Air transport has received plenty of flak about its impact on the environment, but sometimes it can be beneficial. One such little-known example involves a BAe 146 that since 2004 has been used for atmospheric research work all over the world, studying weather patterns, climate change and global warming.
Owned by BAE Systems, the Atmospheric Research Aircraft, or ARA, is flown under subcontract by specialist operator Directflight of the UK. Directflight operates it for the UK's Facility for Airborne Atmospheric Measurements (FAAM), which is run by the Natural Environment Research Council (NERC) and the Met Office. These agencies accept bids for the aircraft's use and help arrange funding.
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The ARA flies around 500 "science hours" each year, and throughout July it has been operating over the east Malaysian state of Sabah in a project that will give researchers a better understanding of how emissions of reactive trace gases from tropical rainforests influence climate change. It is the aircraft's first such research campaign in Asia and by the end of the month it will have completed a 50h mission carrying out tests primarily at 500ft (150m), 2,000ft, 10,000ft and 20,000ft.
"We couldn't do our science without it," says Nick Hewitt, professor of atmospheric chemistry at the UK's Lancaster University and leader of the so-called OP3 project.
OP3 (Oxidant and Particle Photochemical Processes Above a South-East Asian Tropical Rain Forest Research), is a three-year project that began in October. Its aim is to improve understanding of how forests control the composition and chemistry of the Earth's atmosphere, how they affect climate change, and how changes to forests will influence climate.
Research using the ARA comprises the major phase of the project, with supporting ground-based measurements made at the Malaysian Meteorological Department's Bukit Atur global atmospheric watch station in Danum Valley. Funded by the NERC, OP3 involves a consortium of UK universities, the UK's Centre for Ecology and Hydrology and Malaysian partners.
EXTENSIVE UPGRADING
The ARA underwent extensive conversion and upgrading and a regulatory certification programme in 2003 before entering service the following year. It is fitted internally with 4,000kg (8,800lb) of sophisticated test equipment, plus additional equipment specific to individual missions. Externally there is plenty to be seen, such as protruding air sampling and sensing devices as well as video cameras. The ARA is easily recognisable from the many bulges on its fuselage and its unusual wing pylons, which give it the appearance of a missile-equipped military aircraft.
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© Nicholas Ionides/Flight International |
The equipment adds weight and creates drag, which, combined with the need for longer flights than those of a typical 146 in passenger configuration, required an additional fuel tank.
The aircraft was the first 146 manufactured by the former British Aerospace, now BAE Systems. Originally built as a -100, it was first flown in 1981 and used as a test aircraft. It was stretched by 3m to become the first 146-300 in 1987. For a good portion of its life it has been flown by Capt Alan Foster, who was previously with BAe and who is now Directflight's 146 fleet manager. He joined BAe from the UK's air force where he was a qualified test pilot. He is one of the pilots involved in flying FAAM missions globally.
"It's very diverse work. We work in all kinds of remote areas of the world so we are equipped for remote area operations," says Foster. "The background work for these kinds of campaigns is phenomenal, to get the clearances to fly through the airspace, to get the clearances to gather data in the airspace, and it depends on the country how sensitive they are."
The flying is challenging, as Directflight is unique in being approved by the UK Civil Aviation Authority for BAe 146 passenger operations as low as 50ft to as high as 35,000ft. For low-level operations the aircraft has a special system that is activated to inhibit enhanced ground proximity warning system modes, as leaving the system on in standard modes would result in repeated terrain warnings.
Foster says the average science flight is 5h, although in the campaign over the protected rainforest in Malaysian Borneo the average is around 4h. In other campaigns the aircraft often flies for lengthy periods over water or ice - above 200ft-high waves off the southern tip of Greenland, for example, or at just 100ft over Arctic ice for 2.5h on one campaign. As a result it needed a special certification for extended-range operations, which is normally not required for four-engined aircraft flying.
"The aircraft was never built for extended-range flight over water so we have a peculiar thing which we agreed with the UK CAA for extended-range flight," says Foster. "It's like ETOPS, but is not exactly ETOPS because it's not a twin-engined aircraft. Certain specific checks have to be made for an extended-range flight. To my knowledge it is unique."
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© Nicholas Ionides/Flight International |
Extra communications systems include a marine band so the crew can communicate with ships if needed. A satcom system allows for use of telephones, fax, email and internet while airborne. Scientists are all on headsets, allowing for voice communication with the cockpit crew while they view test data on computer screens. The aircraft can carry up to 20 people, including the two pilots, one cabin attendant and 17 scientists.
BASIC UNDERSTANDING
Foster says a basic understanding of the researchers' work is a must. "It is important for us to understand what they are after because if we don't understand it, and we don't have the right exchange, then we are not going to help them get results," he says.
OP3 project leader Hewitt adds: "We have planning meetings with the pilots to discuss what is possible. We say what we would like to do from a scientific point of view and they tell us if it is feasible or possible."
The aircraft is based at Cranfield airport and operates four overseas missions a year, normally of one month each. The remainder of the time is used for maintenance and UK-based campaigns. In addition to the three or four pilots involved in most campaigns, there are operations staff as well as engineers from Avalon Aero, who maintain the aircraft on contract with Directflight.
Other aircraft carry out airborne research work for governments, such as a McDonnell Douglas DC-8 with US space agency NASA, but they are few in number, making flying for environmental research very exclusive. "It's a way of showing how aviation can help," says Foster. "People might say it is contributory to global warming, but it is an able platform."
Source: Flight International
