1、Lessons Learned Entry: 1760Lesson Info:a71 Lesson Number: 1760a71 Lesson Date: 2006-04-28a71 Submitting Organization: JPLa71 Submitted by: Thuykien Nguyena71 POC Name: Jon Cowarta71 POC Email: Jon.Cowart-1ksc.nasa.gova71 POC Phone: 321-861-3042Subject: Process Control to Prevent Incorrect Assembly (
2、Video Lesson) Abstract: A video clip lesson learned on the topic of Process Control. Actuators inside the tail enable the rudder speed brake panels to steer and slow the Space Shuttle during descent and landing. Unusual wear was found on the planet gears of the actuators during an inspection. This l
3、ed to a discovery that when the Shuttle was built the gears were installed incorrectly? a critical flight failure mode. The installation error stemmed from the near identical appearance of component gears that had different design topographies. The robust actuators were able to operate for 20 years
4、(approximately 30 missions) without failure. The mistake was not found sooner because the actuators were certified for the original flight life of the Shuttle? 10 years or 100 missions. New gears were installed, and a process control was implemented that accommodates the demands of ground operations
5、. A dedicated fixture was fabricated for each actuator with physical features that prevent installation of the incorrect gear. Designs should be mistake-proofed so that components cannot be assembled incorrectly. This 4-minute, 33-second video is a product of the Space Shuttle Program and its Proces
6、s Control Focus Group.Description of Driving Event: Click here to view the lesson learned video. Click here to view a QuickTime version of the video. (Longer download time)Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Lesson(s) Learned: Unless mech
7、anical designs are mistake-proofed to prevent incorrect assembly, an assembly error that is not clearly evident from initial inspection may cause a critical flight failure.Recommendation(s): Add physical features to mechanical designs that positively preclude opportunities for incorrect assembly of
8、components.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Exploration SystemsAdditional Key Phrase(s): a71 Missions and Systems Requirements Definition.Human factors impact on mission designa71 Systems Engineering and Analysis.Human facto
9、rs planninga71 Engineering Design (Phase C/D).a71 Engineering Design (Phase C/D).Spacecraft and Spacecraft Instrumentsa71 Mission Operations and Ground Support Systems.Ground processing and manifestinga71 Mission Operations and Ground Support Systems.Ground support systemsa71 Safety and Mission Assu
10、rance.Advanced planning of safety systemsa71 Safety and Mission Assurance.Configuration Change Controla71 Safety and Mission Assurance.Early requirements and standards definitiona71 Safety and Mission Assurance.Impact of human factors on systems requirements and designsa71 Safety and Mission Assuran
11、ce.Maintenancea71 Safety and Mission Assurance.Product Assurancea71 Additional Categories.Flight Equipmenta71 Additional Categories.Ground Equipmenta71 Additional Categories.Ground Operationsa71 Additional Categories.Hardwarea71 Additional Categories.Industrial OperationsProvided by IHSNot for Resal
12、eNo reproduction or networking permitted without license from IHS-,-,-a71 Additional Categories.Parts, Materials, & Processesa71 Additional Categories.Risk Management/Assessmenta71 Additional Categories.Safety & Mission Assurancea71 Additional Categories.SpacecraftAdditional Info: a71 Project: Space ShuttleApproval Info: a71 Approval Date: 2006-12-18a71 Approval Name: ghendersona71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
