Whenever possible, aircraft land and take off into the direction of the wind. This enhances safety by generating more lift when taking off and providing greater stability when aircraft are approaching the airport to land.
The prevailing wind direction at Bristol Airport is westerly or south westerly which means that approximately 68% of take offs initially depart towards the Bristol Channel. Landing aircraft approach from the Bath direction.
When there is an easterly or north easterly wind the operation is reversed with landing aircraft approaching from the Bristol Channel and departing initially towards Bath.
The alignment of the runways at Bristol Airport is east/west, the westerly runway being referred to as “27” from its magnetic heading of 270 degrees, the easterly runway is “09,” its magnetic heading being 090 degrees.
In order to minimise noise disturbance, departing jet aircraft and propeller driven aircraft of more than 5700 kg maximum certificated weight are required to follow noise preferential routings unless otherwise instructed by Air Traffic Control. There are also standard outbound routes for departing aircraft joining the airways system (also known as Standard Instrument Departure Routes, or SIDs). The noise preferential routings require departing aircraft to climb straight ahead to a distance of 4.5 nautical miles (4.7 nautical miles for runway 09) before turning on course, unless instructed otherwise by Air Traffic Control. The departure path should be considered as a narrow band or swathe rather than a thin line along the runway axis, as factors such as wind can affect an aircraft’s initial tracking capabilities until appropriate corrections can be applied. On occasion the noise preferential routings or the SIDS may have to be amended to enable aircraft to avoid adverse weather such as thunderstorms.
Most landing aircraft are guided to the runway by the Instrument Landing System (ILS) a precise landing aid located on the airfield. Aircraft line up with the ILS at a distance of between 7 and 10 miles before descending at an angle of 3 degrees, which equates to a descent rate of 318 feet for each nautical mile travelled along the ground. Runway 27 is fitted with a Category lllb system which permits suitably equipped aircraft to land in periods of reduced visibility, the critical minima being a measured horizontal visibility of 75 metres.
Maps showing indicative flight routes for easterly and westerly operations can be found on page 19 and 20 of the Operations Monitoring Report.