[Federal Register Volume 59, Number 86 (Thursday, May 5, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-10500]


[[Page Unknown]]

[Federal Register: May 5, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 92-ANE-50; Amendment 39-8896; AD 94-09-07]

 

Airworthiness Directives; Teledyne Continental Motors IO-346, IO-
520, and IO-550 Series Piston Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Teledyne Continental Motors (TCM) IO-346, IO-520, 
and IO-550 series piston engines, that requires initial and repetitive 
inspections of the engine mount brackets for cracks, and if found 
cracked, replacement with improved design engine mount brackets. All 
engine mount brackets require replacement with improved design engine 
mount brackets at the next engine removal after the effective date of 
this AD. This amendment is prompted by reports of cracks in engine 
mount brackets on engines that have completed at least one overhaul 
cycle. The actions specified by this AD are intended to prevent engine 
separation from the aircraft due to cracks in the engine mount 
brackets.

DATES: Effective July 5, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 5, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from Teledyne Continental Motors, P.O. Box 90, Mobile, AL 
36601; telephone (205) 438-3411. This information may be examined at 
the Federal Aviation Administration (FAA), New England Region, Office 
of the Assistant Chief Counsel, 12 New England Executive Park, 
Burlington, MA; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Jerry Robinette, Aerospace Engineer, 
Atlanta Aircraft Certification Office, FAA, Small Airplane Directorate, 
1669 Phoenix Parkway, suite 210C, Atlanta, GA 30349; telephone (404) 
991-3810, fax (404) 991-3606.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations to include an airworthiness directive (AD) that is 
applicable to Teledyne Continental Motors (TCM) IO-346, IO-520, and IO-
550 series piston engines was published in the Federal Register on 
October 20, 1993 (58 FR 54072). That action proposed to require initial 
and repetitive dye penetrant inspections for cracks in certain lower 
left engine mount brackets, Part Number (P/N) 630695. If the lower left 
engine mount bracket is found cracked, that proposed rule would require 
replacing both the lower left and lower right engine mount brackets 
with improved design engine mount brackets, P/N 653306 and 653305, 
respectively. If a crack is not detected, the lower left engine mount 
bracket would require repetitive inspections at intervals not to exceed 
500 hours time in service (TIS) until the next engine removal, at which 
time engine mount brackets, P/N 630694 and 630695, would be replaced 
with improved design engine mount brackets, P/N 653306 and 653305. 
Installation of these improved design engine mount brackets would 
constitute terminating action to the inspection requirements of that 
AD. The actions would be required to be accomplished in accordance with 
TCM Service Bulletin (SB) No. M92-13, dated September 4, 1992.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the one comment received.
    The commenter supports the proposed rule but states that the 
interval for the repetitive inspections should be reduced from 500 
hours TIS to 100 hours TIS. The commenter states that if the bracket is 
found broken, the airframe engine mount and surrounding areas should be 
inspected for damage and the upper brackets and all bolts and nuts 
should be replaced as they may be overstressed. The commenter further 
states that the pilot should visually inspect the brackets on each 
preflight.
    The FAA does not concur with the recommendation to reduce the 
repetitive inspection interval to 100 hours TIS. Data provided from the 
manufacturer indicates that the repetitive inspection interval of 500 
hours TIS is sufficient once the initial inspection is satisfactorily 
completed.
    The FAA does not concur with the commenter's recommendation to 
inspect the airframe engine mount and surrounding areas for damage and 
to replace all bolts and nuts if the bottom brackets are found broken. 
Once the bottom brackets are broken, there is essentially no load being 
transmitted to the lower airframe structure. In addition, a structural 
analysis of the bolt strength indicates that with only the two upper 
mounts securing the engine, safety factors exceed required values for 
normal category ``g'' loading. Therefore, none of the bolts and nuts 
should be overstressed.
    The FAA does not concur with the commenter's recommendation to 
require the pilot to visually inspect the brackets on each preflight. 
Based on the data presented above, the FAA has determined that it is 
not necessary to inspect the brackets on each preflight.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    There are approximately 9,750 TCM IO-346, IO-520, and IO-550 series 
piston engines of the affected design in the worldwide fleet. The FAA 
estimates that 8,300 engines installed on aircraft of U.S. registry 
will be affected by this AD, that it will take approximately 2 work 
hours per inspection, and if the engine mount brackets must be 
replaced, an additional 4 work hours will be required. The average 
labor rate is $55 per work hour. Required parts will cost approximately 
$320 per engine. Based on these figures, the total cost impact of the 
AD on U.S. operators is estimated to be $5,395,000.
    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.
    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) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 14 CFR part 
39 of the Federal Aviation Regulations 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:

94-09-07 Teledyne Continental Motors: Amendment 39-8896. Docket 92-
ANE-50.

    Applicability: Teledyne Continental Motors (TCM) engine models 
IO-346A, IO-346B, IO-520C, IO-520CB, and IO-550C; rebuilt engine 
model IO-520C with serial numbers (S/N) 287051-R and lower; rebuilt 
engine model IO-520CB with S/N 282226-R and lower; rebuilt engine 
model IO-550C with S/N 271742-R and lower; and all factory 
overhauled IO-520C, IO-520CB, and IO-550C engines with a build date 
prior to August 6, 1992. These engines are installed on but not 
limited to Beech model A23, A23A, 95-C55, 95-C55A, D55, D55A, E55, 
E55A, 58, and 58A airplanes.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent engine separation from the aircraft due to cracks in 
the engine mount brackets, accomplish the following:
    (a) For engines with engine mount brackets that have completed 
at least one engine overhaul cycle, or have accumulated 2,500 or 
more hours time in service (TIS) on the effective date of this AD, 
inspect the lower left engine mount bracket, Part Number (P/N) 
630695, for cracks using the dye penetrant techniques specified in 
this paragraph and in accordance with TCM Service Bulletin (SB) No. 
M92-13, dated September 4, 1992, within the next 50 hours TIS after 
the effective date of this AD.
    (1) Perform the dye penetrant inspection as follows:

    Note: Military Specification MIL-I-6866 and American Society of 
Testing Materials specifications ASTM E1417-93 and E165-9 contain 
additional information on dye penetrant inspection processes.

    (i) Preparation: clean and dry all parts in such a manner as to 
leave the surfaces free from grease, oil, soaps, alkalies, and other 
substances which would interfere with inspection. Vapor degreasing 
is generally suitable for this purpose.
    (ii) Penetrant Application Procedure: after preparation, spray 
or brush the parts with the penetrant, and allow to stand for not 
less than 5 minutes. The effectiveness of the penetrant increases if 
left standing for a longer time, as the penetrant will reach finer 
discontinuities.
    (iii) Penetrant Cleaning: clean the parts thoroughly using a 
medium which will remove penetrant from the surfaces of parts; wash 
with water when the penetrant is water soluble. When other than 
water soluble penetrants are used, the penetrant shall be removed 
with a suitable cleaner. Avoid excessive cleaning which would remove 
the penetrant from discontinuities.
    (iv) Drying: dry the parts as thoroughly as possible. Drying of 
parts may be accomplished by evaporation at room temperature or by 
placing the parts in a circulating warm air oven or in the air 
stream of a hot air dryer. Avoid excessive drying time or drying 
temperatures above 75 deg.C (165 deg.F) to prevent excessive 
evaporation of the penetrant. If heat is used for drying parts, cool 
parts to approximately 50 deg.C (120 deg.F) before proceeding to the 
developing procedure.
    (v) Developing: apply the developer to the dry parts as lightly 
and as evenly as possible, using as thin a coating of developer as 
is possible. A translucent film is adequate. Mix wet developer by 
agitation immediately prior to applying it. After applying the 
developer, take care that no penetrant indication is disturbed or 
obliterated in subsequent handling.
    (vi) Examination: examine the developed penetrant indications in 
accordance with the dye penetrant manufacturer's instructions. 
Examine parts for indications of discontinuities open to the 
surface.
    (vii) Final cleaning: clean the parts following the inspection 
to remove penetrant and developer.

    Note 1: Caution: Because of differences among penetrants, take 
care to ensure that the final cleaner, the penetrant, the penetrant 
remover, and the developer are suitable for use with each other.

    Note 2: Caution: All penetrant materials should be kept as free 
from moisture as possible.

    Note 3: Caution: Most penetrants, cleaning agents, and developer 
suspensions are low flash point material; use caution to prevent 
fires.
    (2) If no crack is detected, inspect in accordance with 
paragraph (a) of this AD at intervals not to exceed 500 hours TIS 
since the last inspection.
    (3) If a crack is detected, prior to further flight replace both 
the lower left engine mount bracket, P/N 630695, and lower right 
engine mount bracket, P/N 630694, with improved design engine mount 
brackets, P/N 653306 and 653305, respectively.
    (b) For all engines, replace both the lower left engine mount 
bracket, P/N 630695, and lower right engine mount bracket, P/N 
630694, with improved design engine mount brackets, P/N 653306 and 
653305, respectively, at the next engine removal after the effective 
date of this AD.
    (c) Installation of the improved design engine mount brackets, 
P/N 653306 and 653305, constitutes terminating action to the 
inspection requirements of this AD.
    (d) 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, Atlanta Aircraft Certification 
Office. The request should be forwarded through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Atlanta Aircraft Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Atlanta Aircraft Certification 
Office.

    (e) Special flight permits may be issued in accordance with 14 
CFR 21.197 and 21.199 to operate the aircraft to a location where 
the requirements of this AD can be accomplished.
    (f) The inspection and replacement shall be done in accordance 
with the following service bulletin: 

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                    Document No.                          Pages             Revision                Date        
----------------------------------------------------------------------------------------------------------------
TCM SB M92-13.......................................             1-2  Original............  Sept. 4, 1992.      
Total Pages: 2.                                                                                                 
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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 Teledyne Continental Motors, P.O. 
Box 90, Mobile, AL 36601; telephone (205) 438-3411. Copies may be 
inspected at the FAA, New England Region, Office of the Assistant 
Chief Counsel, 12 New England Executive Park, Burlington, MA; or at 
the Office of the Federal Register, 800 North Capitol Street NW., 
suite 700, Washington, DC.
    (g) This amendment becomes effective on July 5, 1994.

    Issued in Burlington, Massachusetts, on April 19, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-10500 Filed 5-4-94; 8:45 am]
BILLING CODE 4910-13-P