Don't look down! The daredevil engineer who works on top of a 330ft wind turbine
Engineer Ross Kennedy balances on top of a wind turbine on Drumderg hill in Perth and Kinross, Scotland, as he carries out a check of the rear aileron
Operating atop the 330ft-tall wind turbine is a dizzying task - not least because the platforms continue to rotate in search of wind during maintenance checks
Mounted at the rear of the nacelle, or engine housing, the aileron contains weather sensors (including, crucially, a highly accurate anemometer, for measuring wind speed) and something called the 'lightning card' - a piece of specially treated material that electromagnetically records how often and how strongly the turbine is struck by lightning.
Bad weather poses no serious risk to the machinery but in strong gales, sensors housed in the nacelle can automatically slow down or halt the blades.
Failing that, the owner of the site, Scottish and Southern Energy, can shut down the turbines remotely from its head office in Perth if any fault is detected.
Operating atop the 330ft-tall structures is a dizzying task - not least because the platforms continue to rotate in search of wind during maintenance checks. Engineers work in a 'buddy system', each relying on their partner to stick to safety rules.
Access to the top of each turbine is via a two-man lift inside the shaft, which brings you out just below the nacelle.
The wind farm consists of 16 turbines that can generate 37 megawatts, enough to power 25,540 homes for a year.