At 12:03 CDT, a Mooney M20B and a Cessna 172P collided while on final approach to runway 17 at the Mesquite Metro Airport. The two occupants of the Mooney were killed; the pilot in the Cessna sustained minor injuries, while his flight instructor escaped without injuries. The flight instructor in the Cessna 172 said they were on their third practice ILS approach to runway 17 when the accident occurred. He said he made a radio call on Unicom when the Cessna was over the outer marker inbound. The instructor further stated that that point he heard the Mooney pilot announcing that he was entering the traffic pattern on a left downwind. The flight instructor stated that he was unable to make visual contact with the Mooney. The flight instructor last announced his position on the Unicom when the airplane was 1.5 miles out on final approach for runway 17. Another pilot in the traffic pattern acknowledge that both other pilots in the pattern were announcing their position and intentions on the Unicom.