Reader Feedback

A Better Mousetrap

In response to the letter in the September issue of Aviation Maintenance (see AM, Sept. 2006, p. 6) and the article in the May issue (see AM, May 2006, p. 22), the idea of cable blocks is very good! However, I would caution those who would use these blocks about a couple of issues. The use of a "squared off" block or one made of metal, can damage the cables.

I have seen cables flattened and even kinked because the technician used a material for the blocks that was too hard, or a material with sharp edges, and/or too much pressure on the cable. I have even seen cables damaged using plywood, simply because there was no trough or channel for the cable to lay in to relieve the forces against the sides of the cable.

I have found that manufacturing blocks of a phenolic (polymer resin) material is best and that by drilling the material to be the size of the outer diameter of the cable and countersinking each end to give them a chamfered or rounded-off corner works well. When you countersink the ends of the penetration on each hole drilled, and then cut the block, you have uniformly softened the edge of the troughs where the cable will lay. Then drill through the mating halves for your bolt/fastener.

On single cable blocks use a fastener on either side of the cable trough and on multi-cable blocks a fastener on both outer edges as well as one between each cable. Then, using a thin blade on a band saw, split the blocks creating two mating halves that will cradle the cables and not crush or damage them. A little time will reap a good tool that can be used for years and save a lot of damage to the cables.

John R. Hefner, Jr.

Flight Research Facility Coordinator

Facility Security Manager

Flight Ground Safety Officer

NASA Langley Research Center

Where Is the Job Aid?

I am an instructor at North Central Institute, a 147 school in Clarksville, Tennessee. I read the article about wiring practices (see AM, March 2006, p. 6) and thought that the described PowerPoint show would be a great help to my students. Unfortunately, I have not been able to access that job aid. The link does not work and a search at the Web site was unsuccessful. Is there any way you can assist me?

Daniel W. (Bill) Johnson

North Central Institute

Clarksville, TN

I contacted the FAA and received an answer to your question. Their Academy Web site was recently redone and some of the information that was previously available had to either be removed or moved to a different Web site. I’d like to thank the FAA for getting back to me so quickly. Here is part of the response the FAA sent to me:

We are sorry for any inconvenience you experienced when trying to locate the Aircraft Wiring Practices Job Aid. It has indeed been moved to a new location and can now be found at: http://employees.faa.gov/org/linebusiness/avs/air/air_cert_train/dist_learn/job_aids/.

Michelle Carpenter

Federal Aviation Administration

Aircraft Certification Service

Correction

In the January Repair Center Directory, the Web site for General Electrodynamics Corporation (GEC) was printed incorrectly. The correct address is www.gecscales.com.