later British Aerospace
|First flight||18 August 1967|
|Variants||BAe Jetstream 41|
Handley Page was in an awkward position in the 1960s, wishing to remain independent of the "big two" British companies (Hawker Siddeley and the British Aircraft Corporation), but without the money needed to develop a large new airliner that would keep them in the market. After studying the problem they decided that their next product would be a highly competitive small airliner instead, filling a niche they identified for a 12-18 seat high-speed design. The design garnered intense interest in the US when it was first introduced, and an order for 20 had been placed even before the drawings were complete.
The original design dates from 1965 as a 12-seat (six rows with a centre aisle) aircraft. The aircraft was a low-wing, high-tail monoplane of conventional layout. Considerable attention was paid to streamlining in order to improve performance, which led to one of the design's more distinctive features, a long nose profile. The fuselage had a circular cross-section to ease pressurization, allowing much higher altitude flights and consequent higher speed and comfort than competing unpressurised designs. One drawback of the design was that fuselage was so small in cross-section that the cabin floor had to be "lowered" to allow stand-up passenger entry and egress through the rear door. This meant that the main spar had to run through the cabin, causing a tripping hazard.
Final assembly took place in a new factory at the Radlett aerodrome, but large portions of the structure were subcontracted, including complete wings being built by Scottish Aviation at Prestwick, Scotland and the tail section by Northwest Industries of Edmonton, Canada. The original design used Turboméca Astazou XIV engines of approximately 840 hp (626 kW), and flew on 18 August 1967 as the Jetstream 1. Throughout the test program the engines proved to be a sore spot, being generally underpowered for the design, and surprisingly temperamental for what was then a mature and widely-used turboshaft design. Testing was eventually moved to the Turboméca factory airfield in the south of France, both to allow faster turnaround with engine work, and in order to improve the schedule by taking advantage of the better weather.
In order to improve sales prospects in the US, the fifth prototype was fitted with the US-built Garrett AiResearch TPE-331 in place of the French Astazou. Changing to the US-built engine was enough to allow the US Air Force to consider it for cargo use. They eventually placed an order for 11, fitted with a cargo door and accommodation for 12 passengers or 6 stretcher cases, to be known as the C-10A, or Jetstream 3M. However the USAF cancelled their order in October 1969 citing late delivery.
The first production model Jetstream 1 flew on 6 December 1968, and over the next year 36 would be delivered. However by this point Handley Page had given up on the original engine, and the Jetstream 2 was launched with the larger 965 hp (720 kW) Astazou XVI, starting deliveries in late 1969. The late delivery and engine problems had driven development costs to over £13 million, far more than the original £3 million projections. Only three Jetstream 2s would be completed before Handley Page went bankrupt, and the production line eventually shut down in 1970.
There was enough interest in the design that it was first picked up by a collaboration of investors and Scottish Aviation who formed a company called Jetstream Aircraft to produce the aircraft. A further ten Jetstream 1s were produced by this team. Scottish Aviation continued production of the Jetstream 2 as well, although they referred to it as the Jetstream 200. In February 1972, 26 Jetstream 201s were ordered by the Royal Air Force, who used them as multi-engine trainers as the Jetstream T.1. Fourteen of these were modified as observer trainers for the Royal Navy, receiving the designation Jetstream T.2.
After Scottish Aviation went bankrupt and was merged into British Aerospace in 1978, BAe decided the design was worth further development, and started work on a "Mark 3" Jetstream. As with the earlier 3M version for the USAF, the new version was re-engined with newer Garrett turboprops which offered more power (flat rated to 1,020 shp/760 kW with a thermodynamic limit of 1,100 shp/820 kW) and longer overhaul intervals over the original Turbomeca units. This allowed the aircraft to be offered in an 18-seat option (six rows, 2+1), with an offset aisle, and with a water methanol option for the engine to allow the ability to operate at maximum load from a greater range of airfields, particularly in the continental United States and Australia.
The result was the Jetstream 31, which first flew on 28 March 1980, being certificated in the UK on 29 June 1982. The new version proved to be as popular as Handley Page hoped the original model would be, and several hundred 31s were built during the 1980s. In 1985, a further engine upgrade was planned, which flew in 1988 as the Jetstream Super 31, also known as the Jetstream 32. Production continued until 1993, by which time 386 31/32s had been produced. Four Jetstream 31s were ordered for the Royal Navy in 1985 as radar observer trainers, the Jetstream T.3, but were later used for VIP transport.
In 1993, British Aerospace adopted the Jetstream name as their brand name for all twin turboprop aircraft. As well as the Jetstream 31 and Jetstream 32, they also built the related Jetstream 41 and the unrelated, but co-branded BAe ATP/Jetstream 61. The Jetstream 61 never entered service, and retained its "ATP" marketing name.
In December 2008, a total of 158 BAE Jetstream 31 and 32 aircraft remain in airline service. Major operators include: Coast Air (8), Direktflyg (7), Sun Air of Scandinavia (8), Blue Islands (5), Boston-Maine Airways (20) and RegionsAir (10) and Air National of New Zealand (5). Some 49 other airlines operate smaller numbers of the types.
In July 2008, a BAE Systems team that included Cranfield Aerospace and the National Flight Laboratory Centre at Cranfield University achieved a major breakthrough in unmanned air systems technology. The team flew a series of missions, totalling 800 mi (1,290 km), in a specially modified Jetstream 31 (G-BWWW) without any human intervention, This was the first time such an undertaking had been achieved. 
Data from Jane's All the World's Aircraft, 1988-1989