Pilot incapacitation named probable cause of fatal CBP helicopter crash

A pilot’s unexplained incapacitation caused a US Customs and Border Protection (CBP) Airbus AS350 B3 to lose control and crash near Potrero, California, on 16 December 2024, the US National Transportation Safety Board (NTSB) has determined.

The NTSB’s final report into the accident, published on 23 September 2026, found no mechanical malfunction or evidence of an external collision. The 53-year-old pilot had severe coronary artery disease and heart damage, while an autopsy could not rule out a heart rhythm disturbance, heart attack or stroke.

Investigators also considered whether the pilot fell asleep after taking the sedating antihistamines diphenhydramine and doxylamine, or because of fatigue following a recent respiratory illness. However, they could not determine the cause of incapacitation.

Federal Aviation Administration (FAA) toxicology testing detected both antihistamines. The FAA advises pilots not to fly within 60 hours of taking either drug, but investigators could not establish when they had been taken.

The helicopter departed Brown Field Municipal Airport in San Diego at about 08:56 hrs on a routine air-support mission. After around 90 minutes of stable flight, it entered two S-turns while descending from 4,200 to 3,100ft. Recorded descent rates exceeded 12,000ft per minute before the aircraft struck the ground.