Federal Register / Vol. 65, No. 103 / Friday, May 26, 2000 / Rules and Regulations 34065

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.

(e) This amendment becomes effective

on June 12, 2000.

Issued in Renton, Washington, on May 18,

2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–13085 Filed 5–25–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99–CE–27–AD; Amendment 39–

11746; AD 2000–10–22]

RIN 2120–AA64

Airworthiness Directives; REVO,

Incorporated Models Lake LA–4, Lake

LA–4A, Lake LA–4P, Lake LA–4–200,

and Lake Model 250 Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule; request for

comments.

SUMMARY: This amendment adopts a

new airworthiness directive (AD) that

applies to certain REVO, Incorporated

(REVO) Models Lake LA–4, Lake LA–

4A, Lake LA–4P, Lake LA–4–200, and

Lake Model 250 airplanes. This AD

requires you to: inspect the left and

right wing upper and lower spar

doublers for cracks; replace any cracked

parts; and incorporate a modification

kit. This AD is the result of a report of

a fatigue crack found at the second most

inboard wing attachment bolt hole on

one of the affected airplanes. Similar

fatigue cracking has since been reported

on seven more of the affected airplanes,

including incidents where the fatigue

cracking occurred on airplanes with less

than 500 hours time-in-service (TIS).

The actions specified by this AD are

intended to detect and correct cracks in

the wing spars, which could result in

the wing separating from the airplane

with consequent loss of control.

DATES: This AD becomes effective on

June 20, 2000.

The Director of the Federal Register

approved the incorporation by reference

of certain publications listed in the

regulation as of June 20, 2000.

The Federal Aviation Administration

(FAA) must receive any comments on

this rule on or before July 28, 2000.

ADDRESSES: Submit comments in

triplicate to the FAA, Central Region,

Office of the Regional Counsel,

Attention: Rules Docket No. 99–CE–27–

AD, 901 Locust, Room 506, Kansas City,

Missouri 64106.

You may get the service information

referenced in this AD from REVO,

Incorporated, P.O. Box 312, One High

Street, Sanford, Maine 04073. You may

examine this information at FAA,

Central Region, Office of the Regional

Counsel, Attention: Rules Docket No.

99–CE–27–AD, 901 Locust, Room 506,

Kansas City, Missouri 64106; or at the

Office of the Federal Register, 800 North

Capitol Street, NW, suite 700,

Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr.

Richard B. Noll, Aerospace Engineer,

FAA, Boston Aircraft Certification

Office, 12 New England Executive Park,

Burlington, Massachusetts 01803;

telephone: (781) 238–7160; facsimile:

(781) 238–7199.

SUPPLEMENTARY INFORMATION:

Discussion

What Caused This AD?

This AD is the result of a report of

fatigue cracks that were found at the

second-most inboard wing attachment

bolt hole on a REVO Lake Model 250

airplane. The cracks were detected

during wing repair where the wing spar

and wing skin were disassembled.

Further analysis indicated that the

cracks initiated at a machined notch at

the flange termination point of the spar

cap.

The REVO Models Lake LA–4, Lake

LA–4A, Lake LA–4P, and Lake LA–4–

200 airplanes are of the same type

design as the Lake Model 250 airplanes.

Fatigue cracking similar to that of the

above-referenced report has been found

on seven more of these airplanes.

What Is the Potential Impact If FAA

Took No Action?

Cracks in the wing spars, if not

detected and corrected in a timely

manner, could result in the wing

separating from the airplane with

consequent loss of control.

Has FAA Taken Any Action to This

Point?

We issued a notice of proposed

rulemaking (NPRM) to amend part 39 of

the Federal Aviation Regulations (14

CFR part 39) to include an AD that

would apply to certain REVO Models

Lake LA–4, Lake LA–4A, Lake LA–4P,

Lake LA–4–200, and Lake Model 250

airplanes. We published this NPRM in

the Federal Register on October 6, 1999

(64 FR 54234). The NPRM proposed to

require you to accomplish the following:

—Inspect the left and right wing upper

and lower spar caps and doublers for

cracks;

—Replace any cracked parts;

—Incorporate a modification kit if

damaged past a certain level; and

—Report the results of the inspection to

FAA.

REVO Service Bulletin B–79, dated

June 12, 1999, includes the procedures

necessary for you to accomplish the

proposed inspection and modification.

Was the Public Invited To Comment?

The FAA offered interested persons

the opportunity to participate in the

making of this amendment. The

following paragraphs present the

comments received on the NPRM. Also

included is FAA’s response to each

comment, including any changes

incorporated into the final rule based on

the comments.

Comment Issue No. 1: Wing Spar

Cracking Does Not Warrant AD Action

What are the Commenters’ Concerns?

Numerous commenters question FAA’s

justification for issuing an AD. Several

commenters do not believe our service

difficulty database provides accurate

information. A few commenters

recommend that we conduct additional

research on the cause of the wing spar

cracks and determine if the cracks are

unique to a particular configuration of

the affected airplanes. Other

commenters propose various causes of

the cracks, including:

—Installation of auxiliary fuel tanks in

the wing floats;

—Increased braking power in the Model

Lake LA–4–200 and Lake Model 250

airplanes; and

—The presence of corrosion.

What is FAA’s Response to the

Concerns? We do not concur that the

AD is not justified. We began our

investigation of the wing spar cracks on

the affected airplanes when the

Australian Civil Aviation Safety

Authority reported cracks in both the

spar cap and doubler in the lower spar

of a Lake Model 250 airplane. We then

received several reports of similar

cracking from personnel of maintenance

and repair facilities that were working

on the affected airplanes. Reports

indicated that both the upper and lower

spars were cracked. These subsequent

reports did not specify corrosion

damage. All of the wing spar cracks

initiated at a machined notch at the

flange termination point of the spar cap

34066 Federal Register / Vol. 65, No. 103 / Friday, May 26, 2000 / Rules and Regulations

at the second-most inboard wing

attachment bolt hole.

We also initiated laboratory

examinations of the cracked spars.

These examinations revealed that

fatigue caused the cracks and were

associated with the roughness of the

notch area. The certification basis for

the affected airplanes did not require an

evaluation of fatigue characteristics. A

database of either analytical results or

test data does not exist. However, we

performed a fatigue analysis of the

affected airplanes in the notch area in

developing the proposed inspection

compliance times. Our analysis of this

situation included working with the

manufacturer to develop inspection

procedures for the spar doublers and

spar cap angles and a modification

(doubler kit) for the wing spar. We then

determined that enough information

existed to implement AD action in order

to assure the continued airworthiness of

the affected airplanes. Thus, we issued

an NPRM to propose inspections for

cracks and repair, replacement, and

modification, as necessary.

We are not changing the AD as a

result of these comments.

Comment Issue No. 2: Do Not Require

the Spar Cap Inspection

What are the Commenters’ Concerns?

Several commenters recommend that

FAA not require the spar cap inspection

in accordance with REVO, Inc. Service

Bulletin B–79, dated June 12, 1999. The

commenters offer the following

explanations for eliminating this

inspection:

—Accomplishing the inspection could

cause damage to the spar cap/doubler;

—The number of personnel with the

expertise necessary to accomplish the

inspection is limited;

—The fluorescent dye penetrant

inspection is difficult to implement

and is less effective than a visual or

borescope examination; and

—There are limited maintenance/repair

facilities capable of conducting the

inspection.

What are FAA’s Responses to the

Concerns? We concur that the spar cap

inspection is not necessary. The

inspection of the spar cap was intended

to look for additional cracks outside of

the notch area. We are eliminating the

spar cap inspection from the AD for the

following reasons:

—The cracks detected on the

previously-referenced airplanes

developed in the notch area and not

in the spar cap; and

—We have received several additional

reports of airplanes with cracks in the

notch area and nowhere else.

We are only requiring a visual

inspection of the wing spar doublers

instead of a dye penetrant inspection.

REVO, Inc. has revised Service Bulletin

B–79 (R1—Revised January 5, 2000) to

incorporate the visual inspection

change.

Comment Issue No. 3: Provide

Alternatives to the Proposed

Requirements

What are the Commenters’ Concerns?

Several commenters recommend

alternative methods of compliance to

meet the safety intent of the AD. These

alternatives are:

—Accomplish the inspection utilizing

borescope procedures;

—Accomplish the inspection utilizing

visual procedures;

—Only inspect the bolt holes;

—Cut inspection holes in the wing skin;

and

—Allow repetitive inspections instead

of requiring the incorporation of the

Aerofab B–79 kit.

What is FAA’s Response to the

Concerns? We do not concur that any of

the alternatives alone are valid to meet

the safety intent of this AD. Inspecting

the wing spar doubler in accordance

with the procedures in REVO, Inc.

Service Bulletin B–79, dated June 12,

1999, assures the airworthiness of this

component prior to installing the

doubler kit (Aerofab B–79 kit). Installing

this doubler kit gives the spar an

adequate fatigue life and eliminates the

need for repetitive inspections. We do

not concur that cutting holes in the

wing skin for inspections is an

acceptable alternative because of the

sensitive nature of the wing skin.

We also do not concur with allowing

repetitive inspections instead of

mandatory incorporation of the Aerofab

B–79 kit. Constant removal of the bolts

could cause unnecessary damage. The

FAA’s policy is to require a

modification when incorporation of that

modification could eliminate or reduce

the number of required inspections.

We are not changing the AD as a

result of these comments.

Comment Issue No. 4: Eliminate Certain

Airplanes From the Applicability of the

AD

What are the Commenters’ Concerns?

Several commenters request that FAA

not include the Model Lake LA–4

airplanes in the applicability of the final

rule AD. The commenters state that the

applicability should be based on the

weight, auxiliary fuel, and brake

differences of the airplanes.

One commenter concurs with the

applicability of the NPRM.

What is FAA’s Response to the

Concerns? We have determined that this

AD should apply to the Model Lake LA–

4 airplanes. The service difficulty

database clearly shows the need to

address the wing spar condition on the

Model Lake LA–4–200 and Lake Model

250 airplanes. The Model Lake LA–4

airplanes are included because:

—The wing/spar attachment design is

the same as the Model Lake LA–4–200

airplanes;

—The gross weight is only 200 pounds

less than the Model Lake LA–4–200

airplanes; and

—These airplanes have been in service

longer than the Model Lake LA–4–200

airplanes.

For these reasons, we have

determined that the Model Lake LA–4

airplanes are also susceptible to wing

spar fatigue cracking and the AD must

apply to these airplanes.

We are not changing the AD as a

result of these comments.

Comment Issue No. 5: Revise the

Methods of Incorporating the Doubler

Kit

What are the Commenters’ Concerns?

Several commenters suggest revisions to

the Aerofab B–79 doubler kit. These

suggestions include:

1. Revising the rivet removal method;

2. Utilizing bolts instead of rivets;

3. Retaining the original bolts for the

Model Lake LA–4 airplanes; and

4. Redesigning the doubler.

What are FAA’s Responses to the

Concerns? We concur with these

suggestions, as follows:

1. We concur and will require

accomplishment in accordance with

Revo, Inc. Service Bulletin B–79 R1,

Revised January 5, 2000. This revised

service bulletin incorporates the

proposed rivet removal methods;

2. We concur. Revo, Inc. Service

Bulletin B–79 R1, Revised January 5,

2000, allows the use of AN3 bolts, and

accomplishment of the AD is required

in accordance with this service bulletin;

3. We do not concur that you may

retain the original bolts for the Model

Lake LA–4 airplanes. The new design

configuration of the wing spar caps with

the doublers requires longer bolts than

originally utilized; and

4. We do not concur with the need to

redesign the doubler. Incorporation of

the doubler kit on the affected airplanes

restores wing spars to their required

strength if a crack is present in the

notch area of a spar cap. Incorporation

of the doubler kit also provides the

strength and stability to prevent future

fatigue cracking.

Federal Register / Vol. 65, No. 103 / Friday, May 26, 2000 / Rules and Regulations 34067

Comment Issue No. 6: Difference

Between the Proposed AD and the

Service Bulletin

What are the Commenters’ Concerns?

Two commenters note a difference

between the service bulletin and the

proposed AD, regarding the dye

penetrant inspection procedure. One of

these commenters also points out that

ASTM E1417–95 was referred to as

ASTM E1417–99 in the NPRM.

What is FAA’s Response to the

Concerns? We concur that there is a

difference between the dye penetrant

inspection procedure proposed in the

NPRM and that contained in the original

service bulletin. When the AD and

service bulletin differ, the AD takes

precedence. In addition, FAA received a

revision to the ASTM document

(E1417–99 from E1417–95) after

preparing the NPRM.

However, as discussed previously,

FAA is not requiring the dye penetrant

inspection.

Comment Issue No. 7: Do Not Include

the Reporting Requirement

What is the Commenters’ Concern?

Seven commenters recommend that

FAA not require the reporting

requirement for the dye penetrant

inspection. These commenters state that

this proposed requirement is irrelevant

to the safety of the aircraft.

What is FAA’s Response to the

Concern? We concur. As discussed

previously, FAA is not including this

inspection in the AD, so there is no

need for the reporting requirement.

We are not including the reporting

requirement in the AD.

Comment Issue No. 8: Inspect the Spar

Caps and Doublers for Corrosion Any

Time a Wing Is Removed

What are the Commenters’ Concerns?

Six commenters request that FAA

require inspection of the of spar caps

and doublers for corrosion any time a

wing is removed. The commenters

recommend this inspection from the

roof rib to the first rib outboard or to the

inboard fuel tank.

What is FAA’s Response to the

Concerns? We do not concur. We have

not received any record of wing

corrosion on the affected airplanes. The

actions in this AD address the unsafe

condition.

We are not changing the AD as result

of these comments.

Comment Issue No. 9: Redesign the

Wing Attachment

What are the Commenters’ Concerns?

One commenter recommends a redesign

of the wing attachment area to correct

the unsafe condition. Another

commenter suggests that the

manufacturer conduct a test of the wing/

fuselage attachment area.

What is FAA’s Response to the

Concerns? We have determined that

incorporating the doubler kit restores

the wing spars of the affected airplanes

to their required strength and addressses

the unsafe condition referenced in this

AD. We will evaluate any data

pertaining to a redesign of the wing

attachment area or other alternative

method of compliance, as long as it is

submitted in accordance with the

procedures included in this AD.

We are not changing the AD as a

result of these comments.

Comment Issue No. 10: The FAA

Underestimated the Cost Impact

What are the Commenters’ Concerns?

Two commenters state that FAA

underestimated the costs of

implementing the actions proposed in

the NPRM. Another commenter states

that the cost impact analysis is

inadequate because it is designed to

address transport category airplanes and

not general aviation aircraft. This

commenter suggests that the costs of

accomplishing this AD could exceed

$5,000 per airplane.

What is FAA’s Response to the

Concerns? We do not concur that the

cost analysis is inadequate. The cost

impact as proposed in the NPRM is

$4,920 per airplane ($2,400 for the

inspections and $2,520 for the

modification). However, we are not

requiring wing removal and a dye

penetrant inspection in the AD. We are

now only requiring a visual inspection

of the wing spar doublers (with

replacement if found cracked) and

modification. This reduces the time and

cost necessary to accomplish the

inspection from approximately 40

workhours per airplane to

approximately 1 workhour per airplane.

Comment Issue No. 11: Withdraw the

AD

What is the Commenter’s Concern?

One commenter requests that FAA

withdraw the NPRM because the service

bulletin is effective.

What is FAA’s Response to the

Concern? We do not concur. The only

way we can assure that all affected

airplane owners/operators accomplish

the actions in a service bulletin is

through the issuance of an AD.

We are not changing the AD as a

result of these comments.

Comment Issue No. 12: Change the

Compliance Time

What are the Commenters’ Concerns?

Several commenters request an

extension to the compliance time. The

commenters state that the available

repair/maintenance facilities could not

accomplish the work on all affected

airplanes within the proposed

compliance time.

One commenter recommends

requiring repetitive inspections of the

bolt holes and only requiring the

doubler kit if cracks are found during an

inspection.

Two commenters request a reduction

in the compliance time to 25 hours

time-in-service (TIS) to coincide with

the service bulletin. This commenter

refers to an incident where the wing

spar was cracked on an affected airplane

with less than 300 hours TIS.

What is FAA’s Response to the

Concerns? Since issuance of the NPRM,

we have received information regarding

wing spar cracks on an airplane with

270 hours TIS. We also have additional

reports of wing spar cracking on

airplanes with 556 hours TIS and 538

hours TIS.

Based on this information, we do not

concur with the request to extend the

compliance time. We are reducing the

compliance time although not to

coincide with the service bulletin. We

have determined that the wing spars on

all of the affected airplanes should be

inspected within 50 hours TIS or 12

months after the effective date of the AD

(whichever occur first), regardless of the

total number of hours currently

accumulated on the wing spar. The

NPRM proposed to allow low time

airplanes to reach 500 hours total TIS on

the wing spar before requiring

inspection and modification. Because

the latest reports show that cracking

could occur prior to 300 hours TIS, we

have determined that the 50-hour TIS or

12-month compliance time will

eliminate the unsafe condition

presented in this AD without

inadvertently grounding any of the

affected airplanes.

We do not concur with allowing

repetitive inspections instead of

mandatory modification. Constant

removal of the bolts could cause

unnecessary damage. The FAA’s policy

is to require a modification when

incorporation of that modification could

eliminate or reduce the number of

required inspections.

The FAA’s Determination and

Followup Action

What Have We Decided?

After careful review of all available

information related to the subject

presented above, including the abovereferenced comments, FAA has

determined that:

34068 Federal Register / Vol. 65, No. 103 / Friday, May 26, 2000 / Rules and Regulations

—The changes to the proposed AD as

described in the above comment

disposition should be incorporated;

and

—AD action should be taken to

incorporate these changes to detect

and correct cracks in the wing spar

doublers, which could result in the

wing separating from the airplane

with consequent loss of control.

What Is Our Next Action?

Since the change in the compliance

time increases the burden on the

owners/operators of the affected

airplanes over what was proposed in the

NPRM, we are required to allow the

public additional time to comment on

the AD.

Because additional reports show the

cracks are occurring in the wing spar

doublers on the affected airplanes with

less hours TIS than initially expected,

FAA finds that notice and opportunity

for public prior comment are

impracticable. Therefore, good cause

exists for making this amendment

effective in less than 30 days.

What Does This AD Require?

This AD requires you to accomplish

the following:

—Inspect the left and right wing upper

and lower spar doublers for cracks;

—Replace any cracked parts; and

—Incorporate a modification kit.

What Procedures Must You Use To

Accomplish This AD?

You must use the procedures in Revo,

Inc. Service Bulletin B–79 R1—Revised

January 5, 2000, to accomplish this AD.

What Is the Compliance Time of This

AD?

At whichever of the following that

occurs first:

—Within the next 50 hours time-inservice (TIS) after June 20, 2000 (the

effective date of this AD); or

—On or before June 20, 2001 (12 months

after the effective date of this AD).

Why Is the Compliance in Both Hours

TIS and Calendar Time?

The fatigue cracks on the wing spar

doublers of affected airplanes may have

already initiated and could be further

developing on the low-usage airplanes

as well as high-usage airplanes.

Utilizing the dual compliance times

would assure that cracks in the wing

spars are detected on all affected

airplanes in a timely manner without

inadvertently grounding any of the

affected airplanes.

Comments Invited

This action is in the form of a final

rule and the FAA did precede it with

notice and opportunity for public

comment. However, the change in

compliance time, as described above,

has changed because of information

received since the notice. FAA is

issuing the information in this final rule

without prior notice because an urgent

situation concerning safety of flight

exists. However, FAA is still inviting

comments on this rule. You may submit

whatever written data, views, or

arguments you choose. You need to

include the rule’s docket number and

submit your comments in triplicate to

the address specified under the caption

ADDRESSES. The FAA will consider all

comments received on or before the

closing date. We may amend this rule in

light of comments received. Factual

information that supports your ideas

and suggestions is extremely helpful in

evaluating the effectiveness of the AD

action and determining whether we

need to take additional rulemaking

action.

The FAA is re-examining the writing

style we currently use in regulatory

documents, in response to the

Presidential memorandum of June 1,

1998. That memorandum requires

federal agencies to communicate more

clearly with the public. We are

interested in your comments on whether

the style of this document is clearer, and

any other suggestions you might have to

improve the clarity of FAA

communications that affect you. You

can get more information about the

Presidential memorandum and the plain

language initiative at http://

www.plainlanguage.gov.

The FAA specifically invites

comments on the overall regulatory,

economic, environmental, and energy

aspects of the rule that might suggest a

need to modify the rule. You may

examine all comments we receive before

and after the closing date of the rule in

the Rules Docket. We will file a report

in the Rules Docket that summarizes

each FAA contact with the public that

concerns the substantive parts of this

AD.

If you want us to acknowledge the

receipt of your comments, you must

include a self-addressed, stamped

postcard. On the postcard, write

‘‘Comments to Docket No. 99–CE–27–

AD.’’ We will date stamp and mail the

postcard back to you.

Regulatory Impact

These regulations will 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, FAA

has determined that this final rule does

not have federalism implications under

Executive Order 13132.

The FAA has determined that this

regulation is an emergency regulation

that must be issued immediately to

correct an unsafe condition in aircraft,

and is not a significant regulatory action

under Executive Order 12866. We have

determined that this action involves an

emergency regulation under DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979). If FAA

determines that this emergency

regulation otherwise would be

significant under DOT Regulatory

Policies and Procedures, we will

prepare a final regulatory evaluation.

You may obtain a copy of the evaluation

(if required) from the Rules Docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Incorporation by Reference,

Safety.

Adoption of the Amendment

Accordingly, under 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. FAA amends § 39.13 by adding a

new airworthiness directive (AD) to

read as follows:

2000–10–22 Revo, Incorporated:

Amendment 39–11746; Docket No. 99–

CE–27–AD.

(a) What airplanes are affected by this AD?

This AD applies to the following model and

serial number airplanes, certificated in any

category; that incorporate any of the wing

spar part numbers (or FAA-approved

equivalent part numbers) that are specified

below the airplane models and serial

numbers:

AFFECTED AIRPLANES

Model Serial Nos.

Lake LA 4 ................. 246 through 421, 423

through 429, 445,

and 446.

Lake LA–4A .............. 244 and 245.

Lake LA–4P .............. 121.

Lake LA–4 200 ......... 422, 430 through

444, and all serial

numbers after 446.

Lake Model 250 ........ 1 through 232.

Federal Register / Vol. 65, No. 103 / Friday, May 26, 2000 / Rules and Regulations 34069

WING SPAR PART NUMBERS

INCORPORATED

Wing spar parts Part Nos.

Upper Spar Cap Angles.2–1610–015 and 2–

1610–016.

Lower Spar Cap Angles.2–1610–075 and 2–

1610–076.

Upper Spar Doublers 2–1610–061 and 2–

1610–081 and 2–

1610–065.

WING SPAR PART NUMBERS

INCORPORATED

Wing spar parts Part Nos.

Lower Spar Doublers 2–1610–063 and 2–

1610–083.

(b) Who must comply with this AD?

This AD applies to anyone who wishes

to operate any of the above airplanes on

the U.S. Register .

(c) What problem does this AD

address? The actions of this AD are

intended to detect and correct cracks in

the wing spars, which could result in

loss of the wing with consequent loss of

control of the airplane.

(d) What actions must I accomplish to

address this problem? To address this

problem, you must accomplish the

following:

Action When Procedures

(1) Inspect the left and right wing upper and

lower spar doublers for cracks.

At whichever of the following that occurs first:

(i) Within the next 50 hours time-in-service

(TIS) after June 20, 2000 (the effective date

of this AD); or.

(ii) On or before June 20, 2001 (12 months

after the effective date of this AD).

In accordance with the Inspection section of

Revo, Inc. Service Bulletin B–79 R1—Revised January 5, 2000.

(2) Replace any cracked wing spar doubler

with a new part that incorporates the same

part number (or FAA-approved equivalent

part number).

Prior to further flight after the required inspection.In accordance with the applicable maintenance manual.

(3) Incorporate Modification Kit B–79 ................ Prior to further flight after the required inspection.In accordance with the Kit Installation section

of Revo, Inc. Service Bulletin B–79 R1—

Revised January 5, 2000.

(e) What if I need to replace a wing

on my airplane? After the effective date

of this AD, you may not install a wing

on any of the affected airplanes, unless

one of the following exists:

(1) The wing is new from the factory;

or

(2) The inspection, applicable

replacement, and kit incorporation

requirements of this AD have been

accomplished at the time of installation.

(f) Can I comply with this AD in any

other way? You may use an alternative

method of compliance or adjust the

compliance time if:

(1) Your alternative method of

compliance provides an equivalent level

of safety; and

(2) The Manager, Boston Aircraft

Certification Office (ACO), approves

your alternative. Submit your request

through an FAA Principal Maintenance

Inspector, who may add comments and

then send it to the Manager, Boston

ACO.

Note: This AD applies to each airplane

identified in paragraph (a) of this AD,

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 (f)

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 you have not

eliminated the unsafe condition, specific

actions you propose to address it.

(g) Where can I get information about

any already-approved alternative

methods of compliance? Contact Mr.

Richard B. Noll, Aerospace Engineer,

FAA, Boston Aircraft Certification

Office, 12 New England Executive Park,

Burlington, Massachusetts 01803;

telephone: (781) 238–7160; facsimile:

(781) 238–7199.

(h) What if I need to fly the airplane

to another location to comply with this

AD? The FAA can issue a special flight

permit under sections 21.197 and

21.199 of the Federal Aviation

Regulations (14 CFR 21.197 and 21.199)

to operate your airplane to a location

where you can accomplish the

requirements of this AD.

(i) Are any service bulletins

incorporated into this AD by reference?

Actions required by this AD must be

done in accordance Revo, Inc. Service

Bulletin B–79 R1—Revised January 5,

2000. The Director of the Federal

Register approved this incorporation by

reference under 5 U.S.C. 552(a) and 1

CFR part 51. You can get copies from

REVO, Incorporated, P.O. Box 312, One

High Street, Sanford, Maine 04073. You

can look at copies at FAA, Central

Region, Office of the Regional Counsel,

901 Locust, Room 506, Kansas City,

Missouri; or at the Office of the Federal

Register, 800 North Capitol Street, NW,

suite 700, Washington, DC.

(j) When does this amendment

become effective? This amendment

becomes effective on June 20, 2000.

Issued in Kansas City, Missouri, on May

17, 2000.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft

Certification Service.

[FR Doc. 00–13084 Filed 5–25–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–NM–99–AD; Amendment

39–11739; AD 2000–10–15]

RIN 2120–AA64

Airworthiness Directives; Airbus Model

A320 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment supersedes

two existing airworthiness directives

(AD), applicable to certain Airbus

Model A320 series airplanes, that

currently require modification of the

rear spar web of the wing and cold

expansion of certain attachment holes

for the forward pintle fitting and certain

holes at the actuating cylinder

anchorage of the main landing gear

(MLG). This amendment adds a

requirement for repetitive inspections to

detect fatigue cracking in certain areas

of the rear spar of the wing, and

corrective action, if necessary. This