When Able When used in conjunction with ATC instructions, gives the pilot the latitude to delay compliance until a condition or event has been reconciled. Unlike "pilot discretion," when instructions are prefaced "when able," the pilot is expected to seek the first opportunity to comply. Once a maneuver has been initiated, the pilot is expected to continue until the specifications of the instructions have been met. "When able," should not be used when expeditious compliance is required.

Aero-Linx: America's Challenge Gas Balloon Race The America's Challenge Gas Balloon Race was founded by the Balloon Fiesta in 1995 due to the vision and efforts of Mark Sullivan, former Balloon Fiesta President and recipient of the Montgolfier Diplome (one of ballooning's highest honors), who saw the need for America to be identified with the world's most prestigious ballooning sport. The America’s Challenge Gas Balloon Race is modeled after the Coupe Aeronautique Gordon Bennett, but it differs from the older event in allowing balloons from all countries, without limits on the number of entries from each. The team that travels the longest distance wins.

"The challenge is to duplicate, using hardware and software, the behavior of the air vehicle when it is flown by a human. For example, we're installing and testing actuators that will move the air vehicle's flight control surfaces in response to commands from a ground control station the same way they would move in response to commands from a pilot in the cockpit." Source: George Spongberg, Northrop Grumman's Fire-X program manager, speaking about Northrop Grumman Corporation and Bell Helicopter's having moved a significant step closer to being able to offer military users a vertical unmanned system that can ferry cargo - either internally or externally - over extended distances.