A DC-8, a Gulfstream III, a Dornier 228 and a Falcon 20 meet up in Iceland. The question is: What are they doing there, this illustrious group of rather exotic aircraft so rarely seen in action? Answer: They’re on a scientific mission. Iceland’s northern latitude makes it a popular starting point for aeronautical research missions from both sides of the North Atlantic. This past summer, research aircraft from the German Aerospace Center (DLR) in Oberpfaffenhofen, in the German state of Bavaria, met there with their American colleagues from NASA’s Palmdale facility in California. The two oldest planes were NASA’s McDonnell Douglas DC-8 and the DLR’s Dassault Falcon 20, built in 1969 and 1974, respectively. These veterans worked as a team to test a new laser technology for measuring wind. The results helped advance the development of the latest wind lidar (light detection and ranging) system, which can measure winds over the North Atlantic more precisely, enabling meteorologists to generate more accurate weather forecasts. ESA will start using the new system on one of its weather satellites in late 2016. The DLR’s Dornier 228, however, like NASA’s Gulfstream aircraft, only touched down in Iceland for a brief stopover. Prior to that, it spent several days flying over Greenland, testing new radar-imaging techniques for measuring the condition of the “eternal ice” up to 50 meters deep from the air.
“The aircraft grow with each task required of them. From a technical standpoint, they’re state of the art: the airframes may be old, but they’re equipped with all the latest technology,” explains DLR pilot Steffen Gemsa after touching down at Keflavik airport in Iceland. He has just completed a four-hour flight from Greenland in a twin-engine Dornier Do 228, built in Oberpfaffenhofen in 1991. Flights like this one are strenuous. The unpressurized cabin means that the pilots have to wear oxygen masks at altitudes above 10,000 feet (around 3,300 meters), often accompanied by protective clothing to keep out the arctic cold. There’s no catering on board, and according to Gemsa, there’s no time to eat, anyway. “We live on coffee and biscuits.” But even this small pleasure is in short supply: “There’s no toilet on board, so we have to strategically plan our coffee consumption. We have a one-cup limit before takeoff.” Despite everything, Gemsa loves his job. For the flight captain, who has already accrued over 7,000 flight hours at the controls of four different DLR research aircraft, “every flight is a special experience, even if we’re sometimes in the air for eight hours a day.”
“These aircraft can do things that no other plane can do, and they are constantly being adapted to face new challenges. You can’t buy that off the rack.”
The aircraft he flies are just as unique as his profession. “They’re all irreplaceable one-offs. Our Dornier 228 was retro-fitted with new engines and five-blade propellers in 2014,” Gemsa explains. “The reason we use such old aircraft is that their technology and sensor systems have undergone so much development over the years that the capabilities of these machines are inimitable. They can do things that no other plane can do, and they are constantly being adapted to face new challenges. You can’t buy that off the rack.” Cost is another reason that research aircraft are usually older models, as notoriously tight scientific budgets aren’t large enough to cover the procurement of new aircraft. “A new plane costs between 30 and 50 million euros, which is more than research projects can afford. All research aircraft have a service life of some 30 to 40 years, so they’ll retire when we do,” says Gemsa with a laugh. But at 43, the pilot is no more ready for the scrap heap than his 24-year-old Dornier.
Behind the scenes with NASA’s DC-8 research aircraft
NASA owns and operates the only passenger DC-8 in the world to still be flying
Impressive stuff, but without a doubt the real eye-catcher in Iceland is the only passenger DC-8 in the world to still be flying—and at 46, the plane is even older than Gemsa. Despite its four engines, the big bird is amazingly quiet in flight—almost silent, even during take-off. This is due mainly to its newer CFM56 engines, which fall under noise category III (quiet). They were fitted in 1986 to replace the much shriller Pratt & Whitney JT3D turbofans that used to power what was then the DC-8-62. This aircraft, which now carried the serial number “-72”, had originally been supplied to Alitalia as a DC-8-60 with production number 458 from the factory in Long Beach, California in May 1969. In 1979, the machine changed hands, flying for the Dallas-based American company Braniff International Airways until 1982. This marked the end of its life as a passenger aircraft: in February 1986, NASA acquired the plane, which had some 40,000 flight hours on the clock, for use as a research aircraft. It took two years of modification work, but the DC-8 had now become an ideal research platform for all kinds of scientific missions from various academic disciplines. The aircraft is based at NASA’s Armstrong Flight Research Center at Edwards Air Force Base in Palmdale, in southern California.
As aircraft go, the DC-8-72 is very economical for long research missions. Scientists can use it to fly nonstop for 11 or even 14 hours to reach remote regions of the globe, enabling them, for instance, to travel from Punta Arenas, Chile to Antarctica and back. “The DC-8 is a very solidly built, robust aircraft based on 1960s design principles. It meets even the toughest requirements, and it can be deployed anywhere in the world,” says NASA research pilot Wayne Ringelberg. The strength of the fuselage is particularly important when it comes to the installation of scientific instruments, which require various openings to be cut in the outer skin or windows to be replaced with panels carrying entire batteries of sensors. “These older aircraft designs feature a lot of built-in leeway, something we don’t find in modern machines,” Ringelberg adds. “With four engines, the main advantage of the DC-8 is its redundancy on long flights.” In order to measure biofuel emissions, NASA’s DC-8 was recently required to fly into the contrails of the DLR Falcon. “We had to keep our speed quite low, but ascend as high as we could go,” Ringelberg recalls.
Flying researcher from NASA and the German Aerospace Center, at Keflavik Airport.
Flying researcher from NASA and the German Aerospace Center, at Keflavik Airport.
Flying researcher from NASA and the German Aerospace Center, at Keflavik Airport.
“We conduct three to six campaigns a year, and it can take two to three weeks just to incorporate and calibrate the tools each time—longer than the mission itself, in some cases.”
A test flight crew usually comprises some 25 people: two pilots and a flight engineer in the cockpit; a navigator in the forward cabin; two mission managers responsible for coordinating the scientific work on board, positioned near the navigator; and two safety technicians to oversee the measuring instruments and provide assistance in emergency situations. That makes a total of eight NASA personnel. Then there are generally an additional two or three scientists per installed instrument on board, bringing the total up to about 25 people working in the very spacious cabin originally designed to accommodate up to 175 passengers. Today the space is filled only with wide, former first-class seats that are mostly surrounded by instruments for all kinds of measurements. Particularly striking are the huge, rectangular windows of the DC-8, which put the famously generous windows of a Boeing 787 or an Airbus A350 to shame.
Another remarkable feature, of course, is the analog cockpit, with its instrument panels full of dials and pointers laid out before the pilots and flight engineer. “Our avionics are based on a modern flight management system, but the autopilot is still original,” Ringelberg explains.
Overall, the NASA DC-8 spends 300 to 400 hours in the air each year. “We conduct three to six campaigns a year, and it can take two to three weeks just to incorporate and calibrate the tools each time—longer than the mission itself, in some cases,” Ringelberg explains. The DC-8 has one distinctive property that the scientists value particularly highly: it allows them to drop probes directly from the cabin through a tube. The DC-8’s indestructible airframe seemingly knows no limits in terms of flight hours; to date this aircraft has completed approximately 54,000. “We expect to keep flying it for at least a decade,” says Ringelberg. But the time will eventually come when it will be too difficult to obtain spare parts from cannibalized aircraft. Ringelberg wouldn’t call his DC-8 a dinosaur—it is, after all, only three years younger than he is. “Put like that, it sounds so negative. I prefer to see it like a well-kept antique car.”