.. _aircraft-capability:

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Aircraft Capability
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With a range of up to 2000 nautical miles (up to approximately 5 hours flying time, altitude and payload depending), the FAAM aircraft is capable of operating all over the world with the exception of Antarctica. FAAM has carried out science projects in over 30 different countries since 2004, taking the aircraft to Europe, North and South America, Africa and Asia. Typically, flights will last anywhere between one and six hours, and we can carry up to 18 scientists onboard. The scientists are responsible for guiding the mission and also support the operation of up to 4 tonnes of scientific equipment. The science equipment fitted to the aircraft (the configuration, or 'config') depends on the project's requirements and is determined during the project planning process. It can generally only be changed before flying for that project commences. 

Some useful information about the aircraft's capabilities and the way we plan flights is given below.

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Height and Altitude
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Minimum height/altitude is weather-dependent, but in good weather:

* Over land, minimum height is typically 500 feet above the ground or tallest obstacle
* Over sea, minimum height is typically 100 feet with temporary dips down to 50 ft
* Over the land/sea boundary, minimum height is 1000 feet due to bird activity

Maximum altitude is approximately 35,000 feet, although this is not achievable at the start of a flight when the aircraft's weight is highest. When fully fueled, the maximum altitude is approximately 27,000 feet (less if conditions are warm). High level flying is best planned towards the middle or end of a flight, when the aircraft's weight has decreased due to fuel burn. Alternatively, a shorter flight can be planned so that less fuel is required and the aircraft is lighter at the start of the flight.

When talking about height or altitude, scientists usually specify the specific measure they are using: height above ground level ('agl'), altitude above mean sea level ('amsl'), flight level (an indication of pressure, not altitude, but expressed as an altitude above sea-level in 100s of ft, based on the standard atmosphere).

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Distance and Speed
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To maintain compatibility with the aviation world, we measure distance in nautical miles (nm), 1 nm = 1.852 km. Our standard science speed is nominally 200 knots indicated air speed (IAS). Indicated air speed is different to true air speed, and because we fly at constant IAS, we go faster at higher altitudes. An approximate guide is as follows:

| Low Level -- 3.5 nm (6.5 km) per minute
| 10 000 feet -- 4 nm (7.5 km) per minute
| 20 000 feet -- 4.5 nm (8.5 km) per minute
| 30 000 feet -- 5.5 nm (10 km) per minute
| 35 000 feet -- 6 nm (11 km) per minute

Our minimum turn radius varies with altitude, from 1 nm at low level to 3 nm at high level.

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Manoeuvres
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Pilots and scientists planning a flight use a set of shared vocabulary to describe the various manoeuvres that can be performed to change altitude and direction. These are shown in the figures below.

.. figure:: static/images/manoeuvres-altitude.png
   :alt: Manoeuvres
   :width: 100%
   :align: center

   Example of manoeuvres used in flight planning, showing altitude changes.

.. figure:: static/images/manoeuvres-heading.png
    :alt: Manoeuvres
    :width: 100%
    :align: center
    
    Example of manoeuvres used in flight planning, showing heading changes.