NTSB Identification: DFW05FA242.
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Accident occurred Sunday, September 18, 2005 in Yukon, OK
Probable Cause Approval Date: 02/26/2007
Aircraft: Akro Tech Aviation Inc. Giles G-300, registration: N300NW
Injuries: 1 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

The 6,700-hour commercial pilot had just started a practice session in preparation for an aerobatic competition when she initiated a 45-to-55-degree nose-up climb. As the airplane began to ascend, witnesses observed the acrylic canopy separate in fragments from the airplane. The airplane continued to climb before it rolled to the right and entered an approximate 60-degree nose-down descent. The engine remained at full power during the descent and no flight control movements were observed after the canopy had separated. A witness made several attempts to contact the pilot via radio, but there was no response. Examination of the canopy revealed that it fastened to the fuselage by two metal hinges that fastened directly to the fuselage with four flat-head bolts. There was no evidence of bonding material or adhesive in the area of the fuselage underneath the mounting plate of either hinge. The forward hinge was never located; however, a closer view of the location where the front canopy hinge was located indicated there were "rub" marks on the surface of the fuselage underneath the hinge pin lock wire, which was indicative to contact wear with the bent end of the hinge pin. The hinge pin lock wire was also worn and flattened in areas, which corresponded to contact wear with the bent end of the hinge pin. The rear hinge was fractured into two pieces through the mounting plate at the fuselage side of the hinge. Deformation was observed around the rivet holes where the hinge was attached to the fuselage, indicative of overstress. Bolt holes in the mounting plate at the canopy side of the hinge were deformed, and the edges of the holes were cracked or fractured, consistent with overstress. One of the four bolts remained in the mounting plate on the canopy side of the hinge. Rub marks similar to those found in the area of the front hinge pin lock wire were not present. In addition, there was no damage to the hinge pin lock wire. A review of aircraft logbooks revealed that the airplane was built in 1997 and had accrued approximately 900 hours at the time of the accident.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The catastrophic separation of the canopy as result of the failure of the forward canopy hinge while performing aerobatics and the subsequent incapacitation of the pilot.

Full narrative available

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