Airworthiness Directives; Boeing Model 737 Series Airplanes
Final Rule; Request For Comments.
This amendment supersedes an existing airworthiness directive (AD), applicable to all Boeing Model 737 series airplanes, that currently requires revising the FAA-approved Airplane Flight Manual (AFM). This new amendment revises the AFM procedure in the existing AD to simplify the instructions for correcting a jammed or restricted flight control condition. This amendment is prompted by an FAA determination that the procedure currently inserted in the AFM by the existing AD is not defined adequately. The actions specified in this AD are intended to ensure that the flight crew is advised of the procedures necessary to address a condition involving a jammed or restricted rudder.
1 action from October 2014
- Actions Will Continue Through
Table of Contents Back to Top
- FOR FURTHER INFORMATION CONTACT:
- SUPPLEMENTARY INFORMATION:
- Actions Since Issuance of Previous Rule
- Explanation of Requirements of Rule
- Interim Action
- Determination of Rule's Effective Date
- Comments Invited
- Regulatory Impact
- List of Subjects in 14 CFR Part 39
- Adoption of the Amendment
- PART 39—AIRWORTHINESS DIRECTIVES
- RESTATEMENT OF CERTAIN REQUIREMENTS OF AD 96-26-07:
- “UNCOMMANDED YAW OR ROLL
- NEW REQUIREMENTS OF THIS AD:
- UNCOMMANDED RUDDER
- Alternative Methods of Compliance
- Special Flight Permits
- Effective Date
DATES: Back to Top
Effective November 13, 2000. Comments for inclusion in the Rules Docket must be received on or before December 26, 2000.
ADDRESSES: Back to Top
Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-325-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: firstname.lastname@example.org. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-325-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.
ADDRESSES: Back to Top
Information pertaining to this amendment may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket No. 2000-NM-325-AD, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Back to Top
Steve O'Neal, Aerospace Engineer, Flight Test Branch, ANM-160S, Seattle Aircraft Certification Office, FAA, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2699; fax (425)227-1181.
SUPPLEMENTARY INFORMATION: Back to Top
On December 23, 1996, the FAA issued AD 96-26-07, amendment 39-9871 (62 FR 15, January 2, 1997), applicable to all Boeing Model 737 series airplanes, to require revising the FAA-approved Airplane Flight Manual (AFM) to include procedures that will enable the flight crew to take appropriate action to maintain control of the airplane during an uncommanded yaw or roll condition, and to correct a jammed or restricted flight control condition. That action was prompted by an FAA determination that such procedures were not defined adequately in the AFM for these airplanes. Because of the potential for uncommanded yaw or roll conditions in these airplanes, and jammed or restricted flight controls, the actions required by that AD are intended to provide the flight crew with a systematic means to isolate flight control hydraulics, eliminate a rudder hardover, and land safely.
Actions Since Issuance of Previous Rule Back to Top
Since the issuance of AD 96-26-07, the FAA has received information from the Independent 737 Flight Controls Engineering and Test Evaluation Board (ETEB) verifying several failure modes in the rudder system of Model 737-100 and -200 (Initial); 737-300, -400, and -500 (Classic); and 737-600, -700, and -800 (Next Generation) series airplanes that can cause an uncommanded rudder hardover. The failure modes include several single jam modes that can cause an uncommanded rudder hardover, in addition to several latent failures or jams that, when combined with a second failure or jam, could cause an uncommanded rudder hardover. Changes in maintenance procedures will be adopted to enhance the detection of latent failure conditions, reducing the potential for an uncommanded hardover. To eliminate these rudder failure modes, the manufacturer is redesigning the rudder system.
The procedure required by AD 96-26-07, and revised by this AD, is not as complete a solution to the rudder hardover concern as is the rudder system redesign, for two reasons:
- First, the procedure is not effective throughout the entire flight envelope, having limited effectiveness during the remote possibility of a hardover during takeoff and landing.
- Second, as a general principal, eliminating the possibility of an in-flight situation is a better alternative than relying on flight crew action to correct such a situation.
The rudder system redesign is likely to eliminate the need for procedures dealing with jammed or restricted flight control conditions, but retrofit of the hardware on existing airplanes will take several years to complete. During this time, procedures for jammed or restricted flight control conditions will continue to be necessary. The ETEB determined that the AFM procedure addressing a jammed or restricted rudder required by AD 96-26-07 is inadequate and must be revised. During evaluations of the existing procedure, the ETEB determined that flight crews were confused by the procedure and were not always able to complete it during simulated rudder system malfunctions. Therefore, the FAA has determined that a revised procedure titled “Uncommanded Rudder,” in lieu of the existing procedure titled “Jammed or Restricted Rudder,” is necessary in the interim period to ensure airplane safety.
Explanation of Requirements of Rule Back to Top
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of this same type design, this AD supersedes AD 96-26-07 to require revising the AFM procedure in the existing AD to simplify the instructions for correcting a jammed or restricted flight control condition.
Interim Action Back to Top
This is considered to be interim action. As previously stated, once the rudder system is redesigned, and the retrofitted rudder is approved and available, the FAA may consider additional rulemaking.
Determination of Rule's Effective Date Back to Top
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Comments Invited Back to Top
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire.Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Submit comments using the following format:
- Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
- For each issue, state what specific change to the AD is being requested.
- Include justification (e.g., reasons or data) for each request.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-325-AD.” The postcard will be date stamped and returned to the commenter.
Regulatory Impact Back to Top
The regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a “significant regulatory action” under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket.A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption “ADDRESSES.”
Adoption of the Amendment Back to Top
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39—AIRWORTHINESS DIRECTIVES Back to Top
1.The authority citation for part 39 continues to read as follows:
§ 39.13 [Amended]
2.Section 39.13 is amended by removing amendment 39-9871 (62 FR 15, January 2, 1997), and by adding a new airworthiness directive (AD), amendment 39-11948, to read as follows:
2000-22-02Boeing: Amendment 39-11948. Docket 2000-NM-325-AD. Supersedes AD 96-26-07, Amendment 39-9871.
Applicability: All Model 737 series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished previously.
To ensure that the flight crew is advised of the procedures necessary to address a condition involving a jammed or restricted rudder, accomplish the following:
RESTATEMENT OF CERTAIN REQUIREMENTS OF AD 96-26-07: Back to Top
(a) Within 30 days after January 17, 1997 (the effective date of AD 96-26-07, amendment 39-9871): Revise the Emergency Procedures Section of the FAA-approvedAirplane Flight Manual (AFM) to include the following recall item, which will enable the flight crew to take appropriate action to maintain control of the airplane during an uncommanded yaw or roll condition. This may be accomplished by inserting a copy of this AD in the AFM.
“UNCOMMANDED YAW OR ROLL
Maintain control of the airplane with all available flight controls. If roll is uncontrollable, immediately reduce angle of attack and increase airspeed. Do not attempt to maintain altitude until control is recovered. If engaged, disconnect autopilot and autothrottle.”
NEW REQUIREMENTS OF THIS AD: Back to Top
(b) Within 30 days after the effective date of this AD: Revise the NormalProcedures Section of the FAA-approved AFM for Model 737-100 and -200 series airplanes or the Non-Normal Procedures Section of the FAA-approved AFM for Model 737-300, -400, -500, -600, -700, and -800 series airplanes, as applicable, to include the following procedure. This may be accomplished by inserting a copy of this AD in the AFM and removing the existing copy (inserted as required by AD 96-26-07), entitled “Jammed Flight Controls.”
UNCOMMANDED RUDDER Back to Top
Condition: Uncommanded rudder pedal displacement or pedal kicks.
AUTOPILOT (if engaged): DISENGAGE.
Maintain control of the airplane with all available flight controls. If roll is uncontrollable, immediately reduce pitch/angle of attack and increase airspeed. Do not attempt to maintain altitude until control is recovered.
AUTOTHROTTLE (if engaged): DISENGAGE.
Verify thrust is symmetrical.
YAW DAMPER SWITCH: OFF.
RUDDER TRIM: CENTER.
RUDDER PEDALS: FREE CENTER.
Use maximum force including a combined effort of both pilots, if required to free and center the rudder pedals.
If rudder pedal position or movement is not normal and the condition is not the result of rudder trim:
SYSTEM B FLIGHT CONTROL SWITCH: STBY RUD.
A slight rudder deflection may remain, but continued rudder pedal pressure may help maintain an in-trim condition.
Sufficient directional control is available on landing using differential braking and nose wheel steering.
Crosswind capability may be reduced.
Do not use autobrakes.
Consider checking rudder freedom of movement at a safe altitude using slow rudder inputs while in the landing configuration and at approach speed.
If condition was the result of rudder trim or environmental factors:
YAW DAMPER SWITCH: ON.
Accomplish the normal DESCENT—APPROACH and LANDING checklists.”
(c) It is acceptable to modify the format of the above procedure to reflect the format used by individual carriers. However, the procedural sequence, memory items, and/or associated text may not be modified, except by submitting a request for an alternative method of compliance (AMOC) as specified in paragraph (d) of this AD.
Alternative Methods of Compliance Back to Top
(d) An AMOC or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Operations Inspector, who may add comments and then send it to the Manager, Seattle ACO.
Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
Special Flight Permits Back to Top
(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.
Effective Date Back to Top
(f) This amendment becomes effective on November 13, 2000.
Issued in Renton, Washington, on October 20, 2000.
John J. Hickey,
Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 00-27508 Filed 10-25-00; 8:45 am]
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