Another FAA official pointed out that the new evidence seemed to counter Boeing’s claims that the pilots had caused the crash.
McGrew spoke up. “We’ve received a lot of public criticism about hiding things and not wanting to spend a lot of money,” he said. “But I frankly don’t care [what it costs]. If there is something wrong with the airplane, I want to fix it.”
Steve O’Neal, the FAA flight-test engineer, was impressed by McGrew’s comments. Until that point, O’Neal had felt McGrew was overprotective of the airplane. But McGrew now seemed sincere in saying that he was open to anything.
The meeting ended. Boeing said it would issue an alert service bulletin to warn airlines about the condition. The bulletin would require mechanics to perform a test every 250 hours, stomping on the pedals to check for jams. The FAA planned to issue an emergency airworthiness directive that mandated the tests. Boeing also said it would develop a long-term plan to redesign the valve to prevent a reversal. That fix was likely to take several years.
These directives were more symbolism than real action, designed to reassure the public that the FAA was taking action. The engineers knew the tests would not be very effective. They would catch a jam if it occurred at the precise moment of the test, but a jam could still occur at any time.
Despite the seriousness of Boeing’s discovery, FAA officials say they did not give serious thought to grounding the 737 fleet. The plane had a good safety record, they said, and a jam was still considered highly unlikely. Even O’Neal, who had wanted to ground the fleet two years earlier, agreed with his bosses this time.
While the Boeing-FAA meeting was going on in Renton, Haueter and Phillips were 2,000 miles away in Pittsburgh, unaware of the dramatic developments. They had returned to the Holiday Inn near the Pittsburgh airport to meet with all the parties. Haueter and each of his group leaders gave updates on the investigation. Phillips reviewed the results of the thermal shock tests (without knowing of Boeing’s finding) and discussed what work still needed to be done. Rick Howes, the Boeing coordinator for the investigation, sat through the all-day meeting without saying a word about the company’s big discovery.
There was the usual sparring between ALPA and Boeing—this time over Boeing’s latest estimates of the rudder movement—and then the meeting ended uneventfully. Haueter put a slide on the overhead projector with a comment that an English scientist once made to Charles Lindbergh. Haueter said it had become the slogan of the 427 investigation: “Everything that happens was once infinitely improbable. Therefore, nothing that happens should be surprising.”
People chuckled and the meeting broke up. Haueter, Phillips, and Tom Jacky, the NTSB performance chairman, took a flight back to Washington. As they got off the plane at National Airport and walked toward the subway station, Haueter’s beeper went off. The NTSB had a new pager system that could transmit words as well as phone numbers.
Haueter glanced down at it. MAJOR FINDING REL TO PIT / DEFECT FOUND ON SERVO VALVE, the pager said.
“This is a joke,” he said. “This isn’t real. Some jerk has figured out our paging system.” They went their separate ways and headed home.
The message had come from Schleede, Haueter’s boss, who had been working late in the NTSB office when McGrew and John Purvis, the head of Boeing’s accident investigations, called to tell him about the finding. Schleede transmitted the message to Haueter and then walked downstairs to the bar at the L’Enfant Plaza Hotel, where Hall was having a drink.
“Jim,” Schleede said, “I think we’ve got it.”
The next day, the FAA briefed Haueter, Phillips, and other NTSB officials about the finding. Haueter realized that it was a major piece of his puzzle.
“This isn’t the way I thought it would end,” he told Phillips as they walked back after the meeting. “I expected it was going to be a fight all the way to the end, putting all these little pieces together, with people saying we wouldn’t have enough evidence. And all of a sudden here is something no one expected.”
That day, Boeing sent a telex message to every airline in the world that flew 737s:
Boeing Alert Service Bulletin 737-27A1202 dated November 1, 1996
The dual servo valve is designed to overcome the effects of a jammed primary or secondary slide. Although there has never been a report of a secondary slide jam, tests just completed at Boeing have shown that, under certain conditions, some jams of the secondary slide can result in anomalous rudder motion.
Anomalous rudder motion. It was a Boeing euphemism for a catastrophic situation—a rudder jam and a reversal.
Cox heard rumblings about the discovery on Halloween night but didn’t hear the news until the morning of November 1, when the alert was issued. He had spent an extra day in Pittsburgh and was summoned to the office of USAir vice president/flight operations William Barr. A group of pilots and safety officials were meeting to discuss the service bulletin and how USAir should respond. There were major implications for USAir because it had the third-largest fleet of 737s in the world.
Barr asked Cox point-blank, “Is the airplane safe?”
“Yes,” Cox said. He was convinced that a jam was still highly unlikely and that, even if one occurred, pilots could recover. USAir had been the first airline to raise its minimum speed above the crossover point, so USAir pilots had an extra cushion of safety. And the airline’s pilots were already doing a rigorous rudder check, which meant they were effectively conducting the test before every flight.
That afternoon Boeing issued a carefully worded press release that downplayed the seriousness of the discovery:
Boeing recently discovered that, under certain conditions, a jam of the PCU’s secondary slide could possibly interfere with the intended operation of the unit. The discovery was made by several Boeing engineers during a careful review of data generated by a National Transportation Safety Board test for the effects of thermal shocks on the PCU….
“This is the nature of our business,” said Charlie Higgins, Boeing vice president/airplane safety and performance. “We identify very unlikely possibilities and take steps to eliminate them, or at least to further reduce their likelihood of ever happening. That’s one of the ways we keep enhancing the safety of the aviation system.”
It was too late for Cox to fly back to St. Petersburg, so he ended up at a Motel 6 near the Pittsburgh airport, watching reports on the rudder discovery on CNN. “This could wrap up 427 quickly,” he said in a phone conversation between reports. “This could be the ‘Aha!’” He said the lack of markings inside the valve was evidence that the gremlin in the rudder system “is a thief in the night. It leaves no trail.”
He praised Boeing for being so forthcoming about the discovery. “I’m extremely pleased. They stepped forward.”
Just before Thanksgiving, Phillips went back to the Parker plant in Irvine to compare the valve from the USAir plane with the ones from the Eastwind and the factory PCUs. He wanted to find out if there was something that made the 427 valve jam when the others would not.
Every rudder valve was slightly different. All valves had to meet certain Boeing and FAA standards, but the holes for hydraulic fluid on each one were never exactly the same. The tests so far suggested that some valves could be more prone to reverse than others.
At Parker, the three valves were each disassembled and examined and then hooked into a test rig to see how far off neutral they had to be moved before the rudder would reverse. The factory valve performed the best. It would not reverse until the outer slide was 38 percent extended. But the USAir and Eastwind valves would reverse more easily, when the slides were 12 and 17 percent extended, respectively. Also, a measurement of the distance between the valve slides found that the USAir unit was considerably tighter than the other two.