AD 2001-06-06

[Federal Register Volume 66, Number 60 (Wednesday, March 28, 2001)]
[Rules and Regulations]
[Pages 16846-16848]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-6786]



[[Page 16846]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-CE-24-AD; Amendment 39-12153; AD 2001-06-06]
RIN 2120-AA64


Airworthiness Directives; Cessna Aircraft Company Model 172RG 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain Cessna Aircraft Company (Cessna) Model 172 
airplanes. This AD requires you to inspect the main landing gear pivot 
assemblies for cracks, replace any cracked main landing gear pivot 
assemblies, and install new bushings on the pivot assembly shaft. This 
AD is the result of many service difficulty reports of cracked main 
landing gear pivot assemblies on the affected airplanes. The actions 
specified by this AD are intended to detect, correct, and prevent 
future cracks on the original design landing gear pivots. Cracked main 
landing gear pivots could fail resulting in gear-up landings or loss of 
braking.

DATES: This AD becomes effective on May 14, 2001.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the regulations as of May 
14, 2001.

ADDRESSES: You may get the service information referenced in this AD 
from the Cessna Aircraft Company, Product Support, P.O. Box 7706, 
Wichita, Kansas 67277; telephone: (316) 517-5800; facsimile: (316) 942-
9006. You may read this information at the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2000-CE-4-AD, 901 Locust, Room 506, 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: Steven Litke, Aerospace Engineer, 
Wichita Aircraft Certification Office, FAA, 1801 Airport Road, Mid-
Continent Airport, Wichita, Kansas 67209; telephone: (316) 946-4127; 
facsimile: (316) 946-4407.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA has received many service difficulty reports of failures of 
pivot assemblies on Cessna Model 172RG airplanes. Failure of the main 
landing gear pivots has resulted in gear-up landings or loss of 
braking. The end of the pivot experiences overload stress because of 
improper bushing clearance. This stress can produce fatigue cracks that 
spread until the pivot fitting fails, preventing the landing gear from 
extending. In other cases, brake fluid leaks through the fatigue crack 
resulting in loss of braking action.
    Original design landing gear pivots (with the original design 
bushings) could crack, fail, and result in gear-up landings or loss of 
braking.
    Cessna has issued Service Bulletin SEB90-1, Revision 3, dated March 
15, 1999. The service bulletin contains procedures for:

--inspecting the main landing gear pivot assemblies for cracks,
--replacing any cracked main landing gear pivot assemblies, and
--installing new bushings on the pivot assembly shaft.

    Has FAA taken any action to this point? We issued a proposal to 
amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to 
include an AD that would apply to certain Cessna Aircraft Company 
(Cessna) Model 172 airplanes. This proposal was published in the 
Federal Register as a notice of proposed rulemaking (NPRM) on October 
30, 2000 (65 FR 64640). The NPRM proposed to require you to inspect the 
main landing gear pivot assemblies for cracks, replace any cracked main 
landing gear pivot assemblies, and install new bushings on the pivot 
assembly shaft.
    What is the potential impact if FAA took no action? Original design 
landing gear pivots (with the original design bushings) could crack, 
fail, and result in gear-up landings or loss of braking.
    Was the public invited to comment? The FAA encouraged interested 
persons to participate in the making of this amendment. The following 
presents the comments received on the proposal and FAA's response to 
each comment:

Comment Issue No. 1: Why Apply the AD Action Since it is Not Cost 
Effective?

    What is the commenter's concern? One commenter states that this 
action is not cost effective because the cost of a gear up landing 
would be less than compliance with the AD. We infer that the commenter 
wants the NPRM withdrawn.
    What is FAA's response to the concern? The FAA disagrees. The cost 
of a repair because of a gear up landing would be substantially more 
than compliance with the AD. The failed pivot would have to be replaced 
as well as repairs made for damage to the skin, antennas, propeller, 
wingtip, and other parts. The most important aspect is the safety 
issue. The passenger injuries that could be prevented through 
compliance with this AD outweigh the cost of compliance with this AD.
    We are not changing the AD based on these comments.

Comment Issue No. 2: Why Not Apply the AD Only to Airplanes That Have 
Experienced Hard Landings?

    What is the commenter's concern? Two commenters recommend that the 
AD only apply to airplanes that have experienced hard landings. The 
service bulletin recommends doing this inspection after hard landings.
    What is FAA's response to the concern? We disagree. The pivot is 
improperly loaded during any landing because the small bushing on the 
pivot allows the small part of the pivot to be loaded before the main 
bearing is loaded. The installation of the service kit removes this 
problem.
    We are not changing the AD based on these comments.

Comment Issue No. 3: Why Not Require the AD Only on High Time Training 
Airplanes Where the Landing Gear Has Experienced Many Landings?

    What is the commenter's concern? Three commenters recommend that 
the AD only be required on high time training airplanes where the 
landing gear has experienced many landings.
    What is FAA's response to the concern? The FAA agrees that the 
reported failures are probably related to the number of landings 
experienced by the pivot. However, there is no way of determining the 
number of landings on these airplanes and failures have happened before 
reaching 2,000 hours time-in-service.
    We are not changing the AD based on these comments.

Comment Issue No. 4: Why Not Wait on Taking Action Until a Leak in the 
Brake System is Detected?

    What is the commenter's concern? Two commenters state that action 
should not be taken unless a leak in the brake system is detected. This 
is because brake fluid can leak out through cracks in the pivot 
fitting.
    What is FAA's response to the concern? The FAA disagrees. Leaking 
brake fluid has not preceded all reported failures. A crack would have 
to be nearly half way through the pivot fitting before any brake fluid 
would leak.

[[Page 16847]]

    We are not changing the AD based on these comments.

Comment Issue No. 5: What is the Provision for Airplanes Already in 
Compliance With Cessna Service Bulletin SEB90-1, Revision 3, Dated 
March 15, 1999?

    What is the commenter's concern? One commenter states that FAA 
should make a provision for airplanes already complying with the 
service bulletin.
    What is FAA's response to the concern? The FAA agrees and we are 
changing the final rule AD to provide for airplanes that already meet 
the requirements of the service bulletin.

Comment Issue No. 6: Why Require an AD Because the Condition Rarely 
Results in Injury to Occupants and Airframes Are Usually Repairable?

    What is the commenter's concern? Three commenters feel that an AD 
is not required because the condition rarely results in injury to 
occupants and airframes are usually repairable. Two of the commenters 
used the risk assessment from the Small Airplane Directorate 
Airworthiness Concern Process Guide to conclude that a Special 
Airworthiness Information Bulletin (SAIB) or General Aviation Alert 
(GAA) would be appropriate instead of the proposed AD. They state that 
a landing gear failure is not a hazardous event, and should not be 
considered a major or minor event when using the risk assessment.
    What is FAA's response to the concern? We disagree that an SAIB or 
GAA would be appropriate. Although injuries in landing gear accidents 
involving the Cessna 172RG are rare, FAA's risk assessment shows that 
an airworthiness directive is required because landing gear failure is 
listed as hazardous in the guide.
    We are not changing the final rule as a result of these comments.

FAA's Determination

    What is FAA's Final Determination on this Issue? We carefully 
reviewed all available information related to the subject presented 
above and determined that air safety and the public interest require 
the adoption of the rule as proposed except for the changes discussed 
above and minor editorial corrections. These changes and corrections 
provide the intent that was proposed in the NPRM for correcting the 
unsafe condition and do not impose any additional burden than what was 
intended in the NPRM.

Cost Impact

    How many airplanes does this AD impact? We estimate that this AD 
affects 766 airplanes in the U.S. registry.
    What is the cost impact of this AD on owners/operators of the 
affected airplanes? We estimate that it would take about 20 workhours 
for each airplane to do both proposed pivot assembly inspections, at an 
average labor rate of $60 an hour. Based on the figures presented 
above, we estimate the total cost impact of the inspection on U.S. 
operators is $919,200, or $1,200 for each airplane.
    We estimate that it would take about 5 workhours for each airplane, 
to do both bushing replacements, at an average labor rate of $60 an 
hour. Parts cost about $200 for each airplane. Based on the figures 
presented above, we estimate the total cost impact of the bushing 
replacement on U.S. operators is $500 for each airplane.
    If a crack is found during the pivot assembly inspection, the pivot 
assembly must be replaced. We estimate that it would take about 3 
workhours to do each pivot assembly replacement, at an average labor 
rate of $60 an hour. Parts cost about $2,783 for each pivot assembly. 
Based on the figures presented above, we estimate the total cost impact 
of the pivot assembly replacement on U.S. operators is $2,963 for each 
pivot assembly.
    We have no way of knowing how many airplanes will require 
replacement pivot assemblies. The total cost for each airplane for this 
AD depends on whether a crack is found during the inspection of the 
pivot assembly. We estimate the total cost impact of this AD for each 
airplane to U.S. operators is:

Neither pivot cracked--$1,700
One pivot cracked--$4,663
Both pivots cracked--$7,626

Regulatory Impact

    Does this AD impact various entities? The regulations adopted will 
not have a substantial direct effect 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. 
We have determined that this rule does not have federalism implications 
under Executive Order 13132.
    Does this AD involve a significant rule or regulatory action? 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. We have 
placed a copy of the regulatory evaluation prepared for this action in 
the Rules Docket. You may get a copy of it by contacting 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, under 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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. FAA amends Sec. 39.13 by adding a new AD to read as follows:

2001-06-06  Cessna Aircraft Company: Amendment 39-12153; Docket No. 
2000-CE-24-AD.

    (a) What airplanes are affected by this AD? This AD affects 
Model 172RG, with the serial numbers 691 and 172RG0001 through 
172RG1191, certified in any category.
    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above airplanes must comply with this AD.
    (c) What problem does this AD address? The actions specified in 
this AD are intended to detect, correct, and prevent future cracks 
on the original design landing gear pivots. Cracked main landing 
gear pivots could fail, resulting in gear-up landings or loss of 
braking.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must do the following, unless already 
done:

[[Page 16848]]



------------------------------------------------------------------------
           Actions              Compliance times         Procedures
------------------------------------------------------------------------
(1) Inspect the main landing  Within the next 100   Do this action
 gear pivot assemblies for     hours time-in-        following the
 cracks.                       service after the     Accomplishment
                               effective date of     Instructions in
                               this AD.              Cessna Service
                                                     Bulletin SEB90-1,
                                                     Revision 3, dated
                                                     March 15, 1999, and
                                                     the Model 172RG
                                                     Series Service
                                                     Manual.
(2) If you find cracks,       Before further        Do this action the
 replace the affected main     flight after the      following
 landing gear pivot assembly   inspection.           Accomplishment
 with the part referenced in                         Instructions in
 the service bulletin.                               Cessna Service
                                                     Bulletin SEB90-1,
                                                     Revision 3, dated
                                                     March 15, 1999, and
                                                     the Model 172RG
                                                     Series Service
                                                     Manual.
(3) Install new bushings on   Before further        Do this action the
 both main landing gear        flight after the      following the
 pivot assemblies using the    inspection.           Accomplishment
 applicable kit referenced                           Instructions in
 in the service bulletin.                            Cessna Service
                                                     Bulletin SEB90-1,
                                                     Revision 3, dated
                                                     March 15, 1999, and
                                                     Model 172RG Series
                                                     Service Manual.
------------------------------------------------------------------------

    (e) Can I comply with this AD in any other way? You may use an 
alternative method of compliance or adjust the compliance time if:
    (1) Your alternative method of compliance provides an equivalent 
level of safety; and
    (2) The Manager, Wichita Aircraft Certification Office, approves 
your alternative. Send your request through an FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Wichita Aircraft Certification Office.

    Note: This AD applies to each airplane identified in paragraph 
(a) of this AD, regardless of whether it has been modified, altered, 
or repaired in the area subject to the requirements of this AD. For 
airplanes that have been modified, altered, or repaired so that the 
performance of the requirements of this AD is affected, the owner/
operator must request approval for an alternative method of 
compliance in accordance with paragraph (e) of this AD. The request 
should include an assessment of the effect of the modification, 
alteration, or repair on the unsafe condition addressed by this AD; 
and, if you have not eliminated the unsafe condition, specific 
actions you propose to address it.

    (f) Where can I get information about any already-approved 
alternative methods of compliance? Contact Steven Litke, Aerospace 
Engineer, Wichita Aircraft Certification Office, FAA, 1801 Airport 
Road, Mid-Continent Airport, Wichita, Kansas 67209; telephone: (316) 
946-4127; facsimile: (316) 946-4407.
    (g) What if I need to fly the airplane to another location to 
comply with this AD? The FAA can issue a special flight permit under 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate your airplane to a location where you 
can do the requirements of this AD.
    (h) Are any service bulletins incorporated into this AD by 
reference? Actions required by this AD must be done in accordance 
with Cessna Service Bulletin SEB90-1, (including Accomplishment 
Instructions), Revision 3, and Cessna Service Kit SK 172-151, all 
dated March 15, 1999. The Director of the Federal Register approved 
this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 
51. You can get copies from the Cessna Aircraft Company, Product 
Support, P.O. Box 7706, Wichita, Kansas 67277. You may look at 
copies at the FAA, Central Region, Office of the Regional Counsel, 
901 Locust, Room 506, Kansas City, Missouri, or at the Office of the 
Federal Register, 800 North Capitol Street, NW, suite 700, 
Washington, DC.
    (i) When does this amendment become effective? This amendment 
becomes effective on May 14, 2001.

    Issued in Kansas City, Missouri, on March 13, 2001.
Larry E. Werth,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-6786 Filed 3-27-01; 8:45 am]
BILLING CODE 4910-13-P