On September 25, 1984, a Hiller UH12ET (registration N9278Z) was involved in an aviation accident near Yuma, AZ. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During low-level pesticide application, a helicopter became uncontrollable and crashed. Post-accident examination revealed a main rotor blade had separated in flight due to fatigue fracture and corrosion.
Accident Details
The pilot was conducting an agricultural application flight, carrying a load of pesticide for application on a broccoli field. The aircraft was in level flight at an altitude of approximately 4 to 8 feet above ground level when it became uncontrollable and impacted the ground. A post-crash fire consumed the aircraft.
Examination Findings
Examination of the wreckage revealed that one of the two main rotor blades had separated in flight. The separated rotor blade exhibited a fatigue-type fracture of the main rotor blade spar tube through the outboard retention bolt holes. Additionally, the failed main rotor blade spar bore evidence of corrosion.
Airworthiness Directive Compliance
The main rotor blade cuff was the subject of an airworthiness directive (AD). According to the aircraft logbooks, the AD had been complied with as required. However, the last three logbook notations documenting compliance with the AD were entered after the accident.