"Gas-free safety, it's still there ...".
The questions centered on the NA-01-1A-35: Aircraft Fuel Cells and Tanks. The main source of confusion was the definition of Hands/Arms/Tool-In Maintenance procedures and the need for a gas-free certification.
Very simply, because of small access areas to fuel cells, such as those found on some aircraft where a person cannot enter the cell with the exception of his or her arms and hands, only lower explosive limit (LEL) checks are required in accordance with NA-01-35. However, if a person's head enters a cell, a gas-free certification is required, also in accordance with NA-01-35 and guidance from regional industrial hygienist. This, in itself sounds easy to understand, so why the confusion?
In the past, every time a cell was opened, a gas-free certification was issued, allowing technicians to begin maintenance in that particular cell. The certification was a way to document LEL checks for safe entry; and, together with visual information display--maintenance action forms (VIDS MAFS), commands maintained a historical look into recent maintenance actions that required opening a fuel cell. However, with the advent of NALCOMIS, safer designs in fuel-cell maintenance, changes in maintenance manuals, and higher tempos in flight operation, gas-free certifications have become utilized less.
With change comes confusion, which is where we are now. Maintenance personnel must understand that disaster is just a spark or zero oxygen breath away when working in open fuel cells. If LEL checks are performed without a gas-free certification, they should be logged on a MAF or in the workcenter's passdown log. In reality, type aircraft wings should ensure that all squadrons under their cognizance are performing and documenting LEL checks in the same manner. The best way to accomplish this task is through wing-directed local command procedures, using the NA-01-1A-35, and following recommendations issued by an industrial hygienist.
If personnel don't use good judgment and follow guidelines, they can die from inhaling gas fumes or in an explosion or fire caused by a tiny spark. Five personnel lost their lives in an explosion while performing fuel-cell maintenance on an E-2C. They did not perform LEL checks, and a simple spark from an unauthorized maintenance light killed them in an instant. We need to protect our folks to prevent the same action from occurring again. To be safe, then, why not issue a gas-free certification? The danger still exists, arms in or head in; you're just as dead by breathing toxic fumes as you are from an explosion.
Chief Hofstad is a maintenance analyst at the Naval Safety Center.
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|Title Annotation:||Power Plants|
|Date:||Dec 22, 2004|
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