President Obama’s 180-day moratorium on new permits for Gulf of Mexico deepwater drilling is beginning to pinch helicopter operators in the region. Bristow Group said the action, triggered by the Deepwater Horizon explosion, was forcing its customers to release seven helicopters used to fly support missions at a cost of $3.8 million a month; however, oil-spill-control flights operated on behalf of BP are largely offsetting this loss in the short term.