[Federal Register Volume 62, Number 1 (Thursday, January 2, 1997)]
[Rules and Regulations]
[Pages 15-16]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-33104]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-266-AD; Amendment 39-9871; AD 96-26-07]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to all Boeing Model 737 series airplanes. This action
requires 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. This amendment is prompted by an FAA determination that such
procedures currently are not defined adequately in the AFM for these
airplanes. The actions specified in this AD are intended to ensure that
the flight crew is advised of the potential hazard associated with a
jammed or restricted flight control condition and of the procedures
necessary to address it.
DATES: Effective January 17, 1997.
Comments for inclusion in the Rules Docket must be received on or
before March 3, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-266-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
The information concerning this amendment may be obtained from or
examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,
SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Les Berven, Flight Test Pilot, Flight
Test Branch, ANM-160S, Seattle Aircraft Certification Office, FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2666; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: As part of its Continuing Operational Safety
Program, the FAA has become aware of new information related to the
safety of Boeing Model 737 series airplanes. Recent tests of the main
rudder power control unit (PCU), conducted at Boeing, demonstrated a
potential failure scenario that was previously unknown. These tests
revealed that, if the secondary slide of the PCU jams in certain
positions, rudder pedal input can cause deformation in the linkage
leading to the primary and secondary slides of the servo valve of the
main rudder PCU. This situation could result in rudder deflection in
the opposite direction of the rudder command, and a jammed rudder.
Other Relevant Rulemaking
The conditions described previously were addressed previously in AD
96-23-51, amendment 39-9818 (61 FR 59317, November 22, 1996), which is
applicable to all Boeing Model 737 series airplanes. That AD requires
repetitive tests to verify proper operation of the rudder power control
unit (PCU), and replacement of the PCU, if necessary. The actions
specified by that AD are intended to prevent rudder motion in the
opposite direction of the rudder command.
FAA's Findings
As a result of analysis related to the previously prescribed tests,
the FAA finds that certain procedures should be included in the FAA-
approved Airplane Flight Manual (AFM) for Model 737 series airplanes to
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. The FAA has
determined that such procedures currently are not defined adequately in
the AFM for these airplanes.
Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other Boeing Model 737 series airplanes of the same
type design, this AD is being issued to ensure that the flight crew is
advised of the potential hazard associated with a jammed or restricted
flight control condition and of the procedures necessary to address it.
This AD requires revising the 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.
Determination of Rule's Effective Date
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
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.
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 96-NM-266-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this final
rule does
[[Page 16]]
not have sufficient federalism implications to warrant the preparation
of a Federalism Assessment.
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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
Adoption of the Amendment
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
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
96-26-07 BOEING: Amendment 39-9871. Docket 96-NM-266-AD.
Applicability: All Model 737 series airplanes, certificated in
any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (b) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
To ensure that the flight crew is advised of the potential
hazard associated with jammed or restricted flight controls and of
the procedures necessary to address it, accomplish the following:
(a) Within 30 days after the effective date of this AD,
accomplish paragraphs (a)(1) and (a)(2) of this AD.
(1) Revise the Emergency Procedures Section of the FAA-approved
Airplane 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
RECALL
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.''
(2) Revise the section entitled ``JAMMED FLIGHT CONTROLS'' of
the Normal Procedures Section (for Model 737-100 and -200 series
airplanes) or the Non-Normal Procedures Section (for Model 737-300,
-400, and -500 series airplanes), as applicable, of the FAA-approved
AFM to include the following procedures, which will enable the
flight crew to take appropriate action to maintain control of the
airplane and to correct a jammed or restricted flight control
condition. This may be accomplished by inserting a copy of this AD
in the AFM.
``JAMMED FLIGHT CONTROLS
JAMMED OR RESTRICTED ELEVATOR OR AILERON:
In the event of a jammed elevator or aileron, do not hesitate to
apply additional force to maintain control of the airplane. Do not
turn off any flight control switches unless the faulty control is
positively identified. Manual trim may be used to offload control
forces.
JAMMED OR RESTRICTED RUDDER:
If the rudder pedals will not move to the pilot commanded
position, or if the pedals are deflected in one direction and
jammed, maintain control of the airplane with all available flight
controls. Disengage the autopilot and autothrottle. Use maximum
force (combined effort by both pilots) to overpower the rudder
system.
After establishing control of the aircraft, check rudder pedal
position. If the rudder pedals have centered, accomplish a normal
descent, approach, and landing. If the rudder pedals remain jammed
and are deflected to a degree that significantly affects the
controllability of the airplane, select System B flight control
switch to STBY RUD. If this action clears the jam/deflection, make a
normal approach and landing, noting that rudder control may be
limited. If moving the System B flight control switch to STBY RUD
does not clear the jam, select System A flight control switch to
off. If pedals do not center, select System B flight control switch
to off. Make approach and landing with flaps 15 at VREF flaps
15. The crosswind capability of the airplane will be greatly
reduced.
YAW DAMPER:
The yaw damper is a separate control and provides a limited
rudder movement in opposition to the yaw rate of the airplane.
Rudder (yaw damper) indicator displacement indicates yaw damper
operation. Yaw damper light illuminates amber when the yaw damper is
not engaged.
(b) An alternative method of compliance 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, Transport Airplane Directorate. 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.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(c) 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.
(d) This amendment becomes effective on January 17, 1997.
Issued in Renton, Washington, on December 23, 1996.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-33104 Filed 12-30-96; 10:25 am]
BILLING CODE 4910-13-U
