Does Landmark Unmanned Flight Spell Doom for Test Pilots?

Zoltan Istvan
National Geographic Channel
April 27, 2004
Last month an experimental aircraft called the X-43A hit a velocity of 5,000 miles (8,045 kilometers) an hour—more 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.

Human Pilots

"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.

For decades flight testing often came down to strapping a person inside experimental aircraft and telling the pilot to spin and roll their planes out of control at an altitude of 30,000 feet (9,150 meters) while traveling hundreds of miles an hour.

Test pilots have to be physically tough enough to withstand forces up to eight g's, a pull eight times the force of gravity, which can distort vision, impair breathing, and sometimes cause regurgitation. It's not only danger that threatens human test pilots. Economics is also involved.

Sometimes it's cheaper to buy a computer-controlled autopilot system than it is to spend the millions of dollars necessary to build a cockpit that can keep the human body safe and comfortable while flying at hypersonic speeds and altitudes higher than the summit of Mount Everest. Additionally, computers make fewer mistakes than even the best human pilots during aviation experiments that require precision flying. It's just another factor escalating the test pilots' battle against machines.

Airborne Scientists

Nearly 100 miles (160 kilometers) north of Los Angeles in the Mohave Desert, the next generation of test pilots is adapting to new challenges at the Edwards Air Force Base. The base is home to the United States Air Force Flight Test Center, a training ground for top pilots. Today's class is a varied mix of test engineers and pilots (some of whom call themselves airborne scientists.)

"If you want to be a test pilot these days, you need to be more than just good at flying," Purifoy, the NASA test pilot, said. "Many of the upcoming test pilots have several degrees in engineering and computer science."

One way test pilots keep themselves in the loop is by working on new planes, from design to testing to production. They no longer just listen to flight engineers, get in a plane, and perform tricks in the air as instructed.

"When not flying, today's test pilots are in front of computers, working on simulation systems, creating design plans, and making sure the experimental aircraft will accomplish what it sets out to do when airborne," Reuter, the Navy test pilot, said. "I just can't imagine a future in aviation without human test pilots. They're indispensable to the whole process of getting experimental aircrafts flying."

According to John Haire, director of strategic communications for the Air Force Flight Test Center at Edwards Air Force Base, three test pilots have died at the base and three others have had to eject from their aircrafts in the past ten years.

The former Muroc Army Air Field was renamed in honor of Capt. Glenn Edwards, who died in June 1948 while test piloting the YB-49 jet fighter.

For more on test pilots, watch this week's Dangerous Jobs. The series airs Wednesdays at 8 p.m. ET/PT in the United States and is available only on the National Geographic Channel.

© 1996-2008 National Geographic Society. All rights reserved.