Document ID: FAA-2009-0495-0013
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Learjet Inc. Model 60 Airplanes
Posted Date: 2010-06-08T04:00Z

[Federal Register: June 8, 2010 (Volume 75, Number 109)]
[Rules and Regulations]               
[Page 32255-32260]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08jn10-3]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0495; Directorate Identifier 2009-NM-049-AD; 
Amendment 39-16316; AD 2010-11-11]
RIN 2120-AA64

 
Airworthiness Directives; Learjet Inc. Model 60 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Model 60 airplanes. This AD requires revising the Tire-Servicing 
section of the airplane maintenance manual and revising the Tires 
Limitation section of the airplane flight manual to incorporate revised 
procedures for servicing tires and checking for proper tire inflation. 
This AD results from a report of the main landing gear tires blowing 
out during a takeoff roll. We are issuing this AD to prevent tire 
failure, which could result in failures of the braking and thrust 
reverser systems. In a critical phase of operation such as takeoff, 
loss of airplane control may result.

DATES: This AD is effective July 13, 2010.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of July 13, 2010.

ADDRESSES: For service information identified in this AD, contact 
Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942; telephone 
316-946-2000; fax 316-946-2220; e-mail ac.ict@aero.bombardier.com; 
Internet http://www.bombardier.com.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the Document Management 
Facility, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Don Ristow, Aerospace Engineer, 
Mechanical Systems and Propulsion Branch, ACE-116W, FAA, Wichita 
Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-
Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4120; fax 
(316) 946-4107.

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an airworthiness directive (AD) that would apply to 
certain Model 60 airplanes. That NPRM was published in the Federal 
Register on May 29, 2009 (74 FR 25682). That NPRM proposed to require 
revising the Tire-Servicing section of the airplane maintenance manual 
(AMM) and revising the Tires Limitation section of the airplane flight 
manual (AFM) to incorporate revised procedures for servicing tires and 
checking for proper tire inflation.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received from the 10 commenters.

Support for the NPRM

    The National Transportation and Safety Board (NTSB), and Mike 
Waggoner, a private citizen, support the NPRM. The NTSB states that it 
would prefer that the tires be checked daily for proper pressure, but 
that 96 hours between pressure checks specified in the Tires 
Limitations section of the AFM (specified in paragraph (h) of the NPRM) 
allows for recognition of an under-inflated tire before it reaches a 
point where the tire would need to be changed. Mr. Waggoner agrees that 
a means of bringing attention to the importance of checking tire 
pressures at a minimum of 96 hours before flight is mandatory.

Request To Extend the Comment Period of the Proposed AD

    Aviation Properties requests that we extend the comment period an 
additional 45 days following the release of the NTSB final report on 
the September 19, 2008, accident of a Model 60 airplane. The commenter 
states that all of the relevant information concerning that accident 
has not been determined and made public, and that extending the comment 
period would allow comments to be made with all the data being 
available to everyone.
    We do not agree to extend the comment period and thereby delay the 
AD. While it is true that the final NTSB report is not published, the 
analysis determined with certainty that the tires were subject to 
internal heat damage resulting from under-inflation, overloading, or a 
combination of both. As a result of the tire blow-out, other airplane 
systems were compromised. Based on the design of the Model 60 airplanes 
in particular, we decided to act now to address the unsafe condition. 
If at a later date additional action is deemed appropriate, we might 
consider further rulemaking, which would allow for public comment at 
that time. We have not changed the AD in this regard.

[[Page 32256]]

Requests To Withdraw the NPRM or Certain Requirements

    Aviation Properties states that the proposed AD is unnecessary for 
three reasons: The tires blowing out on takeoff could potentially be 
traced back to improperly serviced tires; the cost of the AD is 
financially overburdening to U.S. operators; and the AD, as proposed, 
could cause another accident because of the possibility that future 
revisions to the AMM might not include the relevant information in the 
temporary revisions. If unaware of the AD, maintenance persons could 
follow a procedure that does not meet the intent of the AD. We infer 
that the commenter requests that we withdraw the NPRM.
    Cloud Nine Aviation states that the AFM requirement of a pre-flight 
pressure measurement is unnecessary, as the Model 60 has been flying 
for 16 years without a problem except one. The commenter further states 
that the cost is overly burdensome, and that pilots know to pay 
particular attention to tire pressures, for which the recent FAA Safety 
Alert for Operators (SAFO 09012, June 12, 2009) has been a good 
reminder. We infer that the commenter believes the SAFO sufficiently 
addresses the unsafe condition stated in the NPRM. We infer that the 
commenter requests that we remove the AFM requirements from the NPRM.
    We do not agree to withdraw the NPRM or to remove the proposed AFM 
requirements. A review of the Model 60 airplane shows a vulnerability 
to system damage due to a blown tire. Rarely is an accident caused by a 
single event, but rather by a series of events. The AD addresses tire 
inflation pressure, which would mitigate one event of a possible chain 
of events that can lead to an accident. The AD, which requires that the 
temporary revisions be inserted into the AMM and the temporary changes 
be inserted into the AFM, is the appropriate vehicle to address this 
issue and is necessary to prevent the unsafe condition. The AD requires 
that the relevant information from the temporary revisions (TRs) be in 
the general revisions before the TRs can be removed. We have not 
changed the AD in this regard.
    We address the issue of costs in our response to ``Requests to 
Revise the Costs of Compliance'' later in this section of the AD.

Request for Information on Global Efforts for Tire Safety

    Electrolux Home Products (Electrolux) notes that Bombardier 
Advisory Wire 32-046 ``is one element of a strategic effort to promote 
safety across the entire aviation industry with respect to proper tire 
inflation,'' and asks if the FAA will follow suit.
    From this request we infer that the commenter is asking if the FAA 
plans to publish further tire safety information applying to the entire 
aviation industry. No additional publications are planned at this time. 
FAA Advisory Circular (AC) 20-97B, dated April 18, 2005, provides 
guidance on the installation, inflation, maintenance, and removal of 
tires. In addition, that AC provides guidance on those operational 
practices necessary to maintain safe airplane operations. More 
recently, the FAA Flight Standards Service has twice published a safety 
alert for operators (SAFO), titled ``Dangers of Improperly Inflated 
Tires.'' No change to this AD is necessary.

Request for Training

    Aviation Properties and William Detig, a private citizen, suggest 
that training is needed. Aviation Properties asks if there is a plan to 
develop educational material and awareness in lieu of mandating tire 
pressure checks for one specific airplane model, while Mr. Detig 
proposes training pilots to monitor tire pressures with calibrated tire 
gauges, and to comply with required preflight checks to determine that 
tires are in airworthy condition.
    We know of no plans for training on this issue at this time. For 
specific information on tires and tire pressure, FAA Advisory Circular 
(AC) 20-97B, dated April 18, 2005, titled ``Aircraft Tire Maintenance 
and Operational Practices,'' can be found at http://www.rgl.faa.gov. 
The AC provides recommended tire care and maintenance practices needed 
to assure the safety of support personnel and the continued 
airworthiness of airplanes. Specifically, the AC provides guidance on 
the installation, inflation, maintenance, and removal of airplane 
tires. In addition, the AC provides guidance on those operational 
practices necessary to maintain safe airplane operations. We have not 
changed this AD in this regard.

Requests To Include Other Airplane Models in the Applicability

    Electrolux, Chantilly Air, Goodyear Tire & Rubber Company 
(Goodyear), Aviation Properties, the NTSB, and private citizens Mike 
Waggoner and William Detig request that we expand the applicability of 
the NPRM to include other airplane models. In summary, the commenters 
state that checking tire pressure should not be limited to just the 
Model 60 airplanes, that other accidents and incidents have involved 
the Model 35 and Model 55 airplanes, and that this issue is relevant to 
all business jets and other large airplanes and to those with high 
takeoff and landing speeds.
    Electrolux states that tire pressure is a maintenance issue, which 
is relevant to all business jets and other large airplanes, and that 
Bombardier has issued Advisory Wires 32-046, dated December 10, 2008, 
and 32-047, dated March 11, 2009, applying to all models and specifying 
that tire pressures must be checked prior to the first flight of the 
day.
    Chantilly Air states that tire pressure is not just a Model 60 
issue, because the incident described in the NPRM is one of many in 
which malfunctioning airplane tires may have been a safety issue.
    Goodyear states that its recommendations for checking tire pressure 
should be incorporated into maintenance programs for the Model 60 
airplanes and all airplanes.
    Aviation Properties states that improper servicing of tires is a 
danger to any airplanes certified in any category made by any 
manufacturer, that the Model 60 airplanes should not be discriminated 
against, and that any AD written with reference to tire servicing 
procedures should be written to include all certified airplanes.
    The NTSB states that the risk of unsafe tire pressure is not 
limited to the Model 60 airplanes, and the NPRM should be expanded to 
include at least Model 55 airplanes (since the Model 60 airplane design 
is based on the Model 55 airplane design) and any airplanes that have 
high rates of multiple tire failure or that are equipped with tires 
operating near their margin of safety.
    Mr. Waggoner states that several accidents and incidents have 
occurred due to improperly serviced tires, that issuing an AD against 
the Model 60 airplanes will not resolve the problem that all airplanes 
with high takeoff and landing speeds experience, and that the industry 
should do more than issue an AD against any one airplane model.
    Mr. Detig states that all airplanes would be subject to the 
identified unsafe condition if the pilots try to take off with tires 
that are under-serviced.
    We partially agree with the commenters. We agree that the 
importance of ensuring proper tire inflation pressure cannot be over-
emphasized, especially on high-performance airplanes. To this end, both 
Learjet and Goodyear provide tire-care and maintenance instructions. We 
also published Advisory Circular 20-97B (Aircraft Tire Maintenance and

[[Page 32257]]

Operational Practices, April 18, 2005) that is applicable to all 
airplane tires.
    However, we do not agree to expand the AD applicability to include 
other airplanes. This AD applies to the Model 60 airplanes because of 
the disproportionate number of tire failure events per number of 
airplanes built, compared to other models. From the data gathered from 
service difficulty reports, the Model 60 airplanes have more than twice 
the number of tire failure events as the Model 30 series and a third 
greater rate than the Model 55 series. While the Models 55 and 60 
airplanes are similar in design, the Model 60 airplane has a higher 
gross weight and tire pressure than the Model 55 airplane. In addition, 
a review of the hydraulic, brake, and thrust reverser systems of the 
Model 60 airplanes has revealed their vulnerability to damage due to a 
burst tire. For these reasons, we have determined that an unsafe 
condition exists and is more likely to occur in the Model 60 airplanes 
than other models of business jets. If we learn that other airplanes 
blow out tires to the same extent as the Model 60 airplanes and have 
similar system vulnerability, we might consider additional rulemaking. 
We have not changed the AD in this regard.

Requests To Reduce the Pressure Check Interval

    Mike Waggoner and Goodyear request that we remove the 96-hour 
requirement to check tire pressure and replace it with a check prior to 
the first flight of the day. To summarize, the commenters state that 
the Learjet 60 AMM, the Goodyear Aircraft Tire Care And Maintenance 
Manual, and FAA Advisory Circular 20-97B all recommend that tire 
pressure checks be conducted daily.
    Mr. Waggoner recommends performing a tire condition and pressure 
check on all airplanes with high takeoff and landing speeds a minimum 
of 24 hours prior to takeoff, which could be done with available 
technology without the need to hook up tire pressure gauges.
    Goodyear states that its Aircraft Tire Care and Maintenance Manual, 
and FAA Advisory Circular 20-97B, recommend that tire pressure checks 
be conducted daily for the Model 60 airplanes and all airplanes. 
Goodyear sees no reason to depart from its recommendation for checking 
pressure daily or prior to the first flight of the day when tires are 
cool (at ambient temperature).
    We do not agree to require daily pressure checks. While checking 
tire pressure daily is encouraged, regulations do not require it unless 
specifically made a part of an inspection program specified by sections 
91.409(e) and 91.409(f) of the Federal Aviation Regulations (14 CFR 
91.409(e) and 91.409(f)), or an airworthiness limitation or AD action. 
According to this AD, the tire pressure check would be applied 
uniformly to all affected airplanes. To minimize the impact on 
operators of the affected airplanes, we considered the daily average 
tire pressure leakage rate and determined that with a properly serviced 
tire, a period of up to four days (96 hours) could be allowed and still 
be within a safe pressure range. For this reason, we can still mitigate 
an unsafe condition and provide some flexibility to the airplane 
operators. We have not changed the AD in this regard.

Requests for an Exemption Allowing Certain Pilots to Check Tire 
Pressure

    Learjet, Chantilly Air, Goodyear, and Tim Rounds, a private 
citizen, request that we issue an exemption to section 43.3(g) of the 
Federal Aviation Regulations (14 CFR 43.3(g)) that would allow pilots 
operating under part 135 of the Federal Aviation Regulations (14 CFR 
part 135) to perform tire pressure checks. To summarize, the commenters 
state that, without the exemption, only a certificated mechanic could 
check tire pressure under 14 CFR part 135 operating rules. Conversely, 
under part 91 of the Federal Aviation Regulations (14 CFR part 91), a 
pilot is allowed to perform the same tire pressure check.
    Learjet states that not allowing properly trained pilots of 14 CFR 
part 135 airplanes to check tire pressure might overshadow the intended 
consequence of the NPRM, which is to prevent tire failures, and that 
the proposed AD can and should authorize all properly trained pilots to 
conduct pressure checks.
    Chantilly Air requests that we address the issue of pilots under 14 
CFR part 135 not being able to do the pressure checks, which is no more 
or less difficult than checking oil on preflight. Similarly, Goodyear 
states that, with an exemption in place for 14 CFR part 135 operators, 
tire pressure can be checked by the pilot.
    Mr. Rounds requests that an exemption be incorporated into the AD 
for 14 CFR parts 121, 129, and 135 pilots, because some local 
Certificate-Holding District Offices are reluctant to issue such an 
exemption even after training requirements suggested by Bombardier 
Advisory Wire 32-047 have been submitted and aircrews have been 
trained.
    We do not agree to issue an exemption to an operating rule with 
this AD. The AD is intended to globally address an unsafe condition by 
specifying special maintenance practices, regardless of the operating 
rules used. The owner/operator of the airplane determines its intended 
use and, in turn, what set of operating and maintenance procedures 
apply. It is not our intent to distinguish or specify in this AD who 
can perform a tire pressure check, nor to amend or change an existing 
rule in 14 CFR part 43. For this reason, we will treat a request or 
petition for exemption as a separate action to this AD. We have not 
changed the AD in this regard.

Requests To Revise the Costs of Compliance

    Cloud Nine Aviation, Aviation Properties, and Chantilly Air request 
that we revise the Costs of Compliance section of the NPRM to include 
the cost of recurring actions and materials. To summarize, the 
commenters state that the cost estimate covers only one event per 
airplane and not the recurring action.
    Cloud Nine Aviation states that the cost of additional preflight 
tire servicing will be substantial, putting the Model 60 airplanes at 
an economic disadvantage as a charter airplane. The commenter also 
states that costs can accumulate and the actions might be needed more 
than every 96 work hours as specified in the TRs described in the NPRM, 
and that the costs of compliance estimate in the NPRM ignores these 
costs to the operator.
    Aviation Properties states that the costs listed in the NPRM cover 
only one event per airplane and do not consider the recurring action 
that will be required, and that each event will be required at least 
every 10 days and as much as every 4 days. The commenter gives an 
example of the annual costs at those intervals.
    Chantilly Air states that the burden of more costs is being put on 
the operator, especially if hangar time is needed in very cold weather, 
and states that they have been charged $95 to $140 per hour to comply 
with the TRs as proposed in the NPRM.
    We do not agree to revise the Costs of Compliance section of this 
AD as requested. Based on the best data available, the manufacturer 
provided an estimate of one work-hour necessary to do the required 
actions--in this case, to revise the AFM and AMM.
    The number of work-hours represents the time necessary to perform 
only the actions actually required by this AD. We recognize that 
operators might incur incidental costs in addition to the direct costs. 
The cost analysis in AD

[[Page 32258]]

rulemaking actions, however, typically does not include incidental 
costs such as the time required to gain access and close up, time 
necessary for planning, or time necessitated by other administrative 
actions. Those incidental costs, which might vary significantly among 
operators, are almost impossible to calculate.
    Because ADs require explicit actions to address specific unsafe 
conditions, they appear to impose costs that would not otherwise be 
borne by operators. However, because operators are obliged to maintain 
and operate their airplanes in an airworthy condition, this appearance 
is deceptive. Attributing those costs solely to the issuance of this AD 
is unrealistic because, in the interest of maintaining and operating 
safe airplanes, prudent operators would accomplish the required actions 
even if they were not required to do so by the AD. In any case, we have 
determined that the safety benefits of the AD still outweigh the direct 
and incidental costs. We have not changed the AD in this regard.

Request for Definition of ``Cold''

    Cloud Nine Aviation states that ``cold tire in service pressure'' 
is referenced in Table 301 of Learjet TR 12-16, dated March 18, 2009, 
to the Learjet 60 Maintenance Manual (specified in paragraph (g) of 
this AD), and requests that we define ``cold'' as it relates to tire 
pressure.
    We agree to define the term. The TR refers to ``cold tire operating 
pressure range.'' Rather than defining cold as a specific temperature, 
it is the ambient temperature when the tire has been at rest for a 
period of time, generally at least 2 hours since use. We have not 
changed the AD in this regard.

Request for Information About Temperature Changes

    Chantilly Air requests information concerning a specific scenario, 
as follows. Within the content of Learjet TR 12-16, dated March 18, 
2009, to the Learjet 60 Maintenance Manual, in very cold climates, the 
airplane tire pressure has been increased to adjust for a temperature 
drop, which will occur once the airplane is moved outside the hangar 
and has not had a chance to cold soak prior to a quick departure.
    We agree to provide the following information. In the scenario 
presented by the commenter, the airplane should be serviced to readjust 
the tire pressure to within the normal operating range if it is outside 
the allowable pressure range. Learjet TR 12-16, dated March 18, 2009, 
specifies to adjust the tire pressure to account for temperature 
changes if the airplane will be parked for more than one hour. If 
departure is sooner, the tire pressure should be readjusted 
accordingly. We have not changed the AD in this regard.

Request for Clarification of Logbook Entry Requirements

    Chantilly Air requests that we clarify why, within the content of 
Learjet TR 12-16, dated March 18, 2009, to the Learjet 60 Maintenance 
Manual, an airplane logbook entry is not required for the tire pressure 
check.
    We agree to clarify why a logbook entry is not required. A 
maintenance record could be made in the traditional airplane logbook. 
However, as a practical matter, we do not advocate carrying this 
logbook aboard the airplane. Alternatively, according to FAA Advisory 
Circular 43-9C, dated June 8, 1998, titled ``Maintenance Records,'' the 
maintenance records may be kept in any format that provides continuity, 
includes required contents, lends itself to the addition of new 
entries, provides for signature entry, and is intelligible. Airplane 
logbooks are one form of recording maintenance. For the purposes of 
this AD, the example of a tire pressure check record given in Learjet 
TR 12-16, dated March 18, 2009, is one method that meets this 
requirement. We have not changed the AD in this regard.

Request for Definition

    Cloud Nine Aviation requests that we define, within the content of 
Learjet TR 12-16, dated March 18, 2009, to the Learjet 60 Maintenance 
Manual, what is meant by keeping the dual main gear tire pressures ``as 
close as possible.''
    We agree to define the term. The specified normal cold tire 
operating pressure range (10 pounds per square inch gauge difference) 
is sufficient. Ideally, the closer the pressures are, the better to 
minimize unequal tire loading between adjacent tires. We have not 
changed the AD in this regard.

Request for Clarification

    Aviation Properties requests that we clarify the difference between 
``will'' and ``should'' for checking tire pressure on airplanes parked 
for extended periods (10 or more consecutive days) within the content 
of Learjet TR 12-16, dated March 18, 2009, to the Learjet 60 
Maintenance Manual, and Temporary Flight Manual Change 2009-03, dated 
March 9, 2009, to the Learjet 60 and Learjet 60XR AFMs.
    We agree to clarify the terms following a discussion with Learjet 
Inc. In the AFM, the term ``will'' does not mean that a tire pressure 
check is required every 10 days. The appropriate reference for 
servicing the tires is the AMM. Chapter 12 of the AMM stipulates the 
minimum acceptable tire pressure ranges and associated actions (Table 
301) and recommends that the tire pressures ``should'' be checked every 
10 days while the airplane is parked. It is up to the individual owner/
operator to determine if every 10 days is feasible. However, if the 
tires have been rolled or taxied below the minimums specified in the 
AMM, they may not be used and are scrap. We have not changed the AD in 
this regard.

Request for Clarification of AMM Requirement

    Aviation Properties requests that we clarify what is required by 
the AMM versus section 43.9 of the Federal Aviation Regulations (14 CFR 
43.9). The commenter states that Learjet TR 12-16, dated March 18, 
2009, to the Learjet 60 Maintenance Manual, required as proposed in the 
NPRM, specifies both the date and time of each pressure check, while 14 
CFR 43.9 requires only the date.
    We agree to clarify the requirement. The step-by-step instructions 
remain in the appropriate chapter of the AMM. As the commenter 
mentions, 14 CFR 43.9 does not require recording time of completion or 
documentation of tire pressure values. However, the critical aspect of 
this AD is time. We specified 96 hours between tire pressure checks to 
be more precise, as opposed to calendar days which could potentially 
lead to a longer interval between checks. Therefore, it is an 
additional requirement above the minimum specified in 14 CFR 43.9.
    We placed the tire pressure check requirement in the AFM to 
emphasize to the flightcrew the critical nature of tire pressure for 
safely operating the airplane. We decided that the pilot, as the person 
ultimately responsible for the outcome of the flight, should be made 
directly aware of this requirement and be able to take steps to ensure 
that it is satisfied. We have not changed the AD in this regard.

Request for Information About AMM Reference

    Aviation Properties states that within the content of Learjet TR 
12-16, dated March 18, 2009, to the Learjet 60 Maintenance Manual, the 
statement ``Do not decrease pressure of a hot tire'' could not be found 
in the previous revision of Section 12-10-05, Section 1, of the Learjet 
60 Maintenance Manual. The commenter speculates that since the 
statement was not in the previous

[[Page 32259]]

revision, the tires on the incident airplane may have been under-
serviced.
    We infer that the commenter requests that we clarify the manual 
reference. The quoted statement is found in Section 12-10-05, Section 
1, Paragraph 15(f), of the previous revision of the Learjet 60 
Maintenance Manual dated June 27, 2005. We have not changed the AD in 
this regard.

Explanation of Change Made to This AD

    We have revised this AD to identify the legal name of the 
manufacturer as published in the most recent type certificate data 
sheet for the affected airplane models.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the change described previously. We also determined that 
this change will not increase the economic burden on any operator or 
increase the scope of the AD.

Explanation of Change to Costs of Compliance

    Since issuance of the NPRM, we have increased the labor rate used 
in the Costs of Compliance from $80 per work-hour to $85 per work-hour. 
The Costs of Compliance information, below, reflects this increase in 
the specified hourly labor rate.

Costs of Compliance

    We estimate that this AD affects 240 airplanes of U.S. registry. We 
also estimate that it takes about 1 work-hour per product to comply 
with this AD. The average labor rate is $85 per work-hour. Based on 
these figures, we estimate the cost of this AD to the U.S. operators to 
be $20,400, or $85 per product.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. ``Subtitle VII: Aviation 
Programs,'' describes in more detail the scope of the Agency's 
authority.
    We are issuing this rulemaking under the authority described in 
``Subtitle VII, Part A, Subpart III, Section 44701: General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new AD:

2010-11-11 Learjet Inc.: Amendment 39-16316. Docket No. FAA-2009-
0495; Directorate Identifier 2009-NM-049-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective July 13, 
2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Learjet Inc. Model 60 airplanes, 
certificated in any category, serial numbers 60-002 through 60-369 
inclusive.

Subject

    (d) Air Transport Association (ATA) of America Code 32: Landing 
gear.

Unsafe Condition

    (e) This AD results from a report of the main landing gear tires 
blowing out during a takeoff roll. The Federal Aviation 
Administration is issuing this AD to prevent tire failure, which 
could result in failures of the braking and thrust reverser systems. 
In a critical phase of operation such as takeoff, loss of airplane 
control may result.

Compliance

    (f) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Revise the Maintenance Manual (MM)

    (g) Within 14 days after the effective date of this AD, revise 
the Tire--Servicing Section of the Learjet 60 MM to include the 
information in Learjet 60 Temporary Revision (TR) 12-16, dated March 
18, 2009.

    Note 1: The actions required by paragraph (g) of this AD may be 
done by inserting a copy of Learjet 60 TR 12-16, dated March 18, 
2009, into the Learjet 60 MM. When the TR has been included in 
general revisions of the Learjet 60 MM, the general revisions may be 
inserted in the MM, provided the relevant information in the general 
revision is identical to that in the TR.

Revise the Airplane Flight Manual (AFM)

    (h) Within 14 days after the effective date of this AD, revise 
the Tires Limitations Section of the Learjet 60 AFM or Learjet 60XR 
AFM, as applicable, to include the information in the Learjet 60 
Temporary Flight Manual Change (TFMC) 2009-03, dated March 9, 2009. 
Thereafter, operate the airplane according to the limitations and 
procedures in the TFMC.

    Note 2: The actions required by paragraph (h) of this AD may be 
done by inserting a copy of Learjet 60 TFMC 2009-03, dated March 9, 
2009, into the Learjet 60 AFM or Learjet 60XR AFM, as applicable. 
When Learjet 60 TFMC 2009-03 has been included in general revisions 
of the applicable AFM, the general revisions may be inserted in the 
applicable AFM, provided the relevant information in the general 
revision is identical to that in the TFMC.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Wichita Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested using 
the procedures found in 14 CFR 39.19. Send information to Attn: Don 
Ristow, Aerospace Engineer, Mechanical Systems and Propulsion 
Branch, ACE-116W, Wichita Aircraft Certification Office, FAA, 1801 
Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 
67209; telephone (316) 946-4120; fax (316) 946-4107.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies,

[[Page 32260]]

notify your principal maintenance inspector (PMI) or principal 
avionics inspector (PAI), as appropriate, or lacking a principal 
inspector, your local Flight Standards District Office. The AMOC 
approval letter must specifically reference this AD.

Material Incorporated by Reference

    (j) You must use Learjet 60 Temporary Revision 12-16, dated 
March 18, 2009, to the Learjet 60 Maintenance Manual; and Learjet 60 
Temporary Flight Manual Change 2009-03, dated March 9, 2009, to the 
Learjet 60 or Learjet 60XR Airplane Flight Manual; as applicable; to 
do the actions required by this AD, unless the AD specifies 
otherwise. (The issue date of Learjet 60 Temporary Flight Manual 
Change 2009-03 is specified only on the first page of the document.)
    (1) The Director of the Federal Register approved the 
incorporation by reference of this service information under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact 
Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942; 
telephone 316-946-2000; fax 316-946-2220; e-mail 
ac.ict@aero.bombardier.com; Internet http://www.bombardier.com.
    (3) You may review copies of the service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington. For information on the availability of this material at 
the FAA, call 425-227-1221 or 425-227-1152.
    (4) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://
www.archives.gov/federal_register/code_of_federal_regulations/
ibr_locations.html.

    Issued in Renton, Washington, on April 1, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-12676 Filed 6-7-10; 8:45 am]
BILLING CODE 4910-13-P