De Havilland Heron

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DH.114 Heron 2 preserved in the United States

The de Havilland DH.114 Heron is a British propeller-powered airliner of modest size, which conducted its maiden flight on 10 May 1950. Derived from the twin-engine de Havilland Dove, it featured an extended fuselage and was equipped with four engines instead of two. Engineered as a durable, conventional low-wing monoplane with tricycle landing gear, the Heron was intended for regional and commuter aviation services. Production reached a total of 149 units; and it was exported to approximately thirty nations. Various modified versions were developed subsequently, including the Riley Turbo Skyliner and the Saunders ST-27 and ST-28.

Design and development

Towards the end of World War II, de Havilland initiated the design of a new small twin-engine passenger aircraft, the DH 104 Dove, created to succeed the earlier Dragon Rapide. The Dove quickly established itself as a successful platform. Building upon this foundation, de Havilland expanded the design by lengthening the fuselage to accommodate additional passengers or cargo and increasing the wingspan to support two extra engines. The Heron was constructed entirely from metal and followed a conventional layout; many components were interchangeable with those of the Dove, facilitating maintenance and operations for airlines operating both models.

The design prioritized robustness and simplicity to deliver an economical solution for short to medium routes, particularly in remote regions lacking modern airport infrastructure. The Heron employed fixed landing gear and was powered by Gipsy Queen 30 engines, chosen for their avoidance of potentially troublesome features such as reduction gearboxes and superchargers.

The prototype, registered as G-ALZL to de Havilland Aircraft Company based in Hatfield, UK, completed its inaugural flight on 10 May 1950 with Geoffrey Pike as pilot. Initially unpainted, after accumulating 100 flight test hours it was publicly revealed on 8 September 1950 at the Farnborough Airshow in its polished metal finish. By November that year, it had been awarded its British Certificate of Airworthiness and underwent tropical testing flights to Khartoum and Nairobi.

Subsequently painted and outfitted as a company demonstrator, the prototype was evaluated by British European Airways in 1951 on routes serving Scotland. Following successful prototype trials confirming its suitability as a regional airliner, full-scale production commenced. Initial deliveries were made to NAC, New Zealand’s National Airways Corporation (which later merged into Air New Zealand).

In 1960, the base price for a new Heron was approximately £60,000 excluding radio equipment.

Operational service

The initial Heron model, known as the Series 1A, exhibited several shortcomings that became apparent to NAC early on. Primarily, the aircraft was underpowered, with each of its rather heavy engines—approximately 490 pounds (220 kg) apiece—delivering only around 250 hp (190 kW). In contrast, subsequent variants or rebuilt versions, such as the Saunders ST-27, featured engines with up to 50% greater power. Unlike the Dove, the Heron was equipped with a fixed landing gear and lacked nosewheel steering; while this design simplified upkeep, it also limited maximum speed. Another issue arose from the lightweight aluminium alloy wing spars, which frequently cracked due to the heavy engine load and the stresses of rough landings on unprepared airstrips. To address this, NAC replaced the aluminium spars with heavier steel ones, but this modification reduced the Series 1A's performance (reclassified as Series 1B) to levels that were no longer economically viable for New Zealand operations. Consequently, NAC retired these aircraft in 1957.

After producing 51 units of the Series 1, manufacturing transitioned to the Series 2, which introduced retractable landing gear that decreased drag and fuel usage while slightly increasing top speed. The 2A mirrored the basic passenger setup of the 1A. Models like the 1B and its successor, the 2B, featured increased maximum takeoff weights. The 2C incorporated fully feathering propellers; the 2D further raised maximum takeoff weight limits; and the 2E was tailored for VIP transport.

In operational use, pilots and passengers generally regarded the Heron favorably, appreciating the added safety provided by its four-engine configuration. At a time when small airliners were uncommon in remote areas, the DH.114 offered dependable and comfortable service for up to 17 passengers seated individually along either side of a central aisle.

The aircraft’s wider fuselage allowed passengers to stand while moving through the cabin, complemented by large windows for enhanced visibility. Baggage was stored in a rear compartment with an additional smaller space located in the nose. A notable quirk emerged: when passengers occupied the rear seats first, the Heron would gently lower onto its tail skid. To counter this tendency, pilots and ground crews installed a tail brace to prevent awkward tail settling.

Performance across all Heron variants was relatively modest. After production ended at de Havilland’s Chester facility in 1963, several firms—most prominently Riley Aircraft Corporation—offered modification kits focusing mainly on engine replacements that significantly improved takeoff performance and top speed. Riley Aircraft substituted the original Gipsy Queen engines with horizontally opposed Lycoming IO-540 powerplants.

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Prinair Heron featuring an extended fuselage (17 feet or 5.2 metres longer) and equipped with Continental IO-520 engines

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DH Riley Heron powered by Lycoming engines at Cleveland Airport, Ohio in 1982, operated by Fischer Brothers for Allegheny Commuter.

One notable example of such conversions occurred at Opa Locka Airport in Florida, where Puerto Rico-based airline Prinair upgraded their Herons by replacing Gipsy Queen engines with Continental IO-520 units. Additionally, Prinair extensively lengthened their Heron 2 N574PR to accommodate more passengers.

Similarly, Connellan Airways undertook engine conversions using Riley kits. When original airframes reached retirement age, these upgrades revitalized older aircraft during the 1970s and 1980s; among them was N415SA, a Riley Heron still operational in Sweden as of May 20, 2012, and a Riley Turbo Skyliner registered as N600PR in the United States. This latter aircraft notably appeared in the 1986 film Club Paradise, where it played a key role by delivering unsuspecting tourists to a rundown resort.

The most extensive transformation of the original Heron design was embodied by the Saunders ST-27/-28, which significantly altered both configuration and appearance by replacing four relatively low-powered engines with two robust turboprop units. This variant also featured an elongated fuselage, squared-off wingtips instead of rounded ones, and redesigned windows that gave it a distinct profile compared to its predecessor.

Variants

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DH.114 Heron 1B operated by Morton Air Services in 1965. Note the fixed landing gear on this variant

• Heron 1: A four-engine light transport aircraft equipped with fixed landing gear.
  • Heron 1B: This variant featured an increased maximum takeoff weight of 13,000 pounds (5,900 kg).
• Heron 2: Four-engine light transport aircraft fitted with retractable landing gear.
  • Heron 2A: Single Heron 2 unit sold to a civilian operator in the United States.
  • Heron 2B: This version shared the elevated takeoff weight characteristic of the Heron 1B.
  • Heron 2C: Reclassification of the Heron 2B models, capable of being equipped with optional fully feathering propellers.
  • Heron 2D: Four-engine light transport aircraft with a higher maximum takeoff weight of 13,500 pounds (6,120 kg).
  • Heron 2E: Custom-built VIP transport aircraft, only one unit produced.
• Heron C.Mk 3: VIP transport variant developed for the Queen's Flight, Royal Air Force (RAF), with two units constructed.
• Heron C.Mk 4: Another VIP transport model for the Queen's Flight, RAF, with a single example built.
• Sea Heron C.Mk 20: Utilized by the Royal Navy as a transport and communications aircraft; three ex-civilian Heron 2s and two Heron 2Bs were procured in 1961.
• Riley Turbo Skyliner: Aircraft re-engined with 290 hp (216 kW) Lycoming IO-540 flat-six piston engines. Several Herons underwent these modifications performed by the Riley Turbostream Corporation in the United States.

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Japanese customized DH.114 Tawron

• Saunders ST-27: Featuring an extended fuselage by 8 ft 6 in (2.59 m), allowing seating for up to 23 passengers. Powered by two 750 shp (560 kW) Pratt & Whitney Canada PT6A-34 turboprop engines. Twelve Herons were converted by Saunders Aircraft Corporation based in Gimli, Manitoba, Canada.
  • Saunders ST-27A and Saunders ST-27B: Initial designations for what later became the ST-28.
  • Saunders ST-28: Enhanced variant of the ST-27, with one prototype constructed.
• Shin Meiwa Tawron: Japanese modification by Shin Meiwa for Toa AirWays (TAW), replacing original engines with 260 hp (194 kW) Continental IO-470 units. The name combines "TAW" and "Heron."

A De Havilland Heron bearing registration G-AOXL is preserved on stilts outside Airport House, which includes the former Croydon Aerodrome control tower, located on Purley Way, Croydon, Greater London.

Operators

Military users

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Civilian users

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Heron 1B displayed at the Newark Air Museum

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Sabena's Heron 1

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Accidents and incidents

• On 18 April 1955, a Union Aéromaritime de Transport aircraft registered F-BGOI collided with Kupe Mountain in Cameroon, resulting in the loss of 12 out of 14 occupants.
• On 7 November 1956, Braathens SAFE's LN-SUR made a crash landing amid heavy snowfall on Norway's Hummelfjell mountain within Tolga Municipality. This accident claimed the lives of the pilot and one passenger; other crew and passengers survived. It marked Braathens SAFE's first fatal mishap, with severe icing identified as the likely cause.
• On 28 September 1957, British European Airways flight G-AOFY, operating an air ambulance mission, crashed during approach to Glenegedale Airport on Islay in poor weather conditions. All three on board — two crew members and a nurse — perished after the pilot failed to recognize rapid altitude loss while executing a visual half-circuit landing.
• On 15 November 1957, Aviaco's EC-ANZ impacted terrain near Son Bonet Aerodrome during adverse weather following a navigation error at the conclusion of a flight from Barcelona. The crash resulted in fatalities for all six onboard.
• On 19 February 1958, Gulf Aviation's G-APJS crashed near Rome's Ciampino Airport during a ferry flight from Bahrain to England via Athens, due to a navigational mistake; all three aboard died.
• Aviaco’s EC-ANJ crashed into the sea off Barcelona on 14 April 1958 after performing an abrupt avoidance maneuver to prevent a mid-air collision; all sixteen passengers and crew lost their lives.
• On 10 December 1958, a DH.114 1B with registration PK-GHP was damaged beyond repair in Jakarta.[1]
• Itavia’s I-AOMU crashed into Mount Capanne, Italy, on 14 October 1960 under poor weather conditions, killing all eleven individuals aboard.
• Fujita Airlines’ JA6159 struck Mount Hachijō-Fuji shortly after takeoff from Hachijōjima, Japan, on 17 August 1963; this tragedy resulted in the deaths of all nineteen passengers and crew and stands as the deadliest incident involving the de Havilland Heron.
• Air Comoros flight F-OCED overran the runway at Moroni Airport on 27 January 1968 and crashed into the sea; fifteen passengers and crew died while one survived.
• Prinair Flight 277 crashed into mountainous terrain near Fajardo, Puerto Rico on 5 March 1969 during its route from Charlotte-Amalie to San Juan, killing all nineteen aboard.
• On approach to Toncontín International Airport on 26 May 1970, Aero Servicios HR-ASN stalled amid turbulent conditions causing a fatal crash that claimed all six occupants.
• Prinair Flight 191 crashed near Ponce, Puerto Rico on June 24, 1972 while attempting to land; five fatalities occurred among twenty passengers and crew due to pilot error.
• On October 23, 1975, Connair Flight CK1263 operated by VH-CLS crashed into a sugarcane field at Holloways Beach following a missed approach to Cairns Airport during stormy weather; all three crew members and eight passengers perished.
• A PrinAir aircraft crashed during takeoff from Saint Croix-Alexander Hamilton Airport on July 24, 1979; eight of twenty-one onboard including both pilots died. The investigation attributed the crash to exceeding maximum takeoff weight by approximately one thousand pounds and improper center of gravity balance. Ground personnel reportedly failed to provide accurate weight and balance data. Observers noted the aircraft’s nose bouncing during taxi prior to departure.
• On December 27, 1986, Sunflower Airlines’ DQ-FEF crashed short of runway 21 at Nadi International Airport due to right flap malfunction in flight; eleven out of fourteen occupants lost their lives.

Specifications (Heron 2D)

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Instrument panel of the De Havilland Heron

References

Bibliography

• Bain, Gordon. De Havilland: A Pictorial Tribute. London: AirLife, 1992. ISBN 1-85648-243-X.
• Bridgman, Leonard. Jane's All the World's Aircraft 1958–59. London: Sampson Low, Marston & Company, Ltd., 1958.
• Green, William. Macdonald Aircraft Handbook. London: Macdonald & Co. (Publishers) Ltd., 1964.
• Jackson, A.J. De Havilland Aircraft since 1909. London: Putnam, Third edition, 1987.
• Taylor, John W. R. (editor). Jane's All The World's Aircraft 1965–66. London: Sampson Low, Marston, 1965.
• "The Royal Moroccan Air Force...A Seasoned Air Arm". Air International, November 1985, Vol. 29, No. 5. pp. 226–232, 250–252. Template:ISSN.
• Wixey, Ken. Heron at Fifty: De Havilland's Beautiful DH.114. Air Enthusiast 87, May–June 2000, pp. 72–77. Template:ISSN