§ Jim KnightTo ask the Secretary of State for Defence what assessment has been made of(a) the potential and actual interference of radar by wind turbines and (b) the obstruction that wind turbines represent to low-flying aircraft; how long the assessment has taken; and when the results will be published. [27275]
§ Dr. MoonieThe RAF has carried out two trials, one in 1994 and one in 1997, both of which found that if a wind farm is in direct line of sight to radar it can have an extremely detrimental effect upon radar performance as the rotating blades can be a source of interference. The turbines can appear as genuine aircraft targets that could either mask aircraft responses or desensitise the radar within the sector containing the wind farm. Shadowing of aircraft at similar radar to target elevation angles as the wind farm may degrade radar performance even further which could be potentially hazardous to air traffic and impede an air defence control situation.
The Ministry of Defence recognised the need for further research and is currently assisting with a DTI sponsored study that is being undertaken by QinetiQ into the effects of turbines on radar systems. This study began in September 2001 and is due to be completed in September 2002.
Military low flying training takes place within the UK Low Flying System below 2,000 ft for fixed wing aircraft and 500 ft for helicopters. Fixed wing aircraft are permitted to fly down to within a Minimum Separation Distance of 250 ft from the ground or any other obstacle, and helicopters are permitted to fly down to ground level. The presence of wind turbines in most areas of the UK would present no difficulty to low flying aircraft and these and other naturally tall structures are taken into account as part of route planning.
In some circumstances, the presence or proliferation of wind turbines may pose a hazard to, or interfere with, military low flying training to such an extent that the training value is negated. The height of the turbines is often in excess of 70 m (approximately 220 ft) to turbine tip. Within the Tactical Training Areas aircraft can be flown at 100 ft above ground level, which is significantly 330W lower than the 250 ft minimum that applies to the rest of the UK low flying system. Therefore, for the safety of members of the public and aircrew it is imperative that any hazards to low flying aircraft are minimised, especially those that exceed 100 ft in height.