The story of the prototype 707.
- By R.G. Thompson
- Air & Space magazine, May 1987
(Page 3 of 5)
Less than a month later, the airplane lost its nose gear. It happened after Johnston had been heating up the brakes with a series of high-speed ground runs and stops, then taking off to see what happened in the cold temperatures aloft—“cold soaking,” as engineers called it. What happened was an expansion of the hydraulic fluid on the ground and a contraction in the air. Unbeknown to Johnston, the hydraulic system responded by forming bubbles in the lines, which sensors interpreted as a broke brake line. Performing as designed, the sensors promptly shut off fluid flow to the brakes.
Johnston landed daintily, stepped on the brakes, and realized he had none. On one side of the field sat a row of private aircraft; on the other, a line of B-52s. Johnston had one place to go: a grassy median between the two runways. He hoped the soft earth would slow Dash 80 enough to let him swing the airplane around and roll to a stop. He recalls a sudden crunch. Contractors making runway repairs had left a big block of concrete exactly where Dash 80 would find it. It knocked the nose gear off and damaged the belly, but Boeing had Dash 80 flying again in about three days. A redesign of the braking system sensors solved the hydraulics problem.
Not long after that, Dash 80 chalked up a midair landing gear explosion and fire when the new anti-skid brakes turned out to be spectacularly efficient heat reservoirs. Johnston had heated the brakes doing ground runs, then had flown with the wheels down for 15 minutes to cool them. But as soon as the landing gear was retracted, there were several explosions accompanied by the smell of burning rubber. “There was smoke everywhere,” he recalls, “so I speeded up, put the gear down, and blew the fire out.” He didn’t need brakes to stop after landing—5 of the 10 tires were flat.
The final thrill involving Dash 80’s gear occurred during a test of the thrust reversers. After a series of landings, a hydraulic line let go and the flammable fluid leaked out onto a hot brake. The resulting blaze caused the crew to holler for the fire truck and abandon ship. Boeing replaced the entire hydraulic system with one that used less flammable liquid. “It was just another part of the learning curve,” Gannett said.
There were also problems with the design of Dash 80’s tail. All three test pilots had been aware of them from the start of the test flights, and apparently they were noticeable to others as well. However, they were not great enough to prevent Johnston from doing a seemingly impromptu barrel roll in front of 200,000 spectators. Then, for anyone who had missed it, he rolled Dash 80 again. In fact, Johnston’s famous rolls were a sort of pointed rebuttal. “I’d heard that Douglas was telling people our prototype was an unstable airplane,” Johnston says, “and I believe that when you fly for a company, you sell the product by demonstrating what it can do.”
The International Air Transport Association was meeting in Seattle, and airline executives from all over the world were scheduled to be at Lake Washington for the Gold Cup hydroplane races. “I knew we had to do something to impress ‘em,” Johnston recalls.
Earlier, when Allen had asked him to fly over the race course, Johnston decided he would impress ‘em by rolling Dash 80. Copilot Gannett had gotten an inkling of what was coming several hours earlier, when Johnston flew the airplane through a couple of rolls during a test flight. Allen, however, had no idea. When he looked up and saw his company’s biggest investment on its back, he looked like a clinical example of apoplexy, according to people seated near him. Everyone loved the stunt, but Allen never got over it. He fired Johnston at least a thousand times before they met the next morning and cooler heads prevailed. Nonetheless, the infamous maneuver was a forbidden subject in Allen’s presence for many years. At his retirement dinner in 1980, he was given a huge photograph taken from one of Dash 80’s windows while the airplane was upside down. He left it behind.
The stunt may have impressed airline executives, but it didn’t cure the problems in Dash 80’s tail fin, which had both a bad case of flutter and persistent Dutch roll.