The bulletlike, open-wheel Indy racing cars hurtle around oval tracks at breakneck velocities, often approaching speeds of 220 mph or higher. While a crash at this speed is a violent, sometimes tragic event, it is nonetheless a key data source for AFRL researchers seeking ways to create a safer environment for Air Force (AF) fighter pilots during emergency ejection.
Instituting a practical alliance of human peril and scientific research, AFRL engineers are teaming with the Indy Racing League (IRL) to share crash impact and injury data. Indy car drivers wear a miniature earplug accelerometer (see figure) that records vertical, lateral, and longitudinal accelerations of the driver's head during a crash. "This data will provide valuable information for criteria and model validation," states Ms. Erica Doczy, biomedical engineer in AFRL's Biomechanics Branch. "We need reallive human injury data to validate our models and criteria. In the lab, you can't re-create that [trauma], so this is just one way to collect that data, because accidents do occur in the motor sports industry."
The data helps researchers learn more about the dynamics of a highspeed impact and the effects of acceleration and impact on a human's head and neck. Researchers typically create models based on manikin and cadaver testing, but data from living humans is essential for validating the models. With the availability of detailed information about the car's speed and movement, and how the driver's head reacts at each stage of a crash sequence, researchers no longer have to theorize about the exact nature and cause of head and neck injuries. "We'll know what the car did, we'll know what the driver's head did, and we'll have medical data (the end result), so it's a way of validating the entire [series of] criteria," explains Dr. Joseph Pellettiere, technical advisor for the Biomechanics Branch.
The agreement with the IRL builds upon AFRL's long-standing program for improving neck protection for AF aircrew members during all phases of flight, and especially during high-risk, emergency ejection. "We develop the injury criteria and guidelines for how a flight helmet should be developed in terms of its mass properties—such as weight, center of gravity, and location of night vision goggles or other systems— such that it's safe for crew members to wear," elaborates Dr. Pellettiere.
AFRL researchers routinely feed updated data to flight helmet designers and manufacturers, who use the data to create safer next-generation equipment. The researchers also recommend the development and availability of preejection instructions that tell pilots how to physically prepare for ejection, including directions for assuming correct body position and bracing. "New helmet programs are using our criteria now," Dr. Pellettiere points out. "They are making their designs [according] to the guidelines we provide." Both the F-35 Joint Strike Fighter and the Panoramic Night Vision Goggle programs are developing helmets based on AFRL-supplied impact and injury data.
Indy car drivers benefit from the crash data through revised safety and equipment requirements which, in turn, improve racing safety levels. The research team also shares results with the commercial automotive industry through conferences and universities, a practice that can prompt safety-related policy changes for auto manufacturers.
As both technology and policy continue to evolve, the AF must persist in its efforts to evaluate pilot safety. This ongoing need is reflected in the following example, which illustrates how today's heavier helmet, coupled with a revised physical profile for pilots, has increased the risk of serious neck injuries during ejection. To accommodate a broader physical range of females (who currently constitute about 18% of AF pilots), the AF reduced the minimum body-weight limit for pilots to 103 lbs, with an associated decrease in neck muscle size and strength. Helmet weight, however, increases as peripheral systems are added to pilot headgear. A typical (3 lb) flight helmet's weight can increase to nearly 5 lbs after extra items, such as night vision goggles, are installed. According to Ms. Doczy, "Two additional pounds may not seem like much, but during an ejection, it adds a significant amount of force on the pilot's neck."
In addition to realizing safety improvements, the AF expects to achieve significant financial savings as a result of AFRL's neck protection advancements. "The potential for cost savings is tremendous, since the AF invests several million dollars to train each pilot," Ms. Doczy affirms. In addition to lost training dollars, the federal government bears the burden of an injured pilot through hospital and rehabilitation expenses. Preventing injuries and fatalities during ejection would minimize such costs. Cost-related advantages aside, the key goal for AFRL's neck protection program engineers— adeptly expressed in their motto, "Always Come Home Safely"—is to develop technology and use it to keep aircrew safe, not only during ejection, but ultimately in all phases of operational flight situations.
Mr. John Schutte (Ball Aerospace and Technologies Corporation), of the Air Force Research Laboratory's Human Effectiveness Directorate, wrote this article. For more information, contact TECH CONNECT at (800) 203-6451 or place a request at http://www.afrl.af.mil/techconn_index.asp. Reference document HE-H-05-04.
Air Force Research Laboratory Technology Horizons Magazine
This article first appeared in the April, 2006 issue of Air Force Research Laboratory Technology Horizons Magazine.
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