1、Lessons Learned Entry: 1027Lesson Info:a71 Lesson Number: 1027a71 Lesson Date: 1997-02-01a71 Submitting Organization: HQa71 Submitted by: David M. LengyelSubject: Aeronautics/Research and Development/Wind Tunnel Inspections Description of Driving Event: Wind Tunnel Fan Blade Cracking at Ames Researc
2、h CenterLesson(s) Learned: The fan blades on the 40 x 80 x 120 wind tunnel at the Ames Research Center developed cracks after only 2,000 hours of operation. To preclude shutting down the tunnel for the 1 year required to procure and install a new set of blades, it was decided to repair the old blade
3、s while waiting for delivery of the replacements. The repair includes wrapping the root section of the blades, which eliminates the ability to detect crack growth by visual inspection.Recommendation(s): NASA should ensure that a suitable inspection program, including frequent checks using nondestruc
4、tive evaluation methods, is implemented.Evidence of Recurrence Control Effectiveness: As part of the fan blade repair at the National Full-Scale Aerodynamic Complex (NFAC), quality assurance and inservice inspection procedures are being developed and applied to ensure functionality of the repair. Al
5、l blades are being visually examined to assess and establish their condition prior to the start of repair. Throughout the repair process, both ultrasonic and acoustic tap testing is being performed to determine adequacy of the crack fill, as well as the wrap lay-up quality and bonding. After placing
6、 back in service, periodic inspections using acoustic tap testing and a series of full-scale fatigue tests will be implemented to monitor and characterize void growth. Based on these testing results, criteria for the periodic inspections, including frequency and size of Provided by IHSNot for Resale
7、No reproduction or networking permitted without license from IHS-,-,-indications, will be developed.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Aerospace Safety Advisory Panela71 Facilitiesa71 Parts Materials &
8、Processesa71 Policy & Planninga71 Research & Developmenta71 Test FacilityAdditional Info: Approval Info: a71 Approval Date: 2001-11-20a71 Approval Name: Bill Loewya71 Approval Organization: QSa71 Approval Phone Number: 202-358-0528Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
