[Federal Register Volume 63, Number 71 (Tuesday, April 14, 1998)]
[Proposed Rules]
[Pages 18151-18153]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-9584]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-27-AD]
RIN 2120-AA64


Airworthiness Directives; Mitsubishi Heavy Industries, Ltd. MU-2B 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain Mitsubishi Heavy Industries, Ltd. 
(Mitsubishi) MU-2B series airplanes. The proposed action would require 
repetitively inspecting the cockpit windshield and cabin window 
surfaces for damage (damage would be defined as crazing, scratches, and 
cracks). If any of the windshield or window surfaces have damage that 
exceeds certain limits, the proposed AD would require replacing the 
windshield or window. If the damage does not exceed certain limits, 
then the proposed AD would allow blending out the damage following 
maintenance manual procedures. The proposed AD is the result of 
mandatory continuing airworthiness information (MCAI) issued by the 
airworthiness authority for Japan. The actions specified by the 
proposed AD are intended to prevent cockpit windshield or cabin window 
separation during flight, which could result in engine ingestion of 
glass, wing skin damage, or propeller damage, and possible loss of 
control of the airplane.

DATES: Comments must be received on or before May 11, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 97-CE-27-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106. Comments may be inspected at this location 
between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from Mitsubishi Heavy Industries, Ltd., Nagoya Aerospace Systems Works, 
10. OYE-CHO, MINATO-KU, Nagoya, Japan, telephone: NAGOYA (611) 2141, 
telex: 4464561HISI. This information also may be examined at the Rules 
Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. William Roberts, Aerospace 
Engineer, Los Angeles Aircraft Certification Office, FAA, 3960 
Paramount Blvd., Lakewood, California, 90712; telephone (562) 627-5224; 
facsimile (562) 627-5228.

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 should 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 that summarizes 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 No. 97-CE-27-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, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 97-CE-27-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    The Japanese Civil Airworthiness Bureau (JCAB), which is the 
airworthiness authority for Japan, recently notified the FAA that an 
unsafe condition may exist on certain Mitsubishi MU-2B series 
airplanes. The JCAB reports that several Mitsubishi MU-2B series 
airplanes have had windshield or window separation during flight. 
Separation would be defined as shattering glass. Further analysis shows 
that the separation is happening as a result of repeated cabin 
pressurization cycles. These conditions, if not corrected, could result 
in shattering or separation of the cockpit windshield or cabin windows 
during flight, which could cause loss of control of the airplane.

Relevant Service Information

    Mitsubishi has issued MU-2 Service Bulletin (SB) No. 224, dated 
June 30, 1995, and MU-2 SB No. 224A, dated October 30, 1995, which 
specifies procedures for repetitively inspecting and repairing or 
replacing the cockpit windshield (part numbers (P/N) 010A-31450-1/-2, 
P/N 010A-31451-1/-2, and P/N 010A-81874-1/-2 or an FAA-approved 
equivalent part number) or cabin windows (P/N 010A-31870, P/N 010A-
31870-11, and P/N 030A-32402, or an FAA-approved equivalent part 
number), depending on the extent of the scratching, crazing, or 
cracking. If the scratching, crazing, or cracking is within the 
acceptable limits called out in Table 1 of the service bulletin, the 
procedure for repairing or blending out any damage is found in Chapter 
3 of the Mitsubishi maintenance manual.
    The JCAB classified these service bulletins as mandatory and issued 
AD No. TCD-4311-95, dated November 15, 1995, in order to assure the 
continued airworthiness of these airplanes in Japan. The Japanese AD 
confirms that the cause of glass shattering is the repeated 
pressurization of the airplane cabin, and refers the operators to the 
Mitsubishi service bulletins for inspection and repair instructions, 
but the AD did not cite the incidents of shattered windows on the MU-2B 
series airplanes during flight as the reason for the issuance of the 
JCAB AD.

The FAA's Determination

    These Mitsubishi MU-2B series airplanes are manufactured in Japan 
and are type certificated for operation in the United States under the 
provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement. Pursuant 
to this bilateral airworthiness agreement, the JCAB has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the JCAB, reviewed all available information including the 
service information referenced above, and determined that AD action is 
necessary for products of

[[Page 18152]]

this type design that are certificated for operation in the United 
States.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Mitsubishi MU-2B series airplanes of the same 
type design registered in the United States, the FAA is proposing AD 
action. The proposed AD would require repetitively inspecting the 
affected cockpit windshields and cabin windows for damage and repairing 
or replacing the affected glass, depending on the extent of the damage. 
Accomplishment of the proposed inspection, and repair or replacement 
would be in accordance with Mitsubishi MU-2 Service Bulletin (SB) No. 
224, dated June 30, 1995, and MU-2 SB No. 224A, dated October 30, 1995.

Cost Impact

    The FAA estimates that 200 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 8 
workhours to accomplish the proposed inspection, and that the average 
labor rate is approximately $60 an hour. If a replacement window is 
needed, it would take approximately 16 workhours to accomplish the 
replacement with the average labor rate of $60 per hour. Parts are 
provided at no cost by the manufacturer. Based on these figures, the 
total cost for the inspection would be $480 per airplane or $96,000 for 
the entire U.S. registered fleet. If a replacement is needed, the total 
cost impact of the proposed AD on U.S. operators is estimated to be 
$192,000 or $960 per airplane.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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 has been placed in the Rules Docket. A copy of 
it may be obtained by contacting the Rules Docket at the location 
provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

Mitsubishi Heavy Industries, Ltd. (Mitsubishi): Docket No. 97-CE-27-
AD.

    Applicability: Models MU-2B, MU-2B-10, MU-2B-15, MU-2B-20, MU-
2B-25, MU-2B-26 airplanes (serial numbers (S/N) 008 through 312, 314 
through 320, and 322 through 347), and MU-2B-30, MU-2B-35, MU-2B-36 
airplanes (S/N 501 through 651, 653 through 660, and 662 through 
696), certificated in any category, that are equipped with the 
following part numbered windshields and cabin windows:

010A-31450-1/-2.......................  Windshield (LH/RH).             
010A-31451-1/-2.......................  Cockpit side window (LH/RH).    
010A-81874-1/-2.......................  Cockpit side window (LH/RH).    
010A-31870............................  Cabin Window.                   
010A-31870-11.........................  Cabin Window (at door).         
030A-32402............................  Long body-small cabin window.   
                                                                        

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (e) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.
    Compliance: Required within the next 100 hours time-in-service 
(TIS) after the effective date of this AD, unless already 
accomplished, and thereafter at intervals not to exceed 100 hours 
TIS from the last inspection, repair or replacement.
    To prevent cockpit windshield or cabin window separation 
(shattering) during flight, which could result in engine ingestion 
of glass, wing skin damage, or propeller damage, and possible loss 
of control of the airplane, accomplish the following:
    (a) Inspect the cockpit windshields and cabin windows for 
scratching, crazing, and cracking in accordance with Part I and 
Table 1. ``Damage and Definitions'' of the Instructions section in 
Mitsubishi MU-2 Service Bulletin (SB) No. 224, dated June 30, 1995, 
and Mitsubishi MU-2 SB No. 224A, dated October 30, 1995.
    (b) If any of the windshields or windows listed in the 
applicability section of this AD are damaged beyond the limits 
according to Part I, paragraph 3. ``Acceptable Limits for Damage'' 
of the Instructions section, prior to further flight, replace the 
window or windshield in accordance with the Part II ``Windshield/
Window Glass Replacement'' section of the Mitsubishi MU-2 SB No. 
224, dated June 30, 1995, Mitsubishi MU-2 SB No. 224A, dated October 
30, 1995, and Chapter 3 of the applicable Mitsubishi Maintenance 
Manual.
    (c) Prior to further flight, repair any damaged windshield or 
window that is within the limits (referenced in Table 2 of 
Mitsubishi MU-2 SB No. 224, dated June 30, 1995) in accordance with 
Chapter 3 of the applicable Mitsubishi Maintenance Manual.
    (d) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (e) An alternative method of compliance or adjustment of the 
initial or repetitive compliance times that provides an equivalent 
level of safety may be approved by the Manager, Los Angeles Aircraft 
Certification Office, FAA, 3960 Paramount Blvd., Lakewood, 
California, 90712. The request shall be forwarded through an 
appropriate FAA Maintenance Inspector, who may add comments and then 
send it to the Manager, Los Angeles Aircraft Certification Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles Aircraft Certification Office.

    (f) All persons affected by this directive may obtain copies of 
the documents referred to herein upon request to Mitsubishi Heavy 
Industries, Ltd., Nagoya Aerospace Systems Works, 10. OYE-CHO, 
MINATO-KU, Nagoya, Japan; or may examine these documents at the FAA, 
Central Region, Office of the Regional Counsel, Room 1558, 601 E. 
12th Street, Kansas City, Missouri 64106.

    Note 3: The subject of this AD is addressed in Japanese AD No. 
TCD-4311-95, dated November 15, 1995.


[[Page 18153]]


    Issued in Kansas City, Missouri, on April 3, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-9584 Filed 4-13-98; 8:45 am]
BILLING CODE 4910-13-P