AD 2000-10-22

[Federal Register Volume 65, Number 103 (Friday, May 26, 2000)]
[Rules and Regulations]
[Pages 34065-34069]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-13084]


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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.

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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

[[Page 34066]]

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.

[[Page 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 above-referenced comments, FAA 
has determined that:


[[Page 34068]]


--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-in-service (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 <a href="http://www.plainlanguage.gov">http://www.plainlanguage.gov</a>.
    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.


Sec. 39.13  [Amended]

    2. FAA amends Sec. 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.
------------------------------------------------------------------------


[[Page 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.
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    At whichever of     In accordance with
 wing upper and lower spar         the following       the Inspection
 doublers for cracks.              that occurs         section of Revo,
                                   first:.             Inc. Service
                                  (i) Within the       Bulletin B-79 R1--
                                   next 50 hours       Revised January
                                   time-in-service     5, 2000.
                                   (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).
(2) Replace any cracked wing      Prior to further    In accordance with
 spar doubler with a new part      flight after the    the applicable
 that incorporates the same part   required            maintenance
 number (or FAA-approved           inspection.         manual.
 equivalent part number).
(3) Incorporate Modification Kit  Prior to further    In accordance with
 B-79.                             flight after the    the Kit
                                   required            Installation
                                   inspection.         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