[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
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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
