ERA19LA137

During the climb to cruise altitude on a cross-country flight, the pilot heard a loud bang and the pilot's side windshield shattered and the cabin began depressurizing. The pilot returned to the departure airport and landed uneventfully, where he noticed that the seal was extruded in two places around the outer pane. The windshield was sent to the manufacturer for a detailed examination, which revealed that 80% of the fiberglass straps were missing, and they were likely removed by maintenance personnel. A combination of missing straps and heavy delamination caused the outboard ply to become detached from the edge attachment. Moisture ingress at the bottom aft edge caused delamination and arcing. There was no record in the airframe logbook of the straps’ removal.

On March 24, 2019, about 1101 eastern daylight time, a Pilatus PC-12/45, N944BT, was substantially damaged when the pilot's windshield shattered while flying near Fort Lauderdale, Florida. The commercial pilot and two passengers were not injured. Visual meteorological conditions prevailed, and an instrument flight plan was filed for the flight that originated from the Fort Lauderdale Executive Airport (FXE), Fort Lauderdale, Florida, and was destined for Moore-Murrell Airport (MOR), Morristown, Tennessee. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. According to the pilot, he was climbing through 20,000 ft when 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 uneventfully, he examined the windshield and noticed that the seal was extruded in two places around the outer pane. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the pilot-side windshield was shattered but was still attached to the airplane. 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 was burnt. The windshield was sent to the manufacturer for further examination. The examination revealed that about 80% of the fiberglass straps were missing and had been removed by maintenance personnel. The missing straps caused the outboard ply to become detached from the edge attachment. Moisture was then able to ingress the bottom aft edge causing delamination and then allowing arcing to occur. Investigators were unable to determine when these straps were removed, as there was no record of this maintenance in the airframe logbooks. The Pilatus Windows Inspection Check referred to the PPG service information letter which states specifically the straps should not be removed, rather repaired following their prescribed maintenance plan. 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 hours of flight experience, of which 2,600 hours were in the PC-12. The airplane was manufactured in 2002. It was powered by a Pratt and Whitney PT6A-67, 1,250-horsepower engine, equipped with a four-bladed Hartzell propeller. Its most recent annual inspection was completed on January 15, 2019.