LOCKHEED 1329-23E JETSTAR, HOUSTON, TEXAS, MAY 15, 2004–JetStar N57NR sustained minor damage when the left flap assembly detached while the airplane was on approach to Hobby Airport. The airplane was operated by Aircraft Trading Center of Tequesta, Fla. The two ATP pilots and two passengers were not injured.
The 12,500-hour pilot reported that as full flaps were extended on final approach to Runway 4, the airplane decelerated and rolled uncontrollably to the left. He regained control of the airplane by “accelerating to approximately 165 to 170 knots and holding right roll control.” The aircraft landed without further incident.
The crewmembers found that the left inboard flap had separated and the attach bolts were still in the flap attach brackets. The airplane had accumulated approximately 13,534 flight hours and 11,500 cycles.
An FAA inspector found dents on the aft end of the left slipper tank and dents and a hole in an engine nacelle. The NTSB Materials Laboratory found two separate regions of fatigue fractures on both sides of a manufactured hole, with different types of fatigue cracking characteristics. Approximately half of the fractures displayed a river pattern and the remainder displayed a distinct banded appearance, consistent with rapid crack propagation and high-stress fatigue cracking in aluminum alloys. The areas outside the fatigue regions were consistent with overload.