Research summit

Rare aircraft carrying out special missions met in Iceland in summer. Their task: flying in the service of science.

11.2015 | Text: Andreas Spaeth

Text:
Andreas Spaeth has been traveling the world as a free­lance aviation journalist for over 25 years, visiting and writing about air­lines and air­ports. He is frequently invited to appear on radio and TV programs to discuss current events in the sector.

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.”

Steffen Gemsa, DLR research pilot

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.

Slideshow

Behind the scenes with NASA’s DC-8 research aircraft

Slideshow

 

1_Piloten

Wayne Ringelberg (left) and Dave Fedors (right) are research pilots with NASA, based at Armstrong Flight Research Center in Palmdale, California. They surely fly the most unusual former passenger airliners worldwide, serving scientific purposes these days: The last DC-8 in passenger configuration, built in 1969, and a Boeing 747SP of 1977-vintage, formerly flying for Pan Am, today operated by DLR and NASA as flying observatory SOFIA.

2_Steuerknueppel

The control column of the pilot in NASA’s DC-8 shows this aircraft has had a long life already. Since 1969 it has flown about 54,000 hours. 300 to 400 further hours are added each year on scientific missions. At least for another decade the veteran will stay aloft, NASA hopes. Besides a modern Flight Management System, the cockpit still is laid out as it was delivered in the late 1960s.

3_Typenschild

The DC-8-72 that NASA operates today as a scientific platform looks back on a long history, as the type plate in the cockpit demonstrates. It was manufactured by McDonnell Douglas in Long Beach/California in 1969 as a DC-8-60 and delivered to Alitalia on May 14, 1969. There, it flew christened as “Giacomo Puccini”, before being taken over by new owner Braniff International Airways from Dallas/Texas, where it flew until 1982. Only in 1986 it was acquired by NASA for its Airborne Science Program and retrofitted with more modern, quieter CFM56 engines.

4_Kommandostand

The control column of the pilot in NASA’s DC-8 shows this aircraft has had a long life already. Since 1969 it has flown about 54,000 hours. 300 to 400 further hours are added each year on scientific missions. At least for another decade the veteran will stay aloft, NASA hopes. Besides a modern Flight Management System, the cockpit still is laid out as it was delivered in the late 1960s.

5_Luke

The pilot’s cockpit is not the only command post in the NASA DC-8. There are two more in the cabin: One for the navigator and the other, shown here, as “mission control” for the scientific experiments conducted on board and coordination of these with the pilots.

6_Frachtraum

A special kind of “cargo” is carried underneath the cabin, as the leading scientist demonstrates here: The silver cover is hiding a laser emitting a wave length of two mikrons (0.002 millimeters), purpose-built for later use on board the International Space Station (ISS), which is pre-tested on board the science aircraft. It is used, among other things, to detect dust in the air.

7_Messsonde

A specialty of the DC-8 is the possibility to drop out sondes during flight through an airlock. The smallish plastic containers are internally insulated with styrofoam and contain a GPS as well as sensors to measure air and ground temperature, air humidity and pressure. All these measurements are taken during the seven to twelve minutes of free fall of the sondes. One alone costs US$1,000. For the research campaign in Iceland, one hundred were used.

8_Schacht

Through this unusual outlet on the aircraft’s exterior, the drop sondes reach the air through the tube-like airlock. Often one is dropped every 30 minutes during a campaign.

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.

1-Start

A NASA McDonnell Douglas DC-8, built in 1969 (behind), and a Gulfstream, wait for their mission to test new laser technology for wind measurement.

1-Start

A NASA McDonnell Douglas DC-8, built in 1969 (behind), and a Gulfstream, wait for their mission to test new laser technology for wind measurement.

2-Sonde

Measuring instrument on the wing of the NASA DC-8.

2-Sonde

Measuring instrument on the wing of the NASA DC-8.

“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.”

Wayne Ringelberg, NASA research pilot

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.”

The DLR’s “all-purpose weapon” an A320 in research service

1_D-ATRA

D-ATRA The largest research aircraft in the German Aerospace Center’s fleet is an A320 built in 1997 and formerly used as a passenger jet.

1_D-ATRA

D-ATRA The largest research aircraft in the German Aerospace Center’s fleet is an A320 built in 1997 and formerly used as a passenger jet.

Like most air­craft working in the service of science, the Airbus A320 with the serial number 659 is no longer an entirely new air­craft. Its maiden flight was in January 1997, after which it spent almost ten years as a passen­ger air­craft for Aero Lloyd and Niki. But since the end of 2008, the A320 has been flying as a flight test platform for the DLR in Braunschweig. The A320 is equipped with two International Aero Engines V2500 engines, which MTU Aero Engines helps to develop and produce. The Advanced Technology Research Aircraft, which carries the fitting regis­tration D-ATRA, is the largest of the DLR re­search air­craft. The fleet, which comprises a dozen air­planes and heli­copters, is the largest civilian air­craft fleet for re­search use in Europe. The D-ATRA has completed a variety of test series covering very dif­ferent re­search areas, such as wake vortices and high-lift research. For the latter, the A320 has a special concept for high-performance and noise-reducing wing flaps. Missions can also involve unusual tasks, such as flying over the air­field at a maximum height of 15 meters in a bid to collect as many insects on the nose as possible—all part of research being conducted into future ultra-smooth laminar airfoils.

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