[Federal Register Volume 59, Number 238 (Tuesday, December 13, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-30395]


[[Page Unknown]]

[Federal Register: December 13, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-204-AD; Amendment 39-9094; AD 94-25-10]

 

Airworthiness Directives; Beech Model 400, 400A, 400T, and MU-
300-10 Airplanes, and Mitsubishi Model MU-300 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 
is applicable to all Beech Model 400, 400A, 400T, and MU-300-10 
airplanes, and all Mitsubishi Model MU-300 airplanes. This action 
requires a revision to the Airplane Flight Manual that provides pilots 
with special operating procedures during icing conditions. This 
amendment is prompted by the results of icing tests, which demonstrated 
that ice accumulations on the horizontal stabilizer may cause the 
airplane to pitch down at certain flaps settings. The actions specified 
in this AD are intended to prevent uncommanded nose-down pitch at 
certain flap settings during icing conditions.

DATES: Effective December 28, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before February 13, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-204-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The information concerning this amendment may be examined at the 
FAA, Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, 
SW., Renton, Washington; or at the FAA, Small Airplane Directorate, 
Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, 
Mid-Continent Airport, Wichita, Kansas; or at the Office of the Federal 
Register, 800 North Capitol Street NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Tina L. Miller, Aerospace Engineer, 
Flight Test Branch, ACE-160W, FAA, Small Airplane Directorate, Wichita 
Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-
Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4168; fax 
(316) 946-4407.

SUPPLEMENTARY INFORMATION: Recently, the FAA has received the results 
of icing tests conducted on the horizontal stabilizer of a Beech Model 
400 airplane. These icing tests, conducted in an icing wind tunnel, 
demonstrated that, under certain icing conditions, ice (called 
``runback ice'') may accumulate on the horizontal stabilizer aft of the 
heated element on the leading edge. This accumulated ice caused the 
test airplane to pitch down at landing flaps set beyond 10 degrees.
    After further review and evaluation of the test data, Beech has 
developed landing performance data for Beech Model MU-300-10 airplanes 
and Beech Model 400 series airplanes with flaps set at 10 degrees. 
These landing performance data include landing distances, landing brake 
energy, and maximum landing weight. (The 10-degree landing flap 
performance data for Mitsubishi Model MU-300 airplanes were included 
previously in that airplane's Airplane Flight Manual.)
    Subsequent to those icing tests, the FAA received a report of 
tailplane icing that occurred during a maintenance flight of a Beech 
Model 400A airplane. The airplane's tail anti-ice/de-ice systems were 
turned on during this flight, which was only 15 minutes in duration, 
and the airplane did not go above 4,000 feet elevation. During this 
flight, when the flaps were extended beyond 20 degrees, the pilot noted 
some buffet and ``stick walking,'' a pitch control effect in which 
uncommanded oscillation of the control column caused the airplane to 
pitch. The pilot was able to land the airplane without incident with 
the flaps set at 10 degrees. Subsequent investigation revealed that the 
horizontal stabilizer had accumulations of triangularly-shaped runback 
ice formations, which were approximately 2 inches in height. These 
runback ice formations were similar in size and shape to those used in 
the icing tests.
    Such runback ice formations could result in an uncommanded nose-
down pitch at flap settings that exceed 10 degrees.
    Due to the similarity in design of the horizontal stabilizers on 
Beech Model 400A airplanes and Mitsubishi Model MU-300 airplanes, and 
Beech Model 400, 400T, and MU-300-10 airplanes, the FAA has determined 
that all of these airplanes may also be subject to the same unsafe 
condition.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Beech Model 400, 400A, 400T, and MU-300-10 
airplanes and Mitsubishi Model MU-300 airplanes and of the same type 
design, this AD is being issued to prevent uncommanded nose-down pitch 
at flap settings that exceed 10 degrees during icing conditions. This 
AD requires a revision to the Limitations Section and Normal Procedures 
Section of the FAA-approved Airplane Flight Manual (AFM), that provides 
pilots with special operating procedures during icing conditions. The 
landing performance data developed as a result of the icing tests may 
be used under certain conditions for Beech Model MU-300-10 airplanes 
and Model 400 series airplanes.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public 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 flight safety and, thus, was not preceded by 
notice and an opportunity for public 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 shall identify the Rules Docket number and be 
submitted in triplicate to the address specified under the caption 
ADDRESSES. 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 rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-204-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 that it 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. 
A copy of it, if filed, may be obtained from 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.

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 the following new 
airworthiness directive:

94-25-10 Beech Aircraft Corporation and Mitsubishi Heavy Industries 
(MHI), LTD.: Amendment 39-9094. Docket 94-NM-204-AD.

    Applicability: All Beech Model 400, 400A, 400T, and MU-300-10 
airplanes; and all Mitsubishi Model MU-300 airplanes; certificated 
in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent uncommanded nose-down pitch at flap settings 
exceeding 10 degrees during icing conditions, accomplish the 
following:
    (a) Within 20 days after the effective date of this AD, revise 
the Limitations Section and Normal Procedures Section of the FAA-
approved Airplane Flight Manual (AFM) to include the following 
statement. This may be accomplished by inserting a copy of this AD 
in the AFM.

``Icing Conditions

    If icing conditions are encountered during flight, no greater 
than 10 degrees flaps may be utilized for landing unless the 
following conditions are met:
    1.- The icing conditions were encountered for less than 10 
minutes, and the Ram Air Temperature (RAT) during such encounter was 
warmer than -8 degrees C.

or

    2.- A RAT of +5 degrees C or warmer is observed during approach 
and landing.
    If either of the above two conditions are met, 30 degrees flaps 
may be utilized for landing.
    Otherwise,

Flaps (landing flaps setting)--10 degrees
Land Select (LAND SEL) Switch--Flaps 10 degrees

    For Mitsubishi Model MU-300 airplanes: Use landing data for 10 
degrees flaps from Section 6, Performance.
    For Beech Model 400, 400A, 400T, or MU-300-10 airplanes: Use 
landing data for 10 degrees flaps from Appendix 1 of this AD.''
    (b) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Wichita Aircraft Certification 
Office (ACO), FAA, Small Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Wichita ACO.

    Note 1: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Wichita ACO.

    (c) 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.
    (d) This amendment becomes effective on December 28, 1994.

BILLING CODE 4910-13-U

Appendix 1 to AD 94-25-10

TR13DE94.000


TR13DE94.001


TR13DE94.002


TR13DE94.003


TR13DE94.004


TR13DE94.005


BILLING CODE 4910-13-C
    Issued in Renton, Washington, on December 5, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-30395 Filed 12-12-94; 8:45 am]
BILLING CODE 4910-13-U