NTSB Identification: CEN09MA019
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Wednesday, October 15, 2008 in Aurora, IL
Probable Cause Approval Date: 03/11/2010
Aircraft: BELL 222, registration: N992AA
Injuries: 4 Fatal.

NTSB investigators traveled in support of this investigation and used data obtained from various sources to prepare this aircraft accident report.

The emergency medical services (EMS) helicopter was on a night cross-country flight in visual meteorological conditions and was transporting an infant patient from one hospital to another when the accident occurred. During the flight, the pilot contacted DuPage Airport’s (DPA) air traffic control (ATC) facility, reported the helicopter's position and altitude of 1,400 feet above mean sea level (about 700 feet above ground level in Aurora, Illinois) to the air traffic controller, and asked permission to pass through the airspace surrounding the airport. The controller acknowledged the transmission and cleared the helicopter through DPA’s airspace but did not give the pilot specific instructions regarding his flight route because the pilot was flying under visual flight rules and had chosen his specific route of flight on a direct course from the departure point to the destination. (During preflight planning, the pilot should have identified the obstacles along the route of flight, including the radio station tower.) Subsequently, the helicopter struck a radio station tower while flying at the same altitude that had been reported to ATC. Video and still image evidence obtained during the investigation indicated that the strobe lights attached to the radio station tower were operational at the time of the accident.

The accident helicopter was not equipped with a terrain awareness and warning system (TAWS). TAWS detects terrain or other obstructions along the flightpath and provides pilots with an alert to take corrective action. On February 7, 2006, the National Transportation Safety Board (NTSB) issued Safety Recommendation A-06-15, which asked the Federal Aviation Administration (FAA) to require EMS operators to install terrain awareness and warning systems on their aircraft and to provide adequate training to ensure that flight crews are capable of using the systems to safely conduct EMS operations. The FAA responded that, while it would work with industry to address issues related to the installation of TAWS on EMS aircraft, it would address the issue of controlled flight into terrain by emphasizing effective preflight planning. The FAA further stated that the Radio Technical Commission for Aeronautics established a committee tasked with developing helicopter TAWS (H-TAWS) standards and that, in March 2008, the commission completed the development of minimum operational performance standards for H-TAWS. On December 17, 2008, the FAA published Technical Standard Order C194, “Helicopter Terrain Awareness and Warning System,” based on the commission standards. On January 23, 2009, the NTSB indicated that the continuing delays in development of a final rule to require H-TAWS were not acceptable. Pending issuance of a final rule to mandate the installation and use of TAWS on all EMS flights, Safety Recommendation A-06-15 was classified “Open—Unacceptable Response.” On November 4, 2009, the FAA responded by indicating that it was developing a notice of proposed rulemaking (NPRM) to address this recommendation and that it planned to complete work on the NPRM in January 2010; the NPRM had not been issued as of March 2010. On November 13, 2009, the NTSB reiterated Safety Recommendation A-06-15 in its report regarding the September 27, 2008, accident involving an Aerospatiale SA365N1, N92MD, operated by the Maryland State Police, which crashed during approach to landing near District Heights, Maryland. Safety Recommendation A-06-15 is on the NTSB’s Most Wanted List of Transportation Safety Improvements.

The radio station tower was depicted on the Chicago Aeronautical Sectional Chart, the Chicago Visual Flight Rules Terminal Area Chart, the Chicago Helicopter Route Chart, and as an obstruction on the air traffic controller’s radar display. Radar data obtained during the investigation showed the helicopter at a constant altitude and on a straight course to the point of impact with the tower.

The radar information was available to the air traffic controller. Additionally, the position and height of the tower were included in training materials that were to be memorized by the controllers at the ATC facility. According to interviews conducted of the controller on duty at the time of the accident, the accident helicopter was the only aircraft traffic in the area at the time. The controller reported that he was attending to administrative duties at the time that the accident occurred. FAA Order 7110.65, “Air Traffic Control,” paragraph 2-1-2, Duty Priority, states that issuance of safety alerts to aircraft takes first priority over other duties. Further, FAA Order 7110.65, paragraph 2 1-6, Safety Alert, states that controllers should issue a safety alert to an aircraft if they are aware that the aircraft is at an altitude that places it in an unsafe proximity to terrain, obstructions, or other aircraft and notes that “while a controller cannot see immediately the development of every situation where a safety alert must be issued, the controller must remain vigilant for such situations and issue a safety alert when the situation is recognized.” Evidence such as the controller’s failure to notice when the helicopter disappeared from the radar display after striking the antenna indicates that the controller was not monitoring the aircraft’s progress sufficiently to watch for hazards and issue safety alerts as required. While the NTSB recognizes that it was the pilot’s responsibility to “see and avoid” the radio tower, the controller also had a responsibility to issue an alert as required by FAA directives. Review of recorded communications showed that no warnings were issued to the pilot before the accident.

In addition, on August 28, 2007, as a result of an accident involving a Bombardier CL 600-2B19, N431CA, that crashed during takeoff from Blue Grass Airport, Lexington, Kentucky, the NTSB issued Safety Recommendation A-07-48, which asked the FAA to revise Federal Aviation Administration Order 7110.65, “Air Traffic Control,” to indicate that controllers should refrain from performing administrative tasks when moving aircraft are in the controller’s area of responsibility. The FAA responded that it would convene an internal work group to review the safety issues identified in this recommendation as they relate to ATC responsibilities and the impact of reassigning those duties to another position. This recommendation was classified “Open—Acceptable Response” on August 22, 2008. On April 10, 2007, the NTSB issued Safety Recommendation A-07-34 also as a result of the Lexington, Kentucky, accident, which asked the FAA to require all air traffic controllers to complete instructor-led initial and recurrent training in resource management skills that will improve controller judgment, vigilance, and safety awareness. The FAA responded that it had delivered crew resource management workshops, posters, and follow-up support to some larger ATC facilities. The NTSB responded that it was encouraged by the FAA’s actions but that such training should also be provided at smaller ATC facilities. This recommendation was classified “Open—Acceptable Response” on August 28, 2007. On January 15, 2009, the FAA responded that it was conducting training for controllers at larger facilities but did not indicate how it would perform training at smaller facilities.

Vice Chairman Hart did not approve this brief and filed a dissenting statement. The statement can be found in the public docket for this accident.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's failure to maintain clearance from the 734-foot-tall lighted tower during the visual night flight due to inadequate preflight planning, insufficient altitude, and a flight route too low to clear the tower. Contributing to the accident was the air traffic controller's failure to issue a safety alert as required by Federal Aviation Administration Order 7110.65, “Air Traffic Control.”


Vice Chairman Hart did not approve this probable cause and filed a dissenting statement. The statement can be found in the public docket for this accident.

Full narrative available

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