Ron, The town has reviewed the plans. The plans indicate a trench drain along the area where the concrete was poured to the incorrect elevations. However, there is no indication of how the trench drain will discharge. If it is constructed as designed, the trench drain will terminate in the dirt. When it rains it will overflow into the hangar, which is not an acceptable solution. We recommend the following procedure for correcting the problem: 1. Remove all the dirt in the area next to the hangar down to 4” beneath the pipe that currently terminates in this area. 2. Fill the area with concrete in accordance with the engineering details for the sidewalk. Slope from the edge of the existing concrete down to the bottom of the pipe that has the grate cap on the end of it except in the area where the trench drain terminates (it will need to slope from the bottom of the trench drain down to the pipe with the grate cap on the end of it). If this procedure is adhered to, it will not be necessary to revise the engineering drawings. Contact me prior to any pours, concrete cuts or installation of the trench drain. The town will submit the ACO drain to Garver to insure that it is aircraft compliant. If you have any questions, please let me know. Thanks, Clay Barnett, P.E. Town Engineer Town of Addison 16801 Westgrove Drive Addison, TX 75001-2818 Office: (972) 450-2857