Federal Register / Vol. 75, No. 109 / Tuesday, June 8, 2010 / Rules and Regulations 32255 

TABLE 1—MATERIAL INCORPORATED BY REFERENCE

Thielert Service Bulletin No. Page Revision Date 

TM TAE 125–1007 P1 ....................................................................................................... ALL .............. 2 April 29, 2009. 

Total Pages: 4 

TM TAE 125–1009 P1 ....................................................................................................... ALL .............. 3 October 14, 2009. 

Total Pages: 26 

TM TAE 125–0018 ............................................................................................................. ALL .............. 1 November 12, 2008. 

Total Pages: 2 

TM TAE 125–0020, including Annexes A and B ............................................................... ALL .............. 1 November 25, 2009. 

Total Pages: TM TAE 125–0020, 42; Annex A, 3; Annex B, 4 

Issued in Burlington, Massachusetts, on 

May 19, 2010. 

Tracy Murphy, 

Acting Manager, Engine and Propeller 

Directorate, Aircraft Certification Service. 

[FR Doc. 2010–12540 Filed 6–7–10; 8:45 am] 

BILLING CODE 4910–13–P 

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. 

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 underinflated 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. 


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32256 Federal Register / Vol. 75, No. 109 / Tuesday, June 8, 2010 / Rules and Regulations 

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 overemphasized, especially on highperformance 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 


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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 CertificateHolding 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 


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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 


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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 workhour 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 workhour. 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 

■ Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA amends 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. 

§ 39.13 [Amended] 

■ 2. The FAA amends § 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, 


srobinson on DSKHWCL6B1PROD with RULES
32260 Federal Register / Vol. 75, No. 109 / Tuesday, June 8, 2010 / Rules and Regulations 

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 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2009–0982; Directorate 

Identifier 2009–NE–19–AD; Amendment 39– 

16323; AD 2010–12–02] 

RIN 2120–AA64 

Airworthiness Directives; Turbomeca 

S.A. MAKILA 1A and 1A1 Turboshaft 

Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for the 

products listed above. This AD results 

from mandatory continuing 

airworthiness information (MCAI) 

issued by an aviation authority of 

another country to identify and correct 

an unsafe condition on an aviation 

product. The MCAI describes the unsafe 

condition as: 

The installation of TU250 comparator/ 

selector (CS) boards, however, has resulted in 

a few occurrences of erratic engine 

behaviour, in the form of unexpected N1 

variations and/or illumination of the ‘‘GOV’’ 

warning light. The conclusions from an 

investigation by Turbome ́ca are that these 

malfunctions are due to a lapse of quality 

control in the varnishing process applied to 

the boards, and that only boards in a specific 

serial number range, as defined under 

‘‘Applicability’’ and referred to below as the 

‘‘suspect batch’’, are affected. 

We are issuing this AD to prevent loss 

of automatic engine control during flight 

due to an uncommanded engine rollback, which could result in the inability 

to continue safe flight. 

DATES: This AD becomes effective July 

13, 2010. The Director of the Federal 

Register approved the incorporation by 

reference of certain publications listed 

in this AD as of July 13, 2010. 

ADDRESSES: The Docket Operations 

office is located at Docket Management 

Facility, U.S. Department of 

Transportation, 1200 New Jersey 

Avenue, SE., West Building Ground 

Floor, Room W12–140, Washington, DC 

20590–0001. 

FOR FURTHER INFORMATION CONTACT: 

Kevin Dickert, Aerospace Engineer, 

Engine Certification Office, FAA, Engine 

and Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 

01803; e-mail: kevin.dickert@faa.gov; 

telephone (781) 238–7117, fax (781) 

238–7199. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to include an AD that would 

apply to the specified products. That 

NPRM was published in the Federal 

Register on March 31, 2010 (75 FR 

16022). That NPRM proposed to correct 

an unsafe condition for the specified 

products. The MCAI states that: 

The installation of TU250 CS boards, 

however, has resulted in a few occurrences 

of erratic engine behaviour, in the form of 

unexpected N1 variations and/or 

illumination of the ‘‘GOV’’ warning light. The 

conclusions from an investigation by 

Turbomeca are that these malfunctions are 

due to a lapse of quality control in the 

varnishing process applied to the boards, and 

that only boards in a specific serial number 

range, as defined under ‘‘Applicability’’ and 

referred to below as the ‘‘suspect batch’’, are 

affected. 

Comments 

We gave the public the opportunity to 

participate in developing this AD. We 

received no comments on the NPRM or 

on the determination of the cost to the 

public. 

Conclusion 

We reviewed the available data and 

determined that air safety and the 

public interest require adopting the AD 

as proposed. 

Costs of Compliance 

Based on the service information, we 

estimate that this AD will affect about 

10 products of U.S. registry. We also 

estimate that it will take about 1 workhour per product to comply with this 

AD. The average labor rate is $85 per 

work-hour. Required parts will cost 

about $3,500 per product. Based on 

these figures, we estimate the cost of the 

AD on U.S. operators to be $35,850. 

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 

We determined that 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 this AD: 

1. Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866; 


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