The Met. Research Flight (MRF) was a Met Office facility, which operated a well instrumented C-130 Hercules (also referred to as Mk.2 Hercules) aircraft for research purposes. The C-130 was in service from 1972 to 2001 and flew over 1800 research sorties. The large capacity and long endurance of this platform made it ideal for atmospheric research in the areas of cloud physics, atmospheric radiation, atmospheric chemistry, satellite activities, mesoscale meteorology and boundary layer studies.

The BADC holds data collected by the C-130 during NERC (Natural Environment Research Council) funded flights, such as those made during ACSOE (Atmospheric Chemistry Studies in the Oceanic Environment) and UTLS (Upper Troposphere - Lower Stratosphere) projects. The basic set of measurements include ozone, nitrogen oxides, water vapour, aerosols, wind, position and temperature. These are often supplemented by project specific measurements.

The aircraft was able to operate scientifically throughout the troposphere from a minimum altitude of 15 m (50 ft) where permitted, up to a maximum of 10 km. The aircraft had a maximum working flight time of 12 hours.

The C-130 was taken out of service in March 2001 and a new joint NERC-Met Office Facility for Airborne Aircraft Measurements (FAAM) was established operating a BAe-146-301 aircraft.