WEEK 12
H2F brings you the ‘helicopter mayday of the week’ with a short accident report summary. I tell you what happened. You think more about why it happened. We all learn from it. Because that’s what accident reporting is for.
TITLE
In-flight engine fire leads to tail boom separation.
WHAT?
An EC135 air medical helicopter departed Pompano Beach Airpark inbound to a car accident. One minute after takeoff onboard data recorded a simultaneous double N1 and N2 failure of the No. 1 engine’s electronic engine control unit. After 90 seconds, while at 300–400 ft above ground level, the pilot heard a bang and observed rising turbine temperature on the No. 1 engine. An in-flight fire warning lit due to fire around the No. 1 engine exhaust spreading beyond the firewall. Subsequent tail boom separation caused an uncontrolled spinning descent into an apartment building.
WHERE?
Shortly after departure from Pompano Beach, Florida, in a residential area approximately 1 nautical mile from the airport.
WHEN?
August 28, 2023. The NTSB final report was published on September 11, 2025.
HOW?
The double EECU failure shortly after departure froze the fuel control unit at (high) climb power setting. When the pilot later set the No. 1 throttle to idle, it had no effect as it needed to be done manually on the throttle twist grip, and high pressure fuel continued to flow to the engine. The pilot declared an emergency and turned back toward the airport. Then the No. 1 engine fire button illuminated. Although the pilot stated he pressed it, post-accident evidence indicated it was probably not actuated. There was no fire inside the engine, however the turbine temperature reached nearly 1300°C, superheating exhaust gases to over 1,000°C. The gases were probably responsible for igniting adjacent fibreglass and composite structures outside the engine compartment which were not certified to withstand such high temperatures. The fire quickly spread to the tail-boom attachment area, resulting in partial separation and loss of control.
CONDITIONS?
An air-conditioning system had recently been installed which was cased in fiberglass and located near the No.1 engine exhaust. The hot fibreglass ignited meaning that the fire probably originated outside the engine firewalls whereas the fire suppression system was designed for the engine compartment. The emergency locator transmitter did not activate after the crash.
OUTCOME?
The helicopter was destroyed by impact and post-crash fire, falling in to a residential area. One paramedic onboard and one apartment resident were fatally injured with more residents injured. A second paramedic sustained serious injuries, and the pilot sustained minor injuries.
WHY?
- In-flight fire outside the engine firewalls.
- Overheating of the No. 1 engine for undetermined reasons associated with fuel control fault.
- Exhaust gases exceeded structural temperature limits near composite and fibreglass components.
- Partial tail boom separation resulting from fire damage.
- Loss of helicopter control following structural failure.
REFERENCE?
National Transportation Safety Board. (2025, September 11). Aviation investigation final report: Accident number ERA23FA352 (Eurocopter EC135T1, N109BC). National Transportation Safety Board. https://data.ntsb.gov/Docket?ProjectID=192950
Note:
Accident reports selected from the following open source databases: US NTSB; UK AAIB; Flight Safety Foundation’s Aviation Safety Network; Australia’s ATSB. Ireland’s AAIU; Taiwan’s TTSB; France’s BEA; Spain’s CIAIAC. Germany’s BFU.
competentaviators.com 