Interesting discussion
Originally Posted by
Del Prado
160 to 4 non conformance league tables were introduced at a larger neighbouring airport and the problem has been almost eradicated, at least to the stage where it is now a one off occurrence rather than a fleet or airline trend. As an aside, the airline that requests 160 to 5 seems to be able to achieve 160 to 4 there.
The larger neighbouring airport has reasonably flat terrain at both ends, whereas at everybody's favourite busy single (ish) runway airport there are some hills to the west. Combine that with some companies using 1000 AAL and others using 1000ft Radio Altitude as the stable criteria and you can start to see the issue. The terrain under the approach to 08R at Gatwick makes 160 to 4 and stable by 1000 radio very difficult to achieve.
For 160 to 4 on a 3 degree ILS I aim to be 160 selected, F2, gear up. At 4.3 manage speed, gear down, flap 3, flap full and then it will almost always be stable by 1000 aal. In thermally conditions an extra half mile may be necessary. A319s at a light weight will struggle with this, so it all boils down to what the commander and the company consider acceptable.