Opinion ID: 1404383
Heading Depth: 3
Heading Rank: 2

Heading: The Requirement to Power-Down in Significant Surface Ducting Conditions

Text: We next consider the requirement that the Navy power-down its sonar use by 6 dB when significant surface ducting conditions are detected. Although the Navy stresses the importance of training in surface ducting conditions, it admitsโand the record confirmsโthat such conditions occur relatively rarely in the southern California waters in which the Navy has chosen to conduct its exercises. Indeed, the after action reports from JTFEX and COMPTUEX exercises conducted in the Southern California Operating Area in 2006 show that significant surface ducting conditions were not detected during any of those exercises. Yet despite the strike groups' inability to train under such conditions, the Navy certified them. The record, then, undermines the Navy's contention that the district court's mitigation measure regarding surface ducting conditions will significantly impact its ability to certify strike groups. Thus, although the actual effect of the challenged mitigation measures on the exercises at issue is necessarily speculative, data from past Navy exercises and practices supports the district court's conclusion that the imposition of these measures is not likely to prevent effective training and certification of strike groups. After a thorough review of this record, we are not left with the definite and firm conviction that a mistake has been committed. Sports Form, Inc., 686 F.2d at 752. To the contrary, there is significant evidence of the Navy's ability to successfully train and certify its strike groups under the conditions imposed by the district court. We therefore conclude that the district court did not abuse its discretion in ordering the Navy to comply with the challenged mitigation measures.