The capability of the human pilot

The North American X-15 was a hypersonic rocket-powered experimental aircraft flown by the USAF and NASA in the 1960’s. The X-15 holds the official world record for the highest speed ever recorded by a manned aircraft, set in October 1967 when test pilot William J. Knight at 102,100 feet flew Mach 6.70.

Clearly it was a hot rod rocket ride, and obviously important to the advancement of high speed and high altitude aeronautical engineering. But it was also important in understanding the role of the pilot in new highly dynamic systems, and what machine-human interfaces would be functional in those relms (see NASA history page). It’s a theme touched on in the book and movie The Right Stuff — would capsule occupants be spam in a can or pilots in command?

During extensive testing, the X-15 program did show the value of a human in the direct control loop. NASA says “analysis of the first 44 flights showed that 13 would have failed in the absence of a human pilot together with the various redundant systems provided in the vehicle.”

When an X-15 was donated to the Smithsonian Air and Space Museum, where it now hangs in the main hall, the press release stated its human factors importance beyond flying Mach 6:

“The capability of the human pilot for sensing, judging, coping with the unexpected, and employing a fantastic variety of acquired skills remains essentially undiminished in all of the key problem areas of aerospace flight.”

They knew that increasingly complex computers would supplement stick and rudder. Pilots would become more monitors and system managers, but should ultimately be in control. NASA states:

“The program shows clearly that, given precise displays, the pilot can fly rocket-boosted vehicles into space with great accuracy. He cannot do any better than completely automated systems, however. Perhaps his best role will be as a monitor of automatic systems able to contend with malfunctions or to make trajectory changes as needed.

This understanding of the value of pilots was later validated by the success of the Apollo Moon missions. When, for example, a former X-15 test pilot clicked off the autopilot, changed course, and gently hand-flew the Apollo 11 LM on to the surface of the Moon — at a spot where there weren’t boulders the size of houses.

Now, with the B-737 MCAS on our mind, might be a good time to meditate on the fifty-year-old lessons of the X-15. It has come to be that spacecraft launch and dock autonomously. My Tesla Model 3 has new beta software that will drive itself to me in a parking lot, and change lanes on a highway without my input. Airliners are now multiplexed datalinked and geewizzed like a science fiction story.

But clearly pilots are still required.

And to do the job of a pilot we need education on all the critical systems of their ship. And, as required to make sense of the first NASA quote, we need training to acquire the “fantastic variety of acquired skills” required to override automation. Now, none of us is going to be as good as Neil Armstrong; but Boeing, the airlines, and flight training managers can all do better.