[Federal Register Volume 59, Number 102 (Friday, May 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-12717]


[[Page Unknown]]

[Federal Register: May 27, 1994]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-CE-09-AD; Amendment 39-8920; AD 94-11-04]

 

Airworthiness Directives: Mitsubishi Heavy Industries MU-2B 
Series 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 Mitsubishi Heavy Industries MU-2B series airplanes. 
This action requires adjusting the engine underspeed governor minimum 
stop (ground idle) and the airframe condition control linkage, 
modifying the tachometer indicator markings, fabricating and installing 
a placard that specifies a minimum idle speed, and incorporating 
Airplane Flight Manual (AFM) revisions. An accident of one of the 
affected airplanes where the propeller hub assembly failed and the 
propeller separated from the airplane prompted this action. Accident 
investigation analysis indicates a reduction in fatigue strength of the 
propeller hub because of high vibration frequencies during ground idle 
speed. The actions specified by this AD are intended to prevent 
propeller hub arm assembly failure because of high vibration 
frequencies during ground idle speed and possible separation of the 
propeller from the airplane, which could result in loss of control of 
the airplane.

DATES: Effective June 10, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 10, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before July 29, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket 94-CE-09-AD, room 1558, 601 E. 12th 
Street, Kansas City, Missouri 64106.
    Information that relates to this AD may be obtained from the Beech 
Aircraft Corporation, P.O. Box 85, Wichita, Kansas 67201-0085; or 
Mitsubishi Heavy Industries, Ltd., 5-1 Marunouchi 2 Chome, Chiyoda-ku, 
Tokyo Japan. This information may also be examined at the Federal 
Aviation Administration (FAA), Central Region, Office of the Assistant 
Chief Counsel, Attention: Rules Docket 94-CE-09-AD, room 1558, 601 E. 
12th Street, 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. Charles D. Riddle, Aerospace 
Engineer, FAA, Wichita Aircraft Certification Office, 1801 Airport 
Road, room 100, Wichita, Kansas 67209; telephone (316) 946-4144; 
facsimile (316) 946-4407.

SUPPLEMENTARY INFORMATION: A recent accident of a Mitsubishi Model MU-
2B-60 airplane where the propeller hub assembly failed and the 
propeller separated from the airplane prompted the FAA and the National 
Transportation Safety Board (NTSB) to investigate the vibration 
frequency of these airplanes during ground idle operation. Accident 
investigation analysis indicates a reduction in fatigue strength of the 
propeller hub because of high vibration frequencies during ground idle 
speed. These high vibration frequencies, if not corrected, eventually 
will result in the above-referenced propeller hub assembly failure and 
separation of the propeller from the airplane.
    After examining the circumstances and reviewing all available 
information related to the incidents described above, the FAA has 
determined that (1) certain precautions (in addition to those taken by 
previous AD actions and during initial certification of the airplane) 
should be taken to minimize these high vibration frequencies during 
ground idle speed; and (2) AD action should be taken to prevent the 
above-referenced conditions.
    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, this AD requires adjusting the engine underspeed governor 
minimum stop (ground idle) and the airframe condition control linkage, 
modifying the tachometer indicator markings, fabricating and installing 
a placard that specifies a minimum idle speed, and incorporating 
Airplane Flight Manual (AFM) revisions. The ground idle modification is 
required to be accomplished in accordance with the Allied Signal 
Garrett Maintenance Manual (Report No. 72-00-95 for TPE331-10-501M or 
Report No. 72-00-27 for TPE331-501M or -511M), chapter 72-00-00, 
General-Adjustment/Test; and chapter 76-10- 01, Control Linkage 
Assembly, Maintenance Practices. The airframe control linkage 
modification is required to be accomplished in accordance with chapter 
6, Sec. 9.2, of the applicable Mitsubishi MU-2 maintenance manual. The 
revisions to the applicable Airplane Flight Manual are as follows: 

------------------------------------------------------------------------
                                                     Date and revision  
         Model               Effective pages              level         
------------------------------------------------------------------------
MU-2B-26A..............  1, 2, Revision log 2, 1- FAA approved 1-12-77  
                          5, 5-10, 5-13, and 5-    reissued 03-25-86    
                          23.                      revision 4.          
MU-2B-36A..............  1, 2, Revision log 2, 1- FAA approved 01-12-77 
                          5, 2-10, 5-10, 5-13,     reissued 02-28-86    
                          and 5-23.                revision 6.          
MU-2B-40...............  1, 2, Revision log 2, 1- FAA approved 3-2-78   
                          5, 2-10, 5-10, 5-13, 5-  reissued 03-25-86    
                          14, and 5-24.            revision 4.          
MU-2B-60...............  1, 2, Revision log 2, 1- FAA approved 3-2-78   
                          5, 2-9, 5-10, 5-13, 5-   reissued 09-24-85    
                          14, and 5-24.            revision 5.          
MU-2B-36 Modified by     1 through 31...........  FAA approved 2-1-78   
 STC SA2413SW.                                     reissued 12-18-92    
                                                   revision 1.          
------------------------------------------------------------------------

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for public 
prior comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting immediate flight safety and, thus, was not 
preceded by notice and opportunity to comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications 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 will be considered, 
and this rule may be amended in light of the comments received. Factual 
information that supports the commenter's ideas and suggestions is 
extremely helpful in evaluating the effectiveness of the AD action and 
determining whether additional rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 94-CE-09-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket (otherwise, an evaluation is 
not required). A copy of it, if filed, may be obtained 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, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

94-11-04 Mitsubishi Heavy Industries, Ltd.: Amendment 39-8920; 
Docket No. 94-CE-09-AD.

    Applicability: The following model and serial number airplanes, 
certificated in any category: 

------------------------------------------------------------------------
        Model                              Serial No.                   
------------------------------------------------------------------------
MU-2B-26A.............  All serial numbers.                             
MU-2B-36A.............  All serial numbers.                             
MU-2B-40..............  All serial numbers.                             
MU-2B-60..............  All serial numbers.                             
MU-2B-36..............  All serial numbers modified by Supplemental Type
                         Certificate SA2413SW.                          
------------------------------------------------------------------------

    Compliance: Required within the next 25 hours time-in-service 
after the effective date of this AD, unless already accomplished.
    To prevent propeller hub arm assembly failure because of high 
vibration frequencies during ground idle speed and possible 
separation of the propeller from the airplane, which could result in 
loss of control of the airplane, accomplish the following:
    (a) Adjust the underspeed governor minimum stop (ground idle) to 
a range of 76.5 percent to 78.5 percent in accordance with the 
Allied Signal Garrett Maintenance Manual (Report No. 72-00-95 for 
TPE331-10-501M or Report No. 72-00-27 for TPE331-501M or -511M), 
chapter 72-00-00, General-Adjustment /Test; and chapter 76-10-01, 
Control Linkage Assembly, Maintenance Practices.

    Note 1: One clockwise turn of the adjusting screw will increase 
the ground idle engine speed approximately 5 percent.

    (b) Modify the airframe condition control linkage by adjusting 
Rod 1 and Levers 2 and 7 as specified in Figure 1 of this AD in 
accordance with Chapter 6, Sec. 9.2, of the applicable Mitsubishi 
MU-2 maintenance manual.

BILLING CODE 4910-13-U



E:\GRAPHICS\ER27MY94.008
BILLING CODE 4910-13-C
    (c) Modify the tachometer indicator marking by accomplishing the 
following:
    (1) Apply red lacquer (Federal Standard 595a, number 11105 or 
equivalent) to the tachometer indicator glass so that the red 
operating arc extends to 76.5 percent.

    Note 2: The red operating arc range will now be from 50 percent 
to 76.5 percent.

    (2) Using white lacquer (MIL-L-7178, color number 511 or 
equivalent), apply a 1/16-inch wide by 1/4-inch long slip stripe 
over the tachometer glass and indicator case at the 11:30 o'clock 
position as specified in Figure 2 of this AD.

BILLING CODE 4910-13-U



E:\GRAPHICS\ER27MY94.009

BILLING CODE 4910-13-C

    (d) Fabricate a placard with the following words utilizing 
letters at least .10-inch in height: ``Minimum engine idle speed--
76.5 percent''. Install this placard on the instrument panel in 
close proximity to the tachometer within the pilot's full view.
    (e) Modifying the tachometer dial through an FAA-approved 
instrument repair shop to extend the red operating arc to 76.5 
percent is equivalent to those actions required by paragraph (c)(1), 
(c)(2), and (d) of this AD, and may be accomplished in lieu of those 
actions.
    (f) Incorporate the following revision into the applicable 
Airplane Flight Manual: 

------------------------------------------------------------------------
                                                     Date and revision  
         Model               Effective pages              level         
------------------------------------------------------------------------
MU-2B-26A..............  1, 2, Revision Log 2, 1- FAA approved 1-12-77  
                          5, 5-10, 5-13, and 5-    reissued 03-25-86    
                          23.                      revision 4.          
MU-2B-36A..............  1, 2, Revision Log 2, 1- FAA approved 01-12-77 
                          5, 2-10, 5-10, 5-13,     reissued 02-28-86    
                          and 5-23.                revision 6.          
MU-2B-40...............  1, 2, Revision Log 2, 1- FAA approved 3-2-78   
                          5, 2-10, 5-10, 5-13, 5-  reissued 03-25-86    
                          14, and 5-24..           revision 4.          
MU-2B-60...............  1, 2, Revision Log 2, 1- FAA approved 3-2-78   
                          5, 2-9, 5-10, 5-13, 5-   reissued 09-24-85    
                          14, and 5-24.            revision 5.          
MU-2B-36 modified by     1 through 31...........  FAA approved 2-1-78   
 STC SA2413SW.                                     reissued 12-18-92    
                                                   revision 1.          
------------------------------------------------------------------------

    (g) Special flight permits may be issued in accordance with 
Secs. 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.
    (h) An alternative method of compliance other than that 
referenced in paragraph (e) of this AD or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Wichita Aircraft Certification Office 
(ACO), 1801 Airport Road, room 100, Mid-Continent Airport, Wichita, 
Kansas 67209. The request shall be forwarded through an appropriate 
FAA Maintenance Inspector, who may add comments and then send it to 
the Manager, Wichita ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Wichita ACO.
    (i) The incorporation required by this AD shall be done in 
accordance with the following airplane flight manual revisions (as 
applicable):

------------------------------------------------------------------------
                                                     Date and revision  
         Model               Effective pages               level        
------------------------------------------------------------------------
MU-2B-26A..............  1, 2, Revision log 2, 1- FAA approved 1-12-77  
                          5, 5-10, 5-13, and 5-    reissued 03-25-86    
                          23.                      revision 4.          
MU-2B-36A..............  1, 2, revision log 2, 1- FAA approved 01-12-77 
                          5, 2-10, 5-10, 5-13,     reissued 02-28-86    
                          and 5-23.                revision 6.          
MU-2B-40...............  1, 2, revision log 2, 1- FAA approved 3-2-78   
                          5, 2-10, 5-10, 5-13, 5-  reissued 03-25-86    
                          14, and 5-24.            revision 4.          
MU-2B-60...............  1, 2, revision log 2, 1- FAA approved 3-2-78   
                          5, 2-9, 5-10, 5-13, 5-   reissued 09-24-85    
                          14, and 5-24.            revision 5.          
MU-2B-36 modified by     1 through 31...........  FAA approved 2-1-78   
 STC SA2413SW.                                     reissued 12-18-92    
                                                   revsion 1.           
------------------------------------------------------------------------

    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from Mitsubishi Heavy Industries, 
Ltd., 5-1 Marunouchi 2 Chome, Chiyoda-ku, Tokyo Japan. Copies may be 
inspected at the FAA, Central Region, Office of the Assistant Chief 
Counsel, room 1558, 601 E. 12th Street, Kansas City, Missouri, or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
7th floor, suite 700, Washington, DC.
    (j) This amendment (39-8920) becomes effective on June 10, 1994.

    Issued in Kansas City, Missouri, on May 19, 1994.
Dwight A. Young,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-12717 Filed 5-26-94; 8:45 am]
BILLING CODE 4910-13-U