Federal Register / Vol. 62, No. 26 / Friday, February 7, 1997 / Proposed Rules 5785

any leak is detected, prior to further flight,

replace the part with a serviceable part.

(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, Seattle

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, 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.

(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.

Issued in Renton, Washington, on January

31, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–3029 Filed 2–6–97; 8:45 am]

BILLING CODE 4910–13–P

14 CFR Part 39

[Docket No. 96–NM–137–AD]

RIN 2120–AA64

Airworthiness Directives;

Construcciones Aeronauticas, S.A.

(CASA) Model CN–235 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

certain CASA Model CN–235 series

airplanes. This proposal would require

repetitive inspections of the torsion

tubes and fittings of the elevator and

rudder assemblies to detect stress

corrosion cracking, and replacement of

cracked parts. This proposed action also

would require the accomplishment of a

modification that would constitute

terminating action for the repetitive

inspections. This proposal is prompted

by reports indicating that stress

corrosion cracking in these parts has

been found on some airplanes. The

actions specified by the proposed AD

are intended to prevent loss of control

of the elevator and/or rudder, due to

failure of the elevator and/or rudder

assemblies as a result of stress corrosion

cracking.

DATES: Comments must be received by

March 20, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

137–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

Construcciones Aeronauticas, S.A.,

Getafe, Madrid, Spain. This information

may be examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Greg

Dunn, Aerospace Engineer,

Standardization Branch, ANM–113,

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(206) 227–2799; fax (206) 227–1149.

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–137–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.

96–NM–137–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Direccio ́n General de Aviacio ́n

(DGAC), which is the airworthiness

authority for Spain, has notified the

FAA that an unsafe condition may exist

on certain CASA Model CN–235 series

airplanes. The DGAC advises that it has

received reports indicating that stress

corrosion cracks were detected in the

torsion tubes and fittings of the elevator

and rudder assemblies on some of these

airplanes. This condition, if not

corrected, could result in failure of these

assemblies and subsequent loss of

control of the elevator and/or rudder.

Explanation of Relevant Service

Information

CASA has issued Service Bulletin SB–

235–27–05, Revision 1, dated September

29, 1993 (for non-military airplanes),

and Service Bulletin SB–235–27–05M,

Revision 2, dated January 25, 1996 (for

military airplanes). These service

bulletins describe procedures for

conducting repetitive visual inspections

of the torsion tubes for the rudder and

elevator to detect stress corrosion

cracking, and replacement of discrepant

tubes with tubes of a new design.

Installation of the newly-designed

torsion tubes is intended to preclude

stress corrosion cracking and eliminates

the need for repetitive visual

inspections.

The DGAC classified Service Bulletin

SB–235–27–05 (for non-military

airplanes) as mandatory and issued

Spanish airworthiness directive 06/94,

dated August 1994, in order to assure

the continued airworthiness of these

airplanes in Spain. The DGAC classified

Service Bulletin SB–235–27–05M (for

military airplanes) as ‘‘recommended.’’

FAA’s Conclusions

This airplane model is manufactured

in Spain and is type certificated for

operation in the United States under the

provisions of section 21.29 of the

Federal Aviation Regulations (14 CFR

21.29) and the applicable bilateral

airworthiness agreement. Pursuant to

this bilateral airworthiness agreement,

the DGAC has kept the FAA informed

of the situation described above. The

FAA has examined the findings of the

DGAC, reviewed all available

information, and determined that AD

action is necessary for products of this

type design that are certificated for

operation in the United States.
5786 Federal Register / Vol. 62, No. 26 / Friday, February 7, 1997 / Proposed Rules

Explanation of Requirements of

Proposed Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of the same

type design, the proposed AD would

require repetitive visual inspections of

the torsion tubes and fittings of the

rudder and elevator assemblies to detect

stress corrosion cracking, and

replacement of discrepant parts. This

proposed AD also would require the

eventual installation of newly-designed

torsion tubes assemblies on all

airplanes, which, when accomplished,

would constitute terminating action for

the required inspections. The actions

would be required to be accomplished

in accordance with the applicable

service bulletin described previously.

Differences Between Proposed AD and

Parallel Spanish Action

Operators should note that the

Spanish DGAC has not mandated the

accomplishment of the terminating

modification; however, this AD

proposes to require it.

The FAA has determined that long

term continued operational safety will

be better assured by design changes to

remove the source of the problem, rather

than by repetitive inspections. Long

term inspections may not be providing

the degree of safety assurance necessary

for the transport airplane fleet. This,

coupled with a better understanding of

the human factors associated with

numerous continual inspections, has led

the FAA to consider placing less

emphasis on inspections and more

emphasis on design improvements. The

proposed modification requirement is in

consonance with these considerations.

Cost Impact

The FAA estimates that 1 CASA

Model CN–235 series airplane of U.S.

registry would be affected by this

proposed AD.

It would take approximately 6 work

hours per airplane to accomplish each

proposed visual inspection, at an

average labor rate of $60 per work hour.

Based on these figures, the cost impact

of the proposed inspections on the

single affected U.S. operator is

estimated to be $360 per inspection.

It would take approximately 40 work

hours to accomplish the proposed

terminating modification, at an average

labor rate of $60 per work hour. (The

work hour figure does not include the

time needed for preparation of the

airplane or equipment: familiarization

with the service bulletin; curing times

for adhesive, sealant, paint, etc.; tool

collection; or down time.) Required

parts would cost approximately $8,900

per airplane. Based on these figures, the

cost impact of the proposed

modification on the single affected U.S.

operators is estimated to be $9,140.

The cost impact figure discussed

above is 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.

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.

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:

CASA: Docket 96–NM–137–AD.

Applicability: Model CN–235 airplanes as

listed in CASA Service Bulletin SB–235–27–

05, Revision 1, dated September 29, 1993

(non-military airplanes), and CASA Service

Bulletin SB–235–27–05M, Revision 2, dated

January 25, 1996 (military 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

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 (e) 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 loss of control of the elevator

and/or rudder, due to failure of the elevator

and/or rudder assemblies as a result of stress

corrosion cracking in the torsion tubes and

fittings, accomplish the following:

Note 2: Actions required by this AD that

were accomplished previous to the effective

date of this AD, and in accordance with

earlier versions of the specified CASA service

bulletins, are considered acceptable for

compliance with the applicable requirements

of this AD.

(a) At the applicable time specified in

either paragraph (a)(1) or (a)(2) of this AD,

conduct a visual inspection of the torsion

(torsion) tubes on the elevator and rudder

assemblies to detect stress corrosion

cracking, in accordance with CASA Service

Bulletin SB–235–27–05, Revision 1, dated

September 29, 1993 (for non-military

airplanes) or CASA Service Bulletin SB–235–

27–05M, Revision 2, dated January 25, 1996

(for military airplanes), as applicable.

(1) For airplanes that have accumulated

more than 600 total hours time-in-service, or

more than 1,000 total landings, as of the

effective date of this AD: Conduct the

inspection required by paragraph (a) of this

AD prior to the accumulation of 50 hours

time-in-service, or 100 landings, or within 3

months, after the effective date of this AD,

whichever occurs first.

(2) For all other airplanes: Conduct the

inspection required by paragraph (a) of this

AD prior to the accumulation of 600 total

hours time-in-service, or 1,000 total landings,

or within 6 months, after the effective date

of this AD, whichever occurs first.

(b) If no cracking is detected during the

inspection required by paragraph (a) of this

AD, repeat that inspection at intervals not to

exceed 600 hours time-in-service, or 1,000

landings, or 6 months, whichever occurs

first.

(c) If any cracking is detected during the

inspection required by paragraph (a) of this

AD, prior to further flight, accomplish either

paragraph (c)(1) or (c)(2) of this AD.

(1) Replace cracked parts with a new parts

of the original design, in accordance with the
Federal Register / Vol. 62, No. 26 / Friday, February 7, 1997 / Proposed Rules 5787

service bulletin. After replacement, repeat

the visual inspection required by paragraph

(a) of this AD at intervals not to exceed 600

hours time-in-service, or 1,000 landings, or 6

months, whichever occurs first. OR

(2) Replace cracked parts with a newlydesigned parts, in accordance with CASA

Service Bulletin SB–235–27–05, Revision 1,

dated September 29, 1993 (for non-military

airplanes); or CASA Service Bulletin SB–

235–27–05M, Revision 2, dated January

25,1996 (for military airplanes); as

applicable. This replacement constitutes

terminating action for the repetitive visual

inspections of that part required by

paragraph (b) of this AD.

(d) Within 2 years after the effective date

of this AD, replace all original design parts

comprising the torsion tube assemblies on

the elevator and rudder assemblies with

newly-designed parts, in accordance with

CASA Service Bulletin SB–235–27–05,

Revision 1, dated September 29, 1993 (for

non-military airplanes); or CASA Service

Bulletin SB–235–27–05M, Revision 2, dated

January 25, 1996 (for military airplanes); as

applicable. This action constitutes

terminating action for the inspection

requirements of this AD.

(e) 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,

Standardization Branch, ANM–113, 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, Standardization

Branch, ANM–113.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Standardization Branch,

ANM–113.

(f) 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 January

31, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–3028 Filed 2–6–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 90–CE–59–AD]

RIN 2120–AA64

Airworthiness Directives; The New

Piper Aircraft, Inc. (Formerly Piper

Aircraft Corporation) Models PA–31,

PA-31–325, PA–31–350, PA–31P, PA–

31T1, and PA–31T Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Proposed rule; withdrawal.

SUMMARY: This document withdraws a

notice of proposed rulemaking (NPRM)

that proposed a new airworthiness

directive (AD) that would have applied

to The New Piper Aircraft, Inc. (Piper)

Models PA–31, PA–31–325, PA–31–350,

PA–31P, PA–31T1, and PA–31T

airplanes. That NPRM would have

superseded AD 80–26–05 with a new

AD that would have retained the

requirement of repetitively inspecting

the main landing gear (MLG) inboard

door hinges and attachment angles for

cracks, and replacing any cracked MLG

inboard door hinge or attachment angle;

and would have required incorporating

MLG inboard door hinge and

attachment angle assembly, part number

(P/N) 47529–32, as terminating action

for the repetitive inspection

requirement. Since the issuance of the

NPRM, the Federal Aviation

Administration (FAA) has received

reports of cracks in the P/N 47529–32

MLG inboard door hinge and

attachment angle assembly, and has

determined that more information and

analysis is needed before hinge

assembly replacements are mandated

through an AD. The FAA will solicit

service history and comments from

affected airplane owners/operators in a

separate action through an advanced

notice of proposed rulemaking

(ANPRM). Based on the comments, the

FAA may initiate further rulemaking in

the future.

FOR FURTHER INFORMATION CONTACT:

Christina Marsh, Aerospace Engineer,

FAA, Atlanta Aircraft Certification

Office, Campus Building, 1701

Columbia Avenue, suite 2-160, College

Park, Georgia 30337–2748; telephone

(404) 305–7362; facsimile (404) 305–

7348.

SUPPLEMENTARY INFORMATION:

Discussion

A proposal to amend part 39 of the

Federal Aviation Regulations (14 CFR

part 39) to include an AD that would

apply to Piper Models PA–31, PA–31–

325, PA-31–350, PA–31P, PA–31T1, and

PA–31T airplanes was published in the

Federal Register as a notice of proposed

rulemaking (NPRM) on December 7,

1995 (60 FR 62774). The action

proposed to supersede AD 80–26–05,

Amendment 39–3994, with a new AD

that would (1) retain the requirement of

repetitively inspecting the MLG inboard

door hinges and attachment angles for

cracks, and replacing any cracked MLG

inboard door hinge or attachment angle;

and (2) require incorporating a MLG

inboard door hinge and attachment

angle assembly of improved design (part

number 47529–32) or FAA-approved

hinges and angles made of steel as

terminating action for the repetitive

inspection requirement.

Accomplishment of the proposed

inspections would be in accordance

with Piper Service Bulletin (SB) No.

682, dated July 24, 1980.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the one

comment received.

Improved Design Hinge Assemblies

Susceptible to Fatigue Cracking

The commenter believes that the

improved hinge assemblies, part

number (P/N) 47529–32, are also

susceptible to fatigue cracking, and that

installing this assembly should not

eliminate the need for the repetitive

inspections currently required by AD

80–26-05. The commenter states that

three failures and three incidents related

to fatigue cracking of the P/N 47529-32

hinge assemblies have occurred on the

commenter’s fleet of airplanes.

The FAA conducted a review of the

manufacturer’s service history and

service difficulty reports in the FAA

database associated with the P/N

47529–32 main landing gear hinge

assembly. Based on a review of this

information, including the information

received from the commenter, the FAA

has determined that more information

and analysis is needed before hinge

assembly replacements are mandated

through an AD as terminating action for

the repetitive inspections currently

required by AD 80–26–05.

FAA’s Conclusions

Upon further consideration, the FAA

has determined that the NPRM should

be withdrawn until further information

is received and analyzed regarding the

service history of P/N 47529–32 hinge

assemblies. The FAA is issuing an

advance notice of proposed rulemaking

(ANPRM) in a separate action to provide

an opportunity for the general public to

participate in the decision as to what

course of rulemaking the FAA should

take.

Withdrawal of this NPRM constitutes

only such action, and does not preclude

the agency from issuing another notice

in the future, nor does it commit the

agency to any course of action in the

future.

Regulatory Impact

Since this action only withdraws an

NPRM, it is neither a proposed rule nor

a final rule and, therefore, is not covered

under Executive Order 12866, the

Regulatory Flexibility Act, or DOT