737 AD's from FAA for Rudder System only
George
A lot of reasons why the those two 737 passenger jets lost Rudder
control ---- maybe
George
Boeing 737 Series Aeroplanes
AD/B737/48 Rudder Trim 11/90
Applicability: All model 737-300 and 737-400 series.
Requirement: 1. Replace the rudder trim control knob with a smooth
round fluted knob.
2. If the rudder trim control knob is located near the rear of the
cockpit centre console, add a guard rail with a height of approximately
38 mm (1.5 inches) to the rear of the cockpit centre console if no rail
is currently installed; or, if a rail is currently installed, raise the
cockpit centre console rear rail to a height of approximately 38 mm
(1.5 inches).
Note: FAA AD 90-14-02 Amdt 39-6644 and Boeing Service Bulletin
737-27-1165 refer.
Compliance: Prior to 30 November 1991.
Background: This Directive is raised in response to reports of
inadvertent rudder trim actuation. This condition could lead to a
take-off with an improperly trimmed rudder, and may result in a
rejected take-off.
---------------------------------------------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/79 Main Rudder Power Control Unit (PCU) 5/94
Applicability: Model 737 series, line position 1 through 2453 inclusive.
Requirement: Action in accordance with the technical requirements of
FAA AD 94-01-07 Amdt 39-8789.
Note: Boeing SL 737-SL-27-82-B and SB 737-27-1185 refer.
Compliance: As specified in the requirement document with a revised
effective date of 30 April 1994.
Background: Reports of excessive internal leakage in the rudder PCU
which could result in reduced controllability of the aircraft have been
reported.
-------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/84 Main Rudder Power Control Unit (PCU) 5/95
Applicability: All Boeing 737 series aircraft fitted with Part
Number/Serial Number PCU's as Listed in the Requirement Document which
have been modified and/or tested by Aerocontrols Inc. in Auburn,
Washington.
Requirement: Action in accordance with the technical requirements of
FAA Telegraphic AD T95-06-53.
Note: CAO 105 AD/B737/79 makes reference to Boeing SB 737-27-1185 and
FAA AD 94-01-07 which are called up as Ref B and E, respectively, in
the Requirement document.
Compliance: As specified in the Requirement Document.
Background: The FAA has advised that two reports of in-service
malfunctions of certain rudder PCU's has been reported. The PCU's were
removed from the aircraft and subsequently failed their functional
tests. Subsequent investigation confirmed that during modification of
the PCU the proper tooling may not have been used to torque the spring
retainer.
------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/99 Main Rudder Power Control Unit (PCU) 1/97
Applicability: All Boeing 737 models.
Requirement: 1. Perform a test on the main rudder power control unit
(PCU) in accordance with Boeing Alert Service Bulletin (ASB)
737-27A-1202 dated 01 November 1996 to verify proper operation.
2. If, as a result of Requirement 1, the test gives unusual results as
described in the referenced ASB, replace the main rudder PCU and
perform the test of Requirement 1.
Note: FAA AD T96-23-51 refers.
Compliance: 1. For Requirement 1, prior to 14 November 1996 and there
after at intervals not to exceed 250 hours time in service.
2. For Requirement 2, before further flight.
Background: Recent tests on the main rudder PCU conducted by Boeing
demonstrated a potential failure scenario that was previously unknown.
These tests revealed that rudder pedal can cause deformation in the
linkage leading to the primary and secondary slides of the servo valve
of the main rudder PCU if the secondary slide of the PCU jams in
certain positions. This situation could result in rudder motion in the
opposite direction of the rudder command.
-------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/104 Rudder Power Control Unit Inspection 6/97
Applicability: Main rudder power control units (PCU) that are to be
fitted to Model 737 airplanes and which are identified in Boeing
Service Letter 737-SL-27-112-B, dated February 6, 1997.
Requirement: To identify, inspect and repair suspect main rudder PCUs
prior to fitment to Model 737 aircraft in accordance with the
requirements of Boeing Service Letter 737-SL-27-112-B dated February 6,
1997.
Note: FAA AD 97-05-10 refers.
Compliance: After 90 days of the effective date of this Directive, the
requirement is to be completed prior to fitment of a replacement main
rudder PCU to an aircraft.
This Airworthiness Directive becomes effective on 22 May 1997.
Background: The FAA has received a report of cracking of the internal
summing lever of the main rudder PCU on a model 737 airplane.
Investigation showed that a Hi-Lock bolt had been installed in the
lever assembly by a repair station instead of the correct specification
bolt (Boeing Part No. 66-22749-1). The larger bolt radius of the Hi
Lock bolt in the shoulder to shank transition area was such as to
create an interference fit with the bearing that caused the inner race
of the bearing to crack. Such cracking, if not detected and corrected
could lead to seizure of the bearing and possible uncommanded rudder
movement. This Directive requires that all replacement main rudder PCUs
are inspected before fitment to ascertain if they are suspect and if so
to ensure that they have been subject to the corrective action detailed
in US FAA AD 97-05-10.
-----------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/105 Rudder Trim Switch 6/97
Applicability: All Boeing Model 737 -300, -400, -500 aeroplanes
identified in Boeing Service Bulletin 737-27A1198 dated 6 June 1996.
Requirement: Unless previously incorporated, replace the Aileron/Rudder
trim control module in accordance with Service Bulletin 737-27A1198.
Note: FAA AD 97-06-09 Amdt 39-9966 refers
Compliance: Prior to 22 May 1999.
This Airworthiness Directive becomes effective on the 22 May 1997
Background: Operators have reported unwanted rudder trim motion
occurring with the rudder trim actuator after the pilot had adjusted
the trim and released the trim switch. This AD mandates the replacement
of the module to provide a more reliable module and switch to help
prevent the identified condition.
-------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/108 Rudder Standby Power Control Unit - Bearing Replacement 4/98
Applicability: Model 737-100,-200,-300,-400, and 500 series aeroplanes.
Requirement: 1. Perform an inspection to detect galling on the input
shaft in accordance with FAA AD 97-26-01.
2. Replace the Rudder Standby Power Control Unit input shaft bearing
on all applicable aircraft in accordance with Boeing Service Letter
737-SL-27-113 dated 19 February 1997 and Dowty Aerospace Service
Bulletin 1150-27-04 dated 1 Nov 96.
Note: FAA AD 97-26-01 Amdt 36-10244 refers.
Compliance: 1. Within 18 months or 4,500 hours time-in-service after
the effective date of this directive whichever occurs later and
thereafter every 18 months or 4,500 hours time-in-service if
requirement 2 has not been accomplished.
2. Within 3 years of the effective date of this Directive.
This airworthiness directive becomes effective on 26 March 1998.
Background: The current Standby PCU input bearing utilises a lapped
journal bearing. The design has been shown to gall in service (galling
is defined as metal transfer from one surface to another of two similar
materials). Galling in the bearing can increase the force required to
move the input lever to the standby PCU. At high enough force levels,
the galling can cause yaw damper inputs to backdrive the rudder pedals.
This can also lead to increased yaw damper authority. The new lever
installation is designed with rolling element bearings to eliminate the
galling potential. Installation of this design improvement is
considered terminating action for FAA AD 97-26-01. This AD also
includes a lever force check and an inspection that must be
accomplished at certain intervals until the bearing is incorporated.
----------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/109 Flying Control Power Control Unit Cylinder Bore
Replacement 9/97
Applicability: Model 737-100, -200, -300, -400, and -500 series
aeroplanes, having a main rudder power control unit (PCU) having part
number (P/N0 65-44861 - ( ) and a serial number less than 1252A, or an
aileron or elevator PCU having P/N 65-44761 -( ) (except those P/Ns
that contain an "ss") and a serial number less than 5360A.
Requirement: 1. Perform an inspection of the applicable PCUs to
determine if reworked PCU manifold cylinder bores containing chrome
plating are installed, in accordance with Boeing Service Letter
737-SL-27-30 dated April 1, 1985.
2. Any PCUs identified with chrome plated manifold cylinder bores are
to have the bores replaced in accordance with Boeing Service Letter
737-SL-27-30 dated April 1, 1985.
Note: FAA AD 97-09-014 Amendment 39-10010 refers.
Compliance: 1. Within 5 years or 15,000 flights of the effective date
of this directive.
2. Before further flight or the next time the PCU is sent to a repair
facility, whichever occurs first.
This airworthiness directive becomes effective on 14 August 1997.
Background: Investigation into the Boeing 737 flight control system has
revealed system anomalies, which, if not corrected, could lead to
reduced controllability or uncommanded control input. This directive is
issued as a direct result of these investigations, with compliance
times as developed by the FAA.
--------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/110 Amdt 1 Rudder Yaw Damper Valve Replacement 2/99
Applicability: Model 737-100, -200, -300, -400, and -500 series
aeroplanes.
Requirement: 1. Unless already accomplished, perform a one time
inspection of the engage solenoid valve of the yaw damper to determine
the Part Number (P/N) of the valve.
2. If any valve having one of the following part numbers is installed;
Parker P/N 59600-5011 (Boeing P/N 10-60811-9); or
Parker P/N 59600-5007 (Boeing P/N 10-60811-3 (see Note 3)); or
Parker P/N 59600-5003 (Boeing P/N 10-60811-1).
replace it with one of the following valves;
Parker P/N 881600-1001 (Boeing P/N 1060811-13), or
Sterer P/N 45080-1 (Boeing P/N 10-60811-8), or
Sterer P/N 45080 (Boeing P/N 10-60811-3 (see Note 3).
The above actions are to be accomplished in accordance with procedures
specified in Chapter 22-11-61 or Chapter 22-12-21 (for 737 -100 and
-200 series aircraft) of the Boeing Maintenance Manual as applicable;
or Chapter 22-12-21 (for 737-300, -400, and -500 series aircraft) of
the Boeing Maintenance Manual.
Note 1. FAA AD 97-09-15 R1 Amendment 39-10912 refers.
Note 2. Boeing In-Service Activities Report 95-03-2725-10 dated 16
February 1995 (for model 737-100 and -200 series aircraft), or
95-04-2725-10, dated 24 February 1995 (for Model 737-300, -400 and -500
series aircraft) provide additional information concerning
interchangeability of solenoid valve part numbers.
Note 3. Operators should note that, as identified above, two Parker
and Sterer Part Numbers have the same Boeing Part Number (10-60811-3).
If, upon inspection, Boeing Part number 10-60811-3 is found to be
installed, operators must ascertain the vendor part number. Parts with
Boeing P/N 10-60811-3 and Parker P/N 59600-5007 must be replaced and
are not considered to be acceptable replacement parts. In addition,
some engage solenoid valves may be labelled with only the name
"Bertea", rather than "Parker" or "Parker-Bertea".
Compliance: 1. Within 5 years or 15,000 flights of the effective date
of this Directive or at the next time the PCU is removed for
maintenance, whichever is the earlier.
2. Before further flight.
This Amendment becomes effective on 25 February 1999.
Background: Investigation into the Boeing 737 flight control system has
revealed system anomalies, which, if not corrected, could lead to
reduced controllability or uncommanded control input. This Directive is
issued as a direct result of these investigations and is to remove a
potential source of failure within the yaw system.
This Amendment is issued to clarify component identification and
reflects the requirements of the Country of Origin Aviation Authority.
The original issue of this Airworthiness Directive became effective on
17 July 1997.
------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/112 Yaw Damper Coupler Internal Rate Gyroscope 9/98
Applicability: All model 737-100, -200 , -300, -400 and -500 series
aeroplanes.
Requirement: 1. Remove the yaw damper coupler, replace the internal
rate gyroscope with a new or overhauled unit and then test the yaw
damper coupler to verify its integrity. All actions are to be performed
in accordance with Boeing 737 Service Letter 737-SL-22-038 dated 6
April 1998.
2. If the yaw damper coupler fails the Requirement 1 integrity test,
repair the coupler in accordance with 737-SL-22-038.
Note: FAA AD 98-02-01 Amdt 10283 refers.
Compliance: 1. a. For aeroplanes on which the yaw damper has
accumulated less than 12,000 hours time in service since its last
maintenance activity as at the effective date of this directive: Within
6,000 hours time in service from the effective date of this directive
and thereafter at intervals not to exceed 9,000 hours time in service.
b. For aeroplanes on which the yaw damper has accumulated 12,000 or
more hours time in service since its last maintenance activity as at
the effective date of this directive: Within 3,000 hours time in
service from the effective date of this directive and thereafter at
intervals not to exceed 9,000 hours time in service.
2. Prior to installation on an aircraft.
This airworthiness directive becomes effective on 13 August 1998.
Background: The Federal Aviation Administration has determined that the
replacement of the internal rate gyroscope will significantly increase
the reliability of the yaw damper coupler system. This directive is
intended to decrease the likelihood of sudden uncommanded yawing of the
aeroplane due to potential failures within the yaw damper system.
-----------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/113 Rudder Power Control Unit Replacement 3/98
Applicability: Model 737 series aeroplanes, having a main rudder power
control unit (PCU) and vernier control rod bolts that are identified in
Boeing Alert Service Bulletin (ASB) 737-27A1202 Revision 2, dated
August 7, 1997.
Requirement: 1. Perform the test requirements of Part I of the
Accomplishment Instructions of Boeing ASB 737-27A1202.
2. Replace the rudder PCU in accordance with Part II of the
Accomplishment Instructions of Boeing ASB 737-27A1202.
3. Replace the dual servo valve and a bolt in the PCU in accordance
with Part III of the Accomplishment Instructions of Boeing ASB
737-27A1202.
4. Replace the vernier control rod and two dual load path bolts in
accordance with Part IV of the Accomplishment Instructions of Boeing
ASB 737-27A1202.
5. Replace two nutplates on the control rod in accordance with Part V
of the Accomplishment Instructions of Boeing ASB 737-27A1202.
Note 1: Some aircraft may already meet some of the requirements of
Boeing ASB 737-27A1202 through compliance with previous CASA ADs
(B737/79 and B737/99), however, these aircraft may still require
on-going inspections and/or component replacement dependent on the
scope of previous actions completed. This directive supersedes
AD/B737/79 & AD/B737/99. Pending the cancellation of ADs B737/79 & 99,
compliance with this directive can be considered as achieving
compliance with ADs/B737/79 & 99.
Note 2: FAA ADs 97-14-04, 96-23-51 and 94-01-07 all refer to
inspection, test and replacement actions on Boeing 737 rudder systems
and are all referenced in Boeing ASB 737-27A1202.
Compliance: 1. To be completed every "A" check and every time a PCU is
replaced.
2. Within 24 months of the effective date of this Directive.
3. Within 24 months of the effective date of this Directive.
4. Within 24 months of the effective date of this Drective.
5. Within 24 months of the effective date of this Drective.
This airworthiness directive becomes effective on 26 February 1998.
Background: This AD makes compliance with a Boeing ASB mandatory. The
Boeing ASB gives instructions to ensure that the secondary servo slide
in the dual servo valve of the rudder PCU operates correctly. The ASB
also requires the replacement of the vernier control rod and two dual
loadpath bolts in the rudder PCU assembly. The eventual aim of the ASB
is to have all ruddder PCUs replaced with a modified item which is not
prone to jamming.
Previous Boeing Service Bulletins and FAA ADs had addressed some of
the problems identified with the rudder control system, but this latest
bulletin incorporates a comprehensive test, inspection and component
replacement procedure which overcomes the possible effects of a jam in
the secondary slide of the rudder PCU assembly.
---------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/116 Amdt 1 Yaw Damper and Rudder Power Control Unit Wiring
Change 6/99
Applicability: All Boeing 737 -300, -400 and -500 model aircraft up to
and including line position 2907.
Requirement: 1. Install new wiring and associated hardware for a new
yaw damper and pressure reducer bypass valve in accordance with Boeing
Service Bulletin (SB) 737-22-1124 Revision 1 dated 25 March 1999.
Note: FAA AD 97-14-03 Amdt 39-10060 refers.
Compliance: 1. The original compliance of 'No later than 26 March 2002'
remains unchanged.
This Amendment becomes effective on 17 June 1999.
Background: The FAA issued AD 97-14-03 to prevent both excessive rudder
authority resulting in reduced controllability of the aircraft as well
as malfunctions of the yaw damper system which could cause sudden
uncommanded yawing of the aircraft and consequent injury to passengers
and crewmembers. Boeing responded with the issue of SB 737-22-1124,
detailing the installation of new wiring for the proposed hardware
changes which will be the subject of another AD.
This amendment limits the applicability and introduces revised wiring
requirements.
The original issue of this Airworthiness Directive became effective on
26 March 1998.
-----------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/120 Rudder Pedal Pushrods 10/98
Applicability: Model 737 series aircraft; as listed in Boeing Alert
Service Bulletin 737-27A1212, dated March 26, 1998.
Requirement: Perform a one-time inspection to detect discrepancies of
the fasteners that connect the forward ends of the pushrods to the
rudder pedal assemblies, in accordance with Boeing Alert Service
Bulletin 737-27A1212.
Note: FAA AD 98-13-12 Amdt 39-10600 refers.
Compliance: Unless already accomplished, before 10 November 1998.
This airworthiness directive becomes effective on 10 September 1998.
Background: The FAA received a report from an operator indicating that,
on a Model 737-400 series aircraft, during rollout after landing, the
captain's right rudder pedal moved to the full travel position when it
was pushed. The pedal failed to return to its normal position after it
was released even though the rudder remained in the neutral position.
Investigation revealed that the forward end of the pushrod on the right
rudder pedal was not connected to the rudder pedal assembly. The nut
and washer of the pushrod were found in the lower forward compartment.
The cause of the missing hardware has been attributed to incorrect
installation during manufacture.
----------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/123 Rudder Control System Component Changes 2/99
Applicability: All Boeing model 737-100, -200, -300, -400, -500 series
aeroplanes.
Requirements: Install new rudder pressure reducer (RPR) and yaw damper
coupler (YDC) in accordance with the instructions in Boeing Alert
Service Bulletin 737-27A1206 dated 19 November 1998.
Note: FAA AD 97-14-03 Amdt 39-10060 refers.
Compliance: On completion of AD/B737/116 but no later than 26 March
2002.
This Airworthiness Directive becomes effective on 25 February 1999.
Background: To lessen the effects of large rudder deflections, Boeing
has provided instructions to incorporate a hydraulic rudder pressure
reducer in the "A" hydraulic system supply line in the main rudder
power control unit. Also, to improve significantly the reliability of
the YDC, a new unit has been designed using technology that was not
available at the time of the original design. These changes have been
brought about following an investigation into the reliability and
effectiveness of the B737 yaw control system by the FAA and NTSB.
AD/B737/116 was issued in March 1998 to install the wiring changes
necessary for the introduction of the hardware associated with this
Directive.
-----------------------------------------------------------------------
Boeing 737 Series Aeroplanes
AD/B737/130 Rudder PCU - Displacement Tests 8/99
Applicability: Boeing 737 aircraft, all models.
Requirement: 1. Perform the displacement tests on the secondary slide
of the dual servo valve in the rudder PCU in accordance with
instructions in Boeing Alert Service Bulletin 737-27A1221 Revision 1
dated 28 January 1999 (for Model 737-100, -200, -300, -400 and -500
series aeroplanes) or Boeing Alert Service Bulletin 737-27A1222,
Revision 1, dated 28 January 1999 (for Model 737-600, -700 and -800
series aeroplanes).
2. Subject to the results of the tests at requirement 1 above proving
negative (valve fails test), replace the valve assembly in accordance
with the applicable alert service bulletin and repeat the test at
Requirement 1 above.
3. Repeat the test at Requirement 1 above.
4. Do not install on any airplane a main rudder PCU having serial
number 3509A or lower (for Model 737-100, -200, -300, -400 and -500
series airplanes) or serial number 0299 or lower (for Model 737-600,
-700 and -800 series airplanes), unless that PCU's nameplate has been
vibro-engraved with the letter "C" or letters later than "C" following
the serial number. PCU nameplates that have been vibro-engraved with
the letter "C" or later letters following the serial number are
considered to be in compliance with the requirements for the initial
inpsection of this Directive.
Note: US FAA 99-11-05 Amendment 39-11175 dated 24 May 1999 refers.
Compliance: 1. Initial Test (unless previously achieved in
satisfaction of the original issue of the reference Alert Service
Bulletin):
a. For Model 737-100, -200, -300, -400 and -500 series aeroplanes the
test must be completed within 16 months of the effective date of this
directive.
b. For aeroplanes equipped with a PCU having Part No. 65-44861-12 and
having serial number 3509A or lower, the test must be completed within
16 months of the effective date of this Directive.
c. For Model 737-600, -700 and -800 aeroplanes having line numbers 1
through 222 inclusive, conduct the test within 16 months of the
effective date of this directive.
d. For all other aeroplanes, conduct the test prior to the
accumulation of 24,000 total flight hours on the PCU or within 30 days
of the effective date of this directive, whichever is the later.
2. Prior to further flight after test.
3. At intervals not to exceed 24,000 flight hours (total PCU life)
after initial inspection.
4. As of 16 months after the effective date of this Directive.
This Airworthiness Directive becomes effective on 12 August 1999.
Background: As part of the rudder system improvement programme, this
Directive has been introduced to detect cracks in the secondary slide
in the dual concentric servo valve of the rudder PCU. This Directive
reflects a Country of Origin Airworthiness Directive.
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AllKnow909
Good fixes. There hasn't been a B737 (classic) yaw event, other than the Delta
autopilot upset on 2 June, since December 1999. They'd averaged about one a
month for the prior 30 years.
Me
Bertie the Bunyip
<ghboothl...@hotmail.com.invalid> wrote:
>Et al,
>
>A lot of reasons why the those two 737 passenger jets lost Rudder
>control ---- maybe
Shoulda used a sterring servo from a 64 Buick like you told 'em huh
georgy?
Bertie