Federal Register / Vol. 62, No. 50 / Friday, March 14, 1997 / Proposed Rules 12121

Installation of a Continuous Power

Reserve (CPR) System

(a) General. With the CPR system

functioning normally as designed, all

applicable requirements of part 25 must

be met without requiring any unusual

action (other than arming the system

prior to dispatch) by the crew to set

power or thrust.

(b) Performance and Reliability

Requirements.

(1) A CPR failure or combination of

failures.

(i) That prevents the automatic

insertion of CPR thrust or power must

be shown to be an improbable event;

(ii) That prevents the automatic

insertion of APR thrust or power during

the critical time interval defined in

Appendix I of Part 25 must be shown to

be an improbable event; and

(iii) Shall not result in the significant

loss or reduction in thrust or power, or

must be shown to be an extremely

improbable event.

(2) All applicable performance

requirements of part 25 must be met

with an engine failure occurring at the

most critical time with the CPR system

functioning.

(c) Thrust Setting. The maximum

continuous thrust or power setting

specified for use with all engines

operating may not be less than any of

the following:

(1) Ninety (90) percent of the thrust or

power set by the CPR system for which

AFM performance credit is approved;

(2) That required to permit normal

operation of all safety-related systems

and equipment dependent upon engine

thrust or power lever position; or

(3) That shown to be free of hazardous

engine response characteristics when

thrust or power is advanced from the

initial all-engines-operating thrust or

power setting to the maximum approved

maximum continuous/CPR mode thrust

or power setting.

(d) Powerplant Controls.

(1) In addition to the requirements of

§ 25.1141, no single failure or

malfunction, or probable combination

thereof, of the CPR, including associated

systems, may cause the failure of any

powerplant function necessary for

safety.

(2) The CPR system must be designed

to:

(i) In the event of a CPR system

failure, permit manual decrease or

increase in thrust or power up to the

highest maximum continuous thrust or

power approved for the airplane under

existing conditions through the use of

the power lever. For airplanes equipped

with limiters that automatically prevent

engine operating limits from being

exceeded under existing ambient

conditions, other means may be used to

increase the thrust or power in the event

of a CFR failure provided the means is

located on or forward of the power

levers; is easily identified and operated

under all operating conditions by a

single action of either pilot with the

hand that is normally used to actuate

the power levels; and meets the

requirements of § 25.777 (a),(b), and (c).

(ii) Provide a means for the flightcrew

to deactivate the automatic CPR

function. This means must be designed

to prevent inadvertent deactivation.

(iii) Provide a means for the

flightcrew to verify that the CFR system

is in a condition to operate.

(e) Powerplant Instruments. In

addition to the requirements of

§ 25.1305, a means must be provided to

indicate when the CPR is in the armed

or ready condition.

Issued in Renton, Washington, on March 6,

1997.

Neil D. Schalekamp,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service,

ANM–100.

[FR Doc. 97–6528 Filed 3–13–97; 8:45 am]

BILLING CODE 4910–13–M

14 CFR Part 39

[Docket No. 97–NM–28–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 737–100, –200, –300, –400, and

–500 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to all

Boeing Model 737–100, –200, –300,

–400, and –500 series airplanes. This

proposal would require installation of a

newly designed rudder-limiting device

and yaw damper system. This proposal

is prompted by a report indicating that

a full rudder input, either commanded

or uncommanded, could result in a

rapid roll upset; and by reports of

malfunctions of the yaw damper system.

The actions specified by the proposed

AD are intended to prevent excessive

rudder authority and consequent

reduced controllability of the airplane;

and malfunctions of the yaw damper

system, which could result in sudden

uncommanded yawing of the airplane

and consequent injury to passengers and

crewmembers.

DATES: Comments must be received by

April 23, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 97–NM–

28–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9:00 a.m. and 3:00

p.m., Monday through Friday, except

Federal holidays.

FOR FURTHER INFORMATION CONTACT: T.

Tin Truong, Aerospace Engineer,

Systems and Equipment Branch, ANM–

130S, FAA, Transport Airplane

Directorate, Seattle Aircraft Certification

Office, 1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(206) 227–2552; fax (206) 227–1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to

participate in the making of the

proposed 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 above. All communications

received on or before the closing date

for comments, specified above, will be

considered before taking action on the

proposed rule. The proposals contained

in this notice may be changed in light

of the comments received.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the proposed 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

summarizing each FAA-public contact

concerned with the substance of this

proposal will be filed in the Rules

Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this notice

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 97–NM–28–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this

NPRM by submitting a request to the

FAA, Transport Airplane Directorate,

ANM–103, Attention: Rules Docket No.

97–NM–28–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.
12122 Federal Register / Vol. 62, No. 50 / Friday, March 14, 1997 / Proposed Rules

Discussion

In September 1994, an accident

involving a Boeing Model 737–300

series airplane occurred near Pittsburgh,

Pennsylvania. The National

Transportation Safety Board (NTSB) has

not yet determined the cause of that

accident. However, the FAA has

received a report indicating that piloted

computer simulations of the accident

revealed that a full rudder input, either

commanded or uncommanded, could

result in a rapid roll upset similar to the

aircraft responses recorded on the flight

data recorder of the accident airplane.

Investigation revealed that, during

certain combinations of flap settings and

airspeeds, the amount of rudder

deflection available is greater than

needed for control of the airplane. A full

rudder deflection (hardover) with such

excessive rudder authority can result in

a rolling moment due to sideslip that

exceeds the maximum rolling moment

available by control wheel inputs. This

condition, if not corrected, could result

in reduced controllability of the

airplane unless the flight crew takes

prompt and appropriate action. [In this

regard, the FAA issued AD 96–26–07,

amendment 39–9871 (62 FR 15, January

2, 1997) to amend the Airplane Flight

Manual to provide the flight crew with

the proper control techniques in the

event of such an occurrence.]

Additionally, the FAA has received a

number of reports of malfunctions of the

yaw damper system. These

malfunctions may have been caused by

failure of the rate gyroscope of the yaw

damper coupler as a result of wear of

the rotor bearing, and contamination

and shorting of the electrical connectors

or surface position sensors in the area of

the yaw damper servo-actuator. Such

malfunctions of the yaw damper system,

if not corrected, could result in sudden

uncommanded yawing of the airplane

and consequent injury to passengers and

crewmembers.

Boeing has advised the FAA that it

has designed a rudder-limiting device

and a new yaw damper for installation

on the latest versions of Model 737

series airplanes currently undergoing

certification. Both of these systems are

capable of being installed on the

existing fleet of Model 737 series

airplanes. Boeing has not yet released a

service bulletin reflecting these changes.

FAA’s Determinations

In light of this information, the FAA

finds that installation of a newly

designed rudder-limiting device and

yaw damper system are required to

ensure the safety of the affected fleet.

Installation of a rudder-limiting device

is necessary to reduce the rudder

authority at altitudes above 1,500 feet

above ground level (AGL) so that, if any

inadvertent hardover occurs, the

resultant roll upset can be controlled

with control wheel inputs. Installation

of a new yaw damper system is

necessary to improve the reliability of

the system and its fault monitoring

capability, which will prevent

uncommanded yawing of the airplane.

Explanation of Requirements of

Proposed Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other products of this same

type design, the proposed AD would

require installation of a newly designed

rudder-limiting device and yaw damper

system. The actions would be required

to be accomplished in accordance with

a method approved by the FAA.

Cost Impact

There are approximately 2,900 Model

737 series airplanes of the affected

design in the worldwide fleet. The FAA

estimates that 1,350 airplanes of U.S.

registry would be affected by this

proposed AD.

The FAA estimates that it would take

approximately 87 work hours per

airplane to accomplish the proposed

installation of a newly designed rudderlimiting device, and that the average

labor rate is $60 per work hour.

Required parts would be supplied by

the manufacturer at no cost to operators.

Based on these figures, the cost impact

of the proposed AD on U.S. operators is

estimated to be $7,047,000, or $5,220

per airplane.

The FAA also estimates that it would

take approximately 20 work hours per

airplane to accomplish the proposed

installation of a newly designed yaw

damper system, and that the average

labor rate is $60 per work hour.

Required parts would be supplied by

the manufacturer at no cost to operators.

Based on these figures, the cost impact

of the proposed AD on U.S. operators is

estimated to be $1,620,000, or $1,200

per airplane.

The cost impact figures discussed

above are based on assumptions that no

operator has yet accomplished any of

the proposed requirements of this AD

action, and that no operator would

accomplish those actions in the future if

this AD were not adopted.

The FAA recognizes that the

obligation to maintain aircraft in an

airworthy condition is vital, but

sometimes expensive. Because AD’s

require specific actions to address

specific unsafe conditions, they appear

to impose costs that would not

otherwise be borne by operators.

However, because of the general

obligation of operators to maintain

aircraft in an airworthy condition, this

appearance is deceptive. Attributing

those costs solely to the issuance of this

AD is unrealistic because, in the interest

of maintaining safe aircraft, prudent

operators would accomplish the

required actions even if they were not

required to do so by the AD.

A full cost-benefit analysis has not

been accomplished for this proposed

AD. As a matter of law, in order to be

airworthy, an aircraft must conform to

its type design and be in a condition for

safe operation. The type design is

approved only after the FAA makes a

determination that it complies with all

applicable airworthiness requirements.

In adopting and maintaining those

requirements, the FAA has already

made the determination that they

establish a level of safety that is costbeneficial. When the FAA, as in this

proposed AD, makes a finding of an

unsafe condition, this means that the

original cost-beneficial level of safety is

no longer being achieved and that the

proposed actions are necessary to

restore that level of safety. Because this

level of safety has already been

determined to be cost-beneficial, a full

cost-benefit analysis for this proposed

AD would be redundant and

unnecessary.

Regulatory Impact

The regulations proposed herein

would 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

proposal would not have sufficient

federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I

certify that this proposed regulation (1)

is not a ‘‘significant regulatory action’’

under Executive Order 12866; (2) is not

a ‘‘significant rule’’ under the DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979); and (3) if

promulgated, will not have a significant

economic impact, positive or negative,

on a substantial number of small entities

under the criteria of the Regulatory

Flexibility Act. A copy of the draft

regulatory evaluation prepared for this

action is contained in the Rules Docket.

A copy of it may be obtained by

contacting the Rules Docket at the

location provided under the caption

ADDRESSES.
Federal Register / Vol. 62, No. 50 / Friday, March 14, 1997 / Proposed Rules 12123

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration proposes to amend 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:

Boeing: Docket 97–NM–28–AD.

Applicability: All Model 737–100, –200,

–300, –400, and –500 series airplanes,

certificated in any category.

Note 2: 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

otherwise 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 prevent excessive rudder authority and

consequent reduced controllability of the

airplane; and malfunctions of the yaw

damper system, which could result in

sudden uncommanded yawing of the

airplane and consequent injury to passengers

and crewmembers; accomplish the following:

(a) Within 3 years after the effective date

of this AD, accomplish paragraphs (a)(1) and

(a)(2) of this AD in accordance with a method

approved by the Manager, Seattle Aircraft

Certification Office (ACO), FAA, Transport

Airplane Directorate.

(1) Install a newly designed rudderlimiting device that reduces the rudder

authority at altitudes above 1,500 feet above

ground level (AGL).

(2) Install a newly designed yaw damper

system that improves the reliability and fault

monitoring capability.

(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

ACO. Operators shall submit their requests

through an appropriate FAA Principal

Maintenance 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.

Issued in Renton, Washington, on March 7,

1997.

Ronald T. Wojnar,

Manager, Transport Airplane Directorate,

Aircraft Certification Service.

[FR Doc. 97–6436 Filed 3–13–97; 8:45 am]

BILLING CODE 4910–13–P

14 CFR Part 39

[Docket No. 96–NM–152–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 737–100 and –200 Series

Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Supplemental notice of

proposed rulemaking; reopening of

comment period.

SUMMARY: This document revises an

earlier proposed airworthiness directive

(AD), applicable to all Boeing Model

737–100 and –200 series airplanes, that

would have required replacement of

certain outboard and inboard wheel

halves with improved wheel halves.

That action also would have required

cleaning and inspecting certain

outboard and inboard wheel halves for

corrosion, missing paint in large areas,

and cracks; and repair or replacement of

the wheel halves with serviceable wheel

halves, if necessary. That proposal was

prompted by a review of the design of

the flight control systems on Model 737

series airplanes. This action revises the

proposed rule by extending the

compliance time, revising the

applicability of the AD, and clarifying

part and serial numbers of affected

wheel assemblies and halves. The

actions specified by this proposed AD

are intended to prevent failure of the

wheel flanges, which could result in

damage to the hydraulics systems,

jammed flight controls, loss of electrical

power, or other combinations of

failures; and consequent reduced

controllability of the airplane.

DATES: Comments must be received by

April 3, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

152–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9:00 a.m. and 3:00

p.m., Monday through Friday, except

Federal holidays.

The service information referenced in

the proposed rule may be obtained from

Allied Signal Aerospace Company,

Bendix Wheels and Brakes Division,

South Bend, Indiana 46624; and Bendix,

Aircraft Brake and Strut Division, 3520

West Mestmoor Street, South Bend,

Indiana 46624. This information may be

examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

David Herron, Aerospace Engineer,

Systems and Equipment Branch, ANM–

130S, FAA, Seattle Aircraft Certification

Office, 1601 Lind Avenue, SW., Renton,

Washington; telephone (206) 227–2672;

fax (206) 227–1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to

participate in the making of the

proposed 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 above. All communications

received on or before the closing date

for comments, specified above, will be

considered before taking action on the

proposed rule.

The proposals contained in this notice

may be changed in light of the

comments received.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the proposed 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

summarizing each FAA-public contact

concerned with the substance of this

proposal will be filed in the Rules

Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this notice

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 96–NM–152–AD.’’ The

postcard will be date stamped and

returned to the commenter.