ASTM Packaging Standards: Aerospace and Defense Packaging

Part 7: Challenges in Aerospace and Defense Packaging

The aerospace industry deals with packaging for components ranging from delicate electronic avionics to large, heavy structures. Often, these items are high-cost and mission-critical, so any damage in transit can have significant consequences. Aerospace parts may also have to endure long storage periods sometimes years, before use. This requires packaging that can preserve and protect them from corrosion, dust, static, etc.

Shipping can involve multiple modes such as ground, air, sea, potentially exposing packages to wide temperature fluctuations, humidity, and low pressure at high altitudes. Vibration and shock are prominent concerns where an aerospace component might be shipped via military transport aircraft or rough roads to a launch site, experiencing intense vibration or jolts.

Foreign object debris (FOD) is another concern specific to aerospace and packaging must not shed particles or break apart in a way that debris could contaminate sensitive equipment. Additionally, some aerospace shipments involve hazardous materials, like fuels, batteries, or chemicals, which have strict packaging and testing requirements often governed by DOT/UN regulations, but frequently referring to ASTM drop and pressure tests for validation.

For defense and military applications, there are often detailed specifications for packaging (e.g., MIL-STD-2073 and MIL-STD-810 for environmental tests) that contractors must follow, many of which incorporate or reference ASTM standards for testing.

ASTM Standards and Solutions for Aerospace and Defense Packaging

Aerospace manufacturers use ASTM packaging standards to qualify that their packaging designs will protect parts through the worst-case scenarios of logistics and storage. Shock and vibration testing is crucial. Test plans commonly include ASTM D880 (impact shock) and ASTM D5276 (drops) for containers of aircraft parts or spacecraft instruments to ensure they survive accidental drops or impacts during handling.

For heavier aerospace equipment that is craned or palletized, ASTM D6179 (rough handling of unitized loads) is used to simulate things like forklift handling, tip-over, or bumping of crates. Random vibration tests (ASTM D4728) are employed to mimic prolonged vibration, simulating a rocket part traveling on a truck over a long distance, for example.

These tests help verify that cushioning and supports in the packaging, foam inserts or shock mounts, are sufficient to protect against the dynamic forces. Many aerospace components are also sensitive to pressure changes. The ASTM D6653 (altitude test) might be applied to large sealed crates containing satellite equipment, to be sure the crate can equalize pressure or otherwise withstand the low-pressure at 30,000 feet without bursting seals or causing internal damage.

If an aerospace part is sealed in an airtight barrier bag with desiccant, a common practice for long-term storage to prevent corrosion, altitude testing combined with leak testing (per ASTM D4982 or similar) would ensure the bag doesn’t balloon and rupture at altitude.

Moisture and corrosion protection often involve packaging coated with VCI (vapor corrosion inhibitors) or with barrier layers. The ASTM D1748 (not listed above, but a test for corrosion in humidity) and ASTM B117 (salt spray, though for materials) might be used to ensure those barriers are working. Additionally, ASTM D4169 is sometimes used with a custom test plan (Distribution Cycle 18 can be user-defined) to encompass all needed hazards for aerospace shipments. A test lab might create a sequence including high-impact drops, random vibration, thermal cycling, and altitude all in one plan to qualify a packaging system for, say, a guided missile or an aircraft engine.

On the administrative side, defense contracts often specify ASTM D3951 (Standard Practice for Commercial Packaging) for items that do not require specialized military preservation. ASTM D3951 essentially outlines good general packaging requirements such as adequate protection, proper labeling, etc., and is used as a default for many defense procurements. Compliance with D3951 means the item is packaged in a way that should survive typical logistics without damage. Contractors meet this by following the practice and often verifying via some of the performance tests mentioned (drop, vibration) for added assurance.

For sensitive electronics used in aerospace, packaging must also be ESD (electro-static discharge) safe. While ESD packaging standards (like MIL-PRF-81705) are not ASTM, the testing of those materials (like surface resistance) can involve ASTM methods (e.g., ASTM D257 for resistivity). If explosive or flammable items are packaged, such as squibs, rocket propellant samples, they must pass UN hazardous materials packaging tests which include drop, stack, and often pressure tests analogous to ASTM standards. In many cases, the test procedures for UN packaging are based on ASTM equivalents (for instance, a 1.2m drop specified by 49 CFR can be conducted per ASTM D5276).

Solutions and Best Practices for Aerospace and Defense Packaging

Aerospace companies typically overengineer and over-test their packaging due to the high value of cargo. Best practices include performing a hazard analysis to identify what stresses a package will see (vibration spectrum on a C-130 aircraft, crane lifting points, etc.) and then aligning ASTM tests to those hazards.

Often, they will instrument actual shipments or conduct field trials, for example, sending a dummy payload through the actual transport chain with data loggers capturing vibration and shock. That data can then be used to set test levels in the lab (possibly using ASTM D4169 guidelines for establishing test intensities). Long-term storage is addressed by combining ASTM standards by conditioning the package in an environmental chamber for months (ASTM D4332 for conditioning) then testing integrity after storage.

To prevent FOD and contamination, aerospace packaging materials are chosen carefully for their low-shedding, low-outgassing materials where ASTM E595 is used to test outgassing of materials intended for spacecraft, including packaging films or foams, to ensure they won’t release condensable vapors in sensitive environments. Additionally, traceability and documentation are critical in aerospace where packaging designs and test results are documented in detail, and often packaging must be revalidated if any change is made, even a new lot of foam cushioning might trigger a quick drop test to ensure consistency.

By adhering to ASTM packaging standards and integrating them with aerospace specific requirements, the industry achieves a high reliability in delivery, parts arrive on-site undamaged, uncontaminated, and ready for installation, whether it’s a small electronic component or a multi-million-dollar satellite mirror.