Final report of fatal HEMS crash in Florida

On 28 August 2023, an Airbus EC135 helicopter from the Broward County Sheriff’s Office was dispatched from Pompano Beach Airpark at 08:44 hrs local time to attend the scene of a road traffic incident.

Approximately 67 seconds after liftoff, the No. 1 electronic engine control unit reported a simultaneous double N1 and double N2 failure, which should have result in a ‘FADEC FAIL’ cockpit caution; however, the pilot reported that he was alerted to no indication of this warning. The full authority digital engine control (FADEC) is an engine management system that automatically controls the engine’s performance, including fuel flow, ignition, and power output, to ensure optimal performance, fuel efficiency, and safe operation, and a failure of the double N1 and double N2 would have meant that the fuel control unit would have frozen fuel flow at the time of the failure until the end of the flight, which was at a climb power setting, 123L/hr. Because of the FADEC failure, the only way to reduce power would have been a manual throttle closure and not via a switch.

Twenty-three seconds later, while at 300–400ft above ground level (AGL), the pilot reported that he heard a loud bang, and he noted that the turbine outlet temperature (TOT) on the No. 1 engine was rising, although still within limits. At this point the pilot set the engine to idle, reported the emergency and started to return to the airport. However, as mentioned, the FADEC failure meant that the idling was ineffective, unbeknown to the pilot. Regardless of the failure, a full flow of fuel to the engine would not be expected to result in overheating the engine. The pilot then noted that an engine fire warning light was shown on the cockpit panel and he stated that he initiated the fire suppression system; however, the investigation revealed that the button was not pressed. Regardless, even if the suppression system had been used, the fire was outside of the engine bay and the system would have had no effect. The TOT showed that exhaust gases had reached over 1,000°C, which would not have been withstood by the turbine blades, but certainly could not have been resisted by the fiberglass air-conditioner housing and the composite tail boom structure in the direct path of the gases. Furthermore, as there are no indicators available to the pilot to show of a serious fire on the external structures, he would not have known the seriousness of the problem to then land the aircraft immediately.

About 90 seconds after the first bang, a second bang was heard, and this was the partial separation of the tail boom, compromising the Fenestron and causing an uncontrolled descent into an apartment, killing one resident and one of the flight paramedics.

The fire following the crash itself meant evidence was destroyed, making further investigation into the cause of the engine overheating impossible, and the cause only open to speculation.

This fatal accident was the result of a chain of failures, each leading to something more severe until the ultimate terrible outcome.

The full report can be found here:

https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192950/pdf#:~:text=1%20engine%20for%20undetermined%20reasons,in%20a%20partial%20tailboom%20separation.&text=On%20August%2028%2C%202023%2C%20about,accident%20near%20Pompano%20Beach%2C%20Florida

A fatal crash of a fixed-wing air ambulance occurred in Arizona recently.