Despite what constituted the regional jet revolution during the 1990s with low-capacity, twin-engine designs from Canadair, Embraer, and Dornier, the concept had its origins some two and a half decades earlier in France, Russia, and Germany with aircraft of various configurations and success.
Although both need and technology combined to produce a commercial aircraft, the latter, when lacking, either impeded or impacted the result. Yet a single design bureau in the USSR, which itself had only been synonymous with fighters and trainers, succeeded in building the first true regional jet.
“Provision of such an airplane was by no means easy, as is amply shown by the failure of western countries to produce a suitable aircraft in this category in response to the FAA’s design competition in the United States,” according to John Stroud in Soviet Transport Aircraft since 1945 (Putnam, 1968, p. 270).
The requirement that sparked it was then a contradiction: a rugged, reliable, simple, low-capacity design that could replace Aeroflot’s Ilyushin Il-12, Il-14, and Lisunov Li-2 pistonliners on short, multi-sector feeder routes in the remote Soviet Union, yet serve limited-facility Class 5 grass fields with pure-jet performance and speed. What was essentially needed was a DC-3 of the jet age.
While half of Aeroflot’s traffic was carried on these local service routes, they were the last to be addressed, leaving Tupolev to fill the other market segments with its Tu-104, Tu-124, and Tu-134 aircraft.
In 1965, the OKB, or experimental design bureau headed by Aleksandr Yakovlev, was assigned the project of developing just such a feeder transport, and, although propeller powerplants were initially considered, the solution lay in the optimum combination of design features-namely, a straight, high-lift, low wing loading airfoil, three turbofans, and aerodrome-facility autonomy.
The result, the Yak-40, and the design bureau’s first commercial aircraft, fulfilled Aeroflot’s needs and offered considerably increased passenger comfort over a piston type.
“Although western manufacturers such as Lockheed, de Havilland, and Dassault pioneered and developed the executive jet, it was the Russians who were the first in the field with the logical step-up from the biz jet-namely, the truly short-haul jet airliner,” according to Michael Hardy in World Civil Aircraft since 1945 (Charles Scribner’s Sons, 1978, p. 126).
Featuring a circular-section, semi-monocoque fuselage, the Yak-40 featuired straight slightly tapered wings; three 3,308-thrust-pound, twin-shaft, three-stage Ivchenko AI-25 turbofans; and a single-class cabin configured with three-abreast seats, resulting in a 24-passenger capacity at a 29.7-inch pitch.
The Yak-40 weights ranged between 5,070 and 6,172 pounds (payload) and 28,990 and 30,203 pounds (maximum takeoff). Speeds equally varied, from a 350-mph cruise to a 435-mph maximum. Range at a 342-mph speed at a 20,000-foot altitude was 323 nautical miles with 3,968 pounds of fuel and 45-minute reserves. A maximum fuel uplift increased this to 890 miles.
Registered SSR-1966 and piloted by Yu. B. Petrov and A. L. Kolosov, the first of five prototypes first flew on October 21, 1966. Production at the Saratov Aviation Facility the following year led to 1968 certification and service inauguration on September 30, the type becoming the workhorse on Aeroflot’s local service route network.
Because no other regional jet then existed, Aviaexport, the Soviet state aircraft marketing organization, made a major effort to secure sales outside of the communist bloc countries, leading to the Yak-40EC with Collins avionics that achieved western certification.
Aertirrea of Italy, which ordered three, inaugurated service with them at the end of 1970, two of which were later acquired by Avioligure. General Air of Germany also operated five on its third level routes two years later.
Aside from Aeroflot, the regional jet was operated by Cubana, Balkan Bulgarian, CSA, Slov-Air, Air Guinee, LOT Polish, Malev Hungarian, TAAG-Angola, Bakhtar-Afghan, and Communist air forces and governments. It also saw service in Cambodia, Ethiopia, Guatemala, Honduras, Hungary, Laos, Madagascar, the Philippines, Poland, Syria, Vietnam, Yugoslavia, and Zambia.
Of the 1,011 produced between 1967 and 1981, 130 accounted for export sales. Aeroflot operated more than 750 itself.
France’s Avion Dassault, famous for its Falcon 10, 20 and 50 business jets, attempted a regional counterpart, forward which the Flacon 20 logically served as the foundation for a larger, but similarly-configured design aimed at both the executive and passenger transport market.
The first step toward its reality was the March 25, 1964 agreement between Dassault-Breguet and Germany’s Sebelwerke ATG for a 35-percent share in the manufacturing process of a pure-jet design powered either by Rolls Royce or General Electric engines and accommodating between 32 and 40 passengers. Promise came with potential orders for its new aircraft, designated Mystere 30, from Ansett of Australia and Eastern Airlines of the US, leading the way to construction of a prototype. Still-born, it was never built, but led to the October 2, 1967 recommendation of producing both an eight-passenger business jet version and a higher capacity transport.
While the program equally failed to proceed beyond the conceptualization stage, it did lead to the definitive Mystere 30 of 1973, which, powered by two Avco Lycoming ALF-502D turbofans, first took to the sky on May 11 from Merignac.
Not entirely suited to the market because of its capacity, it served as the foundation for a 630 nautical mile Mystere 40 to carry 40 four-abreast passengers, but mated to a new wing. A reduced, 30-passenger variant would have offered greater range, of up to 950 nautical miles.
Dassault Falcon offered its still paper-bound Falcon 30 for $2.4 million per aircraft–$1 million under cost-to Denmark-based Cimber Air, provided that it ordered the type by December 31, 1972, which it failed to do, sounding the death knell for the program.
“The completion of the Falcon 30 made it possible to solve complex aerodynamic and flight quality problems arising from the adaption of a small aircraft with a large fuselage diameter and heavy engines,” according to the Dassault Aviation website. “These engines were relatively noisy, making them incompatible with the level of sound comfort passengers had come to expect. Although orders had been taken at the 1973 Paris Air Show, the program was abandoned in 1975, as much due to the oil crisis as to the financial circumstances of the companies involved.”
Fokker F.28 Fellowship:
Having assessed the regional market with its turboprop F.27 Friendship, Fokker, a name synonymous with aircraft such as the Dr.1 triplane during World War I and the early F.VIIA/3m trimotor airliner, announced the turbojet F.28 Fellowship as both a higher-speed complement to and successor of it at the 1962 Hanover air Show. Intended for low-capacity, short-range routes, which served limited-facility, sometimes unprepared fields that received no previous jet operations, it was slated to become the world’s second purposefully designed regional jet after the Yakovlev Yak-40, but accommodate two to three times as many passengers than it in a significantly wider fuselage. As such, it was envisioned as becoming the largest aircraft in a small airline’s fleet. In size, it would carry some 20 few passengers than either the BAC-111 or the DC-9.
“The F.28 twin-turbofan airliner is designed to serve the short- to medium-haul sector of the commercial aviation market,” according to the Fokker F28 Technical Data publication (Fokker-VFW International, p. 1). “Within that area, it serves a dual purpose. It brings jet speed and comfort to regions which previously have known only turboprop or piston-engine equipment. And it offers the advantage of moderate capacity to carriers operating domestic, regional, and charter services mostly from well-equipped airports.”
Because of the regional route, airport, and capacity realm it was designed for, it had to adhere to numerous parameters, including offer low direct operating costs, 500-nautical mile range capabilities, a 4,500-foot sea level takeoff field length, unprepared surface operation, optimum handling characteristics to cater to engine loss potentialities, low internal and external noise, a rugged airframe to withstand multiple daily sectors spent proportionally higher during climb and descent and at lower, turbulence-associated altitudes, deal with unavoidable crosswinds at single-strip airports, feature low pressure tires for grass and gravel endurance, and offer high degrees of reliability and self-sufficiency for limited and no-facility airfields.
Powered by two aft-mounted Rolls Royce RB.163 Mk 555 Spey Junior turbofans that were lighter and simpler than those employed by the Trident or the BAC-111, it ultimately appeared with a 16-degree swept-back wing, a t-tail, and a unique pedal airbrake, which facilitated steep, controlled descent profiles without the need for power changes, permitted go-arounds with little more than its retraction, and shortened its deceleration roll.
“The powerful fuselage-mounted speedbrake, unique in commercial aircraft operation, allows quick and drastic reduction in altitude and speed without generating buffeting or changes of trim,” according to the Fokker F28 Technical Data publication (ibid, p. 3). “This direct drag facility does not affect wing lift, but ensures good glide path control and touchdown efficiency.”
Accommodating a maximum of 65 five-abreast passengers, the aircraft, in its initial F.28-1000 version, was followed by a stretched -2000 variant, whose capacity increased to 79 with a fuselage stretch; -5000 and -6000 counterparts, which introduced wingspan increases and leading-edge slats; and definitive -3000 and -4000 versions, the latter, with two additional overwing emergency exists and internal reconfiguration accommodating up to 85 passengers.
The dawn first flight of the initial F.28-1000, registered PH-JHS and piloted by Jas Moll, Abe van des Schroof, and Flight Engineer Kees Dik, entailed an 05:19 plunge into crystal morning skies on May 9, 1967 for what became a successful, 75-minute maiden mission.
The second protype, PH-WEV, followed suit three months later, on August 3, and achieved Mach 0.77 airspeeds and 27,000-foot altitudes on its 90-minute sortie.
The third, PH-MOL, first took to the air on October 20, and the 615-hour flight test program, along with an additional 165 hours for certification, led to that milestone on February 24, 1969 by the Dutch airworthiness authority and on March 24 by the FAA. Launch customer LTU Lufttransport Unternehmen, which had ordered two, amassed 150 airborne hours during a 12-day period for crew training and route proving purposes.
US market penetration, always the goal of foreign aircraft manufacturers, was achieved when Empire, which operated a New York State route system similar to once BAC-111-200 carrier Mohawk, ordered the F.28-4000 to supplement its 19-passenger Fairchild Swearingen Metro turboprops on main routes, albeit with jet speed and quadruple the capacity.
Piedmont Airlines, another US operator and eventually the type’s largest, acquired progressively higher numbers of them-first 20 F.28-1000s from Garuda, then 17 F.28-4000s when it took over Empire, and finally an additional eight, giving it a 45-strong Fellowship fleet.
Dutch indigenous and Amsterdam Schiphol-based NLM CityHopper acquired four F.28-4000s between 1978 and 1979, feeding KLM flights with them.
Although F.28 Fellowship production was less than half that of Fokker’s F.27 with 242 aircraft when it ended in 1984, and it could not offer the progressively higher capacities of the DC-9, the 737, and the BAe-146, it nevertheless carved a regional route niche and was operated by 57 customers in 37 countries. Original and secondary airlines included AeroPeru, Aerolineas Argentinas, Air Alsace, Air Anglia, Air Botnia, Air Gabon, Air Ontario, Air Nauru, Air Niugini, Altair, Cimber Air, Empire, Ghana Airways, Horizon Air, Linjeflyg, Nigeria Airways, NLM CityHopper, Piedmont, Royal Swazi, TAT Touraine Air Transport, THY Turkish Airlines, and Time Air, among numerous others.
Aerospatiale SN.601 Corvette:
Small in capacity and little-known, the Aerospatiale SN.601 Corvette straddled the line between the business and regional markets.
Its seed was planted when the French government, continuing its strategy of re-establishing the country’s post-war aviation industry begun with piston airliners such as the Breguet Deux Ponts, the Sud-Est Armagnac, and the Sud-Ouest Bretagne, requested that aircraft manufacturers submit proposals for a compact twin-turbofan liaison/trainer. Then-separate Sud-Aviation and Nord-Aviation elected to jointly develop an executive jet designated the SN.600 Diplomate in January of 1968 when French indigenous SNECMA designed a suitable powerplant for it, the M49 Larzac.
Although it first took to the sky in prototype form on July 16, 1970, the lengthy development of its intended powerplant necessitated the use of two 2,200 thrust-pound Pratt and Whitney Canada JT15D-1s instead.
In overall configuration, the aircraft resembled what later became the standard for this market: a narrow fuselage with five circular windows on either side; a low, swept wing; two aft-mounted turbofans; and, at least in the Corvette’s case, a semi-t-tail. Accommodation was 12, subdivided into six rows of single, side seats and a central aisle. The crew encompassed two pilots, but the number of passengers did not require an accompanying flight attendant.
Its operators were few Air Alpes, which took delivery of two Corvette 100s in 1974 and another two in 1975, operated routes on its own behalf from Paris and those, such as Lyons-Brussels, on Air France’s.
Other Corvette carriers included Air Alsace, Air Champagne, and TAT Touraine Air Transport in France, and Sterling Airways in Denmark. Airbus Industrie used five aircraft as corporate shuttles between 1981 and 2009.
Plagued by prototype accident; a long, corrective development period; a change in powerplant type; costly operation; failure to establish a North American distribution venue; strong competition; management ignorance; and capacity that proved inadequate, the Aerospatiale SN.601 Corvette nevertheless served as an example of one of the three regional jet origins: an all-new design, the conversion of an existing turboprop one, or the use of a business jet platform.
Vereinigte Flugtechnische Werke VFW-614:
Many attempts had been made to produce a more advanced DC-3 replacement powered both by piston and turboprop engines. With turbines, it took form as the regional jet, of which the Yakovlev Yak-40 and the Flacon 30 were early examples, although the latter never proceeded beyond the concept stage. Germany became the third country to enter this fray.
Initially viewed as a “Buschflugzeug,” or “bush aircraft,” the Entwicklungs Nord group, consisting of Focke-Wulf, Hamburger Flugzeugbau (HFB), and Weser, proposed the E.614, a small, simple, rugged, and economical twin-jet with a swing nose for straight-in cargo loading, passenger accommodation of between 36 and 40, two aft-mounted engines, and a t-tail intended for developing countries. The Lycoming PLF1B-2, then being designed in Connecticut, was the intended powerplant.
Intentions, as had occurred with other aircraft concepts, were forced to follow events-in this case, ERNO, the Entwicklungs Nord group, was reorganized into the Bremen-based Vereinigte Flugtechnische Werke (VFW), resulting in the redesignated VFW-614, for which Rolf Stussel was appointed its project leader, and iterations brought about changes to the 451-kph speed and 600-kilometer range of the aircraft first displayed in model form at the 1963 Paris Air Show.
Development of the Lycomiing engine was discontinued, necessitating its replacement with a turbine designed by Rolls Royce, which, because of its later bankruptcy, raised doubts about its own continuation, and the regional jet was subjected to a radical redesign that resulted in an unconventional configuration in order to minimize noise during operation from its intended small, limited-facility, short-field airports.
Finally, VFW, then Germany’s largest aircraft manufacturer since World War II, merged with Fokker of Holland in 1969, a strategy initially envisioned as mutually beneficial. The former would gain a more extensive marketing reach for an aircraft; projected to sell between 300 and 400 units, and the latter would expand its product line that would now encompass both turboprop and pure-jet aircraft, seating between 40 and 80 passengers, in its VFW-614, F.27 Friendship, and F.28 Fellowship models. Development, final assembly, and fight testing would nevertheless remain in Bremen.
Powered by two 7,511 thrust-pound Rolls Royce Bristol SNECMA M45H-01, thrust reverser-devoid turbofans uniquely mounted on above-wing pylons behind the rear spar, the VFW-614 was envisioned as offering numerous benefits because of it, including a maximum degree of payload configuration flexibility, semi-prepared field takeoffs and landings due to elimination of foreign object engine ingestion, high-frequency compressor noise reduction during approaches, the use of short undercarriage struts, an increase in airfoil surface area and hence lift with the avoidance of flap controls, the low ground access that eliminated loading and maintenance equipment, and inherent fuselage stretchability for higher-capacity versions.
Its other design features were otherwise conventional, encompassing a 16-degree wing sweepback, a standard tail, a tricycle undercarriage, and a 40-passenger cabin configured for ten rows of four-abreast seats.
Intended to replace its high-wing, twin-turboprop Nord 262s on European routes. Cimber Air, which provided considerable design input concerning its M45H engine selection, 1,200-meter runway capability, and 40- to 44-passenger capacity, became its launch customer, its two aircraft entering service on August 2, 1975 and April 1, 1976.
Although TAT Touraine Air Transport also ordered the German type, its contract stipulated its cancellation if the Falcon 30 had proceeded into development, since it was first obligated to purchase a French indigenous product.
Air Alsace also operated the type.
Despite the type’s unique features and the program’s high hopes for success, it was officially cancelled in 1977, leaving its commercial operation to cease three years later. Several reasons were cited for its failure, including VFW’s allegations that Fokker focused its sales efforts on its own products to the exclusion of the VFW-614, the German aircraft manufacturer’s ten-year later appearance, the unsuitability of it for Lufthansa’s routes, and its high operational costs.