Federal Register / Vol. 64, No. 78 / Friday, April 23, 1999 /Rules and Regulations 19879

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–NM–337–AD; Amendment

39–11132; AD 99–08–23]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 737–100, –200, –200C, –300,

–400, and –500 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 737–100,

–200, –200C, –300, –400, and –500

series airplanes. This action requires

repetitive inspections to detect cracking

in the web of the aft pressure bulkhead

at body station 1016 at the aft fastener

row attachment to the ‘‘Y’’ chord; and

corrective actions, if necessary. This

amendment is prompted by several

reports of fatigue cracking found at that

location on Model 737 series airplanes.

The actions specified in this AD are

intended to detect and correct such

fatigue cracking, which could result in

rapid decompression of the fuselage.

DATES: Effective May 10, 1999.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of May 10,

1999.

Comments for inclusion in the Rules

Docket must be received on or before

June 22, 1999.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 98–NM–

337–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

FOR FURTHER INFORMATION CONTACT:

Nenita Odesa, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–2557;

fax (425) 227–1181.

SUPPLEMENTARY INFORMATION: The FAA

has received reports of fatigue cracking

found on Boeing Model 737–200 series

airplanes in the web of the aft pressure

bulkhead at body station 1016 at the aft

fastener row attachment to the ‘‘Y’’

chord. An 11-inch crack was found on

an airplane with 40,000 total flight

cycles, and a 3.5-inch crack was found

on an airplane with 28,000 total flight

cycles. Investigation revealed 43

fasteners installed in improperly drilled

holes at the web-to-‘‘Y’’ chord

attachment in the area of the 11-inch

crack. Such fatigue cracking, if not

detected and corrected, could result in

rapid decompression of the fuselage.

Explanation of the Requirements of the

Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of the same

type design, this AD is being issued to

detect and correct fatigue cracking at

certain fastener holes of the aft pressure

bulkhead, which could result in rapid

decompression of the fuselage. This AD

requires repetitive inspections of the

web of the aft pressure bulkhead at body

station 1016 at the aft fastener row

attachment to the ‘‘Y’’ chord, and

corrective actions, if necessary. For

compliance with this inspection

requirement, operators may perform

either a low frequency eddy current

(LFEC) inspection from the aft side of

the bulkhead or a detailed visual

inspection from the forward side of the

bulkhead. Corrective actions include a

high frequency eddy current inspection

to detect cracking of the web at the ‘‘Y’’

chord attachment; a detailed visual

inspection of the bulkhead, if necessary;

and repair in accordance with a method

approved by the FAA.

Differences Between AD and Relevant

Service Information

This AD refers to Boeing 737

Nondestructive Test (NDT) Manual D6–

37239, Part 6, Subject 53–10–54, as the

appropriate source of service

information for accomplishment of the

LFEC inspection. Operators should note

that, unlike the procedures described in

the NDT manual, which specifies that

the web be inspected only from stringer

9 left to stringer 9 right, this AD

expands the area to be inspected.

Because of the safety implications and

consequences associated with fatigue

cracking and because of the unknown

nature of the source of the subject

cracking, the FAA has determined that

an LFEC inspection, if accomplished,

must be performed from stringer 15 left

to stringer 15 right of the upper section

of the bulkhead at body station 1016.

Interim Action

This is considered to be interim

action until final action is identified, at

which time the FAA may consider

further 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

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 98–NM–337–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.
19880 Federal Register / Vol. 64, No. 78 / Friday, April 23, 1999 /Rules and Regulations

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, Incorporation by reference,

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:

99–08–23 Boeing: Amendment 39–11132.

Docket 98–NM–337–AD.

Applicability: All Model 737–100, –200,

–200C, –300, –400, and –500 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 (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 detect and correct fatigue cracking at

certain fastener holes of the aft pressure

bulkhead, which could result in rapid

decompresssion of the fuselage, accomplish

the following:

Initial Inspection

(a) Perform either inspection specified by

paragraph (a)(1) or (a)(2) of this AD at the

time specified in paragraph (b) of this AD.

(1) Perform a low frequency eddy current

inspection from the aft side of the aft

pressure bulkhead to detect discrepancies

(including cracking, misdrilled fastener

holes, and corrosion) of the web of the upper

section of the aft pressure bulkhead at body

station 1016 at the aft fastener row

attachment to the ‘‘Y’’ chord, from stringer 15

left to stringer 15 right, in accordance with

Boeing 737 Nondestructive Test Manual D6–

37239, Part 6, Section 53–10–54, dated

December 5, 1998.

(2) Perform a detailed visual inspection of

the aft fastener row attachment to the ‘‘Y’’

chord from the forward side of the aft

pressure bulkhead to detect discrepancies

(including cracking, misdrilled fastener

holes, and corrosion) of the entire web of the

aft pressure bulkhead at body station 1016.

(b) Perform the inspection required by

paragraph (a) of this AD at the time specified

by paragraph (b)(1), (b)(2), or (b)(3) of this

AD, as applicable.

(1) For airplanes that have accumulated

40,000 or more total flight cycles as of the

effective date of this AD: Inspect within 375

flight cycles or 60 days after the effective date

of this AD, whichever occurs later.

(2) For airplanes that have accumulated

25,000 or more total flight cycles and fewer

than 40,000 total flight cycles as of the

effective date of this AD: Inspect within 750

flight cycles or 90 days after the effective date

of this AD, whichever occurs later.

(3) For airplanes that have accumulated

fewer than 25,000 total flight cycles as of the

effective date of this AD: Inspect prior to the

accumulation of 25,750 total flight cycles.

Repetitive Inspections

(c) Within 1,200 flight cycles after

performing the initial inspection required by

paragraph (a) of this AD, and thereafter at

intervals not to exceed 1,200 flight cycles:

Perform either inspection specified by

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

Corrective Actions

(d) If any discrepancy is detected during

any inspection required by this AD: Prior to

further flight, accomplish the actions

specified by paragraphs (d)(1) and (d)(3), and

paragraph (d)(2) if applicable, of this AD.

(1) Perform a high frequency eddy current

inspection from the forward side of the

bulkhead to detect cracking of the web at the

‘‘Y’’ chord attachment, around the entire

periphery of the ‘‘Y’’ chord, in accordance

with Boeing 737 Nondestructive Test Manual

D6–37239, Part 6, Section 51–00–00, Figure

23, dated November 5, 1997.

(2) If the most recent inspection performed

in accordance with paragraph (a) of this AD

was not a detailed visual inspection:

Accomplish the actions specified by

paragraph (a)(2) of this AD. If the inspection

was a detailed visual inspection, it is not

necessary to repeat that inspection prior to

further flight.

(3) Repair any discrepancy such as

cracking or corrosion or misdrilled fastener

holes in accordance with a method approved

by the Manager, Seattle Aircraft Certification

Office (ACO), FAA, Transport Airplane

Directorate; or in accordance with data

meeting the type certification basis of the

airplane approved by a Boeing Company

Designated Engineering Representative who

has been authorized by the Manager, Seattle

ACO, to make such findings.

Alternative Methods of Compliance

(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, 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.

Special Flight Permits

(f) Special flight permits may be issued in

accordance with §§ 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.

Incorporation by Reference

(g) The eddy current inspections shall be

done in accordance with Boeing 737

Nondestructive Test Manual D6–37239, Part

6, Section 53–10–54, dated December 5,

1998; or Boeing 737 Nondestructive Test

Manual D6–37239, Part 6, Section 51–00–00,

Figure 23, dated November 5, 1995; as

applicable. These references contain the

specified list of effective pages:

Page No. Revision level

shown on page

Date shown on

page

Title Page ................................................................................................................................................ Not Shown ............. February 5, 1995.

List of Effective Pages—Pages 1, 6–12 ................................................................................................. Not Shown ............. December 5, 1998.

List of Effective Pages—Page 2 ............................................................................................................. Not Shown ............. August 5, 1998.

List of Effective Pages—Pages 2A, 3 .................................................................................................... Not Shown ............. November 5, 1997.

List of Effective Pages—Page 4 ............................................................................................................. Not Shown ............. November 5, 1995.
Federal Register / Vol. 64, No. 78 / Friday, April 23, 1999 /Rules and Regulations 19881

Page No. Revision level

shown on page

Date shown on

page

List of Effective Pages—Page 5 ............................................................................................................. Not Shown ............. May 5, 1997.

This incorporation by reference was

approved by the Director of the Federal

Register in accordance with 5 U.S.C. 552(a)

and 1 CFR part 51. Copies may be obtained

from Boeing Commercial Airplane Group,

P.O. Box 3707, Seattle, Washington 98124–

2207. Copies may be inspected at the FAA,

Transport Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at the

Office of the Federal Register, 800 North

Capitol Street, NW., suite 700, Washington,

DC.

(h) This amendment becomes effective on

May 10, 1999. .

Issued in Renton, Washington, on April 9,

1999.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 99–9739 Filed 4–22–99; 8:45 am]

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–SW–44–AD; Amendment

39–11139; AD 99–09–06]

RIN 2120–AA64

Airworthiness Directives; Eurocopter

France Model AS–350B, B1, B2, B3,

BA, and D Helicopters, and Model AS

355E, F, F1, F2 and N Helicopters

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule; request for

comments.

SUMMARY: This amendment adopts a

new airworthiness directive (AD) that is

applicable to Eurocopter France Model

AS–350B, B1, B2, B3, BA, and D

helicopters, and Model AS 355E, F, F1,

F2 and N helicopters. This action

requires inspecting the tail rotor spider

plate bearing (bearing) for the proper

bearing rotational torque, axial play, and

for any brinelling of the bearing. This

amendment is prompted by service

difficulty reports citing the need to

prematurely replace bearings due to

wear, and by two in-flight incidents of

increased tail rotor vibration levels due

to bearing wear. This condition, if not

corrected, could result in seizure of the

bearing, loss of tail rotor control and

subsequent loss of control of the

helicopter.

DATES: Effective May 10, 1999.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of May 10,

1999.

Comments for inclusion in the Rules

Docket must be received on or before

June 22, 1999.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Office of the

Regional Counsel, Southwest Region,

Attention: Rules Docket No. 98–SW–44–

AD, 2601 Meacham Blvd., Room 663,

Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT:

Shep Blackman, Aerospace Engineer,

FAA, Rotorcraft Directorate, Rotorcraft

Standards Staff, 2601 Meacham Blvd.,

Fort Worth, Texas 76137, telephone

(817) 222–5296, fax (817) 222–5961.

SUPPLEMENTARY INFORMATION: The

Direction Generale De L’Aviation Civile

(DGAC), which is the airworthiness

authority for France, recently notified

the FAA that an unsafe condition may

exist on Eurocopter France Model AS–

350B, B1, B2, B3, BA, and D helicopters,

and Model AS 355E, F, F1, F2 and N

helicopters. The DGAC advises that a

one-time measurement of bearing

rotational torque and repetitive

inspections of the bearing for axial play,

binding, or brinelling is necessary to

prevent seizure of the bearing and loss

of control of the helicopter.

Eurocopter France has issued

Eurocopter AS 350 Service Bulletin (SB)

No. 05.00.29, applicable to Model AS–

350 helicopters, and SB No. 05.00.30,

applicable to Model AS 355 helicopters,

both dated February 8, 1999. These SB’s

specify a periodic check of the pitch

change spider plate bearing to prevent

any blocking of the bearing. The DGAC

classified these SB’s as mandatory and

issued AD 1999–084–057(A), and AD

1999–085–076(A), both dated February

24, 1999, applicable to Model AS 355

and Model AS–350 helicopters,

respectively, in order to assure the

continued airworthiness of these

helicopters in France.

These helicopter models are

manufactured in France and are 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.

The FAA estimates that 507

helicopters will be affected by this AD,

that it will take approximately 1 work

hour to accomplish the inspection, and

4 work hours to replace a bearing, if

required, and that the average labor rate

is $60 per work hour. Required parts

will cost approximately $60 per

helicopter. Based on these figures, the

total cost impact of the AD on U.S.

operators is estimated to be $182,520 to

inspect and replace one bearing in each

helicopter in the fleet.

Since an unsafe condition has been

identified that is likely to exist or

develop on other Eurocopter France

Model AS–350B, B1, B2, B3, BA, and D

helicopters, and Model AS 355E, F, F1,

F2 and N helicopters of the same type

design registered in the United States,

this AD is being issued to prevent

seizure of the bearing, loss of tail rotor

control, and subsequent loss of control

of the helicopter. This AD requires,

within 50 hours TIS, measuring the

bearing rotational torque, and thereafter

at intervals not to exceed 100 hours TIS,

inspecting the bearing for axial play,

binding, or brinelling. The short

compliance time involved is required

because the previously described

critical unsafe condition can adversely

affect the controllability of the

helicopter. Therefore, inspecting the

bearing for the proper rotational torque

within the next 50 hours time-in-service

(TIS), and for any bearing roughness at

intervals not to exceed 100 hours TIS is

required, and this AD must be issued

immediately.

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