Last month, the Illinois Department of Transportation gave the green light to the heliport plan.
But residents of the Streeterville neighborhood on the Near North Side who oppose the project have formally appealed to IDOT to reconsider. They say state transportation officials showed a clear bias in favor of the project before public hearings were held.
The residents also say officials never completed a thorough safety analysis. They claim transportation officials ignored a city requirement that an alternative landing site be available for aborted landings.
State transportation officials have 20 days to respond to the appeal.
The new children's hospital opens June 9.
A hospital spokesperson says it is confident IDOT made the right decision on its heliport.