When 42nd Ward alderman Brendan Reilly agreed last month to back plans by Children’s Memorial Hospital to build a new facility downtown, he had one condition: that hospital officials review the safety of a proposed rooftop helipad with a pair of outside experts hired by area residents.

Mayor Daley responded a couple days later by suggesting that Reilly and critics of the plan were more concerned about noise the helicopters would make than about the lives of children. In a subsequent interview, Reilly politely returned the put-down. “I knew the mayor was supportive of the helipad portion of the project,” Reilly said. “Our only real difference of opinion here is that I think the city has an obligation to show that this is not a risk to public safety before we approve it.”

Behind the political jousting, there do appear to be serious questions. The two experts commissioned by the Streeterville Organization of Active Residents (SOAR) are not exactly slouches. One of them, Mark Eugene Doub, is a former aircraft accident investigator and trainer for the U.S. Department of Transportation; the other, Thomas C. Corke, is a professor of aerospace and mechanical engineering at Notre Dame. 

The hospital’s plan [PDF] “paints a very rosy picture of rooftop heliport operations” though it would require pilots to “fly into a hostile physical environment,” Doub writes in his analysis. According to him, the hospital’s plan doesn’t provide adequate emergency landing space, and the proposed helipad is too small and, at 411 feet, too high to be safe for certain helicopters and weather conditions. He concludes that “Children’s Memorial Hospital has not addressed all of the issues necessary to operate this heliport in a manner consistent with current aviation safety practices.”

Corke focuses on a study of area wind patterns commissioned by the hospital. Parts of the hospital’s study, Corke writes, “are contrary to all good engineering approaches” and simply lack reliable data. This study “cannot be used by anyone—including Children’s Memorial Hospital or the City of Chicago—to conclude that it would be safe to use the proposed rooftop airport.”

Julie Pesch, a spokesman for the hospital, notes that its wind study was conducted by Rowan Williams Davies Irwin, a renowned international wind and environmental engineering firm, and that leading aviation consultant and airport planner Landrum & Brown also worked on the helipad plan. “They tell us it’s safe,” she says. “Safety is always our biggest concern.”

She adds that neither Doub nor Corke actually collected data on the conditions of the area—they simply reviewed and critiqued what the hospital's consultants did. “It’s not like they went out and did their own noise and wind studies.”

The City Council’s Committee on Zoning is scheduled to consider the plan on January 24, and if it passes, the full council could vote on it as soon as February. At that point, Pesch says, the Illinois Department of Transportation would conduct its own safety analysis. “But they can’t do it unless the city allows us to build.”

Traditionally the City Council doesn’t approve projects that don’t have the local alderman’s consent, but if Reilly ends up rejecting the helipad plan—he says he doesn't expect to, though the conversation he asked for hasn’t taken place so far—Daley might start lining up the votes to go around him.

Pesch doesn’t foresee any snags. “We’re confident we’ll be allowed to have the heliport,” she says.