This study introduces a novel approach to enhance fire protection in aircraft cargo compartments, motivated by the urgency to address catastrophic in-flight fires recorded between 2006 and 2011. The method uses ultra-high frequency (UHF) radio frequency identification (RFID) temperature sensing tags and advanced algorithmic analysis to enhance fire detection capabilities within unit load devices (ULDs). This approach significantly reduces detection times while minimizing false alarms.

The first objective was to create an economical, battery-free fire detection system with UHF RFID temperature sensing tags installed within ULDs. This positions the temperature sensing tags closer to potential fire sources than traditional cargo compartment ceiling-mounted smoke detectors. Wireless temperature sensing tags allow the ULDs to move in and out of aircraft. Passive sensors address the challenges of batterypowered systems, such as battery changes and thermal runaway risks.

The second objective sought to enhance the RFID-based system with near real-time temperature monitoring capabilities within ULDs. The system provides accurate temperature trend analysis by incorporating a moving average convergence divergence (MACD) algorithm adapted from financial markets. This significant advancement improves fire detection times and supports communication of conditions within ULDs to flight crews, enabling quicker response actions.

The number of thermal runaway incidents from portable electronic devices (PEDs) in the aircraft cabin is growing at a notable rate. Recent data indicates that lithium battery incidents occur on average more than once per week on passenger aircraft. In response to this problem, many airlines have adopted the use of fire containment products as a means to mitigate the spread of fire and toxic fumes. An evaluation was conducted by the FAA to assess the effectiveness of commercially available fire containment products and assess their capability to mitigate the release of smoke, flames and shrapnel produced from a PED fire.

Fire containment products were procured from five different manufacturers and tested with three different fire loads, a tablet containing a 30 Watt-hour (Wh) battery, a 96 Wh power bank and a 154 Wh video camera battery. Products were only evaluated according to the maximum capacity that the product was advertised to withstand.

Key findings from this study include:

• The performance of fire containment products varied amongst the different products. Multiple products struggled to contain the hazards of PED fires near the maximum allowable energy limits permitted on aircraft (100 Wh and 160 Wh).
• Product performance varied based on the PEDs interior cell configuration and the rate at which cells experienced thermal runaway. Short periods between thermal runaway events can produce significant gas buildup, which some products are unable to vent quickly enough. This can create pressure spikes and mechanical failures (rips/tears) in the product.
• The suppression equipment included with some of the containment products was found capable of knocking down flames but unable to prevent heat propagation to adjacent cells.

Testing suggests that some containment products cannot currently meet the airlines’ present expectations for product performance. Further testing on the use of fire containment products may be needed to ensure the safety of aircraft occupants.

As a result of the COVID-19 (SARS-CoV-2) pandemic, over 12.7 billion vaccine doses were shipped and administered across 184 countries. Transportation via aircraft was a significant contributor in this effort. Many of the COVID-19 vaccines need to be stored at extremely low temperatures to maintain efficacy, therefore, dry ice has been used as a method to keep vaccines refrigerated throughout air shipments. Dry ice is categorized as a Class 9 (Miscellaneous) Dangerous Good. Dry ice undergoes a process called sublimation at normal pressure and temperatures, in which the solidified form transitions directly to gaseous CO2. This process can create an oxygen deficient environment in confined areas (including aircraft), which can produce shortness of breath, unconsciousness, or death if exposed over prolonged periods of time.

An assessment was conducted by the Federal Aviation Administration (FAA) to identify parameters pertinent to dry ice sublimation throughout air shipment. This study was motivated by minor sublimation rates (<1% per hour) claimed from container manufacturers. This has important safety implications as decreases in sublimation rates allow for exponential increases in permitted dry ice cargo. Further analysis was needed. Specifically, this study evaluated the following parameters’ impact: temperature, pressure, humidity, dry ice pellet size, container design and durability. Results indicate that dry ice pellet size, container design, and durability had a clear impact on sublimation rate. Sublimation rates differed significantly between the three containers evaluated within this study and were observed to increase as containers were reused. Furthermore, dry ice pellets with smaller nominal diameters were noted to sublimate at a higher rate than those with a larger diameter. Other evaluated parameters within this study produced no clear correlation. Although sublimation was observed to be affected by numerous parameters, data suggests a conservative approach to this subject is prudent. While some external conditions may produce only minor differences in sublimation rates, it would have a major impact on the allowable quantity of dry ice shipped.