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( Go to ALPA Petition )
Captain
H. G. Gibson
Petition
for Reconsideration
Aircraft
Accident
-
Trans
World Airlines, Inc.,
Boeing
727-31, N84OTW, Near Saginaw, Michigan
April
4, 1979
(NTSB-AAR-8
1-8)
RESPONSE
TO PETITION
FOR
RECONSIDERATION
In
accordance with the Safety Board’s rules (49 CFR Part
845),
the
Safety Board has considered the May 2, 1991 Petition for Reconsideration
1
in
the aviation accident involving a Trans World Airline, Inc. (TWA) Boeing
727-31, N84OTW, near Saginaw, Michigan, on April 4, 1979. Based on its review
of the petition and the facts derived during the course of the investigation
and subsequent reviews, the National Transportation Safety Board denies the
petition in its entirety.
On
June 9, 1981, the Safety Board determined that the accident occurred after the
airplane entered an uncontrolled maneuver at 39,000 feet while near Saginaw,
Michigan. The airplane descended to about 5,000 feet in 63 seconds before the
flightcrew regained control and made an emergency landing at Metropolitan
Airport, Detroit, Michigan. The Safety Board’s analysis of the evidence
indicated that the uncontrolled maneuver began after the leading edge slats
were retracted and the airplane’s No. 7 leading edge slat on the right
wing remained in the extended or a partially extended position. The isolated
extension of the No. 7 leading edge slat resulted in a roll which led to a
reduction in the airplane’s lateral control margin to zero or less. The
loss of lateral control was the result of a combination of the extended slat,
Mach number, angle of attack, and sideslip. The airplane entered a descending
right spiral,
and control of the airplane was regained only after the No. 7 slat was torn
from the airplane.
1Submitted
as “petition to reopen the investigation, hold a public hearing, and
reconsider
findings
of
probable cause.”
2629F The
Safety Board’s investigation revealed no evidence of irregularity,
malfunction or failure of the airplane’s ffight control, autopilot,
hydraulic, or flap systems that might have caused or contributed to a lateral
control problem. Further, there was no evidence of any combination of failures
or malfunctions in the airplane’s ffight control system that would have
caused an unscheduled extension of the No. 7 leading edge slat by itself.
In
adopting its report, the Safety Board detemiined that the probable cause of the
accident was, “the isolation of the No. 7 leading edge slat in the full
or a partially extended position after an extension of the Nos. 2, 3, 6, and 7
leading edge slats and the subsequent retraction of the Nos. 2, 3, and 6 slats,
and the captain’s untimely flight control inputs to counter the roll
resulting from the slat asymmetry. Contributing to the cause was a preexisting
misalignment of the No. 7 slat which, when combined with the cruise condition
airloads, interfered with the retraction of that slat. After eliminating all
probable individual or combined mechanical failures or malfunctions which could
lead to slat extension, the Safety Board determined that the extension of the
slats was the result of the flightcrew’s manipulation of the flap/slat
controls. Contributing to the captain’s untimely use of the flight
controls was distraction due probably to his efforts to rectify the source of
the control problem.” Three Board Members voted to adopt the report; two
Members did not participate. Member Francis McAdams, while voting to adopt the
report, filed a concurring and dissenting statement.
On
January 11, 1983, the Air Line Pilots Association (ALPA) submitted a Petition
for Reconsideration of probable cause and a request to reopen the
investigation. The Petitioner contended that it was likely that there was a
mechanical failure of the No. 7 slat actuator which resulted in uncommanded
extension. On June 24, 1983, and August 28, 1983, Petitioner provided
supplemental submissions concerning slat anomalies and the validity of using
the Flight Data Recorder (FDR) data to make aerodynamic drag calculations.
On
December 15, 1983 the Safety Board denied the petition in its entirety. The
denial stated “Petitioner has provided no new evidence in either its
petition or the supplements thereto to establish a valid possibility of a
mechanical failure of the Ronson actuator piston on the accident airplane.
Finally, Petitioner has provided no information to show that the Board’s
findings as to the facts, conditions, or circumstances of the accident are
erroneous, or that the Board’s conclusions regarding the probable cause
of the accident are incorrect.” At that time, the five Safety Board
Members unanimously denied the petition.
On
October 9, 1990, ALPA submitted another Petition for Reconsideration of
probable cause. This petition consists of 116 pages and claims that the Safety
Board and all parties to the investigation erroneously assumed that the No. 7
leading edge slat, which separated from the airplane in flight, was the
initiating cause of the accident. ALPA stated that it now believes that the
previous premise is erroneous. In a cover letter to its petition, ALPA stated
that a malfunction in the rudder control system most likely contributed to the
initial upset. The response to the ALPA petition is being handled separately in
a manner independent of the subject petition from Captain Gibson.
On
December 2, 1991, Trans World Airlines, Inc., filed a petition to reopen the
investigation, hold a public hearing, and reconsider the probable cause in the
subject accident. TWA’s stated purpose of the petition was to
“finally put to rest the questions
-raised
in the petition of Captain Gibson...” The TWA petition is also being
handled independent of the subject petition from Captain Gibson.
The
Petitioner presents eight issues in the Petition, Part One, entitled,
“How Problems with the Boeing 727 Flight Controls Were Covered Up in NTSB
Investigation.” They are as follows:
Issue
No. 1, CVR system checkouts,
Issue
No. 2, Rumor of slat extension by crew generated by NTSB Investigator-in-Charge,
Issue
No. 3, Boeing’s dogma that is impossible for slats on its 727 to deploy
accidentally,
Issue
No. 4, Slat deployment in this case did not occur at 39,000 feet at the
beginning of the upset,
Issue
No.5, Boeing discredits its scenarios...but they remain in the NTSB report and
finding,
Issue
No.6, Boeing writes the probable cause,
Issue
No.7, Boeing and NTSB destroy evidence, and
Issue
No.8, Crew participation frustrated.
Additional
issues are presented in Part Two of the petition entitled, “How Design
Defect in Autopilot and Other Control Problems with the Boeing 727 was Revealed
Despite NTSB Investigation Coverup.” They are as follows:
Issue
No. 9, No. 7 slat extension was the result of the dive rather than cause, Issue
No. 10, Extended No. 7 slat could not have caused the upset, Issue No. 11, TWA
concealed from the NTSB a siniilar control problem.
Issue
No. 12, Publicity surrounding ALPA’s 1990 petition leads to discovery of
other problems,
Issue
No. 13, “Buzz” as a result of outboard aileron bolt failure with
the possible yaw damper and rudder actuating system malfunctions,
Issue
No. 14, Boeing 727 grounded/split rudder condition,
Issue
No.
15,
Control
problems that continue to affect Boeing 727.
The
following discussion addresses the alleged new evidence and/or errors in
analysis in the order presented. No. 1, the cockpit voice recorder (CVR).
Petitioner states, “it is not even known whether the recorder system was
functioning as intended or whether it was influenced by electrical anomalies
following the emergency landing.”
The
Safety Board recognizes that the CVR on board the accident airplane, with its
30-minute recording duration, did not contain contemporaneous information about
the accident scenario. The only audio evidence from the CVR that was available
to the investigation was a brief crew conversation that was detemiined to have
taken place after the airplane had landed in Detroit As a result, the Safety
Board concludes that the CVR information is largely irrelevant to the
investigation and should not be a subject for reconsideration.
No.
2. Petitioner states, “Rumor of slat extension by crew generated by NTSB
investigator-in-charge becomes foundation for Board’s findings of
probable cause.” The “new evidence” presented by the
petitioner is a series of references to an October
15,
1979
Aviation Consumer magazine article and testimony given by the Safety Board
Investigator-in-Charge in an April 1982 deposition for a civil damage case.
With
regard to issue No. 2, Safety Board analysis of the substance of these articles
and a transcript of the testimony indicates that they do not add substantive
material facts to the investigation. As a result, the Safety Board concludes
that this material does not constitute “new evidence” on which to
base a reconsideration.
No.
3. Petitioner states, “Boeing’s dogma that it is impossible for
slats on its 727 to deploy accidentally.” Petitioner submits as
“new evidence” records of eight instances of unscheduled slat
deployments on Boeing 727 flights occurring between January 12, 1978, and
February 28, 1989.
With
regard to issue No. 3, the Safety Board addressed the subject of the
unscheduled extension of leading edge slats in the Board’s Aircraft
Accident Report AAR-81-8, paragraphs 1.16.1 and 1.17.2. These anomalies have
occurred for a variety of reasons. In each instance the flight crew has
recognized the condition and taken corrective action to control the flight
path. These events are part of a continuing airworthiness effort by the Federal
Aviation Administration (FAA) and the manufacturer. As a result, the Safety
Board concludes that this material, as serious as it may appear, does not
constitute “new evidence” on which to base a reconsideration.
No.
4. Petitioner postulates that slat deployment in this case (the accident) did
not occur at 39,000 feet at the beginning of the upset, but close to 12,000
feet near its end.
Petitioner
offers a statement, “When the landing gear was extended, it ruptured
system A hydraulics, which according to Boeing, is what holds the slats
in.” Petitioner does not provide any supporting evidence for the theory
at this point however, the reader is advised that, “All of this is
detaiied in Part II of this petition.”
With
regard to issue No. 4, the Safety Board’s response to this subject
appears after material presented by the petitioner in Part II, issue No.9.
No.
5.
Petitioner
states that “Boeing’s engineers discredit its
“scenarios” about why captain unable to promptly recover
control...but they remain in NTSB report and finding.” Petitioner claims
under the heading of “new evidence” that, “it was
Boeing’s reading of the flight data recorder (FDR)--not Captain Gibson--
that was “spatially disoriented.” Petitioner presents material
which he describes as “fictional scenarios” which were allegedly
used in an investigative coverup. However, petitioner does not present new
material to substantiate a claim of erroneous findings regarding the reading of
the FDR or the detemiination of the flight path.
With
regard to issue No. 5, the Safety Board’s Aircraft Accident Report,
AAR-81-8, addresses the subject within the Analysis section, paragraph 2.5,
Loss of Control. The material presented therein was prepared by Safety Board
staff using a variety of investigative group inputs and the professional
knowledge of flight test and aircraft performance engineers. Analysis of the
flight path contains neither a reference to a roll maneuver of right
-
then
left to 220 degrees
-
then
right, nor does it refer to any “overcotrol” theory. The Safety
Board’s analysis of the flightpath indicates that, “At 2147:45, the
aircraft was in a right bank of about
35
degrees,
after which it rolled rapidly left to near a wings level attitude. About
2147:47, the aircraft began to roll again to the right,...” The Safety
Board believes that the analysis of the flight path is as accurate and correct
as can be detemiined using the type of FDR that was installed in the accident
airplane. As a result, and lacking evidence to the contrary, the Safety Board
concludes that the petitioner has not presented material on which to base a
reconsideration.
No.
6. Petitioner asserts “Boeing writes Board’s finding of probable
cause.” As new evidence, petitioner asserts that words prepared by the
Boeing company were paraphrased by the Safety Board report writer and adopted
by the Board.
With
regard to issue No. 6, 49 Code of Federal Regulations (CFR) 831.14 and 845.27,
relating to investigations, provide and the Safety Board actively encourages
the submission of proposed findings and probable cause statements. It is not
unusual for the Safety Board to adopt wording that may be very similar to the
submittal of one or more parties. It is within the Board’s prerogative
and it is, indeed, an obligation of the Safety Board Act to provide the best
statement of probable cause from whatever source. As a result, the Safety Board
concludes that the Petitioner has not presented material on which to base a
reconsideration.
No.
7. The Petitioner charges, “Boeing and NTSB investigator destroyed
evidence.
The
Safety Board practices regarding the return of parts that have been in the
Safety Board’s custody to the aircraft owner or the owner’s
representative have evolved over tinie to a formalized procedure. Likewise,
investigators’ source material, such as witness statements, reports, and
photos that are used in the preparation of a formal report, are covered by
updated procedures that set forth what should be entered into the public
docket. With regard to the physical evidence related to issue No. 7, the Safety
Board believes that it is more appropriate to characterize the handling of
those items by the Investigator-in-Charge and the Boeing engineering personnel
as disposal of excess material no longer considered necessary for the
continuing investigation. As a result, the Safety Board recognizes that, by
current standards, such material would be handled differently. However, now
lacking the evidence, and any evidence of intent, the Safety Board concludes
that the petitioner has not presented material on which to base a
reconsideration.
No.
8, Crew participation fnistrated. During the investigation, crew members were
formally deposed on two occasions. They were represented by their employer and
their labor organization at all times. Investigative activity was undertaken in
the traditional group manner with the participation of representatives of the
ffightcrew’s employer and labor organization as parties to the
investigation. In addition, 49 CFR 831.14 provides those concerned persons with
an avenue through which to communicate directly with the Safety Board. The
flightcrew did not avail themselves of this opportunity during the progress of
the investigation. However, it should also be noted that it is not the practice
of the Safety Board to invite or permit the involved crew members to
participate actively as a member of an investigative group during the
investigation process.
With
regard to issue No. 8, the Safety Board believes that there was ample
opportunity for the flightcrew to have made its views known during the
investigative process either directly, or through their union or company
representatives; however, they chose not to do so. As a result, the Safety
Board concludes that the petitioner has not presented material on which to base
a reconsideration.
No.
9. Petitioner states No. 7 slat extension was the result of dive rather than
its cause. Petitioner refers to a portion of the Boeing Company’s report
that states “...with no pre-existing damage, that slat would have
departed the aircraft when its speed reached 363 KIAS when the aircraft
descended to approximately 31,500 feet.”
As
part of the research directed toward this reconsideration, the Boeing Company
on January 11, 1993, provided the Safety Board with a revised Figure B.2.1(7),
Estimated Time of Slat Separation, which corresponds with the discussion in the
Boeing Report, paragraph B.2.2.1.2. That discussion states that slat separation
and departure could occur between 360 and 400 knots Equivalent Air Speed.
Petitioner
theorizes that the No. 7 slat did not fail until the end of the dive maneuver.
Offered as evidence are the ground trail of debris and the ability of the
ffightcrew to extend the landing gear with “A” system hydraulic
pressure.
Petitioner
advances the theory that, “Had the No. 7 slat departed the aircraft early
in the dive, at 31,500 feet as calculated by the Boeing Company, then
“A” system hydraulic pressure could. not have been available to
extend the landing gear.”
Petitioner’s
theory appears to be based on the premise that a complete failure of hydraulic
system “A” is coincident with the separation of the No. 7 slat.
This is not the case. Due to the small diameter of the hydraulic lines in the
leading edge slat system, the hydraulic system operating pressure of 3,000
pounds per square inch (psi) will remain available after the system has been
breached until the reservoir is drained, a period of several niinutes.
Investigators
on scene in Detroit found the area aft of No. 7 slat bathed with hydraulic
fluid. However, no such bathing or evidence of escape of a considerable
quantity of hydraulic fluid was observed in the wheel well.
Petitioner’s
statement regarding the extension of the landing gear also indicates a general
assumption that the “A” hydraulic system is necessary to
“extend” the landing gear. While this statement is true regarding
an overall systems description, the statement requires operational
clarification. When the landing gear handle is moved to the down position while
positive “G’s” are applied to the airframe, the main landing
gear will extend by themselves provided there is sufficient hydraulic pressure
available to (1) open the internal gear door actuator locks and (2) open the
landing gear uplocks. It should also be noted that opening the gear doors
causes fluid to be displaced into the return lines, thereby temporarily
“increasing” system quantity.
The
Safety Board believes that the time interval between the loss of No. 7 slat
(with concurrent hydraulic fluid escape) and the movement of the gear handle to
the down position was short enough that sufficient system “A”
hydraulic pressure remained to open the gear door actuator locks and the
landing gear uplocks. Thereafter, positive “G’s” provided
sufficient force to extend (and to overextend and damage) the main landing
gear. However, insufficient hydraulic fluid remained in the system to bathe the
landing gear area from the hydraulic line when it ruptured.
With
regard to issue No. 9, Safety Board review indicates that the Analysis
contained in Aircraft Accident Report AAR-81-8 was based on an appropriate
speed range and appropriate reference to the degree of damage noted on the slat
actuator and landing gear components as they relate to the hydraulic system
“A” of the accident airplane. As a result, the Safety Board
concludes that the petitioner has not presented material on which to base a
reconsideration.
No.
10. Petitioner quotes the following, “The Boeing Company fuither stated
that an extension of the No. 7 leading edge slat at .80 mach and 39,000 feet
would have been easily controllable requiring only approximately half lateral
control authority to counter the right rolling movement.”
The
Safety Board concurs with the above statement. However, the petitioner goes on
to present a statement of conclusion, “Therefore, an extended No. 7
leading edge slat could not have caused the upset.” However, the
petitioner does not offer any basis in fact for this conclusion.
With
regard to issue No. 10, the Safety Board analysis of the accident indicated
that the asynimetrical slat condition resulting from the extended No. 7 slat
was part of a series of events that led to the flightcrew’s loss of
aircraft control. The Safety Board’s probable cause statement recognizes
a series of events, including slat asyninietry and, in addition, “the
captain’s untimely flight control inputs to counter the roll resulting
from the slat asymmetry.” Thus, in these circumstances, the Safety Board
concludes that the petitioner has not presented material on which to base a
reconsideration.
The
following discussion addresses the new evidence and/or errors in analysis as
presented in the Petition with regard to issue No. 11. Petitioner states that
“TWA concealed from NTSB that the same aircraft previously experienced a
similar control problem.’’
The
Safety Board has reviewed the event of May 23, 1977, presented by the
petitioner as (1) a siniilar control problem, and (2) in the sanie aircraft.
The control problem experienced on May 23, 1977, is characterized by the Check
Aimian Captain as an “autopilot disconnect” malfunction. The flying
pilot, another Check Airman, described the condition as follows, “...the
autopilot apparently disconnected (the autopilot paddles dropped to the
disengaged position), but the flight controls became extremely difficult to
manipulate in roll, and there was no annunciation provided to indicate the
source of the problem.”
The
Safety Board notes that the accident scenario which took place on B-727 N840TW
did not include any mention of “difficult to manipulate” flight
controls. On the contrary, the captain of the accident flight offered in his
testimony that “I had full (left) aileron input and full left rudder
input also, and the aircraft was still rolling to the right.”
The
Safety Board believes that the analysis of the flightpath of the accident
airplane derived from the FDR data and the later flight test, as presented in
AAR-81-8, is correct. On the basis of the evidence presented by the petitioner
as comparable, the Safety Board is not able to characterize the events as
similar control problems.
The
petitioner characterizes activity surrounding the 1977 event as
“concealed” from the Safety Board. The Safety Board does not have
evidence of concealment of facts. In any event, the Safety Board does not
believe that the 1977 event was a “similar control problem.”
Also,
there is conflicting information in the Petition for Reconsideration and
associated affidavits related to which airplane experienced the 1977 autopilot
disconnect malfunction. The Safety Board recognizes the inconsistencies in the
archived information. However, with regard to issue No. 11, the Safety Board
must evaluate the information that can be gained to support the factual record
of investigation by pursuit of these inconsistencies. Regardless of which
aircraft was involved in the 1977 incident, the Safety Board believes that the
1977 event was not a similar control problem as that experienced during the
accident flight. As a result, the Safety Board concludes that the petitioner
has not presented material on which to base a reconsideration.
No.
12. Petitioner alleges that “Publicity surrounding ALPA’s 1990
petition leads to discovery of other Boeing 727 control problems.”
Petitioner presents a list of nine events and states, “In every case,
when the pilot tried to bank the airplane or level the wings, he encountered
significant resistance and the aircraft wanted to go in the opposite
direction.”
The
Safety Board recognizes that there have been and will be recorded instances of
autopilot malfunctions. However, in each of the incidents presented by the
petitioner, the flightcrew was able to overcome the difficulties and accomplish
a successful landing. Also, following maintenance actions, the aircraft were
returned to service. Petitioner alleges that the December 1989 TWA incident is
of particular significance as it is a repeat of Flight 841 (the accident
flight) at 37,000 feet.
The
Safety Board does not agree. In the 1989 incident, forceful full right aileron
input was required, and the malfunction was indicative of an autopilot
malfunction that was manageable by the flightcrew. On the contrary, in the
accident circumstances, the flightcrew debriefings, and statements and
depositions related to the flight control inputs indicate that full and
unimpeded movement of all flight controls was possible and applied by the crew.
With regard to issue No. 12, the results of flight tests subsequent to the
accident, in which full control input was available and applied, offered close
comparisons with the FDR data from the accident airplane. As a result, the
Safety Board concludes that the Petitioner has not presented evidence of
similar control problems in other airplanes on which to base a reconsideration.
No.
13. Petitioner suggests that the “buzz and tuniing” at the
beginning of the accident ffight upset was the result of outboard aileron bolt
failure in flight and aileron “float” upwards. Petitioner further
suggests that resultant yawing movement may have resulted in a malfunction of
the yaw daniper and nidder actuating system.
The
Safety Board recognizes that a malfunction of either of these systems would
produce recognizable yawing moments and roll response. However, the Petitioner
has not provided any evidence that yawing moments associated with these systems
were observed by the flightcrew or the passengers. Also, such yawing moments
were not identifiable on the FDR. However, flight tests conducted after the
accident did produce FDR vertical acceleration traces as a result of flap
movement that were consistent with the evidence from the accident
airplane’s FDR. Likewise, drag coefficients resulting in speed changes on
the flight test airplane following flap configuration changes were consistent
with the speed changes observed on the FDR indicated airspeed traces from the
accident airplane. With regard to issue No. 13, the Petitioner has not provided
any new evidence to substantiate the premise that a malfunction of the yaw
damper or the nidder actuating system was present on the accident airplane. As
a result, the Safety Board concludes that the Petitioner has not presented
material on which to base a reconsideration.
No.
14. Petitioner states “Boeing 727 grounded as this petition was being
formulated.” Petitioner details a split rudder condition.
The
Safety Board notes that according to the maintenance report associated with
this event, the malfunction described above ceased when the autopilot was
disengaged. Petitioner implies that any manner of flight control anomaly should
be regarded as an event similar to the flight control difficulties experienced
on the accident flight.
The
Safety Board is concerned that any flight control anomaly has the potential to
become a serious hazard to flight. However, the Board attempts to keep such
anomalies in perspective regarding the airworthiness of the affected aircraft.
With regard to issue No. 14, the Safety Board’s analysis of the reported
event indicates that the flight condition was fully controllable and
correctable. As a result, the Safety Board concludes that the
Petitioner’s statement describing a split rudder condition and
unconimanded yaw does not, in itself, constitute “new evidence” on
which to base a reconsideration of probable cause.
No.
15. The Petitioner suggests that control problems that affected TWA flight 841
continue to affect B727s.
With
regard to the overall focus of issue No.
15,
and
alleged control problems that continue to affect B-727s, petitioner does not
provide specifics or evidence. The Safety Board’s analysis indicates that
the charge of continuing problems siniilar to those evident on the accident
flight has not been verified. As a result, the Safety Board concludes that the
Petitioner’s presentation of continuing control problems does not
constitute “new evidence” on which to reopen the investigation or
base a reconsideration of probable cause.
Also
in the Petition in the Nature of Mandamus filed January 13, 1995, petitioner
alleges that there is “a dangerous design defect in both the Boeing 727
and Boeing 737...,” and that investigation of the March 3, 1991, Boeing
737 accident at Colorado Springs, Colorado revealed, “Boeing 727s and
Boeing 737s share a common control defect.”
Comparative
review of the B-727 and B-737 rudder systems indicates basic design
differences. The B-727 has independent upper and lower rudders, each connected
to an independent power control unit (PCU). Each of the PCU’s control
valves are of a single spool design. The upper PCU is powered by the
“B” hydraulic system and the lower PCU is powered by the
“A” hydraulic system. There are load limit features built into the
hydraulic power sources for the PCUs. The airplane is also equipped with two
yaw damper systems which function independently through the respective upper or
lower PCUs. Rudder travel is +27.5 degrees; however, yaw damper authority is
limited to
±5
degrees. The
B-737, by comparison, has a single rudder surface, and one main rudder PCU of a
different design. The PCU is of a dual concentric control valve design which
incorporates hydraulic power from both the “A and B” hydraulic
systems. The airplane also has one yaw damper system operating at the PCU,
which is limited to 20 or
30,
depending
on the model of the airplane.
There
is one similar component (with a different part number) for the B-727 and B-737
rudder system, the standby rudder actuator. However, it should be noted that in
the B-727 application, the standby actuator functions only on the lower rudder.
In the event of a B-727 malfunction of either the upper or lower rudder control
systems or the yaw damper systems, or in the standby rudder system, sufficient
lateral control authority has been demonstrated in the ffight regime
encountered during the subject accident to overcome any unconimanded rudder
deflections up to and including full control deflection of either the upper or
lower rudder or the yaw damper system. Therefore, with respect to the theory of
a common control defect between the B-727 and B-737, the Safety Board concludes
that the petitioner has not presented evidence regarding this issue on which to
base a reconsideration.
Finally,
the airworthiness of the B-737 lateral control systems has been examined
extensively as part of the ongoing investigation of the US Air 427 accident at
Pittsburgh. If during the continuation of the USAir investigation, or any
future accident or incident investigation, an airworthiness problem is
identified that could result in a loss of control of the B-727, those findings
will be analyzed in depth.
With
regard to the probable cause, the Safety Board has considered the petition to
reopen the investigation, hold a public hearing, and reconsider findings of
probable cause. As a result, the Safety Board concludes that the Petitioner has
not provided new evidence or shown that the Board’s findings as to the
facts, conditions, or circumstances of the accident are erroneous, or that the
Board’s conclusions regarding the probable cause are incorrect.
Accordingly,
Captain H. G. Gibson’s petition for reconsideration of May 2, 1991, to
reopen the investigation, hold a public hearing, and reconsider findings of
probable cause is hereby denied.
Chairman
HALL, Vice Chairman FRANCIS, and Member HAMMERSCHMIDT concurred in the
disposition of this petition for reconsideration.
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