Use of GPS to assist safe descent through cloud
A GPS is not a primary navigation aid. Extreme care should be taken to avoid being caught above cloud cover during a wave flight.
Should you have the misfortune to find yourself above complete cover, or in poor visibility, then the following advice is offered for a GPS -assisted descent to Feshie Airfield.
The descent is based on two waypoints in the Spey Valley 5.6nm apart. Tracking from one waypoint to the other will keep you clear of the mountains and over good outlanding fields. The Insh waypoint is 1.2 nm from Feshie, Ruthven is 6nm from Feshie. See co-ordinates below.
Enter the waypoints in your GPS before take-off. Some models have a route facility and will track from waypoint to waypoint.
To start the descent, GOTO the nearest waypoint. You should arrive at or above 5000ft on Feshie QFE. This will keep you clear of the surrounding mountains.
GOTO the second waypoint. Use airbrake to maintain a good rate of descent. During the leg be sure to apply enough drift towards the into-wind direction to track direct to the waypoint (keep the CDI centred), or you may drift into the mountains. If there is a large crosswind component fly faster than usual to reduce the drift angle.
At the second waypoint, turn through the into-wind direction to track back to the first waypoint. Remember any drift required must now be applied in the opposite direction. Repeat until clear of cloud.
Keep in contact with Feshie Base for cloud base, wind and weather reports.
When clear of cloud, close your airbrakes and if possible return to the airfield, or land out. Call Feshie once you break cloud.
All turns in cloud should be rate one turns upwind.
Ruthven Barracks (RVN) N57 04.32 W004 02.36
Feshie Descent Point (FE3) N57 06.884 W003 56.020 (near Insh Watersports)