You can arrive on station early but, arrive too early and you may not find anything. I usually show up on the scene about 2 to 3 weeks early. You should see periodic airplanes moving to and fro and, little blue markers on the map. If not, look for red colored smoke (though in reality, I believe green phosphorescence was the actual color that downed U.S. pilots used). You don't need to sit on the icon, if there's nothing happening, you might be too early. You'll need to travel to the red smoke markers in order to rescue the pilots. When you see the smoke, go to that location and use your binoculars (go to bridge and scroll your mouse wheel forward). As you close in on the pilot, you'll need to slow down. Keep your binoculars focused on the pilot and eventually, the lifesaver button will light up, allowing you to complete the rescue. Usually, you must rescue at least 5 pilots before the mission completes. When you begin rescuing them, make sure you go to general quarters or have your crew man the anti-aircraft guns. Let them handle the planes while you concentrate on the rescues. Due to enemy aircraft, your probably better off recuing them at night. The planes won't be able to see you on the surface at night.
Just patrol around the star in a 50 Nm. radius, you should see smoke soon.
The icon will eventually turn gray some time after the 19 th. and you have completed the mission.
Highlight the survivors in the binoculars and click on the pick up survivors icon.
OOPS I see WVT beat me too it again, always good advice from him.