Sergeant Norman Piepenbrink, Serial No. 6090, was killed in a helicopter accident while working as an observer with Pilot Willard J. Lehman. The officers were conducting freeway traffic patrol in a Bell 47J helicopter. Piepenbrink, the Officer-in-Charge of the helicopter unit (Air Support Division), departed with Pilot Lehman from the Los Angeles County Sheriff's Department helipad at the Biscailuz Center. Immediately after departure, the aircrew overheard three loud, distinct thumps. The helicopter subsequently crashed, badly burning both Piepenbrink and Lehman.

An investigation revealed that the six rotor driving flange screws in the main rotor transmission had failed. This failure allowed the transmission rotor driving flange to become uncoupled from the transmission upper spider, causing a complete loss of engine torque to the main rotor. The six screws fractured from a static shear overload, resulting in a forced landing on unsuitable terrain. The aircraft was destroyed and Piepenbrink died three days later of his injuries. Officer Lehman survived.

Sergeant Piepenbrink had served with the agency for 18 years. He was survived by his wife and son.