Airworthiness Directives; Learjet Inc. Model 60 Airplanes

[Federal Register Volume 75, Number 109 (Tuesday, June 8, 2010)] [Rules and Regulations] [Pages 32255-32260] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 2010-12676]

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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 [email protected];

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

[email protected]; 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