Aerospace wiring systems are often underappreciated by other aircraft system engineers for their complexity. Aerospace wires and cables, like all aerospace components, undergo a rigorous set of qualification tests before they can be placed on an aircraft. Many in the aerospace industry want to know what the cost of aerospace wire testing is. Wire tests vary depending on the particular type of wire and specification, but they all fall into one of four categories: electrical, thermal, chemical, or mechanical.
Here we discuss the testing that is involved in one of the more common modern wire constructions (AS22759/87) and the costs associated with it, as well as what is involved in a typical testing program. For information on the tests Lectromec performs and the price associated with those tests, we have added a test listing page.
Discussion of tests
Here are the 25 tests that make up the AS22759/87 (or for those old school engineers, MIL-W-22759/87).
|#||Test ID||Test Type|
|4||UV Laser Marking||Usability|
|5||Insulation Strip force||Usability|
|9||Dry Arc Propagation Resistance||Electrical|
|10||Wet Arc Propagation Resistance||Electrical|
|14||Cold bend test||Thermal/Mechanical|
|15||Dynamic cut-through at Temperature||Mechanical/Thermal|
|16||Durability of Wire Manufacturer’s Color and/or Identification||Mechanical|
|18||Thermal Shock Resistance||Thermal|
|22||State of Sinter||Chemical|
Typically, we start any process with a discussion with the client. This helps us better understand the client’s particular needs, and may help to identify tests that better represent the objectives sought. If the client already has a list of tests that needs to have performed, the request can be submitted to myself or email@example.com; we are usually able to get a quote sent out within 24 hours.
After the quote is accepted and Lectromec receives a purchase order, the client ships the samples to Lectromec’s laboratory in Chantilly, Virginia. Once the samples are received, they are catalogued, assigned a unique internal tracking number, and stored in Lectromec’s climate controlled storage area.
The tests are then added to Lectromec’s testing schedule and the individual test samples are prepared.
Most AS22759/87 tests can be carried out in a couple of weeks. However, there are a couple of tests that can make a project run into several months, the main ones being the Thermal Index (#3) and the Forced Hydrolysis (#12) tests. Both of these tests require long-term elevated temperature exposure and subsequent evaluation. The Forced Hydrolysis testing requires at least 30 weeks of elevated temperature exposure. During this time, the samples are wrapped around a mandrel and submerged in a saline solution at an elevated temperature. Since the objective is to determine a wire’s long term survivability in a moist environment , it is necessary to ensure that a long duration test is performed.
The duration of the Temperature Index testing is longer than the forced hydrolysis test and dependent on the material performance. The samples are placed into an oven at a set elevated temperature and periodically assessed and mechanically stressed until failure occurs. The temperature is then reduced and the test is repeated, the goal being to determine the long-term temperature rating of the wire.
The completion of the 25 tests associated with the AS22759/87 comes to $28,000.00.
With each test, the client receives:
- Testing performed by an ISO 17025 certified lab.
- Technical assistance and engineering support from an experienced aerospace wire/cable test lab.
- A complete report discussing the test results, pre-test and post-test photos, description of the test, equipment calibrations, and, if everything passes, Lectromec’s seal of approval.
- If requested, a video of active parts of the tests (e.g. dry arc track resistance testing).
- Regular updates on test results and project progress.
For those customers that have some internal testing capabilities and do not have a need for each of these tests, Lectromec’s test services are quite flexible and a test plan can be created to fill our client’s individual needs.
Looking for Customization?
Roughly half of the testing performed in Lectromec’s lab is customized for our customers’ particular needs. Often the standard tests don’t do justice to the aerospace wire performance characteristics. It is not uncommon to enhance the basic minimal requirements in order to prove better performance. This may be done when one manufacturer is comparing its product against that of another manufacturer. We have the range of equipment and technical expertise to address most custom needs, and if we do not, often we can recommend another lab that does.
Expectations of the Client
Once all of the tests are defined and Lectromec has received the purchase order, Lectromec will need a sufficient wire length for test performance. In the test listing above, roughly 500ft (~150m) of wire is needed.
All test samples are property of the customer. They can be returned if requested or Lectromec will maintain the test samples for at least two years.
Wrapping it up
The testing of any component that goes onto an aircraft is important and has its particular requirements. Lectromec has been working in aerospace wire and cable assessment for more than three decades and has the experience to address particular wire and cable testing needs. Please submit questions in the comment section below or contact Lectromec at firstname.lastname@example.org.