Air Force Lt. Col. Andrew Lourake, an amputee who remained on active duty as a pilot, demonstrates July 17 how he manually switches modes on his computerized prosthesis as Sven Zarling observes. The colonel's current prosthetic leg has two modes, one for walking and one for flying. An improved prosthesis is being developed that will have up to 10 modes and allow for remote-controlled switching. Mr. Zarling is from Otto Bock HealthCare, the company developing the new prosthesis. (DOD photo/Fred W. Baker III)