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The Lockheed TriStar – The Most Intelligent Aircraft Ever to Fly

By Rob Russell

The 1970s saw the beginning of many wide-body designs. The jets almost came to the civil market by default – primarily as a result of the United States Defence Force’s need for a large wide-body long-range jet to transport their equipment around the world. The decade kicked off in style with the Boeing 747's entry into service. McDonnell Douglas's DC-10 followed suit shortly after. The third twin-aisle aircraft to hit the skies commercially was, like the DC-10, another design sporting three engines – the Lockheed Tristar. Whilst a great aircraft, with some very innovative features, it was last in the queue and never achieved the greatness it deserved.

In April 1972, after six years of design and some unforeseen setbacks, the Lockheed California Company (now Lockheed Martin) delivered the most technologically advanced commercial jet of its era, the L-1011 TriStar, to its first client, Eastern Airlines, which entered the plane into service in the same month it was received. However, it was another United States-based carrier that spurred the project to get underway.

American Airlines required a plane that could transfer its passengers from the carrier's hubs in New York and Dallas to routes across the Atlantic and to South America. Boeing was occupied with the development of the 737 primarily for the European markets and was developing the 747 for intercontinental and long-range travel. It was something in between these aircraft that America needed. It wanted to transport more customers than the 737 but also operate something more fuel-efficient than the 747.

Eastern Airlines was primarily an airline that flew around the USA and to several destinations in South America, so the 747 was not suited to its route structure. They considered the Douglas DC10, but it found it unsuitable for its routes and they eventually became the launch customer for the Tristar. Lockheed had ceased airliner manufacturing in 1961 when the production of its L-188 'Electra' turboprop ended. Nonetheless, it was keen to get back into the airliner market. This resulted in the L-1011 TriStar, It boasted previously unheard-of luxuries, including glare-resistant windows, full-sized hideaway closets for coats and a below-deck galley, where meals were cooked on request! The TriStar had a typical capacity of 256 in a mixed-class setting. Meanwhile, its three Rolls-Royce RB211-22 supported it to cruise at 520 kn (963 km/h) and reach a range of up to 2,680 NM (4,963 km). It was just what Eastern Airlines was looking for.

The TriStar's AFCS (Avionic Flight Control system) included some of the period's state-of-the-art features with its speed control, flight control system, navigation system, stability system, direct lift control system, and autopilot. The aircraft's CAT-IIIB Autoland system could also help the trijet land, even in severe weather.

In a similar fashion to other passenger airliners before it, the L-1011 faced daunting challenges on the way to its inaugural flight. The different and constantly changing needs, of competing airlines, led to ongoing design challenges. Financial difficulties ravaged its engine’s manufacturer. Throw in a recession, fuelled by the world’s first oil crisis and the demand for new jets almost dried up, as airlines sought to keep their older narrow-bodied jets flying through the recession.

But the Tristar, like its parent company, survived the storm, including a government loan guarantee, and in the end, more than 4,500 jobs were saved.  Finally, after an exhaustive test flight programme, Eastern Airlines began scheduled service of the L-1011, with the first flight from Miami to New York on the 30th of April 1972.

On the ground, the Lockheed L-1011 TriStar was an undeniable beauty. With its large, curved nose, low-set wings and graceful swept tail, it looked as sleek as a dolphin. But in flight, the L-1011 was nothing short of a miracle, the first commercial airliner capable of flying itself from takeoff to landing.. Passengers loved flying in it, thanks to a unique engine configuration that reduced sound in the cabin. Cabin crews appreciated its extra-wide aisles and the passengers loved the large overhead bins. But it was TriStar’s pilots who had access to its most thrilling feature: an advanced fly-by-wire automatic flight control system (AFCS).

On May 25, 1972, veteran test pilots Anthony LeVier and Charles Hall transported 115 crew members, employees, and reporters on a 4-hour, 13-minute flight from Palmdale, California, to Dulles Airport outside Washington, D.C., with the TriStar’s AFCS feature engaged from takeoff roll to landing. It was a groundbreaking moment: the first cross-country flight without the need for human hands on the controls. Fly-by-wire technology was here to stay.

Thanks to its innovative autopilot feature, the TriStar was certified by the FAA for Cat3b weather landings to land during severe weather conditions. Whereas other wide-bodied jets had to be diverted to alternate airports, L-1011 passengers could rest assured that they would touch down precisely where they were scheduled to land.

Dubbed the Whisperliner by Eastern Airlines due to its quiet takeoffs and a noticeable lack of noise in its passenger cabin, the production of L-1011 continued until 1983. The L-1011 fleet had a remarkable in-service rate that reached 98.1% reliability. 

Throughout its production history, Lockheed manufactured numerous versions of the TriStar. Lockheed ultimately produced 250 examples of the TriStar between 1968 and 1983. Just one example remains operational, launching Pegasus rockets for Orbital Services.

160 of its 250 TriStars were examples of the original L-1011-1 variant. The second model, the L-1011-100, was launched in 1975 and had a longer range than the slightly smaller L-1011-1. An additional centre fuel tank extended this by 930 miles (1,500 km). Lockheed also offered the L-1011-50 as a conversion of the L-1011-1. While this had the same range, its advantage over the L-1011-1 was an increased maximum takeoff weight (MTOW) of 200-205 tonnes (compared to 195 for the -100).

The L-1011-150 conversion then increased this figure further to 210 tonnes. Air Transat took the first of these in 1989. The final conversion option offered by Lockheed was the L-1011-250. This applied to the -1, -100, and -200 models, but Delta only ever took it up for six -1s. These upgrades were all done to compete against its rival - the long-range DC-10-30

The final two production variants of the TriStar were the L-1011-200 and the L-1011-500. The former of these featured Rolls-Royce RB.211-524B engines to improve its 'hot and high' performance. Meanwhile, the -500 had a shorter fuselage (50.05 vs 54.14 meters) but a longer range, a similar tactic to that applied by Boeing to the 747SP. These various options and models were developed as a result of the furious development of other wide-body jets, which also offered more options and ranges.

The TriStar went on to see a varied service life at a range of both military and commercial operators. The former of these saw it serve for armed forces in Algeria, Jordan, Saudi Arabia, and the UK. The RAF acquired their TriStars from British Airways, which found them excess to their fleet requirements, during the merger of British European Airways and BOAC. They went on to provide the backbone of transport and in-flight refuelling for the RAF until they were eventually replaced with the Airbus A330 MRTT.

As for commercial use, the TriStar had a large number of operators in North America. These included Air Canada and Air Transat, as well as Eastern, TWA, Delta Air Lines, Pan Am and, briefly, United Airlines.

The TriStar was also a well-travelled aircraft outside of North America. It became a key medium to long-haul design for flag carrier airlines all over the world. These included Aer Lingus, Air France, Air India, British European Airlines and later British Airways, Gulf Air, and TAAG Angola.

But the financial troubles proved too great to overcome. A total of 250 TriStar jets were produced by Lockheed, and the L-1011 marked the company’s final commercial passenger airliners. A further death knoll was the development of two engine wide-bodies and long-range aircraft – namely the Boeing 757 and 767 family, together with a new competitor in the market – Airbus with its A300. The reliability of two-engine flights proved too much for Lockheed and the end of the finest of the first generation wide bodies.

 But the company exited on a high note, having created, in one pilot’s words, “the most intelligent airliner ever to fly.”



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