64844 Federal Register / Vol. 76, No. 202 / Wednesday, October 19, 2011 / Proposed Rules 

sugar beets, in-process sugars, or 

molasses; and 

(2) Sugar must have been processed in 

the United States. 

(b) Sugar or in-process sugar 

purchased directly from any domestic 

sugar beet and sugarcane processor that 

made the sugar or in-process sugar must 

be credited against its sugar marketing 

allocation to be eligible for purchase 

under this program. 

(c) CCC will purchase sugar located in 

the United States. 

(d) CCC will only purchase an eligible 

commodity if the purchased commodity 

would reduce the likelihood of 

forfeitures of CCC sugar loans, as 

determined by CCC. 

(e) CCC will evaluate an offer to sell 

an eligible commodity to CCC based 

upon CCC’s estimate of the reduction in 

refined sugar supply available for 

human consumption due to the 

purchase. For example, if processing the 

thick juice would yield 70 percent sugar 

for human consumption, then CCC will 

only consider 70 percent of the sugar in 

the thick juice in evaluating the per unit 

sales price. 

§ 1435.603 Eligible sugar seller. 

(a) To be considered an eligible sugar 

seller, the sugar seller must be located 

in the United States. 

(b) [Reserved] 

§ 1435.604 Eligible sugar buyer. 

(a) To be considered an eligible sugar 

buyer, the bioenergy producer must 

produce bioenergy products, including 

fuel grade ethanol or other biofuels. 

(b) The bioenergy producer and its 

production facilities that use CCC sugar 

or in-process sugar must be located in 

the United States. 

§ 1435.605 Competitive procedures. 

(a) CCC will generally submit tenders 

for bids, before entering into contracts 

with any eligible sugar seller and buyer 

that minimize CCC net outlays. 

(b) CCC may, at times, negotiate 

contracts directly with sellers or buyers, 

if CCC determines that such negotiation 

will result in either reduced likelihood 

of forfeited sugar under the CCC sugar 

loan program or reduced costs of 

removing sugar from the market, which 

will reduce the likelihood of sugar 

forfeited to CCC. 

§ 1435.606 Miscellaneous. 

(a) As a sugar buyer, the bioenergy 

producer must take possession of the 

sugar or in-process sugar no more than 

30 days from the date of CCC’s 

purchase. 

(b) CCC, to the maximum extent 

practicable, will not pay storage fees for 

sugar or in-process sugar purchased 

under this program. 

(c) Each bioenergy producer that 

purchases sugar through FFP must 

provide proof to CCC that the sugar has 

been used in the bioenergy factory for 

the production of bioenergy. 

§ 1435.607 Appeals. 

(a) The administrative appeal 

regulations of parts 11 and 780 of this 

title apply to this part. 

(b) [Reserved] 

Signed at Washington, DC, on October 13, 

2011. 

Bruce Nelson, 

Executive Vice President, Commodity Credit 

Corporation. 

[FR Doc. 2011–26974 Filed 10–18–11; 8:45 am] 

BILLING CODE 3410–05–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2010–0068; Directorate 

Identifier 2010–NE–05–AD] 

RIN 2120–AA64 

Airworthiness Directives; General 

Electric Company Turbofan Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: We propose to supersede two 

existing airworthiness directives (ADs) 

that apply to General Electric Company 

(GE) CF6–45 and CF6–50 series turbofan 

engines with certain low-pressure 

turbine (LPT) rotor stage 3 disks 

installed. The existing ADs currently 

require inspections of high pressure 

turbine (HPT) and LPT rotors, engine 

checks, and surveys. Since we issued 

those ADs, GE has determined that the 

low-cycle fatigue (LCF) lives of the LPT 

rotor stage 3 disks affected by those ADs 

are below the current published engine 

manual life limits and has introduced a 

new LPT rotor stage 3 disk part number. 

This proposed AD would establish a 

new lower life limit for the LPT rotor 

stage 3 disks. We are proposing this AD 

to prevent critical life-limited rotating 

engine part failure, which could result 

in an uncontained engine failure and 

damage to the airplane. 

DATES: We must receive comments on 

this proposed AD by December 5, 2011. 

ADDRESSES: You may send comments, 

using the procedures found in 14 CFR 

11.43 and 11.45, by any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: 202–493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, 

M–30, West Building Ground Floor, 

Room W12–140, 1200 New Jersey 

Avenue, SE., Washington, DC 20590. 

• Hand Delivery: Deliver to Mail 

address above between 9 a.m. and 

5 p.m., Monday through Friday, except 

Federal holidays. 

For service information identified in 

this AD, contact General Electric 

Company, GE-Aviation, Room 285, 1 

Neumann Way, Cincinnati, OH 45215, 

phone: 513–552–3272; e-mail: 

geae.aoc@ge.com. You may review 

copies of the referenced service 

information at the FAA, Engine & 

Propeller Directorate, 12 New England 

Executive Park, Burlington, MA. For 

information on the availability of this 

material at the FAA, call 781–238–7125. 

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 proposed AD, the 

regulatory evaluation, any comments 

received, and other information. The 

street address for the Docket Office 

(phone: 800–647–5527) is in the 

ADDRESSES section. Comments will be 

available in the AD docket shortly after 

receipt. 

FOR FURTHER INFORMATION CONTACT: 

Tomasz Rakowski, Aerospace Engineer, 

Engine Certification Office, FAA, Engine 

& Propeller Directorate, 12 New England 

Executive Park, Burlington, MA 01803; 

phone: 781–238–7735; fax: 781–238– 

7199; e-mail: tomasz.rakowski@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to send any written 

relevant data, views, or arguments about 

this proposed AD. Send your comments 

to an address listed under the 

ADDRESSES section. Include ‘‘Docket No. 

FAA–2010–0068; Directorate Identifier 

2010–NE–05–AD’’ at the beginning of 

your comments. We specifically invite 

comments on the overall regulatory, 

economic, environmental, and energy 

aspects of this proposed AD. We will 

consider all comments received by the 

closing date and may amend this 

proposed AD because of those 

comments. 

We will post all comments we 

receive, without change, to http:// 


srobinson on DSK4SPTVN1PROD with PROPOSALS
Federal Register / Vol. 76, No. 202 / Wednesday, October 19, 2011 / Proposed Rules 64845 

www.regulations.gov, including any 

personal information you provide. We 

will also post a report summarizing each 

substantive verbal contact we receive 

about this proposed AD. 

Discussion 

On January 14, 2011, we issued AD 

2011–02–07, Amendment 39–16580 (76 

FR 6323, February 4, 2011), for GE CF6– 

45 and CF6–50 series turbofan engines 

with certain LPT rotor stage 3 disks 

installed. That AD requires initial and 

repetitive HPT rotor stage 1 and stage 2 

blade inspections for wear and damage, 

including excessive airfoil material loss, 

and initial and repetitive exhaust gas 

temperature (EGT) system checks 

(inspections). That AD also requires a 

one-time ultrasonic inspection (UI) of 

the LPT rotor stage 3 disk forward 

spacer arm, fluorescent penetrant 

inspection (FPI) of the LPT rotor stage 

3 disk under certain conditions, and 

removal of cracked disks from service 

before further flight. That AD also 

requires initial and repetitive engine 

core vibration surveys and reporting to 

the FAA any crack findings, disks that 

fail the UI, and engines that fail the 

engine core vibration survey. That AD 

resulted from reports received of 

additional causes of HPT rotor 

imbalance not addressed in AD 2010– 

12–10, Amendment 39–16331 (75 FR 

32649, June 9, 2010), and from two 

additional LPT rotor stage 3 disk events 

since the original AD 2010–06–15, 

Amendment 39–16240 (75 FR 12661, 

March 17, 2010) was issued. 

On August 15, 2011, we issued AD 

2011–18–01, Amendment 39–16783 (76 

FR 52213, August 22, 2011) to require 

performing an FPI of the LPT rotor stage 

3 disk forward spacer arm at every shop 

visit when the LPT module assembly is 

separated from the engine. That AD 

resulted from seven reports of 

uncontained failures of LPT rotor stage 

3 disks and eight reports of cracked LPT 

rotor stage 3 disks found during shop 

visit inspections. 

We issued those ADs to prevent 

critical life-limited rotating engine part 

failure, which could result in an 

uncontained engine failure and damage 

to the airplane. 

Actions Since Existing AD Was Issued 

Since we issued AD 2011–02–07, 

Amendment 39–16580 (76 FR 6323, 

February 4, 2011), GE has determined 

that the LCF lives of the LPT rotor stage 

3 disks affected by that AD were below 

the current published manual life limits, 

and has introduced a new LPT rotor 

stage 3 disk part number. Moreover, we 

no longer require the reporting of 

inspection findings to the FAA. 

FAA’s Determination 

We are proposing this AD because we 

evaluated all the relevant information 

and determined the unsafe condition 

described previously is likely to exist or 

develop in other products of the same 

type design. 

Proposed AD Requirements 

This proposed AD would retain the 

requirements of AD 2011–02–07 

Amendment 39–16580 (76 FR 6323, 

February 4, 2011), and AD 2011–18–01, 

Amendment 39–16783 (76 FR 52213, 

August 22, 2011), except that reporting 

to the FAA would no longer be required 

and there would be an optional LPT 

rotor stage 3 disk removal after a failed 

HPT blade borescope inspection or a 

failed engine core vibration survey. This 

proposed AD would also establish a 

new lower life limit for the LPT rotor 

stage 3 disk part numbers listed in Table 

1 of the proposed AD, and would 

require removing these disks from 

service at times determined by a 

drawdown plan. 

Costs of Compliance 

We estimate that this proposed AD 

would affect 387 CF6–45 and CF6–50 

series turbofan engines installed on 

airplanes of U.S. registry. We also 

estimate that it would take about 8 

work-hours to perform the HPT blade 

inspection, 6 work-hours to perform a 

vibration survey, 4 work-hours to 

perform an ultrasonic inspection, 

2 work-hours to perform an EGT 

resistance check, 1 work-hour to 

perform an EGT thermocouple 

inspection, and 7 work-hours to clean 

and perform an FPI of the LPT rotor 

stage 3 disk for each engine. The average 

labor rate is $85 per work-hour. The cost 

estimate for the work just described was 

covered in the two ADs we are 

proposing to supersede. For this 

proposed AD, we estimate that a 

replacement LPT rotor stage 3 disk 

prorated part cost is $75,000. Based on 

these figures, we estimate the total cost 

of this proposed AD to U.S. operators to 

be $29,025,000. 

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 have determined that this 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would 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 the proposed regulation: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Is not a ‘‘significant rule’’ under 

the DOT Regulatory Policies and 

Procedures (44 FR 11034, February 26, 

1979), 

(3) Will not affect intrastate aviation 

in Alaska, and 

(4) 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. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety. 

The Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 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 

removing airworthiness directive (AD) 

2011–02–07, Amendment 39–16580 (76 

FR 6323, February 4, 2011) and AD 

2011–18–01, Amendment 39–16783 (76 

FR 52213, August 22, 2011), and adding 

the following new AD: 

General Electric Company: Docket No. FAA– 

2010–0068; Directorate Identifier 2010– 

NE–05–AD. 


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64846 Federal Register / Vol. 76, No. 202 / Wednesday, October 19, 2011 / Proposed Rules 

(a) Comments Due Date 

The FAA must receive comments on this 

AD action by December 5, 2011. 

(b) Affected ADs 

This AD supersedes AD 2011–02–07, 

Amendment 39–16580 and AD 2011–18–01, 

Amendment 39–16783. 

(c) Applicability 

This AD applies to General Electric 

Company (GE) CF6–45A, CF6–45A2, CF6– 

50A, CF6–50C, CF6–50CA, CF6–50C1, CF6– 

50C2, CF6–50C2B, CF6–50C2D, CF6–50E, 

CF6–50E1, CF6–50E2, and CF6–50–E2D 

turbofan engines, including engines marked 

on the engine data plate as CF6–50C2–F and 

CF6–50C2–R, with any of the low-pressure 

turbine (LPT) rotor stage 3 disk part numbers 

listed in Table 1 of this AD installed. 

TABLE 1—APPLICABLE LPT ROTOR STAGE 3 DISK PART NUMBERS

9061M23P06 9061M23P07 9061M23P08 9061M23P09 9224M75P01 

9061M23P10 1473M90P01 1473M90P02 1473M90P03 1473M90P04 

9061M23P12 9061M23P14 9061M23P15 9061M23P16 1479M75P01 

1479M75P02 1479M75P03 1479M75P04 1479M75P05 1479M75P06 

1479M75P07 1479M75P08 1479M75P09 1479M75P11 1479M75P13 

1479M75P14 N/A N/A N/A N/A 

(d) Unsafe Condition 

This AD was prompted by the 

determination that a new lower life limit for 

the LPT rotor stage 3 disks listed in Table 1 

of this AD is necessary. We are issuing this 

AD to prevent critical life-limited rotating 

engine part failure, which could result in an 

uncontained engine failure and damage to 

the airplane. 

(e) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(f) Borescope Inspections of HPT Rotor Stage 

1 and Stage 2 Blades 

For the borescope inspections required by 

paragraphs (f)(1), (f)(2), and (f)(3) of this AD, 

inspect the blades from the forward and aft 

directions. Inspect all areas of the blade 

airfoil. Your inspection must include blade 

leading and trailing edges, and their convex 

and concave airfoil surfaces. Inspect for signs 

of impact, cracking, burning, damage, or 

distress. 

(1) Perform an initial borescope inspection 

of the HPT rotor stage 1 and stage 2 blades, 

within 10 cycles after the effective date of 

this AD. 

(2) Thereafter, repeat the borescope 

inspection of the HPT rotor stage 1 and stage 

2 blades within every 75 cycles-since-lastinspection (CSLI). 

(3) Borescope-inspect the HPT rotor stage 

1 and stage 2 blades within the cycle limits 

after the engine has experienced any of the 

events specified in Table 2 of this AD. 

(4) Remove any engine from service before 

further flight if the engine fails any of the 

borescope inspections required by this AD. 

TABLE 2—CONDITIONAL BORESCOPE INSPECTION CRITERIA

If the engine has 

experienced: Then borescope-inspect: 

(i) An exhaust gas temperature (EGT) above redline. Within 10 cycles. 

(ii) A shift in the smoothed EGT trending data that exceeds 18 °F (10 °C), but is less than or equal to 36 °F (20 

°C). 

Within 10 cycles. 

(iii) A shift in the smoothed EGT trending data that exceeds 36 °F (20 °C). Before further flight. 

(iv) Two consecutive raw EGT trend data points that exceed 18 °F (10 °C) above the smoothed average, but is 

less than or equal to 36 °F (20 °C). 

Within 10 cycles. 

(v) Two consecutive raw EGT trend data points that exceed 36 °F (20 °C) above the smoothed average. Before further flight. 

(g) Actions Required for Engines With 

Damaged HPT Rotor Blades 

For those engines that fail any borescope 

inspection requirements of this AD, before 

returning the engine to service: 

(1) Remove the LPT rotor stage 3 disk from 

service; or 

(2) Perform a fluorescent-penetrant 

inspection (FPI) of the inner diameter surface 

forward cone body (forward spacer arm) of 

the LPT rotor stage 3 disk as specified in 

paragraphs (l)(1)(i) through (l)(1)(iii) of this 

AD. 

(h) EGT Thermocouple Probe Inspections 

(1) Inspect the EGT thermocouple probe for 

damage within 50 cycles after the effective 

date of this AD or before accumulating 750 

CSLI, whichever occurs later. 

(2) Thereafter, re-inspect the EGT 

thermocouple probe for damage within every 

750 CSLI. 

(3) If any EGT thermocouple probe shows 

wear through the thermocouple guide sleeve, 

remove and replace the EGT thermocouple 

probe before further flight, and ensure the 

turbine mid-frame liner does not contact the 

EGT thermocouple probe. 

(i) EGT System Resistance Check Inspections 

(1) Perform an EGT system resistance 

check within 50 cycles from the effective 

date of this AD or before accumulating 750 

cycles-since-the-last-resistance check on the 

EGT system, whichever occurs later. 

(2) Thereafter, repeat the EGT system 

resistance check within every 750 cyclessince-the-last-resistance check. 

(3) Remove and replace, or repair any EGT 

system component that fails the resistance 

system check before further flight. 

(j) Ultrasonic Inspection (UI) of the LPT 

Rotor Stage 3 Disk Forward Spacer Arm 

Within 75 cycles after the effective date of 

this AD, perform a UI of the forward cone 

body (forward spacer arm) of the LPT rotor 

stage 3 disk. Use paragraphs E. through K. of 

Appendix A of GE Service Bulletin (SB) No. 

CF6–50–SB 72–1312, Revision 1, dated 

October 18, 2010, to do the UI. 

(k) Engine Core Vibration Survey 

(1) Within 75 cycles after the effective date 

of this AD, perform an initial engine core 

vibration survey. 

(2) Use about a one-minute acceleration 

and a one-minute deceleration of the engine 

between ground idle and 84% N2 (about 

8,250 rpm) to perform the engine core 

vibration survey. 

(3) Use a spectral/trim balance analyzer or 

equivalent to measure the N2 rotor vibration. 

(4) If the vibration level is above 5 mils 

Double Amplitude then, before further flight, 

remove the engine from service. 

(5) For those engines that fail any engine 

core vibration survey requirements of this 

AD, then before returning the engine to 

service: 

(i) Remove the LPT rotor stage 3 disk from 

service; or 

(ii) Perform an FPI of the inner diameter 

surface forward cone body (forward spacer 

arm) of the LPT rotor stage 3 disk as specified 

in paragraphs (l)(1)(i) through (l)(1)(iii) of this 

AD. 


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Federal Register / Vol. 76, No. 202 / Wednesday, October 19, 2011 / Proposed Rules 64847 

(6) Thereafter, within every 350 cyclessince-the-last-engine core vibration survey, 

perform the engine core vibration survey as 

required in paragraphs (k)(1) through (k)(5) of 

this AD. 

(7) If the engine has experienced any 

vibration reported by maintenance or flight 

crew that is suspected to be caused by the 

engine core (N2), perform the engine core 

vibration survey as required in paragraphs 

(k)(1) through (k)(5) of this AD within 10 

cycles after the report. 

(l) Initial and Repetitive FPI of LPT Rotor 

Stage 3 Disks 

(1) At the next shop visit after the effective 

date of this AD: 

(i) Clean the LPT rotor stage 3 disk forward 

spacer arm, including the use of a wetabrasive blast to eliminate residual or 

background fluorescence. 

(ii) Perform an FPI of the LPT rotor stage 

3 disk forward spacer arm for cracks and for 

a band of fluorescence. Include all areas of 

the disk forward spacer arm and the inner 

diameter surface forward cone body (forward 

spacer arm) of the LPT rotor stage 3 disk. 

(iii) Remove the disk from service before 

further flight if a crack or a band of 

fluorescence is present. 

(2) Thereafter, clean and perform an FPI of 

the LPT rotor stage 3 disk forward spacer 

arm, as specified in paragraphs (l)(1)(i) 

through (l)(1)(iii) of this AD, at each engine 

shop visit that occurs after 1,000 cyclessince-the last FPI of the LPT rotor stage 3 

disk forward spacer arm. 

(m) Removal of LPT Rotor Stage 3 Disks 

Remove LPT rotor stage 3 disks listed in 

Table 1 from service as follows: 

(1) For disks that have fewer than 3,200 

flight cycles since new (CSN) on the effective 

date of this AD, remove the disk from service 

before exceeding 6,200 CSN. 

(2) For disks that have 3,200 CSN or more 

on the effective date of this AD, do the 

following: 

(i) If the engine has a shop visit before the 

disk exceeds 6,200 CSN, remove the disk 

from service before exceeding 6,200 CSN. 

(ii) If the engine does not have a shop visit 

before the disk exceeds 6,200 CSN, remove 

the disk from service at the next shop visit 

after 6,200 CSN, not to exceed 3,000 cycles 

from the effective date of this AD. 

(n) Installation Prohibition 

(1) After the effective date of this AD, do 

not install or reinstall in any engine any LPT 

rotor stage 3 disk that exceeds the new life 

limit of 6,200 CSN. 

(2) Remove from service any LPT rotor 

stage 3 disk that is installed or re-installed 

after the effective date of this AD, before the 

disk exceeds the new life limit of 6,200 CSN. 

(o) Definitions 

(1) For the purposes of this AD, an EGT 

above redline is a confirmed overtemperature indication that is not a result of 

EGT system error. 

(2) For the purposes of this AD, a shift in 

the smoothed EGT trending data is a shift in 

a rolling average of EGT readings that can be 

confirmed by a corresponding shift in the 

trending of fuel flow or fan speed/core speed 

(N1/N2) relationship. You can find further 

guidance about evaluating EGT trend data in 

GE Company Service Rep Tip 373 

’’Guidelines For Parameter Trend 

Monitoring.’’ 

(3) For the purposes of this AD, an engine 

shop visit is the induction of an engine into 

the shop after the effective date of this AD, 

where the separation of a major engine flange 

occurs; except the following maintenance 

actions, or any combination, are not 

considered engine shop visits: 

(i) Introduction of an engine into a shop 

solely for removal of the compressor top or 

bottom case for airfoil maintenance or 

variable stator vane bushing replacement. 

(ii) Introduction of an engine into a shop 

solely for removal or replacement of the stage 

1 fan disk. 

(iii) Introduction of an engine into a shop 

solely for replacement of the turbine rear 

frame. 

(iv) Introduction of an engine into a shop 

solely for replacement of the accessory 

gearbox or transfer gearbox, or both. 

(v) Introduction of an engine into a shop 

solely for replacement of the fan forward 

case. 

(p) Previous Credit 

(1) A borescope inspection performed 

before the effective date of this AD using AD 

2010–06–15, Amendment 39–16240 (75 FR 

12661, March 17, 2010) or AD 2010–12–10, 

Amendment 39–16331 (75 FR 32649, June 9, 

2010) or AD 2011–02–07, Amendment 39– 

16580 (76 FR 6323, February 4, 2011) within 

the last 75 cycles, satisfies the initial 

borescope inspection requirement in 

paragraph (f)(1) of this AD. 

(2) A UI performed before the effective date 

of this AD using AD 2011–02–07, 

Amendment 39–16580 (76 FR 6323, February 

4, 2011) or GE SB No. CF6–50–SB 72–1312, 

dated August 9, 2010 or GE SB No. CF6–50– 

SB 72–1312 Revision 1, dated October 18, 

2010, satisfies the inspection requirement in 

paragraph (j) of this AD. 

(3) An engine core vibration survey 

performed before the effective date of this AD 

using AD 2011–02–07, Amendment 39– 

16580 (76 FR 6323, February 4, 2011) or GE 

SB No. CF6–50–SB 72–1313, dated August 9, 

2010 or GE SB No. CF6–50–SB 72–1313 

Revision 1, dated October 18, 2010, within 

the last 350 cycles, satisfies the initial survey 

requirement in paragraphs (k)(1) through 

(k)(5) of this AD. 

(4) An FPI of the LPT rotor stage 3 disk 

forward spacer arm performed before the 

effective date of this AD using AD 2011–18– 

01, Amendment 39–16783 (75 FR 3, 52213, 

August 22, 2011), within the last 1,000 flight 

cycles of the LPT rotor stage 3 disk, satisfies 

the initial inspection requirements in 

paragraphs (l)(1)(i) through (l)(1)(iii) of this 

AD. 

(q) Alternative Methods of Compliance 

(AMOCs) 

(1) AMOCs previously approved for AD 

2010–06–15, Amendment 39–16240 (75 FR 

12661, March 17, 2010) are not approved for 

this AD. However, AMOCs previously 

approved for AD 2010–12–10, Amendment 

39–16331 (75 FR 32649, June 9, 2010), AD 

2011–02–07, Amendment 39–16580 (76 FR 

6323, February 4, 2011), or AD 2011–18–01, 

Amendment 39–16783 (76 FR 52213, August 

22, 2011) are approved for this AD. 

(2) The Manager, Engine Certification 

Office, may approve alternative methods of 

compliance for this AD. Use the procedures 

found in 14 CFR 39.19 to make your request. 

(r) Related Information 

(1) For more information about this AD, 

contact Tomasz Rakowski, Aerospace 

Engineer, Engine Certification Office, FAA, 

Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 

01803; phone: 781–238–7735; fax: 781–238– 

7199; e-mail: tomasz.rakowski@faa.gov. 

(2) For service information identified in 

this AD, contact General Electric Company, 

GE-Aviation, Room 285, 1 Neumann Way, 

Cincinnati, OH 45215, phone: 513–552–3272; 

e-mail: geae.aoc@ge.com. You may review 

copies of the referenced service information 

at the FAA, Engine & Propeller Directorate, 

12 New England Executive Park, Burlington, 

MA. For information on the availability of 

this material at the FAA, call 781–238–7125. 

Issued in Burlington, Massachusetts, on 

October 13, 2011. 

Peter A. White, 

Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

[FR Doc. 2011–27006 Filed 10–18–11; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–1090; Directorate 

Identifier 2011–NM–138–AD] 

RIN 2120–AA64 

Airworthiness Directives; Bombardier, 

Inc. Model DHC–8–400 Series 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: We propose to adopt a new 

airworthiness directive (AD) for the 

products listed above. This proposed 

AD results from mandatory continuing 

airworthiness information (MCAI) 

originated 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: 

One case of the inability to open the 

airstair door while on ground was reported 

in service. The airstair door seal did not 

deflate, preventing the airstair door from 

opening. It was found that the existing 

airstair door pneumatic shut-off valve control 

logic prevents the airstair door seal from 


srobinson on DSK4SPTVN1PROD with PROPOSALS