A retired Air Force colonel with decades of experience as a flight instructor gave one of his students a hands-on lesson in a key principle of flying: Don't run out of gas. Al Uhalt of Colorado Springs made a bumpy but safe landing in a field Thursday when the single-engine Aviat Husky he and a student were flying ran out of fuel near the end of a 45-minute lesson. Neither Uhalt nor the student, 16-year-old Kyle Sundman, was injured and the plane was undamaged.