Rescue workers suspended their search for an airplane believed to have crashed into Santa Monica Bay six days ago but continued looking in the Lake Arrowhead area for another plane missing for seven days. No trace was found of a Piper Seminole that disappeared over the ocean with instructor-pilot William Cody, 23, of Northridge, and Ed Grinstead, 25, of Texas. Civil Air Patrol volunteers continued to search the San Gabriel and San Bernardino mountains for a Cessna 206 that carried John and Pat Morrow of Yorba Linda and their three miniature poodles. CAP Lt. Col. Myron Rogers said several emergency landing system distress signals have been heard in the last week. Ten of those were found to be false alarms, but a faint signal picked up in the Lake Arrowhead area has fueled hope that the plane might be found there.