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Airworthiness Directive packet

AD 95-03-14

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

1 · Quick read — prepared by AircraftDirectives

Our plain-language summary — not the regulation

Requires initial and repetitive inspections of the engine mount brackets for cracks, and if found cracked, replacement with improved design engine mount brackets.

AD number
95-03-14
Federal Register document
95-4124
Citation
60 FR 10308
Amendment
39-9150
Docket
Docket No. 94-ANE-57
Action
Final rule; request for comments.
Published
1995-02-24
Effective
1995-03-13
Effective (as stated in the rule)
Effective March 13, 1995.
Issued by
Transportation Department
Regulation
14 CFR 39
Applies to these models (in our index)
Continental IO-520, Continental IO-550

2 · Official Federal Register document — government source, verbatim

Reproduced unedited from the Federal Register
[Federal Register Volume 60, Number 37 (Friday, February 24, 1995)]
[Rules and Regulations]
[Pages 10308-10310]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-4124]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-57; Amendment 39-9150; AD 95-03-14]


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Teledyne Continental Motors (TCM) IO-346, 
IO-520, and IO-550 series reciprocating engines, that currently 
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 that airworthiness directive 
(AD). This amendment clarifies the identification procedures to 
determine which engine mount brackets must be inspected. This amendment 
is prompted by reports that the engine mount bracket part numbers, 
which are ink stamped, can be easily obliterated. 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 March 13, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 13, 1995.
    Comments for inclusion in the Rules Docket must be received on or 
before April 25, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-57, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    The service information referenced in this AD may be obtained from 
Teledyne Continental Motors, P.O. Box 90, Mobile, AL 36601; telephone 
(334) 438-3411. This information may be examined at the FAA, New 
England Region, Office of the Assistant Chief Counsel, 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, 
Campus Building, 1701 Columbia Ave., Suite 2-160, College Park, GA 
30337-2748; telephone (404) 305-7371, fax (404) 305-7348.

SUPPLEMENTARY INFORMATION: On April 19, 1994, the Federal Aviation 
Administration (FAA) issued airworthiness directive (AD) 94-09-07, 
Amendment 39-8896 (59 FR 23148, May 5, 1994), applicable to certain 
Teledyne Continental Motors (TCM) IO-346, IO-520, and IO-550 series 
reciprocating engines, 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 AD requires 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 requires 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, are replaced with improved design engine mount brackets, P/N 
653306 and 653305. Installation of these improved design engine mount 
brackets constitutes terminating action to the inspection requirements 
of that AD. That action was prompted by reports of cracks in engine 
mount brackets on engines that have completed at least one overhaul 
cycle. That condition, if not corrected, could result in engine 
separation from the aircraft due to cracks in the engine mount 
brackets.
    Since the issuance of that AD, the FAA has received reports of 
difficulty in identifying the engine mount brackets that must be 
inspected. The P/N is ink-stamped on the part and is quite easily 
obliterated. The problem arises when the Casting Number (C/N), which is 
different from the P/N, is mistaken for the P/N, and the AD is 
incorrectly believed to not apply.
    The FAA has reviewed and approved the technical contents of TCM 
Mandatory Service Bulletin (MSB) No. MSB94-9, dated October 21, 1994, 
that provides positive identification of affected engine mount brackets 
that require inspection, and replacement, if necessary.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of this same type design, this AD 
supersedes AD 94-09-07 to clarify the identification procedures to 
determine which engine mount brackets must be inspected. The actions 
are required to be accomplished in accordance with the MSB described 
previously.
    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 should 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-ANE-57.'' 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 
[[Page 10309]] 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. 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, 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 removing Amendment 39-8896 (59 FR 
23148, May 5, 1994), and by adding a new airworthiness directive, 
Amendment 39-9150, to read as follows:

95-03-14  Teledyne Continental Motors: Amendment 39-9150. Docket 94-
ANE-57. Supersedes AD 94-09-07, Amendment 39-8896.

    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 or rebuild cycle, or have accumulated 
2,500 or more hours time in service (TIS) on the effective date of 
this airworthiness directive (AD), inspect the lower left engine 
mount bracket, Part Number (P/N) 630695 or Casting Number (C/N) 
630724, for cracks using the dye penetrant techniques specified in 
this paragraph and in accordance with TCM Mandatory Service Bulletin 
(MSB) No. MSB94-9, dated October 21, 1994, within the next 50 hours 
TIS after the effective date of this AD.

    Note 1: TCM MSB No. MSB94-9, dated October 21, 1994, differs 
from TCM MSB No. M92-13, dated September 4, 1992, which was 
referenced in AD 94-09-07, only in clarification of part 
identification by utilizing a cross reference table for P/N and C/N.
    Note 2: The P/N is ink stamped on the part and may not be 
visible. The engine mount bracket can be identified by the C/N which 
is cast in the engine mount bracket.

    (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 or C/N 630724, and 
lower right engine mount bracket, P/N 630694 or C/N 630723, with 
improved design engine mount brackets, P/N 653306 or C/N 653299, and 
P/N 653305 or C/N 653298, respectively.
    (b) For all engines, replace both the lower left engine mount 
bracket, P/N 630695 or PC/N 630724, and lower right engine mount 
bracket, P/N 630694 or C/N 630723, with improved design engine mount 
brackets, PP/N 653306 or C/N 653299, and P/N 653305 or C/N 653298, 
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 or C/N 653299, and P/N 653305 or C/N 653298, 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 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the aircraft to a location where 
the inspection may be performed. [[Page 10310]] 
    (f) The inspections and replacement shall be done in accordance 
with the following service document:

------------------------------------------------------------------------
               Document No.                 Pages           Date        
------------------------------------------------------------------------
TCM MSB No. MSB94-9......................      1-2  Oct. 21, 1994.      
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 (334) 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 March 13, 1995.

    Issued in Burlington, Massachusetts, on February 8, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-4124 Filed 2-23-95; 8:45 am]
BILLING CODE 4910-13-P

Sources. Section 1 is written by AircraftDirectives from the record below and is a reading aid only. Section 2 is the United States Government's own text, reproduced without edit.

Federal Register: https://www.federalregister.gov/documents/1995/02/24/95-4124/airworthiness-directives-teledyne-continental-motors-io-346-io--520-and-io-550-series-reciprocating

Official PDF: https://www.govinfo.gov/content/pkg/FR-1995-02-24/pdf/95-4124.pdf

Packet generated 2026-08-18 08:52 UTC.

This packet is not an airworthiness determination and not legal or maintenance advice. AircraftDirectives reproduces official records and condenses their wording for easier reading. It does not decide, certify or imply whether any aircraft, engine, appliance or part is airworthy, compliant, affected by this directive, or eligible for return to service. No inspection, approval, or determination of any kind is performed or implied by this document.

Section 1 is a reading aid, not the rule. It is our own plain-language condensation, written to help a reader find the relevant directive quickly. It is NOT a substitute for the regulation, it may omit conditions, exceptions, compliance times, alternative methods of compliance (AMOCs) and applicability limits, and it has no legal force whatsoever. Only the official text governs. Where Section 1 and Section 2 differ in any respect, Section 2 - and the official source it was retrieved from - controls absolutely.

Responsibility remains with the owner/operator. Under 14 CFR §91.403 and §91.417 the owner or operator is responsible for maintaining airworthiness and for required records; under §39.7 no person may operate a product to which an airworthiness directive applies except in accordance with that directive. Determining applicability to a specific serial number and configuration, and performing or supervising any required action, is the responsibility of the owner/operator and appropriately certificated personnel.

Accuracy and currency. Section 2 was retrieved at the time stamped above and is reproduced without edit; Federal Register material is a work of the United States Government. Directives are amended, corrected and superseded over time, and this sheet is a snapshot, not a live record - it does not update after printing. Re-check the official sources before acting on it. This packet is provided without warranty of any kind, express or implied, including fitness for a particular purpose. We do not sell parts and have no commercial interest in any action a directive may require.

AircraftDirectives · AD 95-03-14 · Section 1 is our plain-language reading aid; Section 2 is the official Federal Register text and controls where the two differ. Not an airworthiness determination — 14 CFR §91.403 / §91.417 responsibility remains with the owner/operator. Retrieved 2026-08-18 08:52 UTC.