Air Angels Helicopter Went Down At Night, Killing 4

The NTSB has released a probable cause report in a medical helicopter accident which killed four people in October, 2008. The board found that the probable cause was 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 Christopher  Hart did not approve this probable cause and filed a dissenting statement.

In the probable cause report, the NTSB said 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 (KDPA) 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). On February 7, 2006, the NTSB issued Safety Recommendation A-06-15, which asked the 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 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 his dissent, Vice Chairman Hart (pictured) wrote, in part:
"I respectfully disapprove this Notation item because it includes the controller in the probable cause. In my view, the result that is optimal for the safety of the aviation system is that VFR pilots should continue to receive the clear, unambiguous, and unequivocal message. That for VFR pilots, seeing and avoiding obstacles is solely and exclusively the responsibility of the pilot in command . . . with no exceptions.

That means no exceptions irrespective of any condition or circumstance, including, in this case:

• Whether the controller’s workload is light (which the pilot probably would not know).
• Whether the controller has the appropriate equipment (which the pilot probably would not know) to display that an aircraft is near an obstacle.
• The weather (which would at least have to be VMC, lest the pilot is not appropriately VFR).
• Whether it is day or night."

"(C)ontroller assistance for VFR pilots is completely voluntary and discretionary. Thus, if agreeing to help a VFR pilot avoid other aircraft forces a controller also to accept the responsibility to help the pilot avoid obstacles, controllers would be less willing to provide any assistance to VFR pilots. Because controllers with radar can see other airplanes much better than pilots can visually, and because it is far more difficult for pilots to see and avoid other airplanes than to see and avoid obstacles, the controller assistance that is most valuable and beneficial to VFR pilots, by far, is separating them from other airplanes. To the extent that the added responsibility for obstacle avoidance causes controllers to be reluctant to provide any services to VFR pilots, VFR pilots will lose the benefit of the far more valuable separation services, causing reduced safety due to the increased likelihood of mid-air collisions."

FMI: www.ntsb.gov