Accident Overview
On March 24, 2019, at about 1101 eastern daylight time, a Pilatus PC-12/45, registration N944BT, was substantially damaged when the pilot-side windshield shattered while the aircraft was climbing near Fort Lauderdale, Florida. The commercial pilot and two passengers were not injured. Visual meteorological conditions prevailed, and the flight operated under an instrument flight plan. The aircraft had departed from Fort Lauderdale Executive Airport (FXE) and was en route to Moore-Murrell Airport (MOR) in Morristown, Tennessee, for a personal flight conducted under 14 CFR Part 91.
Pilot and Aircraft Information
The pilot held a commercial pilot certificate with ratings for airplane single-engine land, single-engine sea, and multi-engine land. His most recent FAA third-class medical certificate was issued on November 15, 2017. He reported 9,000 total flight hours, with 2,600 hours in the PC-12. The aircraft was manufactured in 2002 and was powered by a Pratt and Whitney PT6A-67 engine producing 1,250 horsepower, equipped with a four-bladed Hartzell propeller. Its most recent annual inspection was completed on January 15, 2019.
Events During Flight
According to the pilot, while climbing through 20,000 feet, he heard a loud bang and the pilot-side windshield shattered. He immediately notified air traffic control that he was returning to FXE and needed to descend. After landing without incident, he examined the windshield and observed that the seal was extruded in two places around the outer pane.
Examination Findings
An FAA inspector examined the aircraft and found that the pilot-side windshield was shattered but remained attached. The bottom left corner and upper corner of the windshield were pushed outward, and the seal around the windshield was torn. The lower left heating element showed signs of burning.
The windshield was sent to the manufacturer for further analysis. Examination revealed that about 80% of the fiberglass straps were missing, having been removed by maintenance personnel. The absence of these straps caused the outboard ply to become detached from the edge attachment. Moisture then entered the bottom aft edge, leading to delamination and subsequent arcing.
Maintenance Records
Investigators were unable to determine when the straps were removed, as no record of this maintenance was found in the airframe logbooks. The Pilatus Windows Inspection Check referenced the PPG service information letter, which specifically states that the straps should not be removed but rather repaired in accordance with the prescribed maintenance plan.