ERA20LA008

During the initial climb, the flight crew attempted to retract the landing gear; the main landing gear retracted normally but the nose landing gear failed to retract. Several attempts to retract and extend the nose landing gear to a locked position were unsuccessful and the flight crew completed an emergency landing, during which the airplane skidded to a stop on its nose and fuselage. The fuselage sustained substantial damage. Examination of the nose landing gear actuator drag stay found that it was missing its nut, washer, and split pin, and deformation was observed in the attachment area. The nose landing gear leg was removed, overhauled, and re-installed by a contract maintenance facility as part of a broader routine maintenance inspection about 9 months before the accident. The airplane had flown 124 cycles since the removal and re-installation. The maintenance task reportedly followed in the maintenance manual required that the nut, washer, and split pin be installed during the installation, and records indicated that the installation task was performed by a mechanic and verified by a separate quality assurance inspector mechanic at the contract maintenance facility. There were no other inspections performed on the nose landing gear since the overhaul. Thus, it is likely that the split pin was not installed during installation of the nose landing gear following the overhaul, and over the course of the 124 cycles after installation, the nut and washer backed out, which allowed for the actuator arm to disconnect from its attach point. As a result, the actuator arm was free to move during the retraction and extension cycles, which damaged its attachment area and ultimately led to its complete separation. This is consistent with the pilot’s report of hearing a thud and feeling vibration emanating from the nose landing gear area during the retraction cycle.

On October 7, 2019, at 2305 eastern daylight time, a Raytheon Corporate Jets Inc. Hawker 800XP airplane, N86MN, landed with the nose landing gear retracted on runway 6 at Southwest Florida International Airport (RSW), Fort Myers, Florida. The two airline-transport pilots and 2 passengers were not injured. The airplane was operated by Delta Private Jets, as a Title 14 Code of Federal Regulations Part 135 on-demand charter flight. The flight originated from Naples Municipal Airport (APF), Naples, Florida at 1953 and was destined for Kerrville Municipal Airport (ERV), Kerrville, Texas. The pilot-in-command reported that after a normal takeoff roll and rotation from APF, during the initial climb and landing gear retraction, he observed a red warning light that the nose landing gear (NLG) remained in transit and was not fully retracted. He reported that a vibration and a "thud" were felt from the NLG section; at this time the main landing gear indicated that they were retracted. He further reported that the flight crew attempted to extend the landing gear via the checklist but were unable to get the NLG to indicate that it was extended or retracted. Subsequently, the flight crew diverted to RSW due to the availability of a 12,000 ft dry runway; during the landing, the NLG failed to extend, the airplane skidded to a stop on the runway, and the flight crew and passengers performed an emergency evacuation via the main cabin door. Review of photographs that were taken immediately after the landing, showed the main landing gear extended, but the NLG remained retracted in its wheel well. The fuselage sustained substantial damage. Review of photographs provided by the Federal Aviation Administration inspector and operator revealed that the NLG actuator push rod linkage (drag stay) was disconnected from its attach point, and the nut, washer, and split pin assembly were missing. Figure 1 provides a reference to a drawing in the airplane's illustrated parts catalog and a photograph of the actuator as found postaccident. The area circled in red is where the nut, washer, and split pin were normally located. The actuator remained attached at its opposing, as noted as area "A" in Figure 1. Figure 1: Raytheon Hawker 800/ 850XP illustrated parts catalog and postaccident photograph Deformation was observed in the area where the nut, washer, and split pin assembly were expected to be installed. When the NLG was manually extended by hand by operator maintenance personnel, it locked into place. Maintenance records provided by StandardAero, which was the heavy check maintenance facility contracted by Delta Private Jets (DPJ) to perform inspections, revealed that the NLG and main landing gear were overhauled in January 2019, as part of a larger inspection for DPJ's Approved Aircraft Inspection Program (AAIP). StandardAero maintenance task job cards indicated that the nose landing gear unit was removed, overhauled, and reinstalled by a mechanic and was checked and signedoff by a quality assurance inspector. The endorsement for the NLG task stated the work was performed in accordance with the airplane maintenance manual instructions #32-20-12. The StandardAero quality assurance inspector who signed off the work reported it is standard practice to utilize the approved airplane maintenance manuals during inspections and quality assurance inspectors check the work performed by mechanics. There were no discrepancies noted by the quality assurance inspector with regard to the work performed with the NLG. Review of DPJ maintenance records found that there were no other repairs or inspections of the NLG leg or its actuator drag stay since StandardAero completed the work in January 2019. At the time of the accident, the landing gear had accumulated 124 cycles since the overhaul. The airplane's maintenance manual, nose landing gear and nose leg assembly installation instructions (#32-20-12) contained 19 steps and step 6 stated in part: (6) Attach the drag stay to the leg forging with the pin, make sure the flat on the head of the pin engages the flat on the drag stay, install the washer and nut. Tighten the nut and lock with a new split pin.