(CNN) — From the outside, you could easily mistake it for any other small passenger jet. But once you're inside, it's clear that this is not a typical aircraft.
Rows of scientific equipment have replaced most of the seats. In place of overhead storage there are pipes and wiring, and instead of holidaymakers, the passengers are research scientists.
This is no ordinary plane; this is Europe's largest flying lab.
The Airborne Laboratory is operated by the UK's Facility for Airborne Atmospheric Measurements (FAAM) and can be found in skies around the world. Through its research it is helping us better understand challenges like air pollution, climate change and extreme weather.
"Measuring physical and chemical effects in the atmosphere informs climate models and our understanding of how climate will change over time," Alan Woolley, head of FAAM, tells CNN. "We're trying to understand how the environment works (through) the atmosphere so we can be responsible about decisions we take to sustain it."
FAAM -- which is part of National Centre for Atmospheric Science -- began using the jet lab in 2005 and it has since completed more than 15,000 flights, covering 2 million miles. Last November, the airborne laboratory was granted £61 million ($81 million) by the UK government so it could continue its research for another 10 years.
The flying laboratory can reach an altitude of 35,000 feet.
Making a laboratory in the sky
The plane didn't start out as a flying lab: It's a reconfigured BAe 146 commercial passenger plane -- a model once used by many airlines, including Britain's easyJet, and still used today by regional carriers. BAe systems modified it to meet FAAM's needs.
During research flights, the aircraft can carry up to 18 scientists. It can reach an altitude of 35,000 feet and fly as low as 50 feet over the ocean, to better understand the complex interactions between the atmosphere and the sea. "It looks really crazy!" says Woolley of its low-flying antics. "You don't normally see larger aircraft providers doing this."
Because of the skill needed for the job, the plane is often flown by former Royal Air Force pilots.
To reduce risks when flying low, the plane has a high wing structure which adds stability and lifts its engines away from the ground. The plane has extended-range fuel tanks and short takeoff-and-landing capabilities, which makes it easier to access smaller airports and remote locations.
It has also been kitted out with around four tons of equipment to enable cutting-edge research. "Windows have been blanked off and have inlets, (where) we suck in air to analyze gas constituents, like carbon dioxide concentration," explains Woolley.
Particles of cloud, smoke, fog, volcanic dust and pollutants, are captured by sampling probes that hang off the wings, and then brought into the aircraft for analysis. Difficult-to-measure particles, like desert dust or sea-salt aerosols, are analyzed by instruments outside the plane while it's flying.
This probe measures the size and number of cloud droplets.
Woolley says the aircraft "is a bit of a Swiss Army knife," because it can be reconfigured for different research needs.
In 2010, a huge volcanic eruption in Eyjafjallajökull, Iceland, closed airspace across Europe, costing the airline industry more than $1 billion. The flying lab was deployed to survey the atmosphere for signs of ash. Two years later, the plane assisted energy company Total in its response to the Elgin gas platform leak 150 miles off the coast of Scotland, by measuring methane levels in the air. Its work could also save lives. In 2016, FAAM carried out a mission to study India's monsoon, to better understand how clouds evolve over time and predict patterns of rainfall -- work which Woolley says can help ensure food security. Now the team is working on a project monitoring shipping lanes in the North Atlantic to measure the impact of new regulations that limit ships' sulfur emissions in international waters. The data will help to analyze the impact of shipping on health and climate.
The pandemic means several projects have had to be postponed, but the team hopes to continue its work later this year.
"The whole point is really to understand the atmosphere better," says Woolley. That information will help us "make better decisions to lessen the impact that atmospheric effects might have ... on society."