Corrected entry: When the sandstorm covers the plane with sand, all the characters have their eyes covered with goggles, but their ears and noses are not covered. Seems they are able to hear and breathe just fine with all that sand going into their nostrils, ears and mouths after they crash land in the desert. You can see Rick is able to talk to Ardeth and Jonathan while they are traveling inside the sand storm.
XIII
12th Sep 2012
Correction: It was be human instinct to close ones mouth if caught in a sandstorm. I assume that these characters would do the same. I have never heard of someone going deaf or have their noses completely blocked by sand. Unless you see otherwise (shown on screen) we can easily presume that they are not affected by the mystical sandstorm.
XIII