AD 2001-17-31

[Federal Register Volume 66, Number 170 (Friday, August 31, 2001)]
[Rules and Regulations]
[Pages 45921-45924]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-21894]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-27-AD; Amendment 39-12423; AD 2001-17-31]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce Corporation (Formerly 
Allison Engine Company) AE 2100 Turboprop and AE 3007 Turbofan Series 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to Rolls-Royce Corporation (formerly Allison Engine 
Company) AE 2100 turboprop and AE 3007 turbofan series engines. This 
amendment requires a one-time acid etch inspection of the 2nd stage 
high pressure turbine (HPT) wheel for evidence of damaged material 
indicating that a higher probability of cracking in future service 
exists. If the etch inspection reveals damage, this AD requires 
replacement of the turbine wheel with a serviceable part. This 
amendment is prompted by a report of a 2nd stage HPT wheel that was 
returned from the field with cracks in the aft bore face. The actions 
specified by this AD are intended to detect and prevent early 
development of cracks due to low cycle fatigue of the 2nd stage HPT 
wheel in the aft bore face that can lead to wheel failure, power loss, 
and possible damage to the airplane.

DATES: Effective date October 5, 2001. The incorporation by reference 
of certain publications listed in the regulations is approved by the 
Director of the Federal Register as of October 5, 2001.

ADDRESSES: The service information referenced in this AD may be 
obtained from Rolls-Royce Corporation, P.O. Box

[[Page 45922]]

420, Indianapolis, IN 46206-0420; telephone: (888) 255-4766. This 
information may be examined at the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, 12 New 
England Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Michael Downs, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 
2300 E. Devon Ave., Des Plaines, IL 60018; telephone (847) 294-7870, 
fax (847) 294-7834.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that is 
applicable to Rolls-Royce Corporation (formerly Allison Engine Company) 
AE 2100 and AE 3007 series engines was published in the Federal 
Register on December 12, 2000 (65 FR 77528). That action proposed to 
require a one-time acid etch inspection of the 2nd stage HPT wheel for 
cracks. If the wheel is cracked, this AD would require replacement of 
the turbine wheel with a serviceable part in accordance with Rolls-
Royce Alert Service Bulletins (ASB's): AE 2100A-A-72-234, Revision 2, 
dated October 13, 2000; or AE 2100C-A-72-183, Revision 2, dated October 
13, 2000; AE 2100D3-A-72-179, Revision, 2, dated October 13, 2000; AE 
3007A-A-72-179, Revision 2, dated October 17, 2000; and AE 3007C-A-72-
153, Revision 2, dated October 17, 2000, that describe the procedures 
for examining the turbine wheel for damage using the one-time acid etch 
procedure. Since the NPRM was published, Rolls-Royce has issued 
Revision 3, dated June 19, 2001, to all five ASB's because they were 
revised from level 2 to level 3 to align them with changes agreed to by 
the FAA as a result of comments made to the NPRM. also included in this 
amendment are the different types of engines that were omitted from the 
NPRM.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Remove Part Number

    The manufacturer requests that turbine wheel part number (P/N) 
23069438 be removed from the AD. As a result of testing, it was 
discovered that the 1/10,000 minimum crack initiation life is greater 
than the Chapter 5 life limit for the AE 3007A1, A1/1, A1/2, A1/3, and 
A3 and within 100 cycles of the Chapter 5 life for the AE 3007A1P.
    The FAA agrees. The manufacturer completed a comprehensive program 
to quantify the impact on fatigue capability of Udimet 720 material 
damaged by improper tool contact in the same manner as discussed for 
turbine wheel P/N 23050912 in the proposed rule. Program results 
demonstrated that shot peening during manufacturing greatly increases 
the crack initiation life of a wheel containing the damage, thus 
decreasing the likelihood of failure from a crack resulting from that 
damage. The analysis of damaged wheels discussed in the proposed AD did 
not take into consideration wheels that were shot peened during 
manufacture. Thus, the applicability of the AD has been changed to 
reflect that the AD does not apply to engines with turbine wheel P/N 
23069438 installed.

Change Inspection Compliance Times

    The manufacturer also states that Table 2. should be changed to 
reflect increased inspection times for the engines having turbine wheel 
P/N 23069592 with serial number up to (SN) MM183060. as follows:

1. AE 3007A prior to 12,800 cycles.
2. AE 3007C prior to 12,800 cycles.
3. AE 2100A prior to 16,800 cycles.
4. AE 2100C prior to 16,800 cycles.
5. AE 2100D3 prior to 14,100 cycles.

    The FAA agrees that the change is justified because wheel P/N's 
23069438 and 23069592 are both shot peened during manufacturing. The 
effects of shot peening were not considered in the writing of the 
proposed rule. However, P/N 23069592, unlike P/N 23069438, did not have 
a minimum crack initiation life greater than it's chapter 5 life limit. 
Table 2 has been changed accordingly.

Change Definition of Serviceable Part

    The manufacturer also requests that the definition of a serviceable 
part in paragraph (e) be changed to reflect that an acid etch 
inspection does not reveal cracks, but reveals damage that may indicate 
a higher probability that a crack will initiate.
    The FAA agrees and the definition has been changed. The FAA has 
also made a similar change to the discussion in the preamble to this 
final rule.

Table 2 Correction

    Finally, the manufacturer asks that Table 2 be corrected as there 
is a typographical error in column (2); part number 233064473 should be 
23064473.
    The FAA agrees and the change has been made.
    The FAA has also corrected the applicability to reflect that the AD 
applies to AE2100A and AE2100C engines that have turbine wheels with P/
N's other than 23050912 installed, as indicated in Table 2 of the 
proposed rule. Also, P/N's 23070672 and 23070675 were inadvertently 
left out of the original service bulletins and have been added to Table 
2, row 4.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Economic Impact

    Since the issuance of the NPRM, engine models AE 3007A1 series and 
AE 3007A3 have been removed from this proposed amendment and this AD no 
loner applies to the EMB-135 aircraft. As a result, there are now 
approximately 833 engines of the affected design in the worldwide 
fleet. The FAA estimates that approximately 280 engines installed on 
airplanes of US registry would be affected by this proposed AD. The FAA 
estimates that disassembly to perform the acid etch inspection and 
reassembly will take approximately 130 work hours, which includes 
teardown to the HPT, inspection and reassembly, and that the average 
labor rate is $60 per work hour. Labor costs to perform the disassembly 
and reassembly are $7,800, and a test stand run will cost about $5,000, 
for a total cost of $12,800 per engine to conduct the acid etch 
inspection. Based on these figures, the FAA estimates that the total 
cost impact of performing the acid etch inspection on US operators will 
be $3,584,000. If a wheel must be replaced, the cost of a replacement 
wheel is $18,000, and it will take an additional 30 work hours to 
replace the wheel, at $60 per work hour. Therefore, the total cost of 
parts and labor for replacing the wheel will total $19,800 per wheel. 
If all wheels needed to be replaced, the total cost impact of the 
proposed AD on U.S. operators would be $5,544,000. The FAA estimates, 
however, that not all wheels will need replacement and that some labor 
costs required to accomplish the requirements of this proposed AD may 
be reimbursed by the manufacturer, thus reducing the total cost impact 
of the proposed AD on US operators.

[[Page 45923]]

Regulatory Impact

    This final rule does not have federalism implications, as defined 
in Executive Order 13132, because it 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this final rule.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under the DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 
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. A final evaluation has been prepared for 
this action and it is contained in the Rules Docket. A copy of it may 
be obtained by contacting the Rules Docket at the location provided 
under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
to read as follows:

2001-17-31  Rolls-Royce Corporation: Amendment 39-12423. Docket No. 
2000-NE-27-AD.

Applicability

    This airworthiness directive (AD) is applicable to Rolls-Royce 
Corporation (formerly Allison Engine Company) models AE 2100A and AE 
2100C turboprop engines with high pressure turbine (HPT) wheel part 
number (P/N) 23050912 installed; AE 2100A turboprop engine with 
turbine wheel P/N 23063462 serial number (SN) MM14062 installed; AE 
2100A, AE 2100C, AE 2100D3 turboprop and AE 3007A, and AE 3007C 
turbofan engines with 2nd stage HPT wheels with SN's before 
MM183060. These engines are installed on but not limited to Embraer 
EMB-145, Cessna 750, SAAB 2000, and Industi Pesawat Terbang 
Nusantara (IPTN) N-250 series airplanes.

    Note 1: This AD applies to each engine identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For engines that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (g) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

Compliance

    Compliance with this AD is required as indicated, unless already 
done.
    To detect and prevent early development of cracks due to low 
cycle fatigue of the 2nd stage HPT wheel in the aft bore face that 
can lead to wheel failure, power loss, and possible damage to the 
airplane, do the following:

One-time Inspection

    (a) Perform a one-time acid etch inspection to the 2nd stage 
high pressure turbine wheel in accordance with the Accomplishment 
Instructions contained in the following Rolls-Royce Alert Service 
Bulletins:

              Table 1.--Applicable Alert Service Bulletins
------------------------------------------------------------------------
             AE models                  Rolls-Royce service bulletin
------------------------------------------------------------------------
AE 2100A..........................  AE 2100A-A-72-234, Revision 2, dated
                                     October 13, 2000 or Revision 3,
                                     dated June 19, 2001.
AE 2100C..........................  AE 2100C-A-72-183, Revision 2, dated
                                     October 13, 2000 or Revision 3,
                                     dated June 19, 2001.
AE 2100D3.........................  AE 2100D3-A-72-179, Revision 2,
                                     dated October 13, 2000 or Revision
                                     3, dated June 19, 2001.
AE 3007A..........................  AE 3007A-A-72-179, Revision 2, dated
                                     October 17, 2000 or Revision 3,
                                     dated June 19, 2001.
AE 3007C..........................  AE 3007C-A-72-153, Revision 2, dated
                                     October 17, 2000 or Revision 3,
                                     dated June 19, 2001.
------------------------------------------------------------------------

    (b) Perform these inspections according to the following 
compliance times:

                  Table 2.--Inspection Compliance Times
------------------------------------------------------------------------
             Models               With turbine wheel       Mandatory
------------------------------------------------------------------------
(1) AE 2100A, AE2100C...........  23050912..........  Before 4,800
                                                       cycles since new
                                                       (CSN).
(2) AE 2100A....................  23063462-S/N        Before 4,800 CSN.
                                   MM14062.
(3) AE2100D3....................  23050912..........  Before 3,200 CSN.
(4) All other AE 2100A, AE 2100C  23063462,           At next shop
 and AE2100D3.                     23064822,           visit.
                                   23070673,
                                   23065892,
                                   23069116,
                                   23064473,
                                   23064474,
                                   23068072,
                                   23070672 and
                                   23070675 with S/
                                   N's MM183060 and
                                   before.
(5) All AE 3007A, and AE 3007C..  23063462,           At next shop
                                   23065892,           visit.
                                   23069116 with S/N
                                   MM183060 and
                                   before.
(6) All AE 3007A and AE 3007C...  23069592 with S/N   At next exposure
                                   MM183060 and        but not to exceed
                                   before.             12,800 CSN.
(7) All AE 2100A and 23069592 AE  23069592 with S/N   Next exposure but
 2100C.                            MM183060 and        not to exceed
                                   before.             16,800 CSN.
(8) All 2100D3..................  23069592 with S/N   At next exposure
                                   MM183060 and        but not to exceed
                                   before.             14,100 CSN.
------------------------------------------------------------------------


[[Page 45924]]

    (c) If damage is discovered, replace the turbine wheel with a 
serviceable part.

Definitions

    (d) The next shop visit is defined as whenever the engine is 
removed and sent to a maintenance center for inspection or repair.
    (e) A serviceable part is defined as any applicable turbine 
wheel with a serial number greater than MM183060, or a wheel with a 
serial number MM183060 or lower that has undergone an acid etch 
inspection with no indication of damage.
    (f) After the effective date of this AD, do not install any 2nd-
stage gas-generator turbine wheel listed in Table 2 of this AD, 
unless it has been inspected as specified in paragraph (a).

Alternative Methods of Compliance

    (g) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Chicago Aircraft Certification 
Office. Operators must submit their request through an appropriate 
FAA Principal Maintenance Inspector, who may add comments and then 
send it to the Manager, Chicago Aircraft Certification Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Chicago Aircraft Certification 
Office.

Special Flight Permits

    (h) Special flight permits may be issued in accordance 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the aircraft to a location where the 
requirements of this AD can be accomplished.

Documents That Have Been Incorporated by Reference

    (i) The inspection must be done in accordance with the following 
Rolls-Royce Corporation Alert Service Bulletins:

----------------------------------------------------------------------------------------------------------------
             Document No.                        Pages            Revision                   Date
----------------------------------------------------------------------------------------------------------------
ASB AE 2100A-A-72-234................  All.....................           2  October 13, 2000.
ASBAE 2100C-A-72-183.................  All.....................           2  October 13, 2000.
ASB AE 2100D3-A-72-179...............  All.....................           2  October 13, 2000.
 
    Total Pages: 13
ASB AE 2100A-A-72-234................  All.....................           3  June 19, 2001.
ASBAE 2100C-A-72-183.................  All.....................           3  June 19, 2001.
ASB AE 2100D3-A-72-179...............  All.....................           3  June 19, 2001.
 
    Total Pages: 13
ASB AE 3007A-A-72-179................  All.....................           2  October 17, 2000.
ASB AE 3007C-A-72-153................  All.....................           2  October 17, 2000.
 
    Total Pages: 12
ASB AE 3007A-A-72-179................  All.....................           3  June 19, 2001.
ASB AE 3007C-A-72-153................  All.....................           3  June 19, 2001.
 
    Total Pages: 12
----------------------------------------------------------------------------------------------------------------

    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from Rolls-Royce Corporation, P.O. 
Box 420, Indianapolis, IN 46206-0420; telephone: (888) 255-4766 . 
Copies may be inspected at the FAA, New England Region, Office of 
the Regional Counsel, 12 New England Executive Park, Burlington, MA; 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW, suite 700, Washington, DC.

Effective Date of This AD

    (j) This amendment becomes effective on October 5, 2001.

    Issued in Burlington, Massachusetts, on August 21, 2001.
Donald Plouffe,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-21894 Filed 8-30-01; 8:45 am]
BILLING CODE 4910-13-P