REG NASA-LLIS-4256-2011 Lessons Learned - Development of the Current Mass Spectrometer Requirements and Techniques.pdf

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1、Public Lessons Learned Entry: 4256 Lesson Info: Lesson Number: 4256 Lesson Date: 2010-09-23 Submitting Organization: KSC Submitted by: Annette Pitt Subject: Development of the Current Mass Spectrometer Requirements and Techniques Abstract: Leak checks utilizing a mass spectrometer have been an effec

2、tive method of validating the integrity of fluid systems within the aerospace industry for decades. Mass spectrometers provide a high fidelity leak check, however, unlike soap solution or flow meter leak checks, there isnt a sensory method to validate correct performance of a mass spectrometer leak

3、check. Where a soap solution leak check can be validated visually by looking for the presence of bubbles or a flow meter leak check can be validated with a pinch test of the leak check tubing, proper performance of a mass spectrometer leak check relies on maintaining equipment in current calibration

4、, correctly performing pretest and post test checks when putting the equipment in use, and most importantly, ensuring personnel using the equipment are properly trained. Description of Driving Event: Mass spectrometer leak checks performed at Palmdale during Orbiter Maintenance Down Period for OV104

5、 exhibited several inconsistencies, leading to an investigation of the leak check processes used. The investigation found that permeability ratios and response times for equipment used did not conform to the MF0001-003 specification requirements. Equipment flow rates were also out of limits. An insp

6、ection of the equipment and procedures found that filters were not being used in the test probes, leading to contamination and blockage in the units. Leak checks performed on components with known leakages did not give correct readings with the suspect units. As a result, mass spectrometer leak chec

7、ks performed at Palmdale with the suspect units were re-performed at KSC. Lesson(s) Learned: Proper maintenance of equipment and training of personnel are of vital importance in ensuring the integrity of leak checks performed with mass spectrometer units. Detailed processes and procedures for using

8、the equipment must be developed and carefully followed. Recommendation(s): Utilize mass spectrometer leak checks for critical systems where even small external leakages can have serious consequences. Ensure procedures are correct, detailed and followed. Maintain equipment in calibration. Perform pre

9、test and post-test checks of the equipment when performing leak checks. Ensure operations are properly trained and that they have a good working knowledge of the equipment and how to use it. Evidence of Recurrence Control Effectiveness: N/A Documents Related to Lesson: Rockwell International specifi

10、cation MF0001-003 Proof Pressure And Leak Detection-Aerospace Plumbing Systems And Assemblies Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Mass Spec Machine Permeability Ratio Document Click here to download communication document. Mission Directo

11、rate(s): Space Operations Additional Key Phrase(s): 1.Maintenance 1.Test & Verification 1.Configuration Management 1.Long term sustainability and maintenance planning 1.Ground Operations Additional Info: Project: Space Shuttle Program Approval Info: Approval Date: 2011-12-12 Approval Name: mbell Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-