29006 Federal Register / Vol. 61, No. 111 / Friday, June 7, 1996 / Rules and Regulations

APPENDIX 1

[FR Doc. 96–14220 Filed 6–6–96; 8:45 am]

BILLING CODE 4910–13–C
Federal Register / Vol. 61, No. 111 / Friday, June 7, 1996 / Rules and Regulations 29007

14 CFR Part 39

[Docket No. 96–NM–111–AD; Amendment

39–9664; AD 96–12–21]

RIN 2120–AA64

Airworthiness Directives; McDonnell

Douglas Model DC–9–80 Series

Airplanes, Model MD–88 Airplanes, and

Model MD–90 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 McDonnell Douglas

Model DC–9–80 series airplanes, Model

MD–88 airplanes, and Model MD–90

airplanes. This action requires revising

the Airplane Flight Manual to include

limitations and procedures to address

situations in which the autopilot or

autothrottle fails to disengage. This

amendment is prompted by incidents in

which the flightcrew was unable to

disconnect the autopilot or autothrottle

function from the engaged position, due

to a discrepancy in a microswitch that

is associated with the operation of those

functions. The actions specified in this

AD are intended to ensure the flight

crew’s ability to control the airplane

manually if the autopilot or autothrottle

function fails to disengage.

DATES: Effective June 24, 1996.

Comments for inclusion in the Rules

Docket must be received on or before

August 6, 1996.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

111–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Information concerning this

rulemaking action may be examined at

the FAA, Transport Airplane

Directorate, 1601 Lind Avenue, SW.,

Renton, Washington; or at the FAA, Los

Angeles Aircraft Certification Office,

Transport Airplane Directorate, 3960

Paramount Boulevard, Lakewood,

California.

FOR FURTHER INFORMATION CONTACT: J.

Kirk Baker, Aerospace Engineer,

Systems and Equipment Branch, ANM–

130L, FAA, Los Angeles Aircraft

Certification Office, 3960 Paramount

Boulevard, Lakewood, California 90712;

telephone (310) 627–5345; fax (310)

627–5210.

SUPPLEMENTARY INFORMATION: The FAA

has received several reports of incidents

in which either the autopilot or the

autothrottle function on McDonnell

Douglas Model DC–9–80 series

airplanes failed to disconnect from the

engaged position. Two incidents

occurred in which the flight crew was

unable to disengage the autopilot

function. As a result of one of these

incidents, which occurred when the

airplane was on final approach, the

flight crew found it necessary to declare

an emergency and to perform a goaround. At least two other incidents

occurred in which the flight crew was

unable to disengage the autothrottle

function.

Investigation of these incidents

revealed that the toggle/cam assembly of

a microswitch, which is used for the

autopilot and autothrottle functions on

the Digital Flight Guidance Control

Panel (DFGCP), can fail the functions in

the engaged position. Further

investigation revealed that the flight

crew was able to disengage the autopilot

or authrottle function by depressing and

holding the release button for the

functions (which are located on the

control column and throttle levers).

However, once the release button was

released, the function re-engaged.

Failure of the autopilot or autothrottle

function to disconnect from the engaged

position can adversely affect the flight

crew’s ability to control the airplane

manually.

Since the toggle/cam assembly of the

subject microswitch that is installed on

Model DC–9–80 series airplanes may

also be installed on Model MD–88 and

MD–90 airplanes, all of these airplane

models may be subject to this same

unsafe condition.

Explanation of the Requirements of the

Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other Model DC–9–80 series,

Model MD–88, and Model MD–90

airplanes of the same type design, this

AD is being issued to ensure the flight

crew’s ability to continue to control the

airplane manually if the autopilot or

autothrottle function fails to disengage.

This AD requires a revision to the FAAapproved Airplane Flight Manual

(AFM) to include limitations and

procedures to address situations in

which the autopilot or autothrottle fails

to disengage.

The FAA points out that failure of the

autopilot or autothrottle function to

disconnect from the engaged position

can occur during any phase of flight. If

it occurs during cruise, the flight crew

can readily address the situation and

continue to fly the airplane manually

with the autopilot or autothrottle

engaged. However, a safety concern

arises if the failure occurs during

approach, when the flight crews

workload is particularly heavy and the

airplane is close to the ground; the

optimal environment for the flight crew

during approach is one that is free from

distraction. The limitation and

associated abnormal procedures that are

required by this AD to be included in

the AFM will ensure that the flight crew

is briefed on the appropriate procedures

and, thereby, will be less distracted

during that critical phase of flight.

The requirements of this AD are

considered to be interim action until

final action is identified, at which time

the FAA may consider additional

rulemaking.

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
29008 Federal Register / Vol. 61, No. 111 / Friday, June 7, 1996 / Rules and Regulations

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 96–NM–111–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

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.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

96–12–21 McDonnell Douglas: Amendment

39–9664. Docket 96–NM–111–AD.

Applicability: Model DC–9–81 (MD–81),

DC–9–82 (MD–82), DC–9–83 (MD–83), DC–

9–87 (MD–87), MD–88, and MD–90

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 (c) 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 the flight crew’s ability to

continue to control the airplane manually if

the autopilot or autothrottle function fails to

disengage, accomplish the following:

(a) Within 14 days after the effective date

of this AD, revise the Limitations section of

the FAA-approved Airplane Flight Manual

(AFM) to include the following statement.

This may be accomplished by inserting a

copy of this AD in the AFM.

‘‘If the autopilot or autothrottle fails to

disconnect normally, press and hold the

autopilot release button or either autothrottle

release button, as appropriate. Refer to the

Abnormal Procedures section for procedures

if the autopilot or autothrottle fails to

disconnect.’’

(b) Within 14 days after the effective date

of this AD, revise the Abnormal Procedures

section of the FAA-approved AFM to include

the following information. This may be

accomplished by inserting a copy of this AD

in the AFM.

‘‘AUTOPILOT:

If the Autopilot (A/P) disconnects when

the AUTOPILOT RELEASE button on either

control wheel is depressed, and re-engages

when the AUTOPILOT RELEASE button is

released, accomplish the following

procedures:

PROCEDURE: Use Autopilot (as desired)

AUTOPILOT RELEASE button—PRESS

AND HOLD

• Hold either yoke (yellow) Autopilot

Release button while continuing to fly the

aircraft manually. The A/P will remain

disengaged while depressing the button.

• When the Autopilot Release button is

released, the A/P will engage and all A/P

functions should work normally.

TO SILENCE THE AURAL WARNING:

CAWS C/B (P–38)—PULL

• Circuit breaker is located behind the

Captain’s seat.

• Pulling the C/B will disable the Stall

Warning SSRS–1, Landing Gear, Takeoff,

Cabin Altitude, Speed Brake aural warnings,

in addition to the Autopilot aural warning.

CAUTION:

Do not attempt to overpower the autopilot.

When the autopilot is engaged, applying

force to the column may allow the alternate

trim to reposition the stabilizer. If the force

is applied long enough, it will result in an

out-of-trim condition.’’

‘‘AUTOTHROTTLE:

If the Autothrottle (A/T) disconnects when

either throttle disconnect button is

depressed, and re-engages when throttle

disconnect button is released, accomplish the

following procedures:

PROCEDURE: Use Autothrottle System (as

desired)

WHEN A DISCONNECT IS NECESSARY:

AUTOTHROTTLE RELEASE BUTTON—

PRESS AND HOLD

• Press and hold either button until

flashing red A/T annunciation is illuminated.

Flashing red light indicates autothrottle is

disconnected.

• AUTOTHROTTLE RELEASE BUTTON

may then be released.

• The FMA A/T window will annunciate

as though the A/T is engaged.

• The flashing red A/T annunciation of the

FMA cannot be extinguished with repeated

depression of the autothrottle release button.

• If the throttle levers are retarded to the

idle stop, the flashing red A/T annunciation

will extinguish, and the A/T system will reengage.

• If the DFGC is selected to the IAS mode

and the A/T SPEED mode is selected, the A/

T system will re-engage.’’

(c) 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, Los

Angeles Aircraft Certification Office (ACO),

FAA, Transport Airplane Directorate.

Operators shall submit their requests through

an appropriate FAA Principal Maintenance

Inspector, who may add comments and then

send it to the Manager, Los Angeles ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Los Angeles ACO.

(d) 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.

(e) This amendment becomes effective on

June 24, 1996.

Issued in Renton, Washington, on June 3,

1996.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 96–14385 Filed 6–06–96; 8:45 am]

BILLING CODE 4910–13–P