| Issued: 20-AUG-1991 | To: FAA | A-91-077 |
| ISSUE AN AIRWORTHINESS DIRECTIVE REQUIRING A CHECK ON ALL BOEING 737 AND 727 MODEL AIRPLANES WITH THE P/N 1087-23 INPUT SHAFT IN THE RUDDER AUXILIARY ACTUATOR UNIT FOR THE FORCE NEEDED TO ROTATE THE INPUT SHAFT LEVER RELATIVE TO THE P/N 1087-22 BEARING OF THE AUXILIARY ACTUATOR UNIT. DURING THIS CHECK, THE BEARING SHOULD BE INSPECTED TO DETERMINE IF IT ROTATES RELATIVE TO THE HOUSING. ALL SHAFT ASSEMBLIES IN WHICH ROTATION OF THE BEARING OCCURS, OR IN WHICH EXCESSIVE FORCE IS NEEDED TO MOVE THE INPUT LEVER, SHOULD BE REMOVED FROM SERVICE ON AN EXPEDITED BASIS AND THE ASSEMBLIES SHOULD BE REPLACED WITH A P/N 1087-21 SHAFT ASSEMBLY THAT HAS A REDUCED DIAMETER ON THE UNLUBRICATED PORTION OF THE SHAFT IN ACCORDANCE WITH REVISION G OF THE P/N 1087-23 ENGINEERING DRAWING. ALL ASSEMBLIES MEETING THE FORCE REQUIREMENT SHOULD BE RECHECKED AT APPROPRIATE INTERVALS UNTIL REPLACED WITH A P/N 1087-21 SHAFT ASSEMBLY CONTAINING A P/N 1087-23 SHAFT THAT HAS A REDUCED DIAMETER ON THE UNLUBRICATED PORTION OF THE SHAFT. (Closed - Acceptable Alternate Action) |
| Issued: 20-JUL-1992 | To: FAA | A-92-057 |
| DEVELOP AND IMPLEMENT A METEOROLOGICAL PROGRAM TO OBSERVE, DOCUMENT, AND ANALYZE POTENTIAL METEOROLOGICAL AIRCRAFT HAZARDS IN THE AREA OF COLORADO SPRINGS, COLORADO, WITH A FOCUS ON THE APPROACH AND DEPARTURE PATHS OF THE COLORADO SPRINGS MUNICIPAL AIRPORT. THIS PROGRAM SHOULD BE MADE OPERATIONAL BY THE WINTER OF 1992. (Closed - Acceptable Action) |
| Issued: 20-JUL-1992 | To: FAA | A-92-058 |
| DEVELOP A BROADER METEOROLOGICAL AIRCRAFT HAZARD PROGRAM TO INCLUDE OTHER AIRPORTS IN OR NEAR MOUNTAINOUS TERRAIN, BASED ON THE RESULTS OBTAINED IN THE COLORADO SPRINGS, COLORADO, AREA. (Closed - Acceptable Action) |
| Issued: 10-NOV-1992 | To: FAA | A-92-118 |
| REQUIRE THAT BOEING DEVELOP A REPETITIVE MAINTENANCE TEST PROCEDURE TO BE USED BY B-737 OPERATORS TO VERIFY THE PROPER OPERATION OF THE MAIN RUDDER POWER CONTROL UNIT SERVO VALVE UNTIL A DESIGN CHANGE IS IMPLEMENTED THAT WOULD PRECLUDE THE POSSIBILITY OF ANOMALIES ATTRIBUTED TO THE OVERTRAVEL OF THE SECONDARY SLIDE. (Closed - Acceptable Action) |
| Issued: 10-NOV-1992 | To: FAA | A-92-119 |
| REQUIRE THAT BOEING DEVELOP AN APPROVED PREFLIGHT CHECK OF THE RUDDER SYSTEM TO BE USED BY OPERATORS TO VERIFY, TO THE EXTENT POSSIBLE, THE PROPER OPERATION OF THE MAIN RUDDER POWER CONTROL UNIT SERVO VALVE UNTIL A DESIGN CHANGE IS IMPLEMENTED THAT WOULD PRECLUDE THE POSSIBILITY OF RUDDER REVERSALS ATTRIBUTED TO THE OVERTRAVEL OF THE SECONDARY SLIDE. (Closed - Acceptable Alternate Action) |
| Issued: 10-NOV-1992 | To: FAA | A-92-120 |
| REQUIRE OPERATORS, BY AIRWORTHINESS DIRECTIVE, TO INCORPORATE DESIGN CHANGES FOR THE B-737 MAIN RUDDER POWER CONTROL UNIT SERVO VALVE WHEN THESE CHANGES ARE MAKE AVAILABLE BY BOEING. THESE CHANGES SHOULD PRECLUDE THE POSSIBILITY OF RUDDER REVERSALS ATTRIBUTED TO THE OVERTRAVEL OF THE SECONDARY SLIDE. (Closed - Acceptable Action) |
| Issued: 10-NOV-1992 | To: FAA | A-92-121 |
| CONDUCT A DESIGN REVIEW OF SERVO VALVES MANUFACTURED BY PARKER HANNIFIN HAVING A DESIGN SIMILAR TO THE B-737 RUDDER POWER CONTROL UNIT SERVO VALVE THAT CONTROL ESSENTIAL FLIGHT CONTROL HYDRAULIC POWER CONTROL UNITS ON TRANSPORT-CATEGORY AIRPLANES CERTIFIED BY THE FEDERAL AVIATION ADMINISTRATION TO DETERMINE THAT THE DESIGN IS NOT SUSCEPTIBLE TO INDUCING FLIGHT CONTROL MALFUNCTIONS OR REVERSALS DUE TO OVERTRAVEL OF THE SERVO SLIDES. (Closed - Acceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-107 |
| Require the Boeing Commercial Airplane Group, working with other interested parties, to develop immediate operational measures and long-term design changes for the B-737 series airplane to preclude the potential for loss of control from an inadvertent rudder hardover. Once the operational measures and design changes have been developed, issue respective airworthiness directives to implement these actions. (Superseded by A-99-20 through A-99-29) (Closed - Unacceptable Action/Superseded) |
| Issued: 18-OCT-1996 | To: FAA | A-96-108 |
| Revise 14 CFR Section 25.671 to account for the failure or jamming of any flight control surface at its design-limited deflection. Following this revision, reevaluate all transport-category aircraft and ensure compliance with the revised criteria. (Closed - Reconsidered) |
| Issued: 18-OCT-1996 | To: FAA | A-96-109 |
| Require the Boeing Commercial Airplane Group to develop and install a cockpit indicator system for all new production B-737 airplanes that indicates rudder surface position and movement. For existing B-737 airplanes, when implementing the installation of an enhanced-parameter flight data recorder, require the installation of a cockpit indicator system that indicates rudder surface position and movement. (Superseded by A-99-20 through A-99-29) (Closed - Unacceptable Action/Superseded) |
| Issued: 18-OCT-1996 | To: FAA | A-96-110 |
| Conduct a detailed engineering review of the B-737 yaw damper system, and require the Boeing Commercial Airplane Group to redesign the yaw damper system, as necessary, to eliminate the potential for sustained uncommanded yaw damper control events. After the B-737 yaw damper system is redesigned, issue an airworthiness directive to require the installation of the improved yaw damper system on all B-737 series aircraft. (Closed - Acceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-111 |
| Require the Boeing Commercial Airplane Group and the operating airlines to eliminate the procedure for removal and replacement of the main rudder power control unit rudder position transducer from their respective B-737 maintenance manuals unless the manual provides for testing to verify that the replacement transducer performs its intended function. (Closed - Acceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-112 |
| Require the Boeing Commercial Airplane Group to establish appropriate inspection intervals and a service life-limit for the B-737 rudder power control unit. (Superseded by A-99-20 through A-99-29) (Closed - Unacceptable Action/Superseded) |
| Issued: 18-OCT-1996 | To: FAA | A-96-113 |
| Require the Boeing Commercial Airplane Group to devise a method to detect a primary or a secondary jammed slide in the B-737 main rudder power control unit servo valve and ensure appropriate communication of the info to mechanics and pilots. (Superseded by A-99-20 through A-99-29) (Closed - Unacceptable Action/Superseded) |
| Issued: 18-OCT-1996 | To: FAA | A-96-114 |
| Evaluate the adequacy of the chip shearing capacity for all sliding spool control valves used in transport-category aircraft flight control system and take appropriate action to correct any problems identified to preclude potential for actuator jamming, binding, or failure. (Closed - Acceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-115 |
| Require the modification of the input rod bearing on the B-737 series standby rudder actuator to prevent galling and possible discrepant operation of the rudder system by 8/1/97. (Closed - Acceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-116 |
| Define and implement standards for in-service hydraulic fluid cleanliness and sampling intervals for all transport-category aircraft. (Closed - Acceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-117 |
| Conduct a detailed design review of all dual concentric servo valves that control essential flight control system acuators on transport-category airplanes certificated by the FAA to determine if the design is susceptible to inducing flight control malfunctions and/or reversal as a result of unexpected improper positioning of the servo slides. If the design is determined to be susceptible, mandate appropriate design changes. (Closed - Unacceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-118 |
| Require the Boeing Commercial Airplane Group, working with other interested parties, to develop procedures that require B-737 flightcrews to disengage the yaw damper in the event of an uncommanded yaw upset as a memorized or learned action. Once the procedures are developed, require operators to implement these procedures. (Closed - Acceptable Action) |
| Issued: 18-OCT-1996 | To: FAA | A-96-119 |
| Require the Boeing Commercial Airplane Group to develop operational procedures for B-737 flightcrews that effectively deal with a sudden uncommanded movement of the rudder to the limit of its travel for any given flight condition in the airplane\'s operational envelope. Once the operational procedures have been developed, require B-737 operators to provide this training to their pilots. (Superseded by A-97-18) (Closed - Superseded) |
| Issued: 18-OCT-1996 | To: FAA | A-96-120 |
| Require 14 CFR Part 121 and 135 operators to provide training to flightcrews in the recognition of and recovery from unusual attitudes and upset maneuvers, including upsets that occur while the aircraft is being controlled by automatic flight control systems, and unusual attitudes that result from flight control malfunctions and uncommanded flight control surface movements. (Open - Acceptable Response) |
| Issued: 20-FEB-1997 | To: FAA | A-97-016 |
| REQUIRE THE EXPEDITIOUS INSTALLATION OF A REDESIGNED MAIN RUDDER POWER CONTROL UNIT ON BOEING 737 SERIES AIRPLANES TO PRECLUDE REVERS OPERATION OF THE RUDDER & TO ENSURE THAT THE AIRPLANES COMPLY WITH THE INTENT OF THE CERTIFICATION REQUIREMENTS. (Closed - Acceptable Action) |
| Issued: 20-FEB-1997 | To: FAA | A-97-017 |
| ADVISE B-737 PILOTS OF THE POTENTIAL HAZARD FOR A JAMMED SECONDARY SERVO CONTROL VALVE SLIDE IN THE MAIN RUDDER POWER CONTROL UNIT TO CAUSE A REVERSE RESPONSE WHEN A FULL OR HIGH-RATE INPUT IS APPLIED TO THE RUDDER PEDALS. (Closed - Acceptable Action) |
| Issued: 20-FEB-1997 | To: FAA | A-97-018 |
| Require the Boeing Commercial Airplane Group to develop operational procedures for B-737 flightcrews that effectively deal with a sudden uncommanded movement of the rudder to the limit of its travel for any given flight condition in the airplane\'s operational envelope, including specific initial and periodic training in the recognition of and recovery from unusual attitudes and upsets caused by reverse rudder response. Once the procedures are developed, require B-737 operators to provide this training to their pilots. (Superseded by A-99-25) (Closed - Unacceptable Action/Superseded) |
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