All Air Angel operations have been suspended while the National Transportation Safety Board investigates (NTSB).
NTSB investigators spent much of Thursday at the crash site and will move on to look at the debris which has been moved to a nearby airport hangar. They're trying to figure out if it was pilot error, engine failure, or other mechanical problems that led to the accident.
In the meantime, there are other concerns for neighbors and neighborhoods that are near this radio tower that was part of the accident.
Aurora police officers asked hundreds of residents who live within 1,000 feet of a damaged radio tower to evacuate Thursday night. Most followed the advice.
"The officer told us if we are in that range, then we will leave. I wouldn't want to take any chances with my family," said Jason Jamrowski, evacuee.
Residents hope to return home Friday night.
While the investigation into the cause of the crash continues, investigators say it appears the helicopter clipped a wire on a 750-foot tall radio tower before going down in a field.
Officials say the Air Angels crew was transporting 14-month-old Kirstin Blockinger from Valley West Hospital in Sandwich, Illinois, to Chicago's Children's Memorial Hospital when the helicopter went down near Eola Road and Liberty Street around midnight.
Police say all four people -- William Mann, 31, of Chicago, Dell Waugh, 69, of Carmel, Ind., Ronald Battiato, 41, of Peotone, Ill., Kirstian Blockinger, 1, of Leland, Ill. -- onboard were killed. No one on the ground was hurt.
Early indications are the helicopter was flying about 50 feet below the top of the radio tower when it clipped a thick steel wire that's used to support the radio tower. Why was the pilot so close to a well-known transmission tower that was reportedly adequately lit at the time? Federal investigators can safely rule out weather, so now it comes down to pilot error or mechanical failure.
"There were four big pieces of the fuselage and an access door right over here," said Jason Clemens, neighborhood resident.
Chunks of the chopper rained down on a residential neighborhood that sits just south of the transmission tower the helicopter clipped.
On Thursday afternoon, crews hauled away what was left of the three-ton aircraft - including the main rotor-blade.
All are now pieces of a puzzle that federal investigators will try to solve.
"There are a few large pieces of the helicopter remaining but by and large it's in smaller pieces," said John Brannen, National Transportation Safety Board.
Investigators know so far that the Bell 222 helicopter was at most a dozen minutes into its flight from a hospital in Sandwich, Illinois to Children's Memorial in Lincoln Park.
"He hit the tower, there was a lot of sparks and smoke from the motor to the propeller is where it caught fire and it just went down," said Robert Frost, witness.
Local pilots say it's one of about 10 towers in the Chicago-area - all well-known - that are tall enough to intrude on a helicopter's airspace.
Aviation maps of the area clearly show the 734 foot tall radio transmission tower in Aurora. Radar indicates the Air Angels chopper was at 700 feet and had communicated with air traffic controllers.
"We don't have any indication at this point that there was a distress call from the helicopter. As far as whether the helicopter was in distress and descending for that reason we can't speculate on that," said Brannen.
Local flyers say medical helicopters tend to fly between 500 and 700 feet above ground level so air pressure won't complicates a patient's condition.
Other helicopters, including Chopper 7, fly higher to more easily avoid ground obstacles.
None can go above 2,000 feet in most of the region to avoid commercial airliners headed for O'Hare and Midway.
Weather conditions Wednesday night were clear and residents report the radio tower's light beacons were working before the impact.
"That red light on top is constantly going. First thing I noticed was there was no more red light," Carolyn Constantino, witness.
The helicopter -- a Bell 222 -- was a part of the Air Angels air fleet. Agency officials say it had been in service for eight years and was considered a workhorse, making 40 to 50 transportations a month.
Investigators from the National Transportation Safety Board are working to determine exactly what caused the crash.
Sixty-nine year-old Delbert Waugh was at the controls of the helicopter that was carrying one-year-old Kirstian Blockinger to Children's Memorial Hospital.
Friends of Waugh describe him as a dedicated pilot who was passionate about his job saving lives. He had been flying for the air angels for about three years. The choppers fly out of Clowe Airport in Bolingbrook transporting patients to hospitals throughout the Chicago area. The pilots say they are tight-knit group with a camaraderie similar to a firehouse. They say Mr. Waugh was an outstanding man - in and out of the helicopter.
Dell Waugh was a Purple Heart veteran who served in Vietnam. He survived several crashes while he was in the military. He had been flying with the Air Angels for the past three years.
The pilots comforted each other outside their office Thursday as word spread, trying to understand how an accident like this could have happened to a pilot with so much experience.
Based on the history of what that guy has done in the military, all the flights he's done for Air Angels and all the other flying he's done, it would surprise me if it was a pilot error," said John Jacobe, friend.
The airport manager says Waugh was very familiar with the tower that reportedly the helicopter crashed into and that he had flown that route hundreds of times.
"They take this route all the time. They are always transporting back and forth. They knew where the tower was. Now, I don't know -- there is always a strobe on top of the tower and certain types of lighting on the guide wires and things like that. I don't know if these were lit, not lit. I don't know," said Joe DePaulo, airport manager.
Also Thursday in the small farming town of Leland, a community is grieving the loss of 14-month-old Kirstin Blockinger. Her family has lived in Leland for about two years - where several members of her family serve in the volunteer Fire Department.
"The father, grandfather, and aunt are members of the volunteer fire department and they're a nice family, they'll do anything they can for you," said Don Hecathorn, Leland fire chief.
"It was devastating that we lost four people of our country but really devastating when you lose a child that small," said Ernie Petty, family friend.
The girl's father, Robbie Blockinger, serves in the Illinois Guard. At the time of the accident he was in Kansas training for his second tour of duty in Iraq. Family members say he came home this morning to be with friends and family. According to the sheriff here, the family might make a statement sometime Friday.
"We love Kirstin and celebrate her life, however short. We ask for privacy to mourn our loss at this time," said Steve Ogletree, Kirstin's grandfather.
The family of 31-year-old William Mann of Chicago, a nurse and member of the Air Angels flight crew, says they received the call about the death of their loved one at close to 3 a.m. from Air Angels. Their son had worked as a nurse for 10 years in Houston and in Chicago and was dedicated to saving lives.
Family members are trying to deal with the tragic loss at a time when they were all planning a vacation together. Arlette Mann says her son wanted to be an Air Angel since he was twelve years old and that he was a parent's dream.
Mrs. Mann says that her son was going for his second interview at a hospital because she had begged him to get out of being an Air Angel because of all the recent medical crashes.
Ronald Battiato, the paramedic killed in the crash, was the father of six who also worked as a firefighter.
His wife Michelle had their sixth child in May. Battiato's sister-in-law said he always put others first.
Battiato, 41, was a firefighter and paramedic for 20 years, working for about 10 years in his hometown. The fire chief in Peotone says he remembers Battiato as a very caring person who took his job seriously.
He left the town to take on two full-time jobs, one with the South Chicago Heights Fire Department, the other with Air Angels.
His family includes six children, ages 15 to five month, as well as many relatives, who are remembering him as a hero.
A trust has been set up in his memory:
In care of Elizabeth Collins
Ronald Battiato Memorial Fund
Suburban Bank and Trust
400 West Lake Street
Elmhurst, IL 60126
There have been 12 crashes in the past 12 months in the U.S. involving medical transport helicopters, including one back in June. Six people died when two medical choppers crashed in mid-air over Flagstaff, Arizona. Both helicopters were headed to Flagstaff Medical Center. They were about a half mile away from that facility when they collided.
The most recent crash before Wednesday night's crash was outside of Washington DC. A helicopter carrying car accident victims crashed killing four out of the five people on board.
A spokesman for the NTSB says the agency will hold a public hearing on medical helicopter crashes sometime next year to gather more information about how the emergency helicopter services operate and how such accidents can be prevented.
Repairs will be made beginning Friday on the radio tower that the helicopter clipped. Investigators will try to determine if the tower's lights were on at the time of the crash. And the operator of the helicopter, Air angels, will suspend all flights while working with federal investigators.