Why aren’t you considering Steeper approaches for Gatwick arrivals?
The Gatwick approach is currently 3 degrees; this is in line with the international standard defined by ICAO (the International Civil Aviation Authority). The ICAO Pans-Ops Document 8168 states that, ‘In the case of a precision approach, the operationally preferred glide path angle is 3° … An ILS glide path/MLS elevation angle in excess of 3° is used only where alternate means available to satisfy obstacle clearance requirements are impractical’.
If we were to go against this standard and make a case to use an angle in excess of 3° for noise purposes, the increase would be limited to 3.2° as approaches steeper than this this would reduce the airports ability to operate in low visibility conditions. This would mean that when visibility is low there would be increased potential for significant disruption from delay, diversion and increased numbers of go arounds (where pilots abort the approach at low level and ‘go around’ to attempt landing a second time). It is not possible to vary the angle of approach dynamically based on visibility conditions as the Instrument Landing System that defines the approach angle is safety critical equipment that cannot be changed without being fully tested.
Increasing the angle by 0.2° to 3.2 would mean aircraft are approximately 200ft higher at 10 miles out.
This potential benefit is not, at this time, considered significant enough to justify deviation from the international safety standard. However, GAL are monitoring the situation and are open to trialling procedures as soon as technical limitations are overcome such that there is an opportunity for significant benefit whilst maintaining compliance with international safety standards.
Posted in: j) Gatwick