What happened
The aircraft was engaged in a banner towing operation along the coastline when it encountered severe weather conditions that led to a crash into the water. According to the pilot's account, he had noticed thunderstorms forming inland approximately thirty minutes before the incident occurred. Despite this early warning, the storm system moved faster than anticipated, overtaking the aircraft before the pilot could return to his base of operations.
Upon realizing the severity of the approaching weather, the pilot attempted to escape the deteriorating conditions. He applied full power and released the tow banner in an effort to lighten the load and gain altitude. However, the aircraft was caught in a strong downdraft associated with the thunderstorm. This sudden vertical wind shear caused a rapid sink rate that the pilot was unable to arrest, resulting in the aircraft impacting the water surface.
The investigation
Following the accident, investigators reviewed the pilot's statements regarding his awareness of weather avoidance protocols. The pilot confirmed that he was familiar with the thunderstorm avoidance procedures outlined in the Airman's Information Manual. However, he explained that operational pressures prevented him from suspending banner towing activities solely because a storm was located within ten miles of the active operations area.
Findings
The primary factor in this accident was the strong downdraft encountered during the thunderstorm. The pilot's decision to continue operations despite observing developing storms inland contributed to the inability to avoid the hazardous weather conditions. The aircraft was unable to maintain sufficient altitude to clear the water surface after the downdraft impacted the flight path.