That's because one of the choppers, called a BK-17, crash-landed on UC's helipad early Sunday morning.

The National Transportation Safety Board will be at University Hospital Monday to figure out what went wrong with the helicopter. This means that without the helicopters, it's taking rescue crews longer to respond to emergencies.

"Just as he was making his final approach, he heard a loud bang coming from the back of the aircraft," said Dudley Smith, UC Hospital's director of air care.

Smith said about 50 feet above the helipad, something went wrong with the chopper's tail rotor.

Pilot John Robinson had just flown a heart attack patient to Christ Hospital, and picked up a full tank of fuel when it happened.

"The pilot's reaction time has to be really fast," said Chopper 9 Pilot Dale Williams.

Williams, a Gulf War veteran, said rotor problems can mean disaster. But he also said the pilot made all the right moves to get the chopper down in such a tight spot.

Now, the Federal Aviation Administration and the NTSB is investigating what happened. That means, while they investigate, the heliport is closed, and the choppers, grounded.

University Hospital must now call on other hospital choppers in Dayton, Columbus, even Lexington and Louisville, which means response time to local emergencies will be longer.

"It will mean a little bit of a time delay for the patients," Smith said. "But we work cooperatively all the time. There is frequently times we can't make a flight because we have more flight request than aircraft, so we back each other up all the time."

Now, the question is how long it will take the other flight crews to respond.

"Care Flight" crews at Miami Valley Hospital in Dayton said it normally takes them five to seven minutes to get to an emergency in the Dayton area, and it takes them about 18 minutes to fly to the Cincinnati area.