USAir 427 hearings

From: (Byron Acohido)
Organization: The Seattle Times
Date:         04 Dec 95 01:14:57 
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Here are stories from the recent NTSB hearings on USAir 427. I'd welcome
any feedback. Thanks, Byron Acohido, aerospace reporter, Seattle Times.

FILE NUMBER          2153494
EDITION              FINAL
SECTION              NEWS
PAGE                 A23
STORY SIZE           29 INCHES

     SPRINGFIELD, Va. - Without declaring the Boeing 737 unsafe, safety
authorities are stepping up actions to address several troubling
weaknesses in the control system of the world's most popular jetliner.
     The National Transportation Safety Board concluded an unusual
three-day hearing last week urging The Boeing Co. and the Federal Aviation
Administration to take prompt action to improve the 737's flight controls.
      Aviation officials questioned whether the 737's flight-control
system should be redesigned - an astronomical expense considering the
complexity of the system and the more than 2,600 planes in service.
    Yet the safety board is no closer to explaining why USAir Flight 427,
a Boeing 737-300, flipped out of calm, clear skies on Sept. 8, 1994, on
approach to landing in Pittsburgh. Nor can authorities say why a United
737-200 crashed under similar circum stances in Colorado Springs, Colo.,
four years ago.
     Pilots have reported several hundred cases of 737 flight controls
moving inadvertently in flight - more than 45 in the last 14 months.
   "How many more?"
    Relatives of the 132 people killed on Flight 427 are pressing for
answers. At the hearing, many of them were briefed by safety-board
chairman Jim Hall and lead investigator Tom Haueter. Jon Hamley, whose
wife, Sarah Slocum-Hamley, was Flight 427's lea d flight attendant, has
closely tracked the investigation.
     He noted that 737s have crashed in England, Turkey, El Salvador and
Nigeria since Flight 427 went down.
      "How many more 737s have to go down before they do something?" he
asked. "I'm no expert. . . . but 28 years' worth of incidents? Four
crashes since (Flight) 427?"
       In Boeing's view, deceased pilots Peter Germano and Charles Emmett
could be to blame for the crash of Flight 427.
     Jim Kerrigan, principal 737 engineer, testified that a re-creation of
the crash shows the USAir jet's rudder could have swung to the extreme
left, causing the fatal dive.
     But Kerrigan said Boeing has been unable to pinpoint "any particular
failure mode." The only other possibility is pilot error, he said.

 Lingering questions

    Boeing and safety officials still call the 737 one of the safest jets.
But other testimony and records shed light on lingering questions:
      --  Rudder hardover: Officials are concerned the rudder, the part of
the vertical tail piece that controls the jet's left/right heading, could
deflect to an acute angle in flight.
     In certifying the 737 as safe in 1967, the FAA never required Boeing
to prove the jet could safely recover from a rudder hardover; it was
deemed improbable.
      But officials now know of many ways the rudder can, in theory at
least, swing hardover when dirty hydraulic fluid moves through the
flight-control system. NTSB chief technical adviser William Laynor said
there's been no action because there's no con crete evidence of any rudder
hardover in flight.
     Boeing is studying the probability of rudder hardovers in flight, and
the FAA has called for a probe into how sensitive the 737's flight
controls are to dirty fluid.
     But in Seattle Friday, Boeing President Phil Condit said he doubted
that dirty hydraulic fluid caused 737 flight controls to malfunction.
     "I don't see any information that would tell me that," Condit said.
"None. We have done lots of testing. Boy, I don't see anything."
     --  Rudder reversal: One type of hardover can occur when an
out-of-adjustment rudder valve jams and moves too far, causing the rudder
to deflect in the wrong direction.
      The FAA has ordered airlines to replace an internal valve part and
verify proper adjustment of the valve to eliminate the possibility of
rudder reversal.
      But planes with upgraded valves still have problems. NTSB records
show the rudder of an America West 737 moved inadvertently in late August
and again in early September near Phoenix. The jet's valve was upgraded in
response to the FAA order last May.
     After the second incident, the upgraded valve was removed and sent to
its manufacturer, Parker Hannifin, for examination, records show. Haueter,
the safety board's chief investigator, said he was unaware of the status
of that valve.
     --  Yaw damper: This computer makes thousands of small rudder
adjustments during flight. It has been blamed for hundreds of inadvertent
rudder movements over the years. But officials say there's no danger
because the yaw damper can only command compa ratively small rudder
movements, and pilots can easily switch the yaw damper off.
      But Boeing flight-controls engineer Richard Kullberg testified that
the yaw damper can move the rudder more than twice its normal limit,
should a stand-by rudder valve jam.
      Levers on the stand-by valve of both the United jet and the USAir
jet were found "galled," or worn from rubbing too close to each other,
indicating they may have jammed.
     Kullberg said Boeing is working on a "service bulletin" advising
airlines to install a special bushing to make the stand-by valve less
susceptible to jamming, but the improvement is voluntary. He said Boeing
does not consider the matter a safety issu e.
    Jean McGrew, chief 737 project engineer, testified that Boeing is
evaluating improvements to the yaw damper but wouldn't describe them.
     Though Boeing contends "the yaw damper is not involved in the
accident in any way," the company does believe the reliability of the
device needs improvement, McGrew said.
     --  Redesigning flight controls: A rudder hardover is especially
worrisome when the 737 is slowing and descending on approach to landing.
At lower speeds, the pilots lose the ability to counter the effects of the
rudder by turning the control wheel i n the opposite direction, which
extends wing panels called ailerons.
      Retired USAir Capt. Herb LeGrow, representing the Airline Pilots
Association, questioned Boeing engineers about the possibility of
redesigning the ailerons and/or rudder to give pilots more ability to
recover from a rudder hardover at lower speeds.
     One way to do that would be to restrict the rudder's range of
movement once it becomes airborne. Pilots only need an acute rudder
movement in a specific emergency, when one engine shuts down during
takeoff. In that case, deflecting the rudder hardove r helps keep the
plane flying straight ahead.
     Or the ailerons could be made bigger or redesigned to extend at more
acute angles. But redesigning the 737's flight controls would likely
require the plane to be largely recertified, an ALPA source said.
     Art Wolk, an attorney representing families of victims from the
Colorado Springs and Pittsburgh crashes, said authorities have more than
enough evidence to order major 737 improvements.
       "Here's an airplane that's telegraphing it's going to crash, and
nobody is willing to ground it and make Boeing redesign the rudder," Wolk
said. "This is like the Simpson jury wanting a video tape of the crime in
order to convict Simpson."


FILE NUMBER          2153094
EDITION              FINAL
PAGE                 D4
STORY SIZE           13 INCHES

       SPRINGFIELD, Va. - If USAir Flight 427 flew into turbulence
swirling from the wingtips of another jet flying four miles ahead, the
encounter was entirely routine.
       That's what Federal Aviation Administration test pilot Les Berven
concluded after repeatedly flying a Boeing 737 into the "wake vortexes" of
another jet as part of a $1 million experiment last September.
     Berven's testimony, given yesterday at a special National
Transportation Safety Board hearing, seemed to undermine speculation that
a wake vortex encounter disoriented pilots Peter Germano and Charles
Emmett, causing them to fly a fully-loaded 737-30 0 jet into the ground.
     The NTSB has been unable to explain why the USAir jet piloted by
Germano and Emmett suddenly flipped out of calm, clear skies the evening
of Sept. 8, 1994, in Pittsburgh. Nor can authorities say why a United
Airlines 737-200 crashed under similar cir cumstances in Colorado Springs
four years ago.
     Berven said he purposely flew more than 200 times into wake vortexes
and proved what many experts and pilots have long believed: Wake vortex
encounters are inconsequential for big jets.
     "I think we covered just about everything that could be done. We went
up and down and crossways," Berven testified. "You can pull up in there
with absolute impunity. You can fly in any way you want. You can hit any
one or both of the vortexes without
 a controllability problem."
     Despite Berven's testimony, The Boeing Co. used the same wake vortex
test results to lay more groundwork for the startled-pilot theory.
     Boeing test pilot Mike Carriker, who participated in the experiment,
testified that a wake vortex encounter could take airline pilots by
surprise and confuse them. Carriker said most U.S. pilots have "average"
flying skills.
       Carriker showed a videotape of one test flight piloted by himself
and USAir Capt. John Cox in which the test aircraft hit a wake vortex and
rolled sharply to the left. His testimony appeared to contradict Berven's
       But then Cox took the witness stand and pointed out that he and
Carriker had purposely let the airplane drift into the vortex at an
unusual angle - with their hands and feet off the controls and the
autopilot turned off.
      "We literally had our feet flat on the floor and our hands straight
up," Cox said.
       Commercial pilots routinely encounter wake vortexes and
instinctively make the small control adjustments needed to smooth out
flight within seconds, Cox said, adding that he has never become
disoriented while encountering wake vortexes on actual fl ights.
     Another theory for both the Colorado Springs and Pittsburgh crashes
holds that the rudder system jammed and moved the rudder sharply without
it being commanded to do so.
      Flight 427's flight data recorder, which charts the aircraft's
trajectory, shows the jet fell from the sky in a way that can only be
explained by a sudden, acute movement of the rudder.
      Moreover, the cockpit voice recorder captured the sound of the
engines revving, consistent with the rise in engine noise that occurs when
a rudder is deflected in flight.


FILE NUMBER          2152862
EDITION              FINAL
PAGE                 C1
STORY SIZE           25 INCHES

     SPRINGFIELD, Va. - Aviation safety authorities are being urged to
take a harder look at whether dirty hydraulic fluid may be causing the
flight controls of Boeing 737 jetliners to regularly malfunction in

     But a Boeing Co. hydraulics expert, Richard Kullberg, testified
yesterday he could not think of any detective work that hasn't already
been done.

     Those developments came yesterday as the National Transportation
Safety Board opened an unusual hearing to publicly air its investigation
of two unsolved 737 crashes in four years - and more than 45 recent cases
of flight controls moving inadvertentl y on 737 flights.

     A USAir 737-300 inexplicably flipped out of the sky Sept. 8, 1994, in
Pittsburgh, four years after a United 737-200 crashed under similar
circumstances in Colorado Springs, Colo. The two crashes killed 156 in
all. Despite extensive investigations, th e safety board has been unable
to solve either accident.

      Investigators revealed new evidence yesterday indicating the USAir
jet's rudder swung to an extreme position, twisting the fully-loaded
Boeing 737-300 jetliner into a fatal dive.

     Recent analysis of sounds captured on the cockpit voice recorder
indicate the engines changed pitch as the rudder moved acutely to the

     But the central mystery remains whether pilot error or a mechanical
failure caused the rudder to move so drastically.

     Boeing engineer Kullberg, who also serves as a designated Federal
Aviation Administration representative in charge of certifying 737 and 757
flight-control systems, reiterated the company stance that there is no
evidence of equipment failure in eithe r the Colorado Springs or
Pittsburgh crashes.

     Kullberg characterized the 737s long-running flight control problems
as posing no safety hazards.

     Even so, he said Boeing recently responded in writing to 12 of 27
concerns outlined in a special "critical design review" of the 737's
flight control system completed by the FAA last May.

     Among other things, the FAA called for tests to determine how
sensitive the 737's flight controls are to dirty hydraulic fluid as well
as for an investigation into all the ways the 737's wing and tail panels,
including the rudder, can move inadverten tly in flight.

     In response to questioning from safety board Chairman Jim Hall,
Kullberg said Boeing has responded to the FAA's suggestions with extensive
written analysis, though he admitted none of the analysis is supported by
any actual testing.

     The FAA is now reviewing Boeing's response. But Mike Zielinski, a
member of the FAA review team, said no process exists to formally
implement the recommendations outlined in the agency's special review.

     "Personally I have a concern of a lack of closure and continuing
discussion with no real resolution," Zielinski said.

     Kullberg testified, "We still are talking about possibly running some
other tests," but said he was "at a loss to come up with anything that
would make sense that hasn't already been done."

     Other witnesses suggested a couple of possibly fruitful areas that
Boeing and safety authorities thus far have left unexplored.

     FAA hydraulics expert Werner Koch called for someone to conduct tests
to establish how "silting" of hydraulic fluid contaminants affects the
737's rudder over a long period.

     Heavy concentrations of contaminants were found in both the United
and USAir jets that crashed. The NTSB never analyzed the contaminants
retrieved from the wreckage in Colorado Springs, and it permitted Boeing
to conduct comparatively crude tests of contaminants like those recovered
in Pittsburgh. (The tests were conducted under conditions not likely to
exist in flight.)

     Koch said the possible effects of contamination silting now deserve
closer scrutiny.

     "As a result of lack of a smoking gun, that might be a logical place
to look next," Koch said, broadly describing the kind of testing that
investigators could do next.

     The safety board's Hall then turned to NTSB flight controls
investigator Greg Phillips and said, "Mr. Phillips, is that something we
can do?"

     "Yes, it is," Phillips responded.

     "Well, let's do it," Hall said.

     Paul Knerr, a member of an engineering-standards group, said
clarification of how many of the world's 2,600 737s may be flying with
highly contaminated fluid needs to be addressed as well.

     After investigators retrieved highly contaminated fluid from the
USAir jet, they took more than 100 random fluid samples from 21 other 737s
and found 22 percent of the samples were highly contaminated.

     That finding shocked the Society of Automotive Engineers (SAE), a
group that establishes fluid standards for auto, factory, aircraft,
weapons and space systems.

     Knerr, vice president of engineering for Canyon Engineers, a
hydraulics component manufacturer based in Valencia, Calif., said the SAE
had assumed jets were flying with cleaner fluid, and he noted that Boeing
has no established contamination limit fo r fluid used on its airplanes.

     Yet it is well-known that debris can readily contaminate hydraulic
components in the manufacturing process and when they are being used and
serviced on airplanes.

     The SAE is now working with the FAA to create a contamination-level
standard for commercial jets, Knerr said.

     In the meantime, Knerr asked Hall to support an effort to collect and
analyze fluid samples drawn during flights of an older 737.

     These samples would show whether debris tends to circulate in higher
concentrations when the airplane is shaking. Such information could help
investigators sort out whether dirty fluid should be considered more of a
potential threat during takeoffs a nd landings, when the aircraft is
vibrating heavily. It would also help parts makers, like Knerr, design
better components.
       "For a component manufacturer to know that the (contamination) level varies widely is very important in our design," Knerr said.


FILE NUMBER            21526379
PUBLICATION DATE           11/15/95
STORY SIZE             22 INCHES
BYLINE                 BYRON ACOHIDO

      SPRINGFIELD, Va. - Investigators today revealed evidence indicating
that USAir Flight 427's rudder swung to an extreme position, twisting the
fully loaded Boeing 737-300 jetliner into a fatal dive outside Pittsburgh
14 months ago.  Moments before the rudder moved, the jetliner encountered
wingtip turbulence from a 727 trijet flying four miles ahead, recent
testing shows.
     Those findings emerged today at an unusual hearing of the National
Transportation Safety Board to publicly air details of its so-far futile
attempt to solve the Sept. 8, 1994, crash.
      The safety board's acoustic expert, James Cash, described how
investigators analyzed three "thumps" captured on the cockpit voice
recorder moments before the jet ran into trouble.
       Similar thumps turned up on flight tests in which a 737 was
purposely flown back and forth into the wingtip turbulence of a 727 trijet
flying a few miles ahead.
       Cash said sounds recreated on the flight tests showed "the source
of the thumps . . . was most probably an encounter with the wake
turbulence of the preceding 727 aircraft."
       The tests, which cost $1 million, also revealed that 737 engines
produce a heightened roar when the rudder is deflected to an acute angle
in flight. Cash testified that Flight 427's cockpit recorder captured an
engine roar - matching the roar produ ced in the tests - just moments
after the thumps, indicating an acute rudder movement.
      The central mystery remains whether the wake vortex encounter,
normally a routine event, caused veteran pilots Peter Germano and Charles
Emmett to panic and stomp on the rudder control pedals, which would clear
The Boeing Co. of liability in the acc ident.
      Representatives from the Air Line Pilots Association are supporting
the other leading crash theory: that the rudder moved sharply on its own,
due to a malfunction, just after the plane encountered the turbulence.
      NTSB Chairman Jim Hall opened the hearing acknowledging that despite
50,000 investigative staff hours and millions of dollars worth of lab and
flight tests, investigators have been unable to explain the crash of
Flight 427, which killed all 132 peop le on board.
      Nor has it been able to solve the similar crash of a United Airlines
737 four years ago in Colorado Springs, Colo. All 25 people on board died
in that accident.
       Moreover, independent aviation experts have recently begun
questioning whether there may be a correlation between the two crashes and
more than 45 reported incidents of flight controls moving inadvertently on
737 flights in the past 14 months.

     Few expect the hearing, scheduled to run through Friday, to produce
any breakthroughs. At best, insiders said, they might reveal which way
investigators are leaning on the two leading theories: that the 737's
rudder system drastically malfunctioned or that the USAir pilots
overreacted to the wingtip turbulence.

     Among the witnesses scheduled to testify is Malcolm Cohen, a spatial
disorientation expert with the National Aeronautics and Space
Administration's Ames Research Center.

     Cohen is expected to address the issue of whether Germano and Emmett
may have been so relaxed flying a routine approach in clear, calm air that
they were startled by unexpected turbulence, causing them to animatedly
adjust the flight controls.

     The startled-pilot theory has been gaining popularity. A member of
the investigation team, who was not identified, recently told The
Washington Post that co-pilot Emmett was so relaxed he used a fake French
accent to acknowledge a corporate jet flyin g by: "Oh yaa, I seee zee
Jetstream," Emmett is reported to have said.

     Oddly, previously released transcripts of Flight 427's cockpit voice
recorder tape do not describe Emmett using a French accent when making
that statement.

     Later in the hearing, the safety board is expected to re-examine the
possibility that dirty hydraulic fluid caused the rudder to move on its
own, putting Flight 427 into its fatal dive.
       Investigators have acknowledged that dirty hydraulic fluid can, in
theory, cause a 737's rudder to suddenly reverse.

     Authorities also know dirty fluid can cause the rudder to move to an
extreme position, in response to a command for slight movement from the
pilot or the yaw damper, a computer that makes minor rudder adjustments
during flight.
       But investigators say exhaustive testing and analysis have turned up no evidence of such a malfunction occurring on either the USAir or United jets that crashed.
       Last May, the Federal Aviation Administration completed a special
"critical design review" of the 737's flight control systems. The FAA
called for a new combined investigation of the Colorado Springs and
Pittsburgh crashes.
       The agency also said an investigation was needed to determine how sensitive the 737's flight controls are to dirty fluid.
       Mike Zielinski, a member of the FAA review team, testified today
that Boeing has only recently responded to recommended safety improvements
outlined in the review. Zielinski said Boeing's response was under review,
but under questioning he acknowle dged that no formal process exists to
implement the agency's suggestions.

     "Personally I have a concern of a lack of closure and continuing
discussion with no real resolution," Zielinski said. **END OF STORY