On September 3, 2025, at 1211 central daylight time, an Israel Aerospace Industries Ltd. Gulfstream G150, N1927G, was substantially damaged when it was involved in an accident at Chicago Executive Airport (PWK), Wheeling, Illinois. The pilot and copilot were not injured. The flight was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 positioning flight. The pilots reported that on the morning of the accident, they completed a 14 CFR Part 135 charter flight from PWK to Baltimore/Washington International Airport, Baltimore, Maryland, where they dropped off their passengers. For the return flight to PWK, the pilot monitoring (PM), who was also a company check airman, was in the right seat. The copilot was the pilot flying (PF) in the left seat, and this was to be his first landing in the G150. Air traffic control cleared the flight for the RNAV (GPS) runway 30 circle to land runway 34 approach, and reported the runway was 100% wet with a runway condition code of 5-5-5. Due to the gusting crosswind, the pilots added 10 knots to referenced landing speed (Vref), and the PM stated that they used 128 knots as their landing speed. The PF stated that during the final approach the airspeed was a little fast. He added that he landed a little long in the touchdown zone then applied the brakes and deployed the thrust reversers. He felt an initial deceleration, then the airplane stopped decelerating, but he kept pressing the brakes and was pulling really hard on the thrust reverser handles. The PM stated that as the airplane crossed the runway threshold, the airspeed was a little fast and the PF flared a little high. He added that during the landing roll, the PF deployed the thrust reversers and applied the brakes. The airplane initially decelerated for a few seconds, but then stopped decelerating. The PM confirmed that the brake pedals were depressed to the floor. The airplane continued into the left side of the engineered materials arresting system (EMAS) at the end of the runway, then through the airport perimeter fence, where it came to rest next to a road. The pilots confirmed that they did not apply the emergency brake lever, they did not turn the anti-skid Off, and after coming to rest they did not manipulate the air brakes switch. A review of the FAA ADS-B data and airport surveillance videos revealed that about 2,100 ft down the runway, the airplane porpoised, then landed about 2,800 ft down the runway. From the touchdown point, there was about 2,200 ft of runway remaining. As the airplane continued down the runway, the video showed the thrust reversers deployed, and the air brakes were stowed. The responding FAA inspector confirmed that the nose landing gear collapsed, and the airplane sustained substantial damage to the forward fuselage. The ground air brakes switch was found in the OFF position. The cockpit voice recorder (CVR) and flight data recorder (FDR) were removed from the airplane and sent to the NTSB Vehicle Recorder Laboratory for download. A preliminary review of the CVR and FDR data revealed that the pilot received the PWK weather about 30 mins before landing and at that time they did not discuss landing speeds, landing zone, or touchdown points. They stated that Vref would be 119 knots and there was no discussion about adding 10 knots for the gusting wind. About 1,000 ft above ground level the PF asked for gear down and the before landing checklist to be completed. The PM told the PF that they needed to slow down for the gear extension, but there was no before landing checklist completed after that. There was no discussion about the air brakes and the FDR data confirmed that the air brakes were not deployed. A preliminary landing performance calculation was completed based on the accident conditions and airplane’s weight. The wet runway condition minimum landing distance was determined to be 3,600 ft, and the dry condition minimum landing distance was determined to be 2,539 ft. The Vref for the accident conditions should have been 129 knots, with a 10 knot factor for gusting wind (Vref 119 knots + 10). The airplane has been retained for further examination.