August 19, 2011:  The U.S. Air Force recently came up with a brilliant idea that allowed its RQ-4 Global Hawk UAV to land at any airbase. The fix consists of a 6.4 kg (14 pound) kit, small enough to fit inside an existing compartment in the wing. The kit contains a tow bar adaptor and main gear down locks. These two items are needed if the RQ-4 is to be towed using the standard tow bar found in nearly all airports.

As designed, the RQ-4 could not use the standard tow bar, and required a customized one. These the air force placed at air bases the RQ-4 was expected to operate at, or might have to use for an emergency landing. To aid in this, the flight control software on each RQ-4 was programmed to include the locations of airports and airbases that had the custom RQ-4 tow bar. Without the custom tow bar, it was a lot of hassle to move the RQ-4 around once it had landed. Now, with the new kit, the custom tow bars are no longer needed, and every RQ-4 carries the equipment needed to make the standard tow adaptor work. The new kit costs less than $2,000 to make, and less than three weeks to design, test and begin producing. Eight kits are now in use.

The RQ-4 is an unusual aircraft. At 13 tons, the Global Hawk is the size of a commuter airliner (like the Embraer ERJ 145), but costs nearly twice as much. Global Hawk can be equipped with much more powerful, and expensive, sensors, than other UAVs. All this custom equipment included some special ground handling gear as well, and that presented some unique problems when the RQ-4 ran into problems on a long flight and had to find a place to land, quickly. The RQ-4 can cross the Atlantic or Pacific in one long hop, but things do go awry at times, and an emergency landing is necessary, whether the nearest landing strip has special equipment for the RQ-4 or not.