PHOENIX — Federal investigators say a pilot flew a medical helicopter beyond its capabilities on a high-speed, low-level flight across mountainous east-central Arizona before it hit a slope on a ridge, killing two of the crew members aboard.
A National Transportation Safety Board final report on the Dec. 15, 2015, crash said the pilot lost control of the helicopter as the combination of high speed and other factors overtaxed the hydraulics system, causing a phenomenon known as servo transparency.
After the Native Air Ambulance flight operated by Air Methods Corp. cleared one ridgeline on a flight from Mesa back to its base in Globe, it descended and accelerated before crew members saw another ridge directly in its path, according to the NTSB report released Monday.
"According to the paramedic, around this time, the pilot said an expletive in a panicked voice. The paramedic looked up and saw a ridgeline immediately in their path and terrain filling up the view," the report continued.
The Airbus AS350 helicopter banked hard to the right and partially broke apart when it crashed about 15 miles east of Globe, the report said. Air Methods did not immediately respond to a request by The Associated Press for comment on the NTSB findings, but the company headquartered in Englewood, Colorado, previously said regarding the crash that it always followed the "highest safety standards."
The paramedic, Derek Boehm, was severely injured and survived the crash. Pilot David Schneider, 51, died soon after the crash while flight nurse Chad Frary remained alive longer but died before rescuers arrived.
The report said Air Method operations controllers in Denver didn't notice for about two hours that the helicopter was missing, delaying the start of an aerial search.
However, Frary's severe injuries and other circumstances made it unlikely he would have survived even with timely notification of the crash, the report said.
Schneider was an experienced pilot with 5,670 flight hours, including 2,117 in the make and model of the helicopter that crashed. A civilian air-evacuation helicopter and an Arizona Department of Public Safety helicopter located the crash wreckage about 12 miles north of Superior about two hours after the Native Air helicopter was reported missing.
Those helicopters were able to put emergency personnel on the ground, but they lacked the hoist capability to extract Boehm.
However, an Air Force rescue helicopter from Davis-Monthan Air Force Base in Tucson happened to be nearby and was able to head to the crash site, put two rescue officers on the ground and pick up Boehm about four hours after the crash.