National Geographic Channel
Last month an experimental aircraft called the X-43A hit a velocity of 5,000 miles (8,045 kilometers) an hourmore than seven times the speed of sound. It was the first time an oxygen-powered "scramjet" flew freely. But one thing was missing during the aeronautical milestone: the pilot.
The X-43A's pilotless flight signaled a growing trend in modern aviation: unmanned aerial vehicles (UAVs). Economics, pilot error, and concern for human safety are all motivations to replace human test pilots with computers.
Dana Purifoy is a top NASA test pilot for the agency's Dryden Flight Research Center at Edwards Air Force Base in California. Purifoy flew the B-52B launch aircraft that carried the X-43A and its Pegasus booster rocket to a launch destination over the Pacific Ocean.
Flying to an area 400 miles (644 kilometers) off the coast of southern California, Purifoy ignited the booster rocket and the X-43A separated from the B-52B. The booster rocket took the X-43A to an altitude of 95,000 feet (29,000 meters), where the aircraft separated from the rocket and performed its record-breaking flight using a scramjet.
A scramjet (supersonic ramjet) is a jet engine that is fueled largely by oxygen it sucks from the sky. As such, it is virtually nonpolluting and requires no fuel tanks. But it does need a conventional rocket boost to get it into into thr air.
"I'm not worried that just because the X-43A was unmanned, it's a sign of things to come for the profession of test pilots," said Purifoy, who spends much of his time testing experimental jet fighters. "Each aviation experiment is different, and human test pilots will likely always be an integral part of many test flights into the future."
Chuck Yeager was the first test pilot to break the sound barrier during his historic flight in the X-1 rocket plane at California's Muroc Army Air Field (now Edwards Air Force Base). Nearly 57 years later, however, test pilots are increasingly replaced by computerized autopilots or radio-controlled simulation systems when flying is deemed too dangerous.
Some observers speculate that ground-based control rooms filled with computer monitors and engineers will someday make human test pilots obsolete.
Test pilots counter, however, that even the development of UAVs will often require pilots' hands-on expertise just to get the machines off the ground. The aircrafts' autopilot systems are prone to crash too often, they say.
"There are just too many factors involved that a human pilot must test out in an experimental aircraft before many autopilot systems will work properly," said Bill Reuter, a commander with the Naval Air Systems Command based at the division's Patuxent River headquarters in Maryland.
Reuter is the chief test pilot of Air Test and Evaluation Squadron 23 (VX-23), a squadron that tests and evaluates Navy and Marine Corps strike aircraft, such as F/A-18 Hornets and Super Hornets. "Test piloting is not a profession that is going to disappear with technology but simply evolve with it," Reuter said.
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