It is hard to believe that in this day and age that some engineers allow aircraft wire not to be laser marked. The technology is easy to acquire and marking machine prices have gone down from over $100,000 to less than $50,000. The old wire marking standard MIL-W-5088 and the current standard AS50881 both require marking every 3 inches. So why do some engineers not require the use of laser wire marking? Here are the reasons:
Competition between Small and Larger Wire Harness Manufactures
Probably the biggest reason that engineers do not require laser marking is due to competition between wiring harness manufacturers. The barriers to entry in the wire harness manufacturing industry are small compared to other industries. It does not require a lot of capital to get started. There are many “Mom and Pop” shops throughout the United States who simply decide one day to start a business for less than $20,000. They might change their minds if they were required to purchase a $50,000+ laser wire marking machine. Many engineers have heard their complaints and have been sympathetic by not requiring laser wire marking. By doing this they care more about the small wire harness companies than the aircraft technicians who support our war fighters.
Price of Laser Wire Marking Machines
Many engineers have not priced a laser wire marker in more than ten years. They remember that when these machines first came out they were very expensive (hundreds of thousands of dollars). If they would check today, the cost has gone way down. Competition in laser wire marking equipment has made it much more affordable. Now a company can purchase a small, table-top unit for less than $50,000. Alternatively, they can have a supplier mark wires for less than $0.20 per foot.
Ease of Installing “Bag and Tie” Connectors On the F-16
When the F-16 was first developed, there were no laser wire marking machines. Wires at that time were “Hot Stamped”. The F-16 Air Vehicle Specification (AVS) took exception to MIL-W-5088 by not requiring wires to be marked every 3 inches. Instead, the requirement was to place a color coded identifier (i.e. piece of shrink tubing) on the ends of each wire. The identifier simply lists the wire number. This colored identifier is helpful when searching for wires near a connector but does not help an aircraft technician who is trying to repair a wiring harness after it has undergone battle damage.
Unfamiliarity of Aircraft Battle Damage Repair (ABDR) Requirements
When an engineer makes a decision not to mark military aircraft wires every 3 inches he is not thinking of the people who maintain the aircraft in battle situations. He is not supporting the war fighter. Instead he is doing the opposite. The main purpose of marking a wire every 3 inches is for Aircraft Battle Damage Repair (ABDR). When an aircraft is in battle and is hit by small arms fire, it is the job of an aircraft technician to get that aircraft back into battle as soon as possible. If a wiring harness takes a bullet through the bundle, the wires must be spliced back together. Unless the wires are marked every 3 inches this is a formidable task. The technician will have to spend many hours beeping out the ends of each wire from both connectors to the point where the wires are damaged. Instead of simply looking for marked wire numbers, the technician has the horrendous task of trying to figure out which wire is which. A battle can be lost by one aircraft being down due to small arms fire of a wire harness bundle. The original engineer that exempted this requirement never considered the war fighter. Instead he thought about the “Mom and Pop” startup company.
For a free spreadsheet whether a MIL Spec wire is laser markable click below.