Federal Register / Vol. 65, No. 116 / Thursday, June 15, 2000 / Proposed Rules 37497

(2) If any failure of the WEU or loss of any

visual, aural, or tactile alert is detected: Prior

to further flight, replace WEU power supplies

having P/N 285T0035–201, with new or

modified power supplies having P/N

285T0035–202 Mod A; or new or serviceable

power supplies having P/N 285T0035–9, P/

N 285T0035–10, or P/N 285T0035–11; in

accordance with the applicable service

bulletin. Such replacement constitutes

terminating action for the requirements of

this AD.

Replacement

(f) Within 1 year after the effective date of

this AD, replace WEU or MAWEA power

supplies having P/N 285T0035–201, with

new or modified power supplies having P/N

285T0035–202 Mod A; or new or serviceable

power supplies having P/N 285T0035–9, P/

N 285T0035–10, or P/N 285T0035–11; in

accordance with Boeing Service Bulletin

747–31–2288, dated December 17, 1998,

Revision 1, dated January 28, 1999, or

Revision 2, dated November 18, 1999 (for

Model 747–400 and 747–400F series

airplanes); Boeing Service Bulletin 757–31–

0066, Revision 1, dated December 17, 1998,

or Revision 2, dated November 18, 1999 (for

Model 757–200, 757–200CB, and 757–200PF

series airplanes); or Boeing Service Bulletin

767–31–0106, Revision 1, dated December

17, 1998, or Revision 2, dated November 18,

1999 (for Model 767–200, 767–300, and 767–

300F series airplanes); as applicable. After

the effective date of this AD, only Revision

2 of the applicable service bulletin shall be

used. Such replacement constitutes

terminating action for the repetitive

inspection requirements of this AD.

Spares

(g) As of the date specified in paragraph

(g)(1) or (g)(2), as applicable, no person shall

install a WEU or MAWEA power supply

having Boeing P/N 285T0035–201 on any

airplane.

(1) For Model 747–400 series airplanes,

line numbers 1121 through 1177 inclusive;

Model 757–200, –200CB, and –200PF series

airplanes, line numbers 761 through 828

inclusive; and Model 767–200, 767–300, and

–300F series airplanes, line numbers 668

through 723 inclusive: As of September 16,

1999 (the effective date of AD 99–18–16,

amendment 39–11282).

(2) For airplanes other than those

identified in paragraph (g)(1) of this AD: As

of the effective date of this AD.

Alternative Methods of Compliance

(h)(1) 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 Avionics

Inspector, who may add comments and then

send it to the Manager, Seattle ACO.

(2) Alternative methods of compliance,

approved previously by the FAA in

accordance with AD 99–18–16, amendment

39–11282, are approved as alternative

methods of compliance with this AD.

Note 4: 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

(i) 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 June 9,

2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–15189 Filed 6–14–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99–NM–377–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747 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 Boeing Model 747 series

airplanes. This proposal would require

inspections to detect cracking of the

frame web, doubler, and inner chord of

the forward edge frame of main entry

door number 1, and various follow-on

actions. This proposal is prompted by

reports of cracking in the frame web,

doubler, inner chord, and strap of the

forward edge frame of main entry door

number 1. The actions specified by the

proposed AD are intended to prevent

cracks in the frame web and doubler of

the forward edge frame of main entry

door number 1, which could result in

inability of the edge frame to react door

stop loads, and consequent rapid

depressurization of the airplane.

DATES: Comments must be received by

July 31, 2000.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 99–NM–

377–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

Boeing Commercial Airplane Group,

P.O. Box 3707, Seattle, Washington

98124–2207. This information may be

examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Rick

Kawaguchi, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–1153;

fax (425) 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 99–NM–377–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–114, Attention: Rules Docket No.

99–NM–377–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received reports

indicating that cracking has been

detected in the frame web, doubler,

37498 Federal Register / Vol. 65, No. 116 / Thursday, June 15, 2000 / Proposed Rules

inner chord, and strap of the forward

edge frame of main entry door number

1 on several Boeing Model 747 series

airplanes. One operator reported that

the frame web, doubler, inner chord,

and strap were severed at the lower sill.

Cracks initiated in the frame web at the

fastener holes where the sill attach clip

attaches to the frame web. Other

operators have reported small cracks in

the frame web and doubler at the cable

penetration just below the lower sill. On

certain Boeing Model 747 series

airplanes, the subject frame web,

doubler, and inner chord are made from

7075 aluminum. Fatigue cracks in the

frame web and doubler of the forward

edge frame of main entry door number

1, if not detected, could extend to the

inner chord of the frame and cause the

inner chord to break, leading to failure

of the outer chord and adjacent fuselage

skin. This condition, if not corrected,

could result in inability of the edge

frame to react door stop loads, and

consequent rapid depressurization of

the airplane.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Service Bulletin 747–53A2417,

Revision 1, dated July 23, 1998, which

describes procedures for detailed visual

and high frequency eddy current (HFEC)

inspections to detect cracking of the

frame web, doubler, and inner chord of

the forward edge frame of main entry

door number 1, and various follow-on

actions. If no cracking is detected,

follow-on actions include repetitive

detailed visual and HFEC inspections,

reinforcement of the forward edge frame

and repetitive detailed visual

inspections, and eventual repair of the

door frame. If any cracking is detected,

the repair is required prior to further

flight. The repair includes replacement

of the existing frame web and doubler

with a new frame web, doubler, and

splice doubler made of 2024-T3

aluminum, which is a more fatigueresistant material than 7075 aluminum.

Accomplishment of the repair

eliminates the need for the repetitive

inspections described by the service

bulletin.

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 accomplishment of the actions

specified in the service bulletin

described previously, except as

discussed below.

Difference Between This Proposed AD

and Service Information

As described previously, the service

bulletin describes procedures for

detailed visual and HFEC inspections to

detect cracking of the frame web,

doubler, and inner chord of the forward

edge frame of main entry door number

1. Operators should note that paragraph

(c) of this proposed AD also would

require certain repetitive detailed visual

inspections not described in the service

bulletin. These additional inspections

are prompted by two reports that

cracking was detected outside the area

covered by the service bulletin. As a

result of the reports, the FAA has

determined that it is necessary to

propose additional repetitive

inspections. These additional

inspections involve removal of the cover

assembly for the body torque tube

located between the door hinge

attachments, and accomplishment of a

detailed visual inspection to detect

cracking of the aft side of the forward

edge door frame web of main entry door

number 1. The area to be inspected

includes the exposed area from doorstop

ι2 [approximately water line (WL) 218]

to doorstop ι5 (approximately WL 245)

at body station 434.

Cost Impact

There are approximately 685

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

211 airplanes of U.S. registry would be

affected by this proposed AD.

For Group 1 airplanes (approximately

191 U.S.-registered airplanes), it would

take approximately 3 work hours per

airplane to accomplish the proposed

inspections, at an average labor rate of

$60 per work hour. Based on these

figures, the cost impact of the proposed

inspections on U.S. operators of Group

1 airplanes is estimated to be $34,380,

or $180 per airplane, per inspection

cycle.

For Group 2 airplanes (approximately

20 U.S.-registered airplanes), it would

take approximately 2 work hours per

airplane to accomplish the proposed

inspections, at an average labor rate of

$60 per work hour. Based on these

figures, the cost impact of the proposed

inspection on U.S. operators of Group 2

airplanes is estimated to be $2,400, or

$120 per airplane, per inspection cycle.

For Group 1 airplanes (approximately

191 U.S.-registered airplanes), it would

take approximately 128 work hours per

airplane to accomplish the proposed

repair, at an average labor rate of $60

per work hour. Based on these figures,

the cost impact of the proposed repair

on U.S. operators of Group 1 airplanes

is estimated to be $1,466,880, or $7,680

per airplane.

For Group 2 airplanes (approximately

20 U.S.-registered airplanes), it would

take approximately 64 work hours per

airplane to accomplish the proposed

repair, at an average labor rate of $60

per work hour. Based on these figures,

the cost impact of the proposed

inspection on U.S. operators of Group 2

airplanes is estimated to be $76,800, or

$3,840 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.

Should an operator elect to

accomplish the reinforcement of the

door frame on a Group 1 airplane, it

would take approximately 9 work hours

per airplane to accomplish the

reinforcement, at an average labor rate

of $60 per work hour. Based on these

figures, the cost impact of the

reinforcement on a Group 1 airplane is

estimated to be $540 per airplane.

Should an operator elect to

accomplish the reinforcement of the

door frame on a Group 2 airplane, it

would take approximately 5 work hours

per airplane to accomplish the

reinforcement, at an average labor rate

of $60 per work hour. Based on these

figures, the cost impact of the

reinforcement on a Group 2 airplane is

estimated to be $300 per airplane.

Regulatory Impact

The regulations proposed herein

would not have a substantial direct

effect 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,

it is determined that this proposal

would not have federalism implications

under Executive Order 13132.

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. 65, No. 116 / Thursday, June 15, 2000 / Proposed Rules 37499

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 99–NM–377–AD.

Applicability: Model 747 series airplanes,

line numbers 1 through 685 inclusive,

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 (g) 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 fatigue cracking of the frame

web and doubler of the forward edge frame

of main entry door number 1, which could

result in inability of the edge frame to react

door stop loads, and consequent rapid

depressurization of the airplane, accomplish

the following:

Initial Inspection: Compliance Time

(a) At the time specified in paragraph

(a)(1), (a)(2), (a)(3), or (a)(4); as applicable;

accomplish the requirements of paragraphs

(b) and (c) of this AD.

(1) For airplanes that have accumulated

fewer than 13,000 total flight cycles as of the

effective date of this AD: Inspect prior to the

accumulation of 13,000 total flight cycles, or

within 1,500 flight cycles after the effective

date of this AD, whichever occurs later.

(2) For airplanes that have accumulated

13,000 or more total flight cycles but fewer

than 20,000 total flight cycles as of the

effective date of this AD: Inspect prior to the

accumulation of 21,000 total flight cycles, or

within 1,500 flight cycles after the effective

date of this AD, whichever occurs first.

(3) For airplanes that have accumulated

20,000 or more total flight cycles but fewer

than 25,000 total flight cycles as of the

effective date of this AD: Inspect prior to the

accumulation of 25,500 total flight cycles, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs first.

(4) For airplanes that have accumulated

25,000 or more total flight cycles as of the

effective date of this AD: Inspect within 500

flight cycles after the effective date of this

AD.

Initial Detailed Visual and High Frequency

Eddy Current Inspections

(b) Perform a detailed visual inspection

and a high frequency eddy current inspection

of the frame web, doubler, and inner chord

of the forward edge door frame to detect

cracking of main entry door number 1, in

accordance with Boeing Service Bulletin

747–53A2417, Revision 1, dated July 23,

1998. For Group 1 airplanes (as identified in

the service bulletin), accomplish the

inspections on the left and right sides of the

airplane. For Group 2 airplanes (as identified

in the service bulletin), accomplish the

inspections on the left side of the airplane

only.

Note 2: For the purposes of this AD, it is

not necessary to count flight cycles

accumulated at 2.0 pounds per square inch

or less differential pressure.

Note 3: Inspections, reinforcements, and

repairs accomplished prior to the effective

date of this AD in accordance with Boeing

Alert Service Bulletin 747–53A2417, dated

June 25, 1998, are considered acceptable for

compliance with paragraph (b) of this AD.

Note 4: For the purposes of this AD, a

detailed visual inspection is defined as: ‘‘An

intensive visual examination of a specific

structural area, system, installation, or

assembly to detect damage, failure, or

irregularity. Available lighting is normally

supplemented with a direct source of good

lighting at intensity deemed appropriate by

the inspector. Inspection aids such as mirror,

magnifying lenses, etc., may be used. Surface

cleaning and elaborate access procedures

may be required.’’

Repetitive Detailed Visual Inspections (No

Terminating Action)

(c) Remove the cover assembly for the body

torque tube located between the door hinge

attachments. Perform a detailed visual

inspection to detect cracking of the aft side

of the forward edge door frame web of main

entry door number 1 in the exposed area

from doorstop #2 [approximately water line

(WL) 218] to doorstop #2 (approximately WL

245) at body station 434. Pay particular

attention to the row of fasteners that attach

the frame web to the frame outer chord. After

completing inspections, replace the cover

assembly. Repeat the inspection thereafter at

intervals not to exceed 3,000 flight cycles.

Note 5: The inspections required by

paragraph (c) of this AD are not described in

Boeing Service Bulletin 747–53A2417,

Revision 1, dated July 23, 1998.

Note 6: There is no terminating action

currently available for the inspections

required by paragraph (c) of this AD.

Repetitive Inspections/Reinforcement/Repair

(No Cracks Detected)

(d) If no crack is detected during the

inspection required by paragraph (b) of this

AD, prior to further flight, oversize fastener

holes in accordance with Boeing Service

Bulletin 747–53A2417, Revision 1, dated July

23, 1998, and accomplish the requirements of

paragraph (d)(1), (d)(2), or (d)(3) of this AD.

(1) Repeat the inspections specified in

paragraph (b) of this AD one time within

3,000 flight cycles. Within 3,000 flight cycles

after accomplishment of the repeat

inspection, accomplish paragraph (d)(2) or

(d)(3) of this AD.

(2) Reinforce the door frame, in accordance

with Figure 5 of the service bulletin.

Thereafter, at intervals not to exceed 3,000

flight cycles, perform a detailed visual

inspection to detect cracks of the forward and

aft side of the frame, in accordance with

Figure 6 of the service bulletin. Within

10,000 flight cycles after the reinforcement,

accomplish the requirements of paragraph

(d)(3) of this AD.

(3) Accomplish the web replacement repair

(‘‘Terminating Action’’) in accordance with

the service bulletin. Such repair constitutes

terminating action for the repetitive

inspection requirements of paragraphs (d)(1)

and (d)(2) of this AD.

Repair (Cracks Detected)

(e) If any crack is detected during any

inspection required by paragraph (b), (d)(1),

or (d)(2) of this AD, prior to further flight,

accomplish the repair (‘‘Terminating

Action’’) in accordance with Boeing Service

Bulletin 747–53A2417, Revision 1, dated July

23, 1998. Such repair constitutes terminating

action for the repetitive inspection

requirements of paragraphs (d)(1) and (d)(2)

of this AD.

Repair

(f) If any cracking is detected during the

inspection required by paragraph (c) of this

AD, prior to further flight, repair 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 (DER) who has

been authorized by the Manager, Seattle

ACO, to make such findings. For a repair

method to be approved by the Manager,

Seattle ACO, as required by this paragraph,

the approval letter must specifically

reference this AD.

Alternative Methods of Compliance

(g) 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 7: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

37500 Federal Register / Vol. 65, No. 116 / Thursday, June 15, 2000 / Proposed Rules

Special Flight Permits

(h) 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 June 9,

2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–15190 Filed 6–14–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NM–07–AD]

RIN 2120–AA64

Airworthiness Directives; Dornier

Model 328–300 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 Dornier Model 328–300 series

airplanes. This proposal would require

replacement of the hydraulic line tube

assemblies with improved tube

assemblies and flexible hose assemblies.

This action is necessary to prevent

cracking of the hydraulic lines, which

could result in loss of hydraulic

pressure for certain braking systems on

the airplane. This action is intended to

address the identified unsafe condition.

DATES: Comments must be received by

July 17, 2000.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 2000–NM–

07–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. Comments may also

be sent via the Internet using the

following address: 9-anmnprmcomment@faa.gov. Comments sent

via the Internet must contain ‘‘Docket

No. 2000–NM–07–AD’’ in the subject

line and need not be submitted in

triplicate.

The service information referenced in

the proposed rule may be obtained from

FAIRCHILD DORNIER, DORNIER

Luftfahrt GmbH, P.O. Box 1103, D–

82230 Wessling, Germany. This

information may be examined at the

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington.

FOR FURTHER INFORMATION CONTACT:

Norman B. Martenson, Manager,

International Branch, ANM–116, FAA,

Transport Airplane Directorate, 1601

Lind Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–2110;

fax (425) 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.

Submit comments using the following

format:

• Organize comments issue-by-issue.

For example, discuss a request to

change the compliance time and a

request to change the service bulletin

reference as two separate issues.

• For each issue, state what specific

change to the proposed AD is being

requested.

• Include justification (e.g., reasons or

data) for each request.

• 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 2000–NM–07–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–114, Attention: Rules Docket No.

2000–NM–07–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Luftfahrt-Bundesamt (LBA),

which is the airworthiness authority for

Germany, notified the FAA that an

unsafe condition may exist on certain

Dornier Model 328–300 series airplanes.

The LBA advises that pressure spikes

and vibration during manual activation

of the hydraulic changeover valve may

cause cracking of the hydraulic lines

that pressurize the braking systems of

these airplanes. The pressure spikes

create a high bending stress near the

sleeve at the changeover valve. Such

cracking of the hydraulic lines, if not

corrected, could result in loss of

hydraulic pressure for certain braking

systems on the airplane.

Explanation of Relevant Service

Information

Dornier has issued Alert Service

Bulletin ASB–328J–32–003 (including

Annex 1), dated December 17, 1999. The

alert service bulletin describes

procedures for replacement of the

hydraulic line tube assemblies with

improved tube assemblies and flexible

hose assemblies. Accomplishment of the

actions specified in the service bulletin

is intended to adequately address the

identified unsafe condition. The LBA

classified this service bulletin as

mandatory and issued German

airworthiness directive 2000–050, dated

February 24, 2000, in order to assure the

continued airworthiness of these

airplanes in Germany.

FAA’s Conclusions

This airplane model is manufactured

in Germany 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 LBA has kept the FAA informed of

the situation described above. The FAA

has examined the findings of the LBA,

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.

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 registered in the United

States, the proposed AD would require