Weapons systems in use by the Department of Defense (DoD) have several types of oxygen supply systems, all of which eventually develop contamination in the distribution system. These distribution systems require maintenance, periodic cleaning, and emergency cleaning. Maintaining a clean environment in oxygen systems is a critical requirement. Contaminant buildup decreases system performance, increases demand on maintenance resources, and prematurely removes the aircraft from mission support. The objective of this project was to develop and validate an Oxygen Line Cleaning System (OLCS) capable of cleaning contaminated aircraft systems without disassembly and with environmentally acceptable materials.
This project involved the development of a cleaning process that allows the entire oxygen system on DoD aircraft to be cleaned without removal of significant components or disassembly of the aircraft oxygen plumbing. Currently, when an aircraft system is contaminated, the system is broken down into basic components, the components are cleaned (often with FREON or other compounds) and protected, and the system then is reassembled with an attempt made to avoid recontamination of the components or system. The OLCS demonstrated in this project is contained within a 12ft x 7ft trailer that can easily be maneuvered alongside an aircraft. The OLCS connects to the aircraft at the oxygen storage-vessel point with a return line connected at the crew member’s oxygen regulator location. Solvent is then pumped through the existing onboard plumbing system and returned back to the OLCS for analysis, filtration, and eventual distillation for reuse. The complete cleaning cycle leak-tests, washes, rinses, analyzes, evacuates, dry-air purges, and distills the cleaning chemicals.
The full capability of the OLCS was demonstrated by cleaning the oxygen lines of a B-1B aircraft at Tinker Air Force Base (AFB), Oklahoma. All performance objectives were met. Using the B-1B, the demonstration validated the OLCS, proved its environmental acceptability, validated the discovery of a cost-effective alternative to HCFC-141b and CFC-113 (FREON), and proved that the OLCS is a cost-effective method for onboard cleaning of aircraft oxygen systems. The original project scope was expanded to include demonstration cleaning on other aircraft, including the F-16 at Tulsa Air National Guard (ANG) Base, Oklahoma; the F-15 at Robins AFB, Georgia; and the C-130 at the Louisville ANG Base, Kentucky. Cost-benefit analysis was also performed for the T-38.
Successful completion of this project has resulted in removing a dependence on FREON and similar compounds to clean oxygen equipment plumbing. Significant savings have been realized in reduction of manpower, avoidance of aircraft downtime, and reduction of chemical purchase/disposal. Aircraft oxygen systems are anticipated to be more reliable, thereby increasing safety for the crew. This process is valid for all of DoD and is transitioning further into the industry. (Project Completed – 2006)