourne and the unnamed VH-USG. Another DH.86 operator to appear on the Australian Civil Aircraft Register was that of the island trading company W R Carpenter for use in Papua New Guinea, all DH.86B versions, VH-UYU RMA Carmania, VH-UYV RMA Coronia and VH-UYW RMA Carinthia operating as W R Carpenter Airlines. 

Seven of the aircraft were delivered by air to Australia with nine shipped by sea, assembled for their operators at Archerfield (2), Mascot (3) or RAAF Laverton (4). The DH.86 also served with MacRobertson-Miller Aviation in Western Australia acquiring VH-USC, VH-USD and VH-USF from Qantas and VH-USW from ANA.

Qantas Empire Airways is formed

The registration of Q.A.N.T.A.S. Empire Airways Ltd (QEA) in Brisbane on 18 January 1934 with £200,000 capital paved the way for the introduction its DH.86 fleet with the granting of a subsidy of £318,426 over five years to contribute to their operations. The need for a subsidy was quite evident when passenger restrictions were imposed for over water flights. Hudson Fysh’s concerns for passenger safety due to the weight of mail saw the number of passengers reduced from eight to six for the Timor Sea crossing.

At the time Qantas was purchasing the DH.86, QEA managing director Hudson Fysh visited the US in 1933 and experienced the new Boeing 247 first-hand, impressed with its structural features and docile landing characteristics. He praised the aircraft as being ‘British’ with its good structural features and ahead of anything in being built in Britain, with the exception of the Handley Page HP.42. When he visited Douglas, he was even more impressed with the DC-2 and DC-3 with the attention to detail and many refinements absent from the DH.86, such as stressed skin construction and retractable undercarriage. In a letter to prominent British civil aviation pioneer, George Woods-Humphery CBE, Fysh expressed a wish that DH would progress to metal stressed skin construction in its aircraft as that was where the future may be. 

Qantas takes delivery

Qantas sent their chief pilot Captain Lester Brain to take delivery of their first DH.86, VH-USC, and ferry it to Australia. When he arrived at de Havilland, he found the sole DH.86 was equipped for a single pilot operation with a nose modelled on that of the DH.84 Dragon. Considering this unacceptable for the duration of a three and a half days flight to Singapore, from both a safety and fatigue aspect, he sought modification to a two-pilot configuration. Although initially received coolly, de Havilland agreed, but said this would incur a weight and speed penalty, and a delay of nearly two months. After the changes were made, the more streamlined nose resulted in an aircraft length increase of 66cm and actually saw the aircraft cruise five miles per hour faster.

On 24 September 1934 Captain Brain, First Officer R Price and engineer R Pink departed Croydon Airport, London on the first leg of the delivery flight. Also on board in the cabin was a spare Gipsy Six engine mounted on a trestle bolted to the floor with wire bracing and other spares. On departure Brain found the aircraft was very tail heavy despite the loading having been checked by both de Havilland and Imperial Airways with the centre of gravity within limits. On arrival at Lyon in France some of the load was moved to the locker in the extended nose resulting in improved performance although Brain considered it was not stable. The fight continued via Rome, Catania and Benghazi. It was on the leg from Benghazi to the RAF base at Mersa Matruh in Egypt where Brain faced some of the DH.86’s idiosyncrasies. Knowing the aircraft was tail heavy Brain placed Pink in his seat, Price was then flying, while he went to the toilet in the rear. Having a break Brain sat in a seat at the rear. Then things started to happen.

“Among sales were those to Australian operators seeking a larger aircraft to fly on a variety of routes”

The aircraft started a swing to the left followed by a yaw to the right, then again to the left giving the impression it may be commencing a flat spin. As luggage from the hat racks fell down Brain was concerned the spare engine might break free and raced to the cockpit to find two very alarmed colleagues. He quickly swapped places with Pink and brought the aircraft under control. During this experience the aircraft had lost about two to three thousand feet. A safe landing followed at Mersah Matruh. The aircraft finally arrived on 13 October at the QEA base at Archerfield with Brain conducting a test flight after an inspection on 28 October and received its Australian CofA on 22 January 1935.

Into domestic service

While the Qantas activity with its introduction of the DH.86 into its network had been taking place, the aircraft was being readied for Australian domestic operations with Holyman’s Airways. The DH.86 was ordered by Tasmanian Aerial Services Ltd in March 1934 with the airline becoming Holyman’s Airways Pty Ltd in July 1934, later to become Australian National Airways Pty Ltd on 13 May 1936. Their first aircraft, VH-URN, was built in July 1934 and shipped the following month as crated cargo on board SS Baradine. During September 1934 the aircraft was assembled at RAAF Laverton and test flown by Alan Murray Jones MC DFC of De Havilland Aircraft Pty Ltd (later chairman of directors of that company and subsequently deputy chairman of Hawker De Havilland Australia Pty Ltd). A trial Laverton to Launceston flight was made on 28 September and on 1 October Holyman’s Airways Captain Ken Frewin ferried the aircraft from Laverton to Hobart. At a ceremony at Western Junction Aerodrome, Launceston on 2 October, the governor of Tasmania Sir Ernest Clark, GCMG, KCB, CBE named the aircraft Miss Hobart.

One can imagine the excitement and pride surrounding the introduction of this service, linking Victoria to Tasmania across Bass Strait with a modern new aircraft appropriately named. On 3 October the inaugural scheduled service was flown from Launceston to Laverton by Ken Frewin, the Victorian destination selected because of doubts that Essendon could cope with that aircraft’s size.

Holyman’s DH.86s were also referred to as Commonwealth Class Air Liners in their timetable. They were configured as 12 seaters, six on each side. They were described as, “Modern 12 passenger, four-engined Air Liners of the latest construction, maintained by certified Engineers, and flown over Certified and Chartered routes by efficient pilots, carry you in regal comfort at a cruising speed of 145 miles per hour, and a maximum speed of 180 miles per hour, providing safe and fast travel with a complete absence of thrills. Any two engines will sustain the plane in flight with a full load.”

It all looked so promising then the unimaginable happened. On 19 October 1934 after a 9:00am departure in fine weather, VH-URN was now operating a Launceston to Essendon service. Routine radio messages were sent at 9:50 and 10:20, the latter reporting “Over Rodondo Island; all well”. Sometime after this transmission the aircraft disappeared without trace over Bass Strait, somewhere in the region off Wilson’s Promontory. Lost were Holyman’s chief pilot Captain Gilbert Jenkins, the airline’s co-founder Captain Victor Holyman flying as co-pilot/radio operator and ten passengers. An immediate search got underway from the day of disappearance with both civil and RAAF aircraft. The RAAF used both of their Supermarine Southampton Mk 1 flying boats, A11-1 and A11-2 from RAAF Point Cook the following day on Search and Rescue flights. The only discovery was an oil slick with a length of about 3km south of the Glennie Group of islands to the west of Wilsons Promontory. There was understandable anxiety following the loss of a new airliner with a tragic loss of life when such high hopes were held for the new service. The only tangible wreckage later located was a grey armchair, later confirmed as coming from the DH.86, washed ashore at Waratah Bay, north west of Wilsons Promontory on 18 November.

The awe in which the DH.86 was regarded in the popular press is summed up by this comment, “She is the latest machine of her type in the British Empire, and one of the largest and most luxuriously appointed in the Commonwealth”. The was extensive newspaper coverage throughout Australia of the loss of VH-URN. Expressing grief at the loss of all those on board and of the setback to the introduction into service of a modern large airliner that would enhance speedy air services in Australia. There was also hope raised by the statement by the Controller of Civil Aviation, Captain E C Johnson DFC, of the probability that the aircraft may have had to land in an uninhabited area with the occupants unable to make their location known. Some newspapers even wrote that this mysterious disappearance ranked with that of the Southern Cloud in March 1931. However, despite all the positive speculation, hopes faded and a thorough search using aircraft and ships was gradually scaled back in the days ahead. Despite this setback, during the year ahead Holyman’s expanded their routes to other destinations.

“Over time, 16 DH-86S served in Australia with varying degrees of satisfaction with both operators and pilots”

A setback for Qantas

While the public was trying to come to grips with this tragedy, worse was soon to come. In an effort to speed the QEA deliveries, Imperial Airways was enlisted to help with the delivery of VH-USG by flying it to Australia rather than shipped by sea. The aircraft was built at the de Havilland Hatfield factory in October 1934 and received its British CofA on 18 October and departed from London on 31 October. The crew assembled for the flight comprised Captain Archer R Prendergast, W V Creates as co-pilot/wireless operator role and F R Charlton as engineer. After making multiple stops en route the aircraft arrived in Darwin on 13 November. Apart from the crew, also carried onboard was a spare Gipsy Six engine and other spare parts.

When Prendergast had reached Darwin he said, “I think the DH.86 will be well suited for the Brisbane-Singapore section of the air mail service. It is fast and safe. Even if two engines were put out of action, the other two could keep the ‘plane flying perfectly.” Prendergast said he had been on holiday and was commissioned to deliver the aircraft, viewing the venture as a joy trip out ending with ten days in Australia before returning to England by boat to resume his leave. The DH.86 left Darwin on Tuesday, 13 November and after flying about 1,000km stayed overnight at Avon Downs. The crew had also had difficulty navigating over the expanse of the Northern Territory with Prendergast claiming the map supplied in Darwin lacked accuracy leading to an unscheduled stop for fuel at the Alroy Downs cattle station, west of Avon Downs. There was no prepared landing area at the location and the place to land was assessed from the air. The crew continued with the flight to Longreach.

On Thursday, 15 November VH-USG departed from Longreach on the final leg of the delivery flight to Brisbane. Also now on board was E H Broadfoot, a representative of the Shell Oil Company from Sydney who was their serviceman at Mascot. Broadfoot had earlier been in Darwin as part of a Shell team for the MacRobertson Centenary Air Race. Prior to departure repairs had been made to the starboard inner engine involving the clamping ring controlling the advance and retard adjustment and the aircraft had been refuelled with all four tanks full. A witness said the weather was fair with some cloud with wind from the south east. At 5:40am the aircraft took off heading south-east to Blackall reported to be flying at a height of 1,000 feet.

There were several eye-witness reports regarding the following event after the aircraft had flown about 25 miles. Generally, they mentioned the aircraft entering a spin. Some said the engines were firing in bursts. The aircraft came down at about 5:50am two miles from the homestead at Barsdale Station at Ilfracombe with a young lady, Doreen May Coleman at the Station saying she observed the aircraft going into a spin from a height of about 200ft before impacting the ground near a dry watercourse. Other eyewitness reports from homestead residents said the aircraft had recovered from the spin but it was too late. 

A kangaroo shooter Mr A Rodgers was first on the scene with a newspaper reporting, “He watched the great machine for a moment, and saw it begin a spiral descent.” Rodgers was joined by other rescuers, Johnson Barr owner of the homestead, and Gilbert Hosier an adjacent property owner of Combemartin Station. Sadly, all on board were lost or died soon after following rescue attempts. Barr said he saw the aircraft at about a 1,000ft altitude, viewed from about three and a half miles away, enter and continue to spin until impact. Also quoted in the newspaper, “Mr J Murphy, the postmaster at Ilfracombe, reported that the ‘plane appeared to be in difficulties when it was passing over Barradale, and the pilot turned it in the direction of Longreach.” (Initial reports quoted the location as Barradale homestead.)

When news of the tragedy reached Longreach, the Coroner, police and large numbers of residents drove to the accident site. A message from the Governor-General, Sir Isaac Isaacs GCB GCMG PC KC, was sent to QEA that day, “I extend to Imperial Airways, and through them the relatives of those who lost their lives in the air disaster at Longreach, Queensland, today, my profound sorrow and deep sympathy.”

The aftermath of this accident saw only one DH.86 then remaining in Australia pending further deliveries.

The aftermath of this accident saw only one DH.86 then remaining in Australia pending further deliveries. The loss of two DH.86s in the space of a few weeks was a major setback to the aircraft’s reputation and civil aviation safety in the eyes of the public. An announcement was made stating there would be no more flying of the type until enquiries into both losses were concluded. Expressing great regret, the Acting Prime Minister, Dr Earle Page, said in the House of Representatives that the Air Accidents Investigation Committee (AAIC) had flown to Longreach to conduct enquiries. Among the team was Wing Commander Eric Harrison from the AAIC, Captain Murray Jones, Australian manager of de Havilland, and Mr A R McComb. In the end, teams of experts were now being flown from Melbourne, Sydney and Brisbane to Longreach. So much had been expected of the DH.86 and the urgency to discover a cause was vital.

A fault discovered in the investigation of this accident by Qantas and the joint RAAF – civil AAIC focused on the role of a bias screw for fin-trim adjustment which was 3/16s of one-inch rearwards of its optimum position. A check of the other QEA DH.86s revealed three of five aircraft had similar problems, which became a cause for concern after this accident to a new aircraft.

This writer early in his working career met a colleague who became aware of my aviation interest. He remarked he had been working at Longreach and had taken a photograph of a Qantas aircraft that had crashed nearby. He said there was excitement that a very modern aircraft had arrived in Longreach to join Qantas and then they were very saddened at what had happened. He then brought in a photo album with a large full-page image of the wreckage of VH-USG. It was a devastating sight with small fragments spread across the landscape in front of main wreckage which hit the ground with such force it seemed to be compressed.

The subsequent investigation revealed that the time of the crash the pilot had been to the rear of the aircraft with the engineer in his seat. The cause was determined to be failure of the tail fin trim mechanism stemming back to a manufacturing error with the bias crew not in the correct position. There were also thoughts about the centre of gravity being further aft than normal. What all this did do was to reinforce Lester Brain’s contention that the DH.86 was inherently directionally unstable. With this serious accident occurring less than a month after the disappearance of Miss Hobart, the reputation of the DH.86 had been dealt a serious blow. However, it should be said that in the years ahead the aircraft proved to be reliable in the QEA Australia-Singapore service, no doubt due to the experience of senior pilots aware of the handling quirks of the DH.86.