[Federal Register Volume 63, Number 174 (Wednesday, September 9, 1998)]
[Proposed Rules]
[Pages 48140-48141]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24185]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-36-AD]
RIN 2120-AA64


Airworthiness Directives; Williams International FJ44-1A Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Williams International FJ44-1A 
turbofan engines. This proposal would require removing the high 
pressure turbine (HPT) disk from service prior to accumulating a 
reduced cyclic life limit of 1,900 cycles since new (CSN) and replacing 
with a serviceable disk. As an option, the HPT nozzle can be modified 
thereby increasing the HPT disk cyclic life limit from the new reduced 
cyclic life limit. This proposal is prompted by a revised life analysis 
conducted by the manufacturer after the failure of a similarly designed 
HPT disk. The actions specified by the proposed AD are intended to 
prevent HPT disk rim failure, which could result in an uncontained 
engine failure and damage to the aircraft.

DATES: Comments must be received by November 9, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 98-ANE-36-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ad-
[email protected]''. Comments sent via the Internet must contain 
the docket number in the subject line. Comments may be inspected at 
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Patricia Bonnen, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 
2300 East Devon Avenue, Des Plaines, IL 60018; telephone (847) 294-
7134, fax (847) 294-7834.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-ANE-36-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 98-ANE-36-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    Williams International, manufacturer of FJ44-1A turbofan engines, 
recently conducted a revised life limit analysis of high pressure 
turbine (HPT) disks, part number (P/N) 55291. This revised analysis was 
prompted by the failure of a similarly designed HPT disk. The revised 
analysis revealed that the calculated low cycle fatigue lives are 
significantly lower than the current published maximum approved service 
lives. To this date no failures of HPT disk, P/N 55291, have been 
reported. This condition, if not corrected, could result in HPT disk 
rim failure, which could result in an uncontained engine failure and 
damage to the aircraft.
    Williams International has also published service information which 
authorizes certain modifications to the

[[Page 48141]]

HPT nozzle assembly and subsequent reidentification of the HPT disk and 
assembly. Incorporation of these modifications increases the approved 
service life limit from the new reduced service life.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require removing the HPT disk from service prior to 
accumulating a reduced cyclic life limit of 1,900 cycles since new 
(CSN) and replacing with a serviceable disk.
    There are approximately 223 engines of the affected design in the 
worldwide fleet. The FAA estimates that 165 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD. The 
cost of removing a disk earlier than the original life-limit rather 
than reworking the disk is $12,546 per engine. The costs of reworking 
the HPT nozzle assembly to obtain increased HPT life are substantially 
less than the costs of replacement of the HPT disk. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $2,070,090 assuming all disks are replaced. The actual 
total cost to U.S. operators, however, will be less depending on how 
many operators exercise the rework option. In addition, the 
manufacturer may reimburse operators for the costs of removing disks 
earlier than the original life limit reducing even further the total 
cost impact for U.S. operators.
    The regulations proposed herein would not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this 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); 
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 copy of the draft 
regulatory evaluation prepared for this action 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, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 the following new 
airworthiness directive:

Williams International: Docket No. 98-ANE-36-AD.

    Applicability: Williams International FJ44-1A turbofan engines, 
installed on but not limited to Cessna 525 series aircraft.

    Note 1: This airworthiness directive (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 (c) 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: Required as indicated, unless accomplished 
previously.
    To prevent high pressure turbine (HPT) disk rim failure, which 
could result in an uncontained engine failure and damage to the 
aircraft, accomplish the following:
    (a) Prior to accumulating 1,900 cycles since new (CSN), remove 
from service HPT disk, part number (P/N) 55291, and replace with a 
serviceable part.
    (b) As an option to paragraph (a), modify the HPT nozzle 
assembly and remark the HPT disk and assembly with new part numbers 
in accordance with Williams International Service Bulletin FJ44-72-
36, dated October 21, 1997.

    Note 2: The low cycle fatigue retirement lives for the HPT disks 
remarked with new part numbers in accordance with paragraph (b) of 
this AD may be found in Williams SB FJ44-A-72-38, dated October 21, 
1997.

    (c) 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 shall 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 3: 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.

    (d) Thereafter, except as provided in paragraph (c) of this AD, 
no alternative replacement times or life limits may be approved for 
HPT disk, P/N 55291.
    (e) Special flight permits may be issued in accordance with 
sections 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.

    Issued in Burlington, Massachusetts, on September 2, 1998.
Donald E. Plouffe,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 98-24185 Filed 9-8-98; 8:45 am]
BILLING CODE 4910-13-U