19981127043289A

(.19) On November 27, 1998, at 1420 central standard time, a Lockheed L-1329, 4 engine jet airplane, N787WB, impacted an airport sign and terrain following a loss of nose wheel steering during the landing roll on runway 13R, robert mueller municipal airport, Austin, Texas. The airplane was owned and operated by banair, inc., houston, Texas under title 14 CFR part 91. The two airline transport rated crew members and the passenger did not receive injuries, and the airplane sustained substantial damage. Visual meteorological conditions prevailed for the business flight originating from houston, Texas. An IFR flight plan was filed. The pilot reported hearing a loud pop when the nose gear settled onto the runway. The aircraft veered hard to the right and application of the left brake had no effect. The airplane skidded for 978 feet before exiting the runway. The airplane struck a runway marker and traveled an additional 120 feet before coming to a stop. Upon examining the nose gear, the pilot/mechanic and the FAA inspector found the steering actuator failed and the hydraulic fluid loss from the steering actuator. Structural damage occurred to the fuselage. (.4) during the landing roll, the nose gear settled onto the runway, and the aircraft veered hard to the right. Application of the left brake had no effect. The airplane skidded, exited the runway, struck a runway marker, and collapsed the nose landing gear. The steering actuator had failed, the hydraulic fluid was lost from the steering actuator, and the fuselange received structural damage. The steering actuator assembly, p/n 1501-4, had accumulated 5,938.0 hours since new and had not been repaired or over hauled. Examination of the nose gear steering actuator cylinder by the metallurgist revealed that the cylinder fracture was the result of fatigue cracking initiated by an abrupt machining transition from the 45 degree thread ring chamfer to the straight wall of the cylinder. The engineering drawings appear to depict the radius at the fatigue origin as a continuation of the 0.03 inch to 0.06 inch radius adjacent to the fracture. However, the drawing is not clear on the specific intent of the transition between the nearby radius and the internal threads for the nut. (-23) on November 27, 1998 at approximately 08:30PM local time a Lockheed l -1329-25, (jetstar ii), N787WB, operated by banair inc. under FAR part 91 rules, during landing, lost directional control of the nose wheel steering, left the active runway and then impacted one of distance markers at the Austin, mueller airport. VFR conditions prevailed; however an IFR flight plan was filed. The aircraft sustained substantial damage, but there were no injuries to the two flight crew members or the sole passenger. The pilot of this flight was a Mr. Wesley v. harrison, certificate #464334436. This flight had originated earlier in the day from houston, Texas. The initial investigation revealed an obvious failure of the nose wheel steering system. A component teardown report will follow.